for tcspc, qkd and quantum optics spds: single photon … brochure 12-4-14.pdfpage 1 photon...
TRANSCRIPT
Boston Electronics (800)347-5445 or [email protected]
For TCSPC, QKD and Quantum Optics
SPDs: Single Photon Counters: Silicon SPADS: 350 - 900 nm InGaAs SPADs: 900 - 1700 nm Superconducting Nanowires: 600 – 1700 nm
Short pulse diode lasers: 1550 nm entangled photon pair generator 1310 and 1550 nm telecom wavelengths
RNGs: random number generators 110100010001110111…
From
via
Boston Electronics Corporation 91 Boylston Street, Brookline, Massachusetts 02445 USA (800)347-5445 or (617)566-3821 fax (617)731-0935 www.boselec.com [email protected]
Page 1
Photon CPhoton CPhoton CPhoton Countountountountinginginging
for Bfor Bfor Bfor Brainies.rainies.rainies.rainies.
0. Preamble
This document gives a general overview on InGaAs/InP, APD based photon counting at telecom wavelengths. In common language telecom wavelengths are the O band, centered around 1310nm (1260 to 1360 nm) and the C band, centered around 1550nm (1530 to 1565 nm) where the fibre attenuation is the lowest. Also the principles of photon counting at visible wavelengths are similar; the performance are very different. Values for VIS photon counter are given in chapter 10 of this document.
Page 2
Table of contents 1. Avalanche photodiodes 2. Principle of photon counting 3. Terminology and explanation 4. Analogue versus Geiger mode 5. Free running versus gated mode 6. Effect of deadtime /afterpulsing
7. Nominal versus Effective Gate width 8. Linearity of Detection Probability 9. Photon counting at VIS wavelength 10. Our photon counters products 11. Our other products 12. Remark
Page 3
1. Avalanche photodiodes In electronics, a diode is a two-terminal electronic component with an asymmetric transfer characteristic, with low (ideally zero) resistance to current flow in one direction, and high (ideally infinite) resistance in the other. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p-n junction connected to two electrical terminals. The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction).
A photodiode is a type of photodetector capable of converting light into either current or voltage, depending upon the mode of operation. Photodiodes are similar to regular semiconductor diodes except that they may be either exposed or packaged with a window or optical fiber connection to allow light to reach the sensitive part of the device. Many diodes designed for use specifically as a photodiode use a PIN junction rather than a p-n junction, to increase the speed of response. A photodiode is designed to operate in reverse bias.
An avalanche photodiode (APD) is a highly sensitive semiconductor electronic device that exploits the photoelectric effect (Figure 1) to convert light to electricity. APDs can be thought of as photodetectors that provide a built-in first stage of gain through avalanche multiplication. By applying a high reverse bias voltage, APDs show an internal current gain effect due to impact ionization (avalanche effect). In general, the higher the reverse voltage the higher the gain. For APD the reverse voltage is always below the breakdown voltage and APD are not sensitive enough to detect single photon Figure 1
Single-Photon Avalanche Diode (SPAD) (also known as a Geiger-mode APD) identifies a class of solid-state photodetectors based on a reverse biased p-n junction in which a photo-generated carrier can trigger an avalanche current due to the impact ionization mechanism. This device is able to detect low intensity signals (down to the single photon). SPADs, like the avalanche photodiode (APD), exploit the photon-triggered avalanche current of a reverse biased p-n junction to detect an incident radiation. The fundamental difference between SPAD and APD is that SPADs are specifically designed to operate with a reverse bias voltage well above the breakdown voltage (on the contrary APDs operate at a bias lesser than the breakdown voltage). This kind of operation is also called Geiger mode in literature, for the analogy with the Geiger counter.
2. Principle of photon counting Figure 2 represents the I-V characteristics of an APD and illustrates how single-photon sensitivity can be achieved. This mode is also known as Geiger mode. The APD is biased, with an excess bias voltage, above the breakdown value VBr and is in a metastable state (point A). It remains in this state until a primary charge carrier is created. In this case, the amplification effectively becomes infinite, and even a single-photon absorption causes an avalanche resulting in a macroscopic current pulse (point A to B), which can readily be detected by appropriate electronic circuitry. This circuitry must also limit the value of the current flowing through the device to prevent its destruction and quench the avalanche to reset the device (point B to C). After a certain time, the excess bias voltage is restored (point C to A) and the APD is again ready to detect a single photon. The actual value of the breakdown voltage depends on the semiconductor material, the device structure and the temperature. For InGaAs/InP APD’s, it is typically around 50V. The detection efficiency but also the noise of an APD in Geiger mode depends o
n the excess bias voltage.
A
B
C
I
V
VBr
Figure 2
Above Below
Page 4
3. Terminology and explanation
a) Detection efficiency The performance of an avalanche photodiode APD in single-photon detection mode is characterized first by its detection efficiency. This quantity corresponds to the probability for a photon impinging on the photodiode to be detected. The detection efficiency results from two different factors:
- The probability that a photon is absorbed in the InGaAs layer
- The probability that the photo-generated carrier triggers an avalanche when crossing the multiplication zone
In fiber based photon counter there can be some coupling losses between the fiber and the active area. In order to compensate this the bias voltage is slightly increase in order to get the same detection efficiency, thus slightly increasing the dark count rate.
The quantum detection efficiency increases when the excess bias voltage is raised. At 1550 nm, a detection efficiency value as high as 25% is typical, for an InGaAs/InP photodiode. For InGaAs/InP photon counter modules the detection efficiency is adjustable.
Example for an InGaAs/InP photodiode
b) Dark counts In an APD, avalanches are not only caused by the absorption of a photon, but can also be randomly triggered by carriers generated in thermal, tunnelling or trapping processes taking place in the junction. They cause self triggering effects called dark counts.
The easiest way to reduce dark counts is to cool the detector. This reduces the occurrence of thermally generated carriers. At low temperature, dark counts are thus dominated by carriers generated by band to band tunnelling and more importantly trapped charges (see below). Raising the excess bias voltage increases the occurrence of dark counts, increases the detection efficiency and decreases the timing jitter. The operation point, in terms of bias voltage, must thus carefully be selected. In gated mode, one typically quantifies this effect as a dark count probability per nanosecond of gate duration. Example: Dark counts in [Hz]: 1’350 counts gate width: 20 [ns] trigger rate: 10 [MHz] Dark counts in ns of gate = 2’000 / 20 / 10’000’000 = 6.75E-06
c) Afterpulses Perhaps the major problem limiting the performance of present InGaAs/InP APD’s is the enhancing of the dark count rate by so-called afterpulses. This spurious effect arises from the trapping of charge carriers during an avalanche by trap levels inside the high field region of the junction, where impact ionization occurs. When subsequently released, these trapped carriers can trigger a so-called afterpulse. The lifetime of the trapped charges is typically a few µs for InGaAs/InP APD’s. The probability of these events is also proportional to the number of filled traps, which is in turn proportional to the charge
Page 5
crossing the junction in an avalanche before the quenching takes place. The total charge can be limited by ensuring prompt quenching of the avalanches. It is also important to note that reducing the operation temperature of the APD increases the lifetime of the trapped charges. The cooling temperature must thus carefully be chosen to minimize the total dark count probability (including afterpulses). Although it depends on the counting rate, this optimal temperature is typically around 220 K for current InGaAs/InP APD’s. So far, the cure to get rid of the dark count enhancement by afterpulses has been to use the gated mode detection scheme (see below). If the voltage across the APD is kept below the breakdown voltage for a sufficiently long time interval, longer than the trap lifetime, between two subsequent gates, trap levels are empty and cannot trigger an avalanche. With typical trapping time in the µs range for InGaAs/InP APD’s. Using a deadtime to inhibit gates for a time long compared to the trapped charges lifetime after each avalanche also proves useful. At a trigger rate of 100MHz the time interval between 2 gates is 10ns; so a deadtime of 1us will inhibit the next 100 gates and the maximum counting rate will be limited at 1 MHz.
d) Timing resolution For many applications, the timing resolution, or jitter, of the detector is also important. Jitter is the undesired deviation from true periodicity of an assumed periodic signal. It is the time variation of the electric output signal of the detector for a constant arriving light signal. Timing performance typically improves with an increase of the excess bias voltage. In order to quantify it, one sends short (shorter than 100 ps) and weak pulses on the detector. The spread of the onset of the avalanche pulses is then monitored with a time-to-amplitude converter. At a 25% detection efficiency, a timing resolution of about 200 ps FWHM is typical. In the future, optimisation of the photodiode structure could lead to improvements.
Timing jitter measurement on the InGaAs/InP id210 device
Page 6
4. Analogue versus Geiger mode a) Avalanche mode (linear modes) Avalanche photodiodes (APD) are working in so-called analogue mode. Means the bias-voltage applied on the diode is always below break down voltage. The output signal is proportional to the incoming light intensity. APD in analogue mode are NOT sensitive enough to detect single photons. b) Single photon avalanche mode (Geiger mode) Our products id100, id210, id220 and id400 are SPAD (=Single Photon Avalanche Diode) based module. SPAD (Single Photon Avalanche Diode) also called photon counter They are working in digital mode, also called Geiger mode. Means the bias-voltage applied on the diode is above breakdown. When a photon is detected it creates an avalanche which has to be quenched, means the bias-voltage is brought below breakdown in order to stop (quench) the avalanche and then brought back above break down to make it sensitive again. The detector is only sensitive when the bias voltage is above break down. The output signal is NOT proportional to the incoming light intensity. SPAD are sensitive enough to detect single photons!!!!!!!!!!
Avalanche mode (linear) vs single photon avalanche mode
Page 7
5. Free running versus gated mode Free running mode:
Only after an avalanche the bias voltage is for a very short time brought below break down, called dead time, in order to quench the avalanche.
When the bias voltage is above break down: the APD state is ON. When an avalanche occurs in the APD after detection of a photon or a dark count, it is sensed by the capture electronics. A pulse of adjustable width is produced on the detection output of the device and the quenching electronics stops the avalanche. In order to limit afterpulsing, the APD bias voltage is maintained below breakdown (APD state is OFF) until the end of the dead time.
The free-running mode is very convenient for application where the photon arrival is unknown.
Free-running mode description
Deadtime can be set by the user for InGaAs/InP devices:
• id210 from 1us to 100us. • id220 from 1us to 25us.
Gated mode:
In order to reduce dark count rate, the APD can be biased above breakdown voltage during a short period of time. This period of time (=duration) is called the gate and is adjustable in width and frequency. This gate is then periodically repeated. This is the trigger frequency (external or internal trigger). The detector is only sensitive during the gates. So, the gated mode is used for applications where the photon arrival is known and this mode significantly reduces dark count. A photon won't be detected if there gate is not open OR a deadtime is applied (after a previous detection). When an avalanche occurs within the gate because of a detection of a photon or a dark count, a pulse of adjustable width is output at the detection connector. The quenching electronics closes the gate and a dead time can be applied, resulting in one or more blanked pulses.
Gated mode description
Page 8
Free running versus gated mode
Free running mode
time time
Gated mode
VbdVbd
time time
output output
6. Effect of deadtime /afterpulsing The deadtime is applied after each detection (real or dark count). If the voltage across the APD is kept below the breakdown voltage for a sufficiently long time interval, longer than the trap lifetime, trap levels are empty and cannot trigger an avalanche. The typical trapping time is in the µs range for InGaAs/InP APD’s.
id220: Typical DCR vs deadtime at 10%, 15% and 20% detection efficiencies
When a photon arrives on the InGaAs/InP photodiode and creates an avalanche, a deadtime has to be applied after the Quenching (stopping the avalanche). Thanks to the deadtime (time while no voltage is applied on the photodiode), the number of carriers and holes decreases significantly and so it avoid an high afterpulsing probability: if too many carriers are trapped in the photodiode, when the next gate will be open or when the deadtime ends, a new avalanche will occur and you will have a count which is an afterpulse (=”noise”).
If you use a short deadtime (or no deadtime), you will have a large amount of afterpulses. Then you can believe that you have a high count rate and a good quantum efficiency, but this is just some noise.
Page 9
Please see below the shape of the curves “Count rate vs trigger rate” with different deadtimes. Please note that this measurements were done with ambient light to have a significant number of counts and huge afterpulsing rate.
id210: Number of counts vs Frequency depending on the deadtime in gated mode
Thus you would see clearly the impact of deadtime on afterpulsing rate. As an example, you can clearly see that a 5us deadtime has a significant effect on the afterpulsing rate when the trigger rate is higher than 1MHz. Let us remind you kindly that those measurements were done with ambient light to have a significant number of counts and huge afterpulsing rate; it means that the deadtime reduces the afterpulsing rate but also the number of detections coming from light.
Page 10
7. Nominal versus Effective Gate width In the timing diagram below, a realistic chronogram is shown taking into account the slew rates of the different electronic stages (the transit time in the electronic stages are assumed negligible). One can note that the gate control signal width differs from the gate output signal width. More important, the gate control signal width (the width applied by the user through the id210 interface) is larger than the effective gate width. The difference decreases when the excess voltage voltage i.e. the efficiency is raised. Note that this effect can also be seen by building an histogram in memory of the dark counts using a time-to-digital or time-to-analog converters.
This simplified explanation done, we inform the users that:
- a difference exists between the gate width set through the id210 interface and the effective gate width,
- a setting of a small gate width through the id210 interface may result in a lower peak efficiency than that of the current set level, even in no efficiency (possible at low excess bias voltage),
- the dark count rate specified for the id210 is fairly evaluated with a measured FWHM effective gate width of 1ns. Indeed, a dark count rate expressed per ns of the gate control signal width would be significantly underestimated in case of a gate control signal width greatly larger than the effective gate width.
Note finally that the shrinkage of the effective gate width finds also explanation in the avalanche current build up duration.
Gate Control Signal
Gate Output Signal
V -APDAC
V -APDDC
VBD
time
Detection CountRate effective gate width
V -APDAC
V -APDDC
VBD
time
Detection CountRate
effective gate width
high detection efficiency low detection efficiency
Ve Ve
Gate Control Signal
Gate Output Signal
Page 11
8. Linearity of Detection Probability
Linearity of Detection Probability a) Gated mode When using a photon counter, you can easily saturate the device: If you use a laser source sending in average 2 photons per pulse you will have a count rate double as if you would send in average one photon per pulse; this what is called linearity of the photon counters. If no optical signal is sent on the APD, then the detection rate would be your dark count rate. Between the saturation region and the dark count rate region, your detector is "linear": the count rate of the detector is proportional to the number of photons arriving on the APD. Attention: this is valid only if a deadtime is applied (cf paragraph 6 "Effect of deadtime /afterpulsing"). b) Free-running mode This will be very similar except that the saturation region is defined by your deadtime: For a 5us deadtime, the maximum count rate is 1/5us = 200kHz => saturation.
9. Photon counting at VIS wavelength Silicon devices (for visible wavelength 350-900nm) does normally not have an adjustable quantum efficiency.
Deadtime is 45ns for the silicon photon counter id100 and is NOT adjustable.
For silicon devices, the trapping time is in the range of few tens of nanoseconds and the afterpulsing probability is low.
Silicon device have a lower jitter, as low as 45ps for the id100, and works usually in free running mode only.
Detection efficiency for silicon based photon counter
Page 12
10. Our photon counters products
id100 (350-900 nm)
Si
35% @ 500 nm
Up to less than 2 Hz
40 ps
Free running mode
id210 (900-1700 nm)
InGaAs/InP
Up to 25%
1.10-5 per gate
200 ps
Gated orfree running mode
id400 (1064 nm)
InGaAsP/InP
Up to 30%
150 Hz at 7.5% SPDE
Typically 300 ps
Gated or free running mode
Product & Wavlengthrange
Diode material
Quantum Efficiency:
Dark Count Rate:
Timing jitter:
Operating mode
id220(900-1700 nm)
InGaAs/InP
Up to 20%
1 kHz at 10% SPDE
250 ps
Free running mode
11. Our other products: id300 short pulse laser source
Wavelength: 1310nm or 1550nm Electrical input: NIM, ECL, TTL Laser: Fabry-Perot or DFB Pulse duration: < 300ps id300
id800-TDC; time to digital converter
Functionalities: Time to Digital Converter Time interval analyser Coincidence counter
id800-TDC
Clavis2: Quatum Key Distribution (QKD) system for R&D
Applications: Quantum cryptography research Implementation of novel protocols Education and training Demonstrations and technology evaluation Clavis 2
Quantis: Physical random number generator exploiting an elementary quantum optics process.
Applications: Cryptography Secure printing PCI Express USB Mobile prepaid system Numerical simulations
PCI OEM 12. Remark Part of the information have been taken from http://en.wikipedia.org/ / ID Quantique, March 2013
Figures of merits: 8 channel TDC 81ps resolution count rates up to 12.5 million Deadtime from 1us to 25us USB interface
Peak power: 1mW Output power at 1MHz: -35dBm Max trigger frequency: 500MHz
Gambling, lotteries PIN number generation Statistical research
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
IDQ’s id100 series consists of compact and affordable single-photon detector modules with best-in-class
timing resolution and state-of-the-art dark count rate based on a reliable silicon avalanche photodiode
sensitive in the visible spectral range. The id100 series detectors come as:
free-space modules, the id100-20 and id100-50 with a 20mm and respectively a 50mm diameter
photosensitive area,
fiber-coupled modules, the id100-SMF20, id100-MMF50 and the id100-MMF100 coming with a standard
FC/PC optical input.
The modules are available in three dark count grades, with dark count rate as low as 2Hz.
With a timing resolution as low as 40ps and a remarkably short dead time of 45ns, these modules outperform
existing commercial detectors in all applications requiring single-photon detection with high timing accuracy
and stability up to count rates of at least 10MHz.
REDEFINING PRECISION
id100 SERIESSINGLE-PHOTON DETECTORS FOR VISIBLE LIGHT WITH BEST-IN-CLASS TIMING ACCURACY
APPLICATIONSKEY FEATURES
Time correlated single photon counting (TCSPC)
Fluorescence and luminescence detection
Single molecule detection, DNA sequencing
Fluorescence correlation spectroscopy
Flow cytometry, spectrophotometry
Quantum cryptography, quantum optics
Laser scanning microscopy
Adaptive optics
Best-in-class timing resolution (40ps)
Low dead time (45ns)
Small IRF shift at high count rates
Standard and Ultra-Low Noise grades
Peak photon detection at l = 500nm
Active area diameter of 20mm or 50mm
Free-space or fiber coupling
Not damaged by strong illumination
No bistability
NEWwith NEW devices and NEW grades
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
SPECIFICATIONS
0.0 0.5 1.0 1.5 2.0 2.5 3.00
10k
20k
30k
40k
50k
60k
70k
Co
un
ts[H
z]
Time [ns]
FWHM Timing Resolution 40ps
Parameter Min Typical Max Units
Wavelength range 350 900 nm
Timing resolution [FWHM] 40 60 ps
Single-photon detection probability (SPDE)
at 400nm 15 18 %
at 500nm 30 35 %
at 600nm 20 25 %
at 700nm 15 18 %
at 800nm 5 7 %
at 900nm 3 4 %
Afterpulsing probability 3 %
Output pulse width 9 10 15 ns
Output pulse amplitude 1.5 2 2.5 V
Deadtime 45 50 ns
Maximum count rate (pulsed light) 20 MHz
Supply voltage 5.6 6 6.5 V
Supply current 100 150 mA
Storage temperature -40 70 °C
Cooling time 5 s
3 5
3
55
7
4
2 1
Dark count rate: IDQ´s modules are available in three grades: Regular, Standard and Ultra-Low Noise, depending on dark count rate specifications.
Active Area Diameter TE cooled Regular Ultra-Low Noise
< 200Hzyes
< 2Hz
yes50 mm
yes < 20Hz< 200Hz
20 mm
7
400 500 600 700 800 9000
5
10
15
20
25
30
35
Ph
oto
nD
etec
tio
nP
rob
abili
ty[%
]
Wavelength [nm]
Photon Detection Probability versus l3
0.1 1 10 100 10000
1
2
3
4
5
6
7
8
Au
toco
rrel
atio
nF
un
ctio
n
Time [ms]
Typical autocorrelation function of a constant laser signal, recorded at a count rate of 10kHz.
0.0 0.5 1.0 1.5 2.0 2.5 3.00
10k
20k
30k
40k
50k
60k
70k
Co
un
ts[H
z]
Time [ns]
IRF Shift with Output Count Rate
Extremely low shift of instrument response function with output count rate (less than 70ps from 10kHz to 8MHz).
2
1 Timing Resolution
Output Pulse5
Typical pulse of 2V amplitude and 10ns width observed at the output of an id100 terminated with 50W load. Recommended trigger level: 1V. For timing applications, triggering on rising edge is recommended to take full advantage of the detector´s timing resolution.
10ns
Dead Time
Measurement obtained with an oscilloscope in infinite persistance mode: the dead time consists of the output pulse width and the hold-off time during which
6
hold-off time
dead time
10ns
The detector output is designed to avoid distorsion and ringing when driving a 50W load.
The id100 is free of indicating LEDs to maintain complete darkness during measurements.
The id100-MMF50 contains a 50/125mm multi-mode fiber optimized for visible spectral range with 0.22 numerical aperture. The coupling efficiency is larger than 80%.
Universal network adapter provided (110/220V).Optimal timing resolution is obtained when incoming photons are focused on the photosensitive area.
See on page 4 the A-PPI-D pulse shaper for negative input equipment compatibility.
3
4
5
4
1
6
id100-50
id100-MMF50
id100-20
Afterpulsing4
7
1
2
Standard
< 60Hz
< 80Hz
yesid100-SMF20
yes8id100-MMF100
6
The id100-SMF20 contains a single mode fiber optimized to your operating wavelength
6
The id100-MMF100 contains a 100/140mm multi-mode fiber optimized for visible spectral range with 0.22 numerical aperture. The coupling efficiency is larger than 50%.
8
NEW
NEW
NEW
NEW
NEW
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
7 Maximum Count Rate - Pulsed Lightid100-20 / id100-50 Front View
id100-20 / id100-50 Bottom View
id100-20 / id100-50 Top View
id100-MMF50 Front View
id100-MMF50 Top View
C-M
OU
NT
39.0
+/-
0.5
87.0 +/- 0.5
61.0 +/- 0.5
C-MOUNT: O1inch-32threads/inch
20mm or 50mm active area
C-MOUNT adapter
87.0 +/- 0.5
FC/PC connector
+
+
79.0 +/- 0.5
FC/PC connector
+
+
M4
DIMENSIONAL OUTLINE
61.0 +/- 0.5
+
+80.0
+/-
0.5
57.0
+/-
0.5
8.0 +/- 0.2
4.0
+/-
0.5
79.0 +/- 0.5
C-MOUNT adapter
The short dead time of the id100 allows operation at very high repetition frequencies, up to 20MHz.
20ns
+6V
DC
DC
50W Output Driver
Hold-off Time Circuit
+5V
SMB jack(female)
Input Filter&
Linear Regulator
TO5 header
10ns
2V
QuenchingCircuit
APDDetection
TECTemperature
Controller
R(T)
High Voltage Supply
Chip
PRINCIPLE OF OPERATION
BLOCK DIAGRAM
MOUNTING OPTIONS
(in mm)
The id100 series comes with different mounting options:
Use mounting brackets supplied with the module using screws with diameters up to 4mm.Use a standard optical post holder (not supplied)using the M4 thread located on the bottom side of the id100-20 & id100-50 detectors.Use the C-MOUNT adapter to add optical elements in front of the detector (id100-20 & id100-50 only).
The id100 consists of an avalanche
photodiode (APD) and an active quenching
circuit integrated on the same silicon chip.
The chip is mounted on a thermo-electric
cooler and packaged in a standard TO5
header with a transparent window cap. A
thermistor is used to measure temperature.
The APD is operated in Geiger mode, i.e.
biased above breakdown voltage. A high
voltage supply used to bias the diode is
provided by a DC/DC converter. The
quenching circuit is supplied with +5V. The
module output pulse indicates the arrival of
a photon with high timing resolution. The
pulse is shaped using a hold-off time circuit
and sent to a 50W output driver. All internal
settings are preset for optimal operation at
room temperature.
In the fiber-coupled version, a fiber pigtail
with FC/PC connector is coupled to the
detector.
39.0
+/-
0.5
151.1
+/-
0.5
127.3
+/-
0.5
8.0 +/- 0.2
4.0
+/-
0.5
id100-SMF20 Front View
id100-MMF100 Front View
id100-SMF20 Top View
id100-MMF100 Top View
IIDD QQuuaannttiiqquuee SSAA 1227 Carouge/Geneva T +41 22 301 83 71 [email protected]
REDEFINING PRECISION
id101 SERIESMMIINNIIAATTUURREE PPHHOOTTOONN CCOOUUNNTTEERR FFOORR OOEEMM AAPPPPLLIICCAATTIIOONNSS
Intended for large-volume OEM applications, the id101 is the smallest, most reliable and most efficient single photon detector on the market. It consists of a CMOS (Complementary Metal Oxide Semiconductor) silicon chip packaged in a standard TO5-8pin header with a transparent window cap. The chip combines either a 20µm (id101-20) or a 50µm diameter (id101-50) single-photon avalanche diode and a fast active quenching circuit, which guarantees a dead time of less than 50ns. The chip is mounted on top of a single-stage thermoelectric cooler (TEC). A fiber-coupled version, the id101-MMF50, is also available. The maximum photon detection probability is measured in the blue spectral range (35% at 500nm). An outstanding timing resolution of less than 60ps allows high accuracy measurements. The performance of the id101 detectors is comparable to that of the id100-20 and id100-50 modules.The id101 can be mounted on a printed circuit board and integrated in apparatuses such as spectrometers or microscopes. The module is used in biological/chemical instrumentation, quantum optics, aerospace and defense applications.Contrary to legacy photomultiplier tubes (PMTs) and other silicon-based counters manufactured with non-standard custom process, the id101 detector is fabricated using a qualified commercial CMOS process, which guarantees high reliability.
tor
AAPPPPLLIICCAATTIIOONNSSKKEEYY FFEEAATTUURREESSTime correlated single photon counting (TCSPC)Fluorescence and luminescence detectionSingle molecule detection, DNA sequencingFluorescence correlation spectroscopyFlow cytometry, spectrophotometryQuantum cryptography, quantum opticsLaser scanning microscopyAdaptive optics
Best-in-class timing resolution (40ps)Low dead time (45ns)Small IRF shift at high count ratesPeak photon detection at λ = 500nm
Active area diameter of 20µm or 50µmFree-space or multimode fiber couplingNot damaged by strong illuminationIntegrated thermoelectric cooler and thermistor
Boston Electronics (800)347-5445 or [email protected]
IIDD QQuuaannttiiqquuee SSAA 1227 Carouge/Geneva T +41 22 301 83 71 [email protected]
BBLLOOCCKK DDIIAAGGRRAAMM2The id101 is based on a 0.8x0.8mm CMOS silicon chip
containing a 20µm or 50µm diameter avalanche diode and its active quenching circuit. To operate in the Geiger mode, the diode anode is biased with a negative voltage V . Theop
cathode is linked to VDD through a polysilicon resistor R .q
Before the photon arrival, the switch is open (non-conducting) and the cathode is at VDD. When a photon strikes the diode, the voltage drop induced on the cathode is sensed by the sensing circuit. The output pin OUT switches to VDD. The feedback circuit closes the switch: the diode is biased below its breakdown voltage resulting in the avalanche quenching. The diode is then kept below breakdown and the recharge takes place with the opening of the switch. The full cycle is defined as the sensor dead time. In any single photon avalanche diode, thermally generated carriers induce false counts, called dark counts. A single-stage thermoelectric cooler (TEC) allows to cool the device to reduce the dark count rate. Furthermore, the photon detection probability in a single photon avalanche diode is dependent on the excess bias voltage above breakdown. The breakdown voltage being temperature dependent, it is often crucial to keep the sensor at a constant temperature. The thermistor included in the id101 allows one to implement a temperature control circuit.
RRqq
sensingcircuit output
driver
VVDDDD
feedbackcircuit
GGNNDD
OOUUTT
VVOOPP
RR((TT))
TTEECC
TTEECC((--)) TTEECC((++))
TTHHEERRMM((11))TTHHEERRMM((22))
PPRRIINNCCIIPPLLEE OOFF OOPPEERRAATTIIOONN
DDIIMMEENNSSIIOONNAALL OOUUTTLLIINNEE AANNDD PPIINNOOUUTT
∅ +/-0.18.33
∅ 9.1 +/-0.1
+/-0
.10.
6+/
-0.2
1.9
+/-0
.26.
6
∅ 0.43 +/-0.05
tthheerrmmiissttoorrssiinnggllee--ssttaaggee TTEECC
ssiilliiccoonn cchhiipp iinncclluuddiinngg tthhee ssiinnggllee pphhoottoonn aavvaallaanncchheepphhoottooddiiooddee aanndd tthhee aaccttiivveeqquueenncchhiinngg cciirrccuuiitt
TTOO55 -- 88 ppiinnss hheeaaddeerr
UNIT: millimeters
- Window material: glass- Pin material: gold plated- The 20µm or 50 m active area is aligned with the centre
of the glass window. The positioning accuracy is +/-100microns.
µ
∅ 2
0.0
+/-0
.5
FFCC//PPCCccoonnnneeccttoorr
mmuullttiimmooddee ffiibbeerr ttyypp..lleennggtthh==115500mmmm
TTOO55 ffiibbeerr ppiiggttaaiill50.0
iidd110011--MMMMFF5500 ffiibbeerr--ccoouupplleedd vveerrssiioonn
ppiinn ##1122334455667788
ccoonnnneeccttiioonnVVOOPP
VVDDDDtthheerrmmiissttoorrtthheerrmmiissttoorrGGNNDDOOUUTTTTEECC((--))TTEECC((++))
((iinn mmmm))
Boston Electronics (800)347-5445 or [email protected]
IIDD QQuuaannttiiqquuee SSAA 1227 Carouge/Geneva T +41 22 301 83 71 [email protected]
PPhhoottoonn DDeetteeccttiioonn PPrroobbaabbiilliittyy vveerrssuuss λ
0.0 0.5 1.0 1.5 2.0 2.5 3.00
10k
20k
30k
40k
50k
60k
70k
CCoouunn
ttss[[HH
zz]]
TTiimmee [[nnss]]
FFWWHHMM TTiimmiinngg RReessoolluuttiioonn 4400ppss
SSPPEECCIIFFIICCAATTIIOONNSS
33
0.1 1 10 100 10000
1
2
3
4
5
6
7
8
AAuuttoo
ccoorrrree
llaattiioo
nnFFuu
nnccttiioo
nn
TTiimmee [[µss]]
AAfftteerrppuullssiinngg
Typical autocorrelation function of a constant laser signal, recorded at a count rate of 10kHz.
22
11 TTiimmiinngg RReessoolluuttiioonn
The id101-MMF50 comes with a 50/125µm multimode fiber pigtail with a 0.22 numerical aperture. The overall coupling efficiencyexceeds 80%.
TTHHEERRMMOOEELLEECCTTRRIICC CCOOOOLLEERR SSPPEECCIIFFIICCAATTIIOONNSS
TEC mounting soldering, 117°CThermosensor mounting epoxy glueWire mounting soldering, 183°C
MMOOUUNNTTIINNGG DDEETTAAIILLSSTTHHEERRMMOOSSEENNSSOORR SSPPEECCIIFFIICCAATTIIOONNSS
The thermistor resistance can be calculated by: R = R exp(β(293-T)/(293 T))T 293K* *
PPaarraammeetteerr UUnniitt VVaalluuee ((ccoonnddiittiioonnss))
Resistance ACR Ω 3.56 +/- 0.16 (at
Maximum Current I A 0.4 +/- 0.02 (at ∆T )max max
Maximum Voltage Drop U V 1.35 +/- 0.07 (at ∆T )max max
Maximum Delta-T ∆t K 67.0 +/- 2.0 (Vacuum, Q=0, T =300K)max r
Maximum Cooling Capacity Q W 0.29 +/- 0.01 (at ∆T=0)max
T =300K)r
PPaarraammeetteerr UUnniitt VVaalluuee ((ccoonnddiittiioonnss))
Resistance R0 kΩ 2.2 +/- 0.16 at 293K-1Beta Constant β K 2918.9 +/- 5%
400 500 600 700 800 9000
5
10
15
20
25
30
35
PPhhoott
oonnDDee
tteecctt
iioonn
PPrroobb
aabbiilliitt
yy[[%%
]]
WWaavveelleennggtthh [[nnmm]]
PPaarraammeetteerr MMiinn TTyyppiiccaall MMaaxx UUnniittssWavelength range 350 900 nmActive area diameter
id101-20 20 µmid101-50 50 µm
Timing resolution [FWHM] 40 60 psSingle-photon detection probability (SPDE)
at 400nm 15 18 %at 500nm 30 35 %at 600nm 20 25 %at 700nm 15 18 %at 800nm 5 7 %at 900nm 3 4 %
Dark count rate (DCR)id101-20 15 50 Hzid101-50 100 300 Hz
Afterpulsing probability 3 %Output pulse width
id101-20 30 35 40 nsid101-50 and id101-MMF50 40 45 50 ns
Output pulse amplitude (in high impedance) VDD VOutput driver capability 4 mADeadtime
id101-20 30 35 40 nsid101-50 and id101-MMF50 40 45 50 ns
Maximum count rate (pulsed light)id101-20 28 MHzid101-50 and id101-MMF50 22 MHz
VDD supply voltage 4.8 5.0 5.2 VCurrent on VDD 0.25 2.2 mAV supply voltage -24 -26 VOP
Current on V 100 µAOP
Storage temperature -40 70 °C
11
33
22 11
11
66aa66bb
44aa
44aa44bb
44bb
55aa55bb
Boston Electronics (800)347-5445 or [email protected]
IIDD QQuuaannttiiqquuee SSAA 1227 Carouge/Geneva T +41 22 301 83 71 [email protected]
Many industrial applications would greatly benefit from a single photon detector array. When the required array size is reasonably small (i.e. < 10x10), it is possible to assemble several closely spaced TO5 headers to form an array. Asillustrated in the figure, opposite, for a 3x3 array,several TO headers can be mounted on a printed circuit board. The minimum center-to-center pitch is 9.5 mm. Common electronic circuits for power supply, output stage and temperature control can be implemented on the PCB. If a high accuracy for the distance from pixel to pixel is required or if a large array is needed, IDQ offers a custom design service for the design of an application-specific CMOS chip.
EElleecc
ttrroonnii
cc CCiirrcc
uuiittss
ffoorr::
--ppooww
eerr ssuu
ppppllyy
--oouutt
ppuutt dd
rriivveerr
--tteemm
ppeerraa
ttuurree
ccoonntt
rrooll
An evaluation board has been developed for preliminary optical and electrical testing of the id101. The id101 under test can be plugged into a socket intended for TO5 headers. The evaluation board comes with a power supply with universal range of input plugs and a 1m coaxial cable ended with a BNC connector.
66aa
66bb
44aa
44bb
55aa
55bb
Typical pulses observed at the id101-20 (4a) and id101-50 or id101-MMF50 (4b) outputs in high impedance.
Extended pulses observed at the id101-20 (5a) and id101-50 or id101-MMF50 (5b) outputs at high illumination level. When an avalanche is triggered during the recharge process, the output remains high, giving an extended pulse. This effect leads to a decrease of the output count rate.
The short dead time of the id101 allows operation at very high repetition frequencies, up to 28MHz for the id101-20 (6a) and 22MHz for the id101-50 or id101-MMF50 (6b).
1100nnss11VV
1100nnss11VV
1100nnss11VV
1100nnss11VV 1100nnss
11VV
1100nnss11VV
iidd110011--EEVVAA EEVVAALLUUAATTIIOONN BBOOAARRDD
AAPPPPLLIICCAATTIIOONN EEXXAAMMPPLLEE -- CCOOMMBBIINNAATTIIOONN IINN AARRRRAAYY
Boston Electronics (800)347-5445 or [email protected]
IIDD QQuuaannttiiqquuee SSAA 1227 Carouge/Geneva T +41 22 301 83 71 [email protected]
TTYYPPIICCAALL AAPPPPLLIICCAATTIIOONN CCIIRRCCUUIITT
RRqq
sensingcircuit output
driver
VVDDDD
feedbackcircuit
GGNNDD
OOUUTT
VVOOPP
RR((TT))
TTEECCTTEECC((--)) TTEECC((++))
TTHHEERRMM((11))TTHHEERRMM((22))
invertingDC/DC
converter
++55VV
D QCPC
11
temperaturecontroller
1
OOUUTT
++55VV
delay
PPoowweerr SSttaaggeeThe id101 requires two power supplies VDD and V . A standard inverting DC/DC converter can convert the +5V level OP
to the high negative voltage level V . The remaining electronic circuits on the PCB board can be supplied with the OP
same +5V power. Two 100nF capacitances must be added as close as possible to the output pins for decoupling purpose.
OOuuttppuutt SSttaaggeeThe id101 output can be shaped for the back-end electronic circuits (e.g. counter, TDC, TAC) using the circuit shown below. A D-type Flip-Flop with asynchroneous clear combined with a delay generator (RC for instance) and an inverter with a Schmitt trigger input allows to set the pulse width and the dead time.
TTeemmppeerraattuurree CCoonnttrroollFor proper operation, it is highly recommended to implement a thermal stabilisation circuit on the final printed circuit board, using the single-stage TEC and the 2.2kΩ thermistor provided. Integrated temperature controllers for Peltier modules are commercially available.
,
IDQ provides as an option a pulse shaper (A-PPI-D) which can be used with equipments requiring negative input pulses. The id100 output pulse leading edge is converted in a sharp negative pulse of typical amplitudes 1.4V in 50Ω load and 2.5V in high impedance load. The pulse shaper is delivered with two SMA/BNC adapters.
Typical output pulse of an id100 equippedwith aA-PPI-D pulse shaper in 50Ω load.
AACCCCEESSSSOORRYY -- OOPPTTIIOONNAALL PPUULLSSEE SSHHAAPPEERR
Typical output pulse of an id100 equipped with aA-PPI-D pulse shaper in high impedance load.
Boston Electronics (800)347-5445 or [email protected]
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
PRELI
MIN
ARY
NEW
REDEFINING PRECISION
id110 - VIS - GATEDGATED VISIBLE SINGLE PHOTON DETECTOR
Adjustable photon detection probability
Adjustable delays, gate width and deadtime
Up to 100MHz external / internal gating frequency
Universal Inputs/Outputs
Quantum optics
Quantum memory
Optical tomography
KEY FEATURES
Free gating mode
Ethernet remote control (Option)
Two-channel auxiliary event counter
Auxiliary coincidence counter
Data export through USB memory
Real time statistics, charts, sound alarms
Setup storage in internal memory
Fluorescence, fluorescence life time
Photoluminescence
1
The id110 brings a major breakthrough for single avalanche signal (also called post-gating), the
photon detection at visible wavelengths in id110 operates in real GATED MODE and offers
demanding conditions. Conventional single- the best discrimination performance. The figure
photon detectors based on Silicon Avalanche below shows the detection rate after sending an
Photodiodes (APD) are typically operated in free- intense light pulse on the APD (1000 photons) at
running mode. Their performance can be strongly 100kHz repetition rate. The extra-noise originated
impacted by intense optical pulses. The detector by the strong pulses in free-running mode (due to
is blinded by the intense pulse due to the dead- afterpulsing effect) is larger than the one in gated
time effect occurring after each detection. This mode (due to charge persistence) whereas the
deadtime can extend to 100's of ns. In addition, noise level is higher in free-running mode.
the charges trapped in the APD junction, as a Additionnaly, in gated mode, the APD is NOT
result of intense optical pulses, increase the noise blinded.
level, potentially masking the signal of interest.
The id110 Gated Visible Single Photon Detector
brings a solution to these problems by operating
the APD in GATED MODE. The bias voltage is
kept below breakdown to deactivate the detector
and enhance trap discharge, except when
detection is specifically enabled. Contrary to other
products on the market, which simulate GATED
MODE by controlling the activation of the output
APPLICATIONS
100 1000 10000
0.1
1
10
100
1000
10000
100000
1000000
APD w orkin g in ga ted mo de (20 ns
p ulse w idth)
APD w orkin g in free -runn ing m od e
(70 ns de ad t im e & 10n s co incid ence
p ulse w idth)
Co
un
t(H
z)
Delay (ns)
la ser pulse
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
PRELI
MIN
ARY
The System hardware
The system hardware allows the id110 to operate in free-running, free-gating, internal gated or external gated modes.
The APD is biased above breakdown during gates of adjustable width and frequency. Internal gating is a
synchronous mode based on a clock provided by the internal clock generator. The 50% duty cycle clock signal is
available at the clock output and counted by the HF clock counter. A user-adjustable trigger delay can be set between
the clock and the gate signals. A gate of width set by the user is opened on the rising edge of the delayed trigger. An
avalanche event within the gate increments the HF detection counter and causes a pulse of adjustable width at
detection1 and detection2 connectors. The quenching electronics closes the gate and, if selected by the user, a dead
time is applied resulting in one or several blanked pulses after a detection.
Internal-gating mode:
2
Internal gated mode
Clock Output
Gate Output
Trigger Delay
Gate Width
Width Detection 1&2
blanked gate
Quenching
Detection 1&2 Outputs
HF Gate Counter
HF Detection Counter
HF Clock Counter
Dead Time
+1 +1 +1 +1
+1 +1 +1
+1
1/Internal Gating Frequency
External gated mode
HF Gate Counter
HF Detection Counter
HF Clock Counter
Gate Output
Trigger Delay
Gate Width
Width Detection 1&2
+1 +1 +1
Dead Time
+1 +1
+1
Trigger Input
+1
+1
blanked gate
Quenching
Detection 1&2 Outputs
External-gating mode:
The operation in external gating mode is very similar to the internal gating mode except that the clock is provided by the
user at the trigger input.
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
PRELI
MIN
ARY
3
QuenchingQuenching
Gate Output
Detection 1&2 OutputsWidth Detection 1&2
Dead Time
HF Gate Counter +1 +1
HF Detection Counter +1 +1 +1
Quenching
+1
Free-running mode (asynchronous)
Free-running mode (asynchronous mode):
Until photon absorption or dark count generation, the APD is biased above its breakdown voltage in Geiger mode. The
gate output that reflects the APD state (i.e. On:photosensitive or Off:blind) is at high level. When an avalanche takes
place in the APD, it is sensed by the capture electronics. A pulse of adjustable width is produced on detection1 and
detection2 outputs, the detection HF counter is incremented and the quenching electronics stops the avalanche. To
limit afterpulsing, the APD is maintained below breakdown until the end of the dead time. In this mode, the HF gate
counter and HF detection counter rates are equal.
Free-gating mode
Dead Time
Gate Output
+1
+1
Reset/Enable Input
gate partially blanked
+1 +1 +1
+1 +1
HF Gate Counter
HF Detection Counter
Quenching Quenching
Detection 1&2 OutputsWidth Detection 1&2
blanked gate
Quenching
Free-gating mode:
The user supplies an electrical signal at the reset/enable input. When no avalanche occurs, the gate output that
reflects the APD state (On/Off) is identical to the reset/enable input signal. When an avalanche occurs during a gate, a
pulse of adjustable width is produced at detection1 and detection2 outputs, the HF detection counter is incremented
and the quenching electronics stops the gate. When a dead time is applied for limiting the afterpulsing, the gate signal
remains at low level whatever the reset/enable state. This results in blanked gate(s) or partially blanked gates. The HF
gate counter provides the effective gates rate applied to the APD.
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
PRELI
MIN
ARY
4
Parameter Min Typical Max Units
Wavelength range 350 900 nm
Optical fiber type MMF (diam. 105 um)
Single-photon detection probability (SPDE)
at 405nm 13 %
at 530nm 24 %
at 590nm 24 %
at 660nm 17 %
at 850nm 4 %
Deadtime range 0.070 100 us
Deadtime step 10 ns
Timing resolution at max. efficiency (25%) 200 ps
External trigger frequency 100 MHz
Internal trigger frequency 1,2,5,10,20,50,100,200,500 kHz 1,2,5,10,20,50,100 MHz
Effective gate width range 0.5 25 ns
Gate width step 10 ps
Trigger delay range 20 ns
Trigger delay resolution 10 ps
Optical connector FC/APC
SPECIFICATIONS
1
id110-MMF105
Model
0.1Hz 0.25Hz 100Hz 250Hz
Probability of dark count rate at 530nm for a 1ns effective gate width in gated mode:
Freq.=100kHz, 70ns deadtime Freq.=100MHz, deadtime=1ms
10% efficiency 20% efficiency 10% efficiency 20% efficiency
2
DisclaimerThe information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2013 ID Quantique SA - All rights reserved - id110 v2013 04 24 - Specifications as of April 24 2013
SUPPLIED ACCESSORIES
Power Cable
Optical fiber cleaner
User guide on USB key
Compact USB keyboard
1m FC/APC patch cord MMF105
ORDERING INFORMATION
id110-MMF105-100MHz module with multimode fibre input (core diameter 105um)100MHz internal / external trigger rate
OTHER SCIENTIFIC INSTRUMENTATION PRODUCTS
id100: Photon counter module in the VIS spectrum
id150: Miniature 8-channel photon counter for OEM applications in the VIS spectrum
id400: Single photon detection system for 1064nm (900 to 1150nm)
id210: Single photon detection system - Telecom wavelength
id220: Free-running single photon detection module - Near infrared
id300: Short-pulse laser source at 1310nm or 1550nm
id800: 8 channel Time to Digital Converter TDC
Calibrated at l=530 nm.
Photon Detection Probability
versus l
Ethernet cable (optional)
1
2
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
VISIBLE SINGLE-PHOTON COUNTER
ID120 HIGH QUANTUM EFFICIENCY AT 650NM AND AT 800NM LARGE ACTIVE AREA 500UM
IDQ’s ID120 series consists of compact and
affordable single-photon detector modules based
on a reliable silicon avalanche photodiode
sensitive in the visible spectral range. Up to now,
the ID100 series was limited to detectors with high
efficiency values in the green region (around
500nm). The two new detectors of the ID100 series
have high efficiency values in the red region of the
visible spectrum and a ultra high active area.
These new detectors come as :
free-space module, passive quenching, maximal
efficiency value around 650nm
free-space module, passive quenching, maximal
efficiency value around 800nm
Those two detection modules are highly versatile
thanks to an USB connection and a Labview
¡
¡
KEY FEATURES
¡¡¡¡¡¡¡¡¡
60% Quantum Efficiency at 650nm
80% Quantum Efficiency at 800nm
Tunable quantum efficiency
Tunable temperature of the diode
Adjustable deadtime
Universal dual output
Labview interface
C-mount, SM1, cage compatible
Integrated electronic counter (optional)
APPLICATIONS
¡
¡¡¡¡¡
Time correlated single photon counting (TCSPC)
Fluorescence and luminescence detection
Single molecule detection, DNA sequencing
Fluorescence correlation spectroscopy
Spectrophotometry
Laser scanning microscopy
interface allowing the user to change the bias voltage and the temperature of the diode. The modules are
equipped with a dual universal output signal port which can be set through the software interface. The
modules are compatible with C-mount, SM1 and cage technologies from Thorlabs. This allows an easy
coupling of the light beam onto the active area of the detectors.
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
Best-in-Class Performance
VISIBLE SINGLE-PHOTON COUNTER
2
Parameter Min Typical Max
Wavelength range 350 1000
Active area 500
Single-photon detection probability (SPDE)
at 650nm (at max. excess bias) 60
at 800nm (at max. excess bias) 40
Dark Count Rate
Down to 500
Timing resolution [FWHM] 200 400 1000
Deadtime 1
Output pulse NIM & LVTTL & Variable
Output pulse width 100
Storage temperature -40 70
Min Typical Max Units
350 1000 nm
500 um
55 %
80 %
200 Hz
200 400 1000 ps
1 us
NIM & LVTTL & Variable
100 ns
-40 70 °C
ID120-500-650nm ID120-500-800nm
1
The ID120 is a versatile device allowing you to adjust the excess bias, the deadtime and the temperature. Please note that the values in the specification table are dependent on the user-defined parameters. To have a fair overview of the specifications, it is recommended to carefully review the curves «Efficiency vs excess bias» and «Dark count rate vs temperature».
SPECIFICATIONS
Disclaimer - The information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2014 ID Quantique SA - All rights reserved -ID120 v2014 07 10 - Specifications as of July 2014
2
1 Quantum efficiency vs lambda 2 Efficiency vs excess bias at 655nm and 808nm
ID120-500-650nm Photon counter with 500mm active area. for 650nmID120-500-800nm-STD Photon counter with 500mm active area for 800nm with DCR < 3000HzID120-500-800nm-ULN Photon counter with 500mm active area for 800nm with DCR < 200HzSupplied accessories: USB cable, power supply, USB memory stick including software, adapter to mount Thorlabs components.
ORDERING INFORMATION
3 Software
Delivered with software to:- display count rate- control quantum efficiency- control deadtime- control temperature
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
8 CHANNEL VISIBLE SINGLE-PHOTON COUNTER
ID150 MINIATURE 8-CHANNEL PHOTON COUNTERFOR OEM APPLICATIONS
The ID150-1x8 is the only multichannel solid-state
single photon detector on the market. It consists of
a CMOS silicon chip packaged in a standard TO8-
16pin header with a transparent window cap. The
chip combines 8 in-line single photon avalanche
diodes that can be accessed simultaneously for
parallel processing. The square diodes are
40x40mm in area with a center-to-center pitch of
60mm . A fast active quenching circuit is integrated
within each pixel in order to operate each diode in
photon counting regime. The chip is mounted on a
printed circuit board on top of a single-stage
thermoelectric cooler (TEC). A thermistor can be
used to measure the temperature of the chip. Two
power supplies (+5V and -25V) are sufficient for
KEY FEATURES
¡¡¡¡¡¡¡¡
1x8 linear array with independent outputs
Pixel active area of 40x40mm2
Center-to-center pitch of 60mm
Best-in-class timing resolution (40ps)
Low dead time (45ns) and dark count rate
Peak photon detection at λ = 500nm
No crosstalk
Not damaged by strong illumination
APPLICATIONS
¡¡¡¡¡¡¡¡
High-throughput single molecule detection
Parallel DNA sequencing
Multi-Channel TCSPC
Fluorescence and luminescence detection
Decay and multiple decay time measurements
Fluorescence correlation spectroscopy
Flow cytometry, spectrophotometry
Quantum optics
operation in photon counting mode. The fast active quenching circuit leads to a dead time of less than 50ns
per channel. An outstanding timing resolution of less than 60ps allows high accuracy measurements.
The ID150-1x8 can be mounted on a printed circuit board and integrated in apparatus such as spectrometers
or microscopes. The module is used in biological/chemical instrumentation, quantum optics, aerospace and
defense applications. The small detector size is ideal for portable device applications.
Contrary to legacy photomultiplier tubes (PMTs) and other silicon-based counters manufactured with non-
standard custom process, the ID150-1x8 is fabricated using a qualified commercial CMOS process, which
guarantees high reliability.
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
Best-in-Class Performance
Parameter Min Typical Max Units
Wavelength range 350 900 nm
Pixel active area 40x40 mm
Center-to-center pitch 60 mm
Timing resolution [FWHM] 40 60 ps
Single-photon detection probability (SPDE)
at 400nm 15 18 %
at 500nm 30 35 %
at 600nm 20 25 %
at 700nm 15 18 %
at 800nm 5 7 %
at 900nm 3 4 %
Dark count rate (DCR)
DCR / channel 15 kHz
Mean DCR over the 8 channels 3.5 kHz
Afterpulsing probability 3 %
Output pulse width 40 45 50 ns
Output pulse amplitude (in high impedance) VDD V
Output driver capability 4 mA
Deadtime 50 ns
VDD supply voltage 4.8 5.0 5.2 V
V supply voltage -24 -26 VOP
Storage temperature -40 70 °C
SPECIFICATIONS
1
3
2
Measured at 273K with V = -25.5VOP1
1
3
1
0.0 0.5 1.0 1.5 2.0 2.5 3.00
10k
20k
30k
40k
50k
60k
70k
Co
un
ts[H
z]
Time [ns]
Extremely low shift of instrument response function with output count rate (less than 70ps from 10kHz to 8MHz).
0.0 0.5 1.0 1.5 2.0 2.5 3.00
10k
20k
30k
40k
50k
60k
70k
Co
un
ts[H
z]
Time [ns]
FWHM Timing Resolution 40ps
1 Timing Resolution IRF Shift with OutputCount Rate
2
0.1 1 10 100 10000
1
2
3
4
5
6
7
8
Au
toco
rrel
atio
nF
un
ctio
n
Time [ms]
Typical autocorrelation function of a constant laser signal, recorded at a count rate of 10kHz.
Afterpulsing4
400 500 600 700 800 9000
5
10
15
20
25
30
35
Ph
oto
nD
etec
tio
nP
rob
abili
ty[%
]
Wavelength [nm]
Photon Detection
Probability versus l
Optimal timing resolution is obtained when incoming photons are focused on the photosensitive area.
3
Disclaimer - The information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2014 ID Quantique SA - All rights reserved -ID150 v2014 07 10 - Specifications as of July 2014
2
3
8 CHANNEL VISIBLE SINGLE-PHOTON COUNTER
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
Best-in-Class Performance
PRINCIPLE OF OPERATION
BLOCK DIAGRAM
VDD
GND
VOP1
R(T)
TEC
TEC(-) TEC(+)
THERM(1)THERM(2)
OUT1
Rq
AQC
OUT2
Rq
AQC
OUT3
Rq
AQC
OUT4
Rq
AQC
OUT5
Rq
AQC
OUT6
Rq
AQC
OUT7
Rq
AQC
OUT8
Rq
AQC
VOP2
LINEAR ARRAY PICTURE
active quenching circuits
active quenching circuits
1x8 SPAD array 1 2 3 4 5 6 7 8
2The ID150-1x8 is based on a 1.2x1.4mm CMOS silicon chip containing 8 in-line independent single photon detectors. Each pixel combines a square avalanche photodiode of
240x40mm area and its active quenching circuit. The pixel
center-to-center pitch is 60mm (fill factor exceeds 75%).
To operate in the Geiger mode, each diode anode is biased with a negative voltage. In the ID150-1x8, the cathode of pixels 1, 3, 5 and 7 are connected together to V pad, while op1
the cathode of pixels 2, 4, 6 and 8 are connected to V pad. op2
Each cathode is linked to VDD through a polysilicon resistor R . Prior to the detection of a photon on a pixel, the switch is q
open (non-conducting) and the cathode is at VDD. When a photon strikes the diode, the voltage drop induced on the cathode is sensed by the active quenching circuit. The corresponding output pin OUT switches to VDD. The i
feedback circuit closes the switch: the diode is biased below its breakdown voltage resulting in the avalanche quenching. The diode is then kept below breakdown and the recharge takes place with the opening of the switch. The full cycle is defined as the pixel dead time.
In any single photon avalanche diode, thermally generated carriers induce false counts, called dark counts. A single-stage thermoelectric cooler (TEC) allows one to cool the device to reduce the dark count rate. Furthermore, the photon detection probability in a single photon avalanche diode depends on the excess bias voltage.
The breakdown voltage being temperature dependent, it is often crucial to keep the sensor at a constant temperature. The thermistor included in the ID150-1x8 allows one to implement a temperature control circuit. For efficient cooling, an additional heat-sink combined with a air fan must be added by the user. The heat-sink can either surround the TO8 header or be fixed using the UNC 4-40 thread.
3
8 CHANNEL VISIBLE SINGLE-PHOTON COUNTER
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
Best-in-Class Performance
DIMENSIONAL OUTLINE AND PINOUT (in mm)
TEC mounting soldering, 117°C
Thermosensor mounting epoxy glue
Wire mounting soldering, 183°C
THERMOELECTRIC COOLER SPECIFICATIONS
MOUNTING DETAILS
THERMOSENSOR SPECIFICATIONS
- Window material: glass- Pin material: gold plated
The thermistor resistance can be calculated by: R = R exp(b(293-T)/(293 T)T 293K* *
pin #12345678910111213141516
connectionTEC(-)
thermistorthermistor
TEC(+)OUT8OUT6OUT4OUT2VOP2
VDDGNDVOP1
OUT1OUT3OUT5OUT7
1
2
3
4
12
11
10
9
5678
16151413
Æ 0.43 +/-0.05
Æ 11.1 +/-0.2
Æ 14.0 +/-0.2
Æ 15.3 +/-0.2
+/-
0.1
50.8
8 +
/-0.1
50.2
5
+/-
0.2
59.5
0
> 3
.0
+/-
0.3
01.5
0
TO8 - 16pins header silicon chip including 8 single photon avalanche diodesand active quenching circuits
printed circuit board glued on top of a 1-stage TEC
9.50
1.9
0
0.70
3.50
Recommended Footprint
UNC4-40
6.5
0TOP VIEW
Parameter Unit Value (conditions)
Maximum Current I A 1.15 +/- 0.02 (at DT )max max
Maximum Voltage Drop U V 2.90 +/- 0.07 (at DT )max max
Maximum Delta-T Dt K 69.0 +/- 2.0 (Vacuum, Q=0, T =300K)max r
Maximum Cooling Capacity Q W 1.85 +/- 0.01 (at DT=0)max
Parameter Unit Value (conditions)
Resistance R0 kW 2.2 +/- 0.16 at 293K-1Beta Constant b K 2918.9 +/- 5%
4
8 CHANNEL VISIBLE SINGLE-PHOTON COUNTER
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
Best-in-Class Performance
ACCESSORIES
ID150-1x8-TM option:
To accelerate integration of the ID150-1x8 in an optical set-up, the following accessories are available.
The ID150-1x8-TM consists of a ID150-1x8 welded on a
47.8mmx36.8mm printed circuit board. Required decoupling
capacitances are mounted on the PCB bottom side, close to ID150-1x8
pins. A heat sink is glued around the ID150-1x8 TO8 package. Electrical
connections are provided by 4 straight pin headers. Each 4-poles header
consists of 0.63mmx0.63mm gold-plated pins with 2.54mm pitch. The
recommended footprint and pinout are given below.
ID150-1x8-EVA option: The ID150-1x8-TM is provided with the ID150-1x8-EVA evaluation
board of 66mmx107mm in size. The ID150-1x8-TM is inserted on the
ID150-1x8-EVA board using four 4-poles sockets. Assembly marks
ensure a proper insertion.
The outputs are provided at SMB-type connectors. For V , GND, VDD, op
TEC(+), TEC(-) and thermistor, 4mm banana connectors are used.
The bias voltages V and V can be disconnected by removing the op1 op2
corresponding jumpers .
OUT8 OUT7
TE
C(+
)
the
rmis
tor
the
rmis
tor
TE
C(-)
ID150-1x8-TM
OU
T1
OU
T3
OU
T5
OU
T7
OU
T2
OU
T4
OU
T6
OU
T8
Vop2
VDD
Vop1
TEC(+)thermistorthermistorTEC(-)
1
2
3
4
12
11
10
9
16151413
5678
ID150-1x8-TM pinout
GND
20.1
22.6
25.2
27.7
45.3
47.8
2.4
2.4
14.6
17.2 19.7
22.3
34.3 36.8
1.2 [16x]
3.5
ID150-1x8-TM recommended footprint
ID150-1x8-EVAassembly marks
Vop1 & Vop2 jumpers
OUT2
OUT4
OUT6
OUT1
OUT3
OUT5
VD
D
GN
D
Vo
p1&
2
unit: millimeters
5
8 CHANNEL VISIBLE SINGLE-PHOTON COUNTER
¡
¡
¡
ID150-1x8:TO8 head including 8 independent single-photon 2detectors with 40x40mm active area and 60mm center-to-center
pitch.
ID150-1x8-TM: ID150-1x8 mounted on a printed circuit board including heat-sink and decoupling capacitances.
ID150-1x8-EVA: ID150-1x8-TM and evaluation electronic board with connectors.
ORDERING INFORMATION
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
REDEFINING PRECISION
id210ADVANCED SYSTEM FOR SINGLE PHOTON DETECTION
Adjustable photon detection probability
Adjustable delays, gate width and deadtime
Up to 100MHz external / internal gating frequency
Universal Inputs/Outputs
Quantum optics, quantum cryptography
Fiber optics characterization
Single-photon source characterization
APPLICATIONS
KEY FEATURES
Free gating mode
Failure analysis of electronic circuits
Eye-safe Laser Ranging (LIDAR)
Spectroscopy, Raman spectroscopy
The id210 brings a major breakthrough for single photon detection at telecom wavelengths. Its
performance in high-speed gating at internal or external frequencies up to 100MHz by far surpasses the
performance of existing detectors and of its predecessor, the id200-id201, that has been used by
researchers around the globe since first launched in 2002. Photons can be detected with probability up to
25% at 1550nm, while maintaining a low dark count rate. A timing resolution lower than 200ps can be
achieved. The id210 provides adjustable delays, adjustable gate duration from 0.5ns to 25ns and adjustable
deadtime up to 100us. For applications requiring an asynchronous detection scheme, the id210 can operate
in free-running mode with detection probability up to 10%. Beside performance, a particular effort has been
made for providing a practical user interface, universal compatibility with scientific equipment, application-
oriented functionalities including statistics and coincidence counting. Built around an advanced embedded-
PC and FPGA, the id210 allows remote control, connection of external screen and keyboard, data export on
USB key and setups saving.
Ethernet remote control (or USB with adapter)
Stand alone application and Labview Vi
Two-channel auxiliary event counter
Auxiliary coincidence counter
xternal monitor / projector VGA HD15 output for e
Data export through USB memory
5.7" VGA TFT-LED color display
Real time statistics, sound alarms
Setup storage in internal memory
SMF or MMF optical input
Asynchronous detection mode (free-running)
Photoluminescence
Singlet oxygen measurement
Fluorescence, fluorescence life time
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
[email protected] com 2
Block Diagram
PRINCIPLE OF OPERATION
The id210 Advanced System for Single Photon Detection is built around the following blocks:
Trigger, Reset/Enable, Aux1 and Aux2 inputs blocks with SMA connectors on the id210 front panel.
Through the id210 user interface, each input can be set independently for receiving LVTTL-LVCMOS, NIM, NECL,
PECL3.3V or PECL5V signals. A VAR mode is also provided with a large input voltage range, an adjustable threshold
and slope/logic definition. AC/DC coupling selection is possible for the Trigger input. (see Inputs Specifications on
page 6 for more details).
Clock, Gate, Detection1 and Detection2 outputs blocks with SMA connectors on the id210 front panel.
Through the id210 user interface, each output can be set independently for providing LVTTL-LVCMOS, NIM, NECL,
PECL3.3V or PECL5V signals. The user can also switch to VAR mode in which the pulse width, the logic definition, the
high and low signal levels and the load can be adjusted. (see Outputs Specifications on page 6 for more details).
an avalanche photodiode and associated electronics.The key component at the heart of the id210 is a
cooled InGaAs fiber-coupled avalanche photodiode (APD). The fiber (single mode or multi-mode) is connectorized to a
FC/PC connector on the id210 front panel. The APD terminals are connected to:
- a DC high voltage controlled by the system to reach the efficiency set through the id210 interface,
- a Pulser Electronics that produces constant amplitude pulses for operation in single photon regime.
BLOCK DIAGRAM
Detection 1 Output
High LevelDetection1
50W
Low LevelDetection1
Buffer Detection 1
LogicDetection1
WidthDetection1
Trigger Input Relay
Trigger
PolarizationTrigger
Comp.Trigger
50W
ThresholdTrigger
Slope/LogicTrigger
Pulse ShapingTrigger
CouplingTrigger
Reset/Enable Input
RelayReset/Enable
PolarizationReset/Enable
Comp.R/E
50W
ThresholdReset/Enable
Slope/LogicReset/Enable
Pulse IDReset
Detection 2 Output
High LevelDetection2
50W
Low LevelDetection2
Buffer Detection2
LogicDetection2
WidthDetection2
Gate Output
High LevelGate
50W
Low LevelGate
Buffer Gate
LogicGate
Clock Output
High LevelClock
50W
Low LevelClock
Buffer Clock
LogicClock
Internal Clock Generator
TriggerDelay
GateWidth
PulserElectronics
CaptureElectronics
APD bias control
QuenchingElectronicsAPD
DeadTime
HF ClockCounter
Mode
Pulse ID Mode
DC High / Free-runningDC Low / Disabled
Efficiency
Mode
Load
Load
Load
Load
Aux1 Input Relay
Aux1
PolarizationAux1
Comp.Aux1
50W
ThresholdAux1
Slope/LogicAux1
Pulse ShapingAux1&Aux2
HF CounterAux1
Aux2 Input Relay
Aux2
Comp.Aux2
50W
ThresholdAux2
Slope/LogicAux2
Pulse ShapingAux2
HF CounterAux2
HF CounterAux1&Aux2
Pulse ShapingAux1
PolarizationAux2
HF GateCounter
Frequency
Optical Input
HF DetectionCounter
Aux2 input block
Aux1 input block
Reset/Enable input block
Trigger input block
Detection 2 output block
Detection 1 output block
Gate output block
Clock output block
2-channel event counter / coincidence counter cooled APD & associated electronic
InternalReset
InternalReset
InternalReset
InternalReset
InternalReset
InternalReset
HF CounterDetection
Reset
HF CounterDetection
Reset
System hardware
Mode
Cooled
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
[email protected] com 3
The Capture Electronics detects the avalanche events (resulting from photon absorption or dark generation) and feeds
the Detection 1&2 outputs blocks and the HF (high frequency) detection counter. The Quenching Electronics inhibits
the pulser until avalanche quenching.
the System hardware
The system hardware allows the id210 operation in internal gated, external gated, modes.free-running or free-gating
Internal gated mode
Clock Output
Gate Output
Trigger Delay
Gate Width
Width Detection 1&2
blanked gate
Quenching
Detection 1&2 Outputs
HF Gate Counter
HF Detection Counter
HF Clock Counter
Dead Time
+1 +1 +1 +1
+1 +1 +1
+1
1/Internal Gating Frequency
External gated mode
HF Gate Counter
HF Detection Counter
HF Clock Counter
Gate Output
Trigger Delay
Gate Width
Width Detection 1&2
+1 +1 +1
Dead Time
+1 +1
+1
Trigger Input
+1
+1
blanked gate
Quenching
Detection 1&2 Outputs
Internal-gating mode:
The APD is biased above breakdown during gates of adjustable Width and Frequency. Internal gating is a synchronous
mode based on a clock provided by the internal clock generator. The 50% duty cycle clock signal is available at the
Clock Output and counted by the HF Clock Counter. A user-adjustable Trigger Delay can be set between the Clock and
the Gate signals. A gate of Width set by user is open on the rising edge of the delayed trigger. As consequence of an
avalanche event within the gate, the HF Detection Counter is incremented and a pulse of adjustable Width is outputted
at Detection1 and Detection2 connectors. The Quenching Electronics closes the gate and, if selected by the user, a
Dead Time is applied resulting in one or several blanked pulses after a detection.
The HF Gate Counter provides an exact count of the effective gates seen by the APD.
External-gating mode:
The operation in external gating mode is very similar to the internal gating mode except that the clock is provided by the
user at the Trigger input.
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
[email protected] com 4
QuenchingQuenching
Gate Output
Detection 1&2 OutputsWidth Detection 1&2
Dead Time
HF Gate Counter +1 +1
HF Detection Counter +1 +1 +1
Quenching
+1
Free-running mode (asynchronous)
Free-gating mode
Dead Time
Gate Output
+1
+1
Reset/Enable Input
gate partially blanked
+1 +1 +1
+1 +1
HF Gate Counter
HF Detection Counter
Quenching Quenching
Detection 1&2 OutputsWidth Detection 1&2
blanked gate
Quenching
Free-gating mode:
The user feeds an electrical signal at the Reset/Enable input. The signal, after transit in the input block, passes through
multiplexers and the Dead Time stage. When no avalanche occurs, the Gate Output that reflects the APD state (On/Off)
is identical to the Reset/Enable input signal. When an avalanche occurs during a gate, a pulse of adjustable Width is
produced at Detection1 and Detection2 outputs, the Detection HF Counter is incremented and the Quenching
Electronics stops the gate. When a Dead Time is applied for limiting the afterpulsing, the Gate signal remains at low
level whatever the Reset/Enable state. This results in blanked gate(s) or partially blanked gates. The HF Gate Counter
provides the effective gates rate applied to the APD.
NEW
NEW
Free-running mode (asynchronous mode):
A DC control signal travels through multiplexers and the Dead Time stage and sets the Pulser Electronics to High. Until
photon absorption or dark count generation, the APD is biased above its breakdown voltage in Geiger mode. The Gate
Output that reflects the APD state (i.e. On:photosensitive or Off:blind) is at high level. When an avalanche takes place in
the APD, it is sensed by the Capture Electronics. A pulse of adjustable Width is produced on Detection1 and Detection2
outputs, the Detection HF Counter is incremented and the Quenching Electronics stops the avalanche. For limiting
afterpulsing, the APD is maintained below breakdown until the end of the Dead Time. In this mode, the HF Gate Counter
and HF Detection Counter rates are equal.
A two-channel event counter and a coincidence counter as an auxiliary independent block.
The signals outputted by Aux1 and Aux2
inputs blocks feed HF Counter Aux1 and HF
Counter Aux2 after pulse shaping. The block
also performs a logic AND of the two inputs
that feeds a coincidence counter: HF Counter
Aux1&Aux2.
Aux1 Input
Aux2 Input
HF Counter Aux1
Aux1&Aux2
HF Counter Aux1&Aux2
HF Counter Aux2
+1 +1 +1
+1
+1 +1 +1
+1
+1
+1 +1
+1
+1
+1+1
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
[email protected] com 5
Parameter Min Typical Max Units
Wavelength range 900 1700 nm
Optical fiber type SMF or MMF
Efficiency range (except free-running mode) 5 25 %
Efficiency range in free-running mode 2.5 10 %
Efficiency resolution (all modes) 2.5
Deadtime range 0.1 100 us
Deadtime step 100 ns
Timing resolution at max. efficiency (25%) 200 ps
External trigger frequency 100 MHz
Internal trigger frequency 1,2,5,10,20,50,100,200,500 kHz 1,2,5,10,20,50,100 MHz
Effective gate width range 0.5 25 ns
Gate width resolution 10 ps
Trigger delay range 20 ns
Trigger delay resolution 10 ps
Operating temperature +10 +30 °C
Dimensions LxWXH 387x256x167 mm
Weight 8.2 kg
Optical connector FC/PC
Power supply 110 230 VAC
Cooling time 7 min
InGaAs/InP APD Telcordia GR-468-CORE
SPECIFICATIONS
1 Calibrated at l=1550nm
10%
25%
900 1000 1100 1200 1300 1400 1500 1600 1700
0
5
10
15
20
25
30
Eff
icie
nc
y[%
]
Wavelength [nm]
1 Efficiency versus wavelength at 10% and 25% levels (l=1550nm)
Note that the effective gate width is evaluated by measuring the full width at h a l f - m a x i m u m o f t h e histogram of time interval
between the gate signal (start) and the detection signal (stop) in the dark. This provides a true evaluation of the dark count rate in contrast with dark count rate assessment based on the gate electrical signal. To take into account the electrical signal width always leads to a huge underestimation of the DCR.Please contact IDQ for more details about the assessment of the dark count rate in gated mode.
id210-SMF-A
id210-SMF-B
id210-SMF-C
id210-MMF
Model
1kHz
1kHz
6.5kHz
7.5kHz
2.5% efficiency
1.5kHz
1.5kHz
9kHz
10kHz
5% efficiency
2.2kHz
2.2kHz
11.5kHz
12.5kHz
7.5% efficiency
3kHz
3kHz
13.5kHz
14.5kHz
10% efficiency
Dark count rate (maximum values) in free-running mode with 50ms deadtime:
id210-SMF-A
id210-SMF-B
id210-SMF-C
id210-MMF
Model
0.4Hz
1Hz
6Hz
8Hz
2Hz
5Hz
30Hz
40Hz
0.4kHz
1kHz
6kHz
8kHz
2kHz
5kHz
30kHz
40kHz
Dark count rate for a 1ns effective gate width in gated mode:
Freq.=100kHz, no deadtime Freq.=100MHz, deadtime=10ms
10% efficiency 25% efficiency 10% efficiency 25% efficiency
IDQ´s SMF modules are available in three grades: Standard (C) and Ultra-Low Noise (B) and Ultra-Ultra Low Noise (A),
depending on dark count rate specifications.
1 1
2
2 A 20MHz trigger rate limited version is also available. The id210 can be later on remotely upgraded to 100MHz.
A version of the id210 without free-running mode is also available.
2
3
3
44
44
4
30% Quantum Efficiency at 1550 nm version available on request
(Dark Count Rate to be discussed)
Typ. Typ. Typ. Typ.Max. Max. Max. Max.
6.5kHz
6.5kHz
6.5kHz
7.5kHz
9kHz
9kHz
9kHz
10kHz
11.5kHz
11.5kHz
11.5kHz
12.5kHz
13.5kHz
13.5kHz
13.5kHz
14.5kHz
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
[email protected] com 6
Block Diagram
Parameter Min Typical Max Units
Frequency (Aux1, Aux2) 300 MHz
Frequency (Reset/Enable, Trigger) 100 MHz
Pulse duration 500 ps
Voltage range in VAR mode -2.5 +2.5 V
Impedance 50 W
Pulse amplitude +0.1 +5 V
Coupling (Trigger) DC or AC
Coupling (Aux1, Aux2, Reset/Enable) DC
Threshold voltage range in VAR mode -2.5 +2.5 V
Threshold voltage resolution in VAR mode +10 mV
Predefined standards LVTTL/LVCMOS -
Connectors SMA
Protection ESD
NIM - NECL - PECL3.3V - PECL5V
INPUTS SPECIFICATIONS
1
1
Parameter Min Typical Max Units
High level voltage range (high Z to ground) -2.0 +7.0 V
High level voltage range (50W to ground) -1.0 +3.5 V
Low level voltage range (high Z to ground) -3.0 +5.0 V
Low level voltage range (50W to ground) -1.5 +2.5 V
Voltage swing (high Z to ground) +0.1 +7.0 V
Voltage swing (50W to ground) +0.05 +3.5 V
Logic + or -
Short pulse width (Detection1, Detection2) 4.5 5 5.5 ns
Large pulse width (Detection1, Detection2) 90 100 110 ns
Rise/fall times at 5V swing (10%-90%) 2.5 ns
Predefined standards LVTTL/LVCMOS -
Connectors SMA
Protection ESD
NIM - NECL - PECL3.3V - PECL5V
OUTPUTS SPECIFICATIONS
For NECL, PECL3.3V and PECL5V, the id210 input
provides standard termination scheme (NECL: 50W to -2V,
PECL3.3V: 50W to +1.3V, PECL5V: 50W to +3V).
The Inputs parameters or Predefined Standards are
included in setup files that can be saved on internal memory.
2
1 Starting with a Predefined Standard, all the parameters
can be modified by the user.
The Outputs parameters or Predefined Standards are
included in setup files that can be saved on internal memory.
2
-1 0 + 1 + 2
0
+ 1
+ 2
+ 3
+ 4
+ 5
Max.
Low level [V]
Voltage swing [V]
50 W to ground
Min.
-2 -1 0 + 1 + 2 + 3
-1
0
+ 1
+ 2
+ 3
+ 4
Low level [V]
High level [V]
50 W to ground
-3 -2 -1 0 + 1 + 2 + 3 + 4 + 5
Low level [V]
High level [V]High Z to ground
-2
-1
0
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
-3 -2 -1 0 + 1 + 2 + 3 + 4 + 5
Max.
Low level [V]
Voltage swing [V]
High Z to ground
Min.
0
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+ 10
1 2 3 4
1
13
324
Minimum and maximum voltage swings
when the output is loaded at high impedance
to ground.
Low level and high level voltage ranges
when the output is loaded at high impedance
to ground.
Low level and high level voltage ranges
when the output is loaded at 50W to ground.
Minimum and maximum voltage swings
when the output is loaded at 50W to ground.
2
1 2
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
[email protected] com 7
All the user parameters are intuitively adjustable with direct access buttons (Detector, Inputs/Outputs, Display, System,
Setups and Acquisition), submenus control buttons and the control wheel on the id210 front panel.
The bicolor indicating LEDs associated to SMA connectors inputs or outputs provide relevant informations such as valid
triggers, pulses traffic at the outputs or unused inputs/outputs in the selected mode. Two USB connectors on the front
panel can be used for connecting a keyboard or for data export on a storage key. The backlight intensity is adjusted
automatically. The id210 is equipped with a buzzer that can be optionally used for indicating, for instance, the end of the
cooling phase. On the rear panel, Ethernet and USB connectors can be used for remote control. A VGA HD-15
connector for external monitor/projector is accessible as well on the rear panel.
The id210 contains 6 HF counters providing the Detection, Clock, Gate, Aux1, Aux2 and Aux1&Aux2 coincidence rates.
The id210 displays indicators associated to counters. Up to 5 different views can be set, saved and restored. A view
defines the number of indicators displayed simultaneously (selected between 1 and 4) and the counter associated to
each indicator.
USER INTERFACE - DATA & SETUP RECOVERY
Inputs
System Start/Stop
USB
Help
Setups
Display
Acquisition
Detector
Inputs/Outputs
Aux 1Power Aux 2 Trigger Reset/Enable Gate Detection 1 Detection 2
Outputs
Clock
id210 - Advanced System for Single Photon Detection
direct access buttons control wheel
help
access
start/stop
button
FC/PC
optical fiber
input
submenu control buttons
USB connectors
(keyboard, storage key)
Inputs/Outputs SMA connectors
and indicating LEDs
ON/OFF power button
with status LED
5.7" VGA TFT-LED color display optical window for automatic backlight intensity adjustement
REMOTE CONTROL (OPTIONAL)
A stand-alone application allowing you to control your
id210, to plot graphics and to export measurements of
counters remotely is delivered. No additional program is
necessary to drive the id210.
The remote control "id210 Front panel" application, built
using Labview, is delivered with its Labview Vi file - thus,
you can modify the remote control application if you own a
Labview license from National Instruments.
Additionally, a command reference guide is provided,
enabling you to write your own remote control application
in any programming language such as C or C++.
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
REDEFINING PRECISION
NEW! MMF input also available
id220-FRCOST-EFFECTIVE MODULE FOR SINGLE PHOTON DETECTION AT TELECOM WAVELENGTHS
ASYNCHRONOUS
1 s-25ms adjustable deadtimem
Quantum optics, quantum cryptography
Fiber optics characterization
Single-photon source characterization
APPLICATIONSKEY FEATURES
10%-15%-20% photon detection probability levels
Failure analysis of electronic circuits
Eye-safe Laser Ranging (LIDAR)
Spectroscopy, Raman spectroscopy
The id220-FR brings a major breakthrough for single photon detection in free-running mode at telecom
wavelengths. It provides a cost-effective solution for applications in which asynchronous photon detection
is essential. The cooled InGaAs/InP avalanche photodiode and associated electronics have been specially
designed for achieving low dark count and afterpulsing rates in free-running mode. The module can operate
at three detection probability levels of 10%, 15% and 20% with a deadtime that can be set between 1ms and
25ms. Arrival time of photons is reflected by a 100ns LVTTL pulse available at the SMA connector with a
timing resolution as low as 250ps at 20% efficiency. A simple USB interface allows the user to set the
efficiency level and the deadtime. A standard FC/PC connector followed by a single mode fiber is provided as
optical input. The id220-FR comes with a +12V 60W adapter .
SMF or MMF optical input
Asynchronous detection mode (free-running)
Photoluminescence
Singlet oxygen measurement
Fluorescence, fluorescence life time
Timing resolution as low as 250ps
Low dark and afterpulsing rates
100ns LVTTL output pulse at SMA connector
1
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
Parameter Min Typical Max Units
Wavelength range 900 1700 nm
Optical fiber type SMF or MMF
Efficiency range 10, 15 or 20 %
Dark count rate (10us deadtime)
SMF 10% 15% 20% efficiency 1 / 2.5 / 5 kHz
MMF 10% 15% 20% efficiency 1.2 / 3 / 6 kHz
Timing resolution (FWHM)
10% 15% 20% efficiency 400 / 300 / 250 ps
Deadtime range 1 25 ms
Deadtime step 1 ms
Detection output pulse LVTTL / 100ns width
Output connector SMA
Operating temperature +10 +30 °C
Dimensions LxWXH 230x110x120 mm
Weight 2.5 kg
Optical connector FC/PC
60W AC/DC +12V green power adapter
Input voltage 90~264 VAC - 135~370VDC
Frequency range 47~63 Hz
AC current 1.4A/115VAC 1A/230VAC
Cooling time 3 min
SPECIFICATIONS1 Calibrated at l=1.55 µm.
2
1
2
In contrast with usual gated operation of detectors based on InGaAs/InP avalanche photodiodes (APDs), the
id220-FR operates in free-running (asynchronous) mode. The APD is biased above its breakdown voltage in
the so-called Geiger mode. Upon photon absorption, the photon arrival time is reflected by the rising edge of
a 100ns width LVTTL pulse at the output.The id220-FR has been designed for providing a fast avalanche
quenching, thus limiting the afterpulsing rate. This allows the operation at reasonably short deadtimes of
values that can be optimized depending on the applications and the efficiency level.
Typical DCR versus Deadtime at 10%, 15% and
20% efficiencies.
Quenching
APD State
Detection Output100ns Detection
Output Pulse
Dead Time [1 to 25ms]
Quenching
Free-running mode (asynchronous)
ON
OFF
Avalanche
Detection Detection
100ns DetectionOutput Pulse
Dead Time [1 to 25ms]
Photonarrival
No detection !Detector is OFF
Time [0 to s]¥
2
Single Mode Fibre SMF28, Numerical Aperture = 0.14 orMulti Mode Fibre with a 62.5um core diameter, Numerical Aperture = 0.275
SMA Female connector: Male body (outside threads) with female inner hole.
3
3
4
4
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
SOFTWARE
The id220-FR comes with a software that allows the user to set the efficiency level and the deadtime through a simple USB interface. The module can also operate disconnected from the PC. The settings are reloaded upon each power up.
3
IDQ provides as an option a pulse shaper (A-PPI-D) which can be used with devices requiring negative input pulses. The leading edge of the id220 output pulse is converted into a sharp negative pulse with typical amplitudes of 1.4V for a 50W load and 2.5V for a high impedance load. The pulse shaper comes with two SMA/BNC adapters.
Ordering information: idacc-A-PPI-D Pulse shaper
Typical output pulse of an id220 equipped with a A-PPI-D pulse shaper in 50W load.
Typical output pulse of an id220 equipped with a A-PPI-D pulse shaper in high impedance load.
ACCESSORY - OPTIONAL PULSE SHAPER
ACCESSORY - OPTIONAL SMA ELECTRICAL CABLE
To connect your id220 to other devices, such as the pulse shaper (A-PPI-D) or certain acquisition card (SPC-130 from Becker & Hickl), IDQ recommends this SMA Male / SMA Male Cable. SMA Male means Female body (inside threads) with male inner pin (see picture)
Ordering information: idacc-SMA-SMA-1m SMA Male to SMA Male electrical Cable
ACCESSORY - METALLIC OPTICAL FIBRE
The standard optical patchcord can be transparent. Unwanted photons from the ambient environment can pass by the cladding of the fiber and so perturbate your measurement. The metallic jacket fiber is delivered with FC/PC connectors
Ordering information: idacc-SMF-Steel-2m SMF28 fiber and length 2m.idacc-MMF-Steel-2m core diameter 62.5um and length 2m.
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
PRELI
MIN
ARY
INFRARED SINGLE-PHOTON COUNTER
ID230 FREE-RUNNING InGaAs/InP PHOTON COUNTER WITH 50Hz DARK COUNT RATE AT 10% QUANTUM EFFICIENCY
The ID230 is a major breakthrough for single
photon detection in free-running mode at telecom
wavelengths. Based on the existing ID220, this
new series offers a significantly decreased dark
count rate thanks to an improved cooling system
and adapted electronics. The avalanche
photodiode working in Geiger mode is cooled down
to -100°C. This series has been especially
designed for applications in which asynchronous
photon detection is essential. The module can
operate at detection probability levels of up to 25%,
with a deadtime that can be set between 1ms and
100ms. The photon arrival time is reflected by a
100ns LVTTL pulse, with a timing resolution of
KEY FEATURES
¡¡¡
¡¡¡¡¡
900-1700nm
Asynchronous detection (free-running)
Best-in-class dark count rate < 50Hz at 10% quantum efficiency < 200Hz at 20% quantum efficiency
Adjustable quantum efficiency up to 25%
Adjustable deadtime from 1us to 100us
Adjustable temperature from -50°C to -100°C
Single mode fiber optical input
User-friendly and intuitive Labview interface
APPLICATIONS
¡¡¡¡¡¡¡¡¡
Quantum cryptography
Fiber optics characterization
Single-photon source characterization
Failure analysis of electronic circuits
Eye-safe Laser Ranging (LIDAR)
Spectroscopy, Raman spectroscopy
Singlet oxygen measurement
Photoluminescence
Fluorescence lifetime measurement
200ps at 25% efficiency. A simple USB interface allows the user to set the efficiency , the temperaure of the
avalanche photodiode and the deadtime. A standard FC/PC connector is provided as optical input.
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
PRELI
MIN
ARY
Best-in-Class Performance
INFRARED SINGLE-PHOTON COUNTER
SPECIFICATIONS
Parameter Min Typical Max Units
Wavelength range 900 1700 nm
Optical fiber type SMF
Efficiency range at 1550nm 0 25 %
Calibrated quantum efficiencies 8 values to be defined by the customer
Dark count rate @ -90°C
10% 50 Hz
20% 200 Hz
Afterpulsing probability with 20us deadtime (-90°C) 5 %
Deadtime range 1 100 us
Deadtime step 1 us
Detection output pulse LVTTL / 100ns width
Output connector SMA
Operating temperature +10 +30 °C
Dimensions LxWXH 400x300x300 mm
Weight 25 kg
Optical connector FC/PC
Power supply 550W AC/DC
Cooling time 15 min
2
1
Dark count rate vs efficiency2
In contrast to most detectors based on InGaAs/InP avalanche photodiodes (APDs), which operate in gated
mode, the ID230 operates in free-running (asynchronous) mode. The APD is biased above its breakdown
voltage, i.e. in Geiger mode. Upon photon absorption, the photon arrival time is reflected by the rising edge of
a 100ns width LVTTL pulse at the output of the detector. The ID230 has been designed to provide fast
avalanche quenching, thus limiting afterpulsing. This allows the operation at reasonably short deadtimes of
values that can be optimized depending on the applications and efficiency setting.
Quenching
APD State
Detection Output100ns Detection
Output Pulse
Dead Time [1 to 100ms]
Quenching
Free-running mode (asynchronous)
ON
OFF
Avalanche
Detection Detection
100ns DetectionOutput Pulse
Dead Time [1 to 100ms]
Photonarrival
No detection !Detector is OFF
Time [0 to s]¥
1 Quantum efficiency vs wavelength
10%
25%
900 1000 1100 1200 1300 1400 1500 1600 1700
0
5
10
15
20
25
30
Eff
icie
nc
y[%
]
Wavelength [nm]
SPAD2
Disclaimer - The information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2014 ID Quantique SA - All rights reserved - id230 v2014 09 10 - Specifications as of July 2014
2
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
PRELIMINARY
SUPERCONDUCTING NANOWIRE SINGLE-PHOTON DETECTOR
ID280 SUPERCONDUCTING NANOWIRE WITH 50% QUANTUM EFFICIENCY AND FASTEST ELECTRONICS
IDQ's ID280 series detection system consists of a
superconducting nanowire detector combined with
high performance electronics. With quantum
efficiencies higher than 50%, count rates of up to
20 MHz, dark counts <50 Hz (at 2.3K), jitter below
70ps and no afterpulsing, this system outperforms
all commercial single photon detectors in all
parameters.
Besides the nanowire and electronics, the ID280
comes with everything that is necessary to install it
in your own cryostat; including feed-throughs and
cryogenic cables and connectors.
ID280 detectors are designed and produced by
Shanghai Institute of Microsystem and Information
KEY FEATURES
¡¡¡¡¡¡¡¡
600-1700nm
Free-running mode
Best-in-class quantum efficiency: 50%
Low dark count rate (<100Hz)
20MHz maximum count rate
Stand alone software and Labview Vi
Not damaged by strong illumination
No afterpulsing
APPLICATIONS
¡¡¡¡¡¡¡¡
Quantum Key Distribution
Single-photon source characterization
Eye-safe Laser Ranging (LIDAR)
Singlet oxygen measurement
Photoluminescence
Fluorescence lifetime measurement
Fiber optics characterizazion
Failure analysis of electronics circuits
Technology (SIMIT, CAS), which take advantage of SIMIT's advanced superconductor electronics facilities.
ID280 detectors made of NbN or NbTiN ultrathin films achieve high performance at 2.3 K, a temperature
achievable in simple closed cycle refrigerators (not included).
The ID280 detector includes all necessary electronics: stable adjustable bias current source, amplification
stage, discriminator and counter. The device can be controlled through the included (.exe) software or
through the provided LabView VI.
POWERED BY
ID Quantique Geneva / Switzerland
T +41 22 301 83 71F +41 22 301 83 79
Best-in-Class Performance
SUPERCONDUCTING NANOWIRE SINGLE-PHOTON DETECTOR
Disclaimer - The information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2014 ID Quantique SA - All rights reserved -ID250 v2014 09 22 - Specifications as of September 2014
SPECIFICATIONS
Parameter Min Typical Max Units
Wavelength range 600 1700 nm
Optical fiber type SMF
Efficiency range at 1550nm 50 %
Dark count rate at 2.3K 100 Hz
Recovery time 70 ns
Count rate 20 Mhz
Timing resolution 70 ps
Pulse width 30 ns
Output connector SMA
Operating temperature 2.5 K
Dimensions of the package without fiber 13 x 20 x 25 mm
Optical connector FC/PC
21
Dark count rate vs efficiency21 Quantum efficiency vs wavelength
3
Recovery time3 Detector delivered with all electronics and software4
C u s to m i ze d SN SPD w i t h b e t t e r performances:
quantum efficiency > 70% at specific wavelength (600-1700nm)
dark count rate below 1Hz
¡
¡
IMPORTANT
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
REDEFINING PRECISION
SUB-NANOSECOND PULSED LASER SOURCE
id300 SERIES
Sub-nanosecond laser pulses
Repetition rate from 0 to 500MHz
Wavelength: 1310nm or 1550nm
(DWDM ls available upon request)
Compact and reliable stand-alone unit
Quantum optics
Fiber optics characterization
Optical measurements
APPLICATIONS
IDQ has been designed to meet the specific requirements
of researchers who need to generate short laser pulses at a wavelength of 1310nm or
1550nm.
The laser source, based on Fabry-Perot (FP) or on distributed-feedback (DFB) laser diodes,
is triggered externally via a trigger input to produce sub-nanosecond laser pulses with a
repetition rate ranging from 0 to 500MHz.
The id300 laser source is ideally suited to work in combination with IDQ’s Single Photon
Detection and Counting Modules (id210 series).
The laser source can be directly triggered by the id210's internal clock. Used in combination
with a variable optical attenuator, this short-pulse laser source makes an ideal cost-effective
single-photon source.
’s id300 Short-Pulse Laser Source
KEY FEATURES
External trigger
FC/PC connector
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
DisclaimerThe information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2006-2011 ID Quantique SA - All rights reserved - id300 v4.0 - Specifications as of March 2012
+10°C to +30°C
185 mm x 172 mm x 55 mm
915 g
FC-PC
BNC
SMF
100 - 240 VAC (autoselect)
Operating Temperature
Dimensions LxWxH
Weight
Optical Connector
Electronic Connector
Fiber Type
Power Supply
REDEFINING PRECISION
id300 SERIES
SPECIFICATIONS (T=25ºC)
OPERATING PRINCIPLE
ORDERING INFORMATION AND SALES CONTACT
GENERAL INFORMATION
Parameter Min Typical Max Units
Wavelength 1290 1310 1330 nm
Wavelength 1520 1550 1580 nm
Spectral width (FWHM) - FP laser type 7 15 nm
Spectral width (FWHM) - DFB laser type 0.6 1.5 nm
Frequency range 0 500 MHz
Pulse duration 0.3* 0.5 ns
Peak power 0.7 1 mW
Output power at 1MHz -36 -35 -34 dBm
Trigger input** NIM, ECL, PECL, LVPECL, TTL, TTL 50W
* can be increased up to 2ns upon request
** choose one trigger input from this list. See ordering information below.
1ms
Average power = -35 dBm
Peak power = 0 dBm
0.3ns
Electrical input: e.g. NIM signal (example: frequency = 1MHz)
Optical output:
Part number: id300-XXXX-YYY-ZZZ
XXXX: Select wavelength. Choose between 1310 and 1550.
YYY: Select laser type. Choose between FP (Fabry-Perot) and DFB (distributed
feedback).
ZZZ: Select trigger input signal specifications. Choose between NIM, ECL, PECL,
LVPECL, TTL, TTL 50W.
WARNING
CLASS 1 LASER PRODUCT
CLASSIFIED PER IEC 60825-1, Ed 1.2, 2001-08
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
IDQ's ID350 series consists of a packaged
Periodically Poled Lithium Niobate (PPLN) crystal
designed to generate photon pairs at telecom
wavelengths using spontaneous parametric down-
conversion (SPDC), where a single photon at
775nm generates a pair of photons at 1550nm.
The ID350 can also be used for Second Harmonic
Generation (SHG) or Sum Frequency Generation
(SFG). The crystal comes fiber-coupled to provide
minimal insertion losses. It contains an internal
temperature controller able to adjust wavelength
(phase matching) through a USB connection and
GUI software (Labview VI also delivered).
REDEFINING PRECISION
Photon Pair SourceID350-PPLN Periodically Poled Lithium Niobate
KEY FEATURES
¢
¢
Type 0 SPDC from 775nm to 1550nm or from
780nm to 1560nm (contact ID Quantique for
other wavelength options)
Temperature tuning range 5nm (e.g. SHG can
be obtained with 1550-1555nm pump)
¢
¢
¢
¢
¢
¢
¢
Total insertion Loss @ 1550nm: ~4 dB
SHG Conversion Efficiency: ~25%/W (1550 "
775nm)
SHG Sidelobe Suppression: <15% of peak
(1550 775nm)
Heralding efficiency: ~60% (775 " 1550nm)-7 SPDC Efficiency: ~10 (775 " 1550nm)
PPLN length: 35mm typ.
Bandwidth: ~0.04nm typ.
"
FUNCTIONALITIES
APPLICATIONS
¢
¢
¢
¢
¢
¢
¢
¢
¢
USB connection
GUI software included
Labview VI included
FC/PC connectors with1550nm SM fiber on
both ends standard (other on request)
Spontaneous down-conversion
Entangled photon source
Heralded photon source
Second Harmonic Generation
Sum Frequency Generation
NEW
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
2
SECOND HARMONIC GENERATION (SHG)OUTPUT AS A FUNCTION OF WAVELENGTH
Constructed from high quality PPLN gratings with sufficient length and built-in temperature stabilization, the device generates an output with a sharp main spectral peak and minimal side lobes.
PHOTON PAIR COUNT EXPERIMENT
λ /λ VS λ AT FIXED TEMPERATURE, I S PUMPTYPICAL SHAPE
λ /λ λI S PUMPVS TEMPERATURE AT FIXED , TYPICAL SHAPE
ORDERING INFORMATION
ID350-PPLN- 775-1550: Type 0 SPDC from 775nm to 1550nm with FC/PC connectors and 1550nm SM fiber on both ends ID350-PPLN-780-1560:Type 0 SPDC from 780nm to 1560nm with FC/PC connectors and 1550nm SM fiber on both ends
Supplied accessories: Power supply, USB cable, GUI software and Labview VI
Boston Electronics Corporation 91 Boylston Street, Brookline, Massachusetts 02445 USA (800)347-5445 or (617)566-3821 fax (617)731-0935
www.boselec.com [email protected]
Accessory 785 nm laser known to be suitable for use with the id350 Entangled Photon Source:
Thorlabs
Model#: LPS‐PM785‐FC ‐ 785 nm, 6.25 mW, PM Fiber Pigtailed Laser Diode FC/PC (cost ~ $822.80)
Model#: ITC4001 ‐ Benchtop Laser Diode/TEC Controller 1A/96W (cost ~ $2950)
Model#: LM9LP ‐ LD/TEC Mount for Thorlabs Fiber‐Pigtailed Laser Diodes (cost ~ $569.00)
Costs shown from Thorlabs website July 2014
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
REDEFINING PRECISION
id400 SERIESSINGLE-PHOTON DETECTOR FOR 1064NM
Adjustable detection probability up to 30%
Gated or free running modes
Internal or external gated modes
Adjustable gate width from 500ps to 2µs
Adjustable internal clock up to 4MHz
Adjustable delays up to 1µs by steps of 50ps
Free-space optical communications
Satellite laser ranging
Atmospheric research and meteorology
APPLICATIONSKEY FEATURES
Adjustable deadtime up to 100µs
Laser range finder
Free-space quantum cryptography
Quantum optics
The id400 single photon detection module consists of a detection head and a control unit.
The detection head is built around a cooled InGaAsP/InP avalanche photodiode (APD)
optimized for 1064nm single-photon detection and a fast sensing and quenching electronic
circuit. Single-photon detection efficiency can be adjusted at three preset levels and the
detector can be operated both in free running or gated modes.
The control unit performs APD temperature control and regulation, power supply, gate
generation and dead time setting. It also includes BNC connectors for input-output signals
and a USB interface. The detector is controlled using a LabVIEW virtual instrument, which
offers intuitive menus and a graphical interface.
The id400 includes invaluable functions, such as an adjustable deadtime or electronic delay
lines, which allow the optimization of its performance and make it a simple tool to use.
Internal counters
Spectroscopy
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
The id400 is a complete single photon counting system based on a cooled InGaAsP/InP avalanche photodiode
(APD) optimized for 1064nm. The APD temperature is set to -40°C upon assembly to optimize the id400 overall
performance. The id400 offers advanced functionalities, including:
Free-running, internal gating or external gating modes:
In free-running or asynchronous mode, the APD is biased above the breakdown voltage in the so-called
Geiger mode. Upon a photon arrival (or a dark count generation), an avalanche takes place in the APD. The
avalanche is sensed by the id400 and reflected at Detection OUT by the rising edge of a TTL pulse. The id400 pulser
provides a fast avalanche quenching required to limit the afterpulsing rate. The operating voltage is then restored at
the end of the dead time and the id400 is ready to detect a subsequent photon.
In gating or synchronous mode, a voltage pulse is applied to raise the bias above APD breakdown voltage
upon triggering. The gating can be either internal or external. The APD is only active during gates. The gating mode
is used in applications where the arrival time of the photon is known. It allows a reduction of the dark count rate.
Adjustable single photon detection probability level. In any avalanche photodiode, the single photon detection
probability increases with the excess bias voltage (difference between operating and breakdown voltages). The
timing resolution is also improved at high excess bias voltages. On the other hand, the dark count and afterpulsing
rates increase with the excess bias voltage. The id400 provides three levels of single photon detection probability
(7.5 %, 15% and 30%, measured at 1064nm).
Adjustable dead time. At high gating frequencies or when operated in free-running mode, afterpulsing may
significantly deteriorate performances. To suppress detrimental afterpulsing effects, the id400 includes a deadtime
(1µs to100µs by step of 1µs). In deadtime mode, the id400 monitors the effective gate rate.
Gate generator (for internal gating mode) with adjustable gate duration (500ps to 2µs by step of 10ps) and
frequency (1Hz to 4MHz).
Electronic delays (for internal gating mode) between Reference OUT(clock signal) and Gate OUT and between
Reference OUT(clock signal) and the actual detector gate for simple detector synchronization.
Internal counters, whose results are displayed on the Labview Virtual Instrument monitor detection and effective
gate rates. For each detection, the module also produces a TTL pulse available on the id400 control unit front panel
BNC connector.
All the user-adjustable parameters can be easily set using the Labview Virtual Instrument. They can also be stored
by the control unit for operation without PC.
PRINCIPLE OF OPERATION
Reference OUT
Gate OUT
Detection OUT
External Trigger IN
id400 control unitid400 detection head
APDTEC
Detection
Power/Control DB9 cable
Gate Command
Microcontroller
TemperatureControl
Det.Proba.7.5/15/30 %
USB
+12V
Modefree-runningint. gatingext. gating
Dead Time1/100usstep 1us
Gate Width500ps/2usstep 10ps
InternalGateFrequency
DelaysRef-Gate OUTRef-Actual Gate
FPGA
Pulser
Counter
BLOCK DIAGRAM
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
Parameter Conditions Min Typical Max Units Internal External Free
Gating Gating Running
Wavelength range 900 1150 nm
Effective optical diameter 80 µm
Single-photon detection probability (SPDE) 7.5, 15, 30 % üüü
Timing resolution at 7.5% SPDE ps üüü
Timing resolution at 15% SPDE ps üüü
Timing resolution at 30% SPDE ps üüü
Dark count rate at 7.5% SPDE with 20µs deadtime 150 Hz ü
Dark count rate at 15% SPDE with 20µs deadtime 400 Hz ü
Dark count rate at 30% SPDE with 20µs deadtime 2000 Hz ü
Adjustable deadtime range 1 100 µs üüü
Adjustable deadtime step 1 µs üüü6Internal gating frequency (f ) 1 4x10 Hz üint gating
Gate width (t ) 5 2000 ns ügate out
Gate adjustment step 10 ps ü
∆ adjustable delay range 0 ps ütref out/gate out
∆ adjustable delay range 0 ps ütref out/actual gate
Adjustable delay step 50 ps ü
Reference OUT pulse width 8 10 ns ü
Reference OUT pulse amplitude (50Ω) 2.3 3.3 V ü
Detection OUT pulse width 100 130 ns üü
Detection OUT pulse width 90 ns ü
Detection OUT pulse amplitude (50Ω) 2.3 3.3 V üüü
Gate OUT pulse amplitude (50Ω) 2.3 3.3 V ü ü
Trigger IN pulse width ns ü6Trigger IN frequency 1 4x10 Hz ü
∆ adjustable delay range 0 10 ns üext trigger/actual gate
Adjustable delay step 50 ps ü
External Trigger IN amplitude 1.6 3.8 V ü
External Trigger IN load 50 Ω ü
Cooling time at 25°C room temperature 5 min üüü
Electronic connectors BNC üüü
Detection head dimensions LxWxH 97x90x36 mm üüü
Control unit dimensions LxWxH 225x170x50 mm üüü
Detection head weight 290 g üüü
Control unit weight 1180 g üüü
Operating temperature 0 25 °C üüü
Storage temperature 0 40 °C üüü
üüü
üüü
SPECIFICATIONS
33 Maximum delay values versusinternal gating frequency
4 Maximum gate width versus internalgating frequency
1
2
5
6
7
Calibrated at 1064nm.
Contact IDQ for more information.
Uncertainty on internal frequency 2 8given by (f ) / 1.2x10 .int gating
For a frequency of 1MHz, uncertainty amounts to 8.333kHz.
In internal gating mode, output pulse width depends on photon arrival time, but is less than the gating period 1 / f .int gating
Duty cycle (t / t + t ) of external on on off
gating signal must be less than 70%.
1
2
2
2
3
6
4
3 4 5
7
7
3
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
LabVIEW APPLICATION
id100 Single photon counting module for the visible spectral range
id201 Single photon counting module for the 1100-1700nm spectral range
id300 Short pulse laser source
Quantis Quantum Random Number Generator2Clavis Quantum Key Distribution System for R&D
Cerberis Layer 2 encryptor with Quantum Key Distribution
Centauris Layer 2 encryptor
id400-80-1064 Detector module including:1 x APD detection head with mounting plate
(effective active diameter: 80µm)1 x Control Unit
ORDERING INFORMATION
OTHER PRODUCTS
SUPPLIED ACCESSORIES
Composite cable (2m): 2x BNC-SMB, 1x DB9-DB9
USB cable (4.5m)
Power supply (12V/2.5A)
CD-Rom with User Guide, LabVIEW Run-time
Engine Version 7.0, LabVIEW application installer
Acquisition mode: plot of the mean detector count rate over the specified integration time.
Standard mode: adjustment of parameters, display of count rate and effective gate rate.
Supported Operating Systems: Windows XP, Windows Vista 32 bits
The id400 detector comes with a id400.exe LabVIEW application operating in two different modes:
90.0
79.0
30.0
37.5
37.5
20.020.4 30.4
38.1
38.1
M4
AP
D
mounting plate
Ordering information and sales contact
97.0
63.5
AP
Dmounting plate
mounting plate
36.0
30.0
AP
Dmounting plate
APD
mounting plate
DB9 SMBSMB
DETECTION HEAD DIMENSIONAL OUTLINE (in mm)
The id400 detection head includes a
mounting plate with:
One M4 hole for mounting on
standard post assemblies,
4 holes (∅ 6.5mm) with “ ”
spacing (75mm and 50mm) for
mounting on standard plates or
translation stages,
4 holes with “ ” spacing (3 and 2
inches) for mounting on standard
plates or translation stages.
metric
US
DisclaimerThe information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2008-2010 ID Quantique SA - All rights reserved - id400 v3.2 - Specifications as of May 2010
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
NEW
REDEFINING PRECISION
8 CHANNEL TIME TO DIGITAL CONVERTER
id800-TDC
8 Channels
Easy to use control Software
High timing resolution with bin size
APPLICATIONS
IDQ
This system is used to transfer the time-tags of registered events with picosecond precision and at high rates
to a PC. Additionally, it can count single and multiple channel coincident events at even higher rates
internally and report the totals to a PC.
The id800-TDC registers incoming signal events on 8 independent channels, records their exact time (bin
size 81 ps) and channel number and broadcasts these to a PC. A graphical user interface is supplied for
Windows®, software examples are available for C and Labview™.
’s id800-TDC is an 8-channel time-to-digital converter, coincidence counter, and time interval analyzer.
KEY FEATURES
High event count rates up to 12.5 million
USB 2.0 Interface
Integrated coincidence counter
as low as 81 ps
events per second
Data transfer up to 2.5 million events per second
Time correlated single photon counting (TCSPC)
Fluorescence lifetime imaging
High energy physics
Fluorescence correlation spectroscopy
Single photon counting
Quantum cryptography
Precision time measurement
LIDAR
Correlation measurement
Quantum Optics
Optical measurements
Minimal time between two consecutive counts in the same channel is 5.5ns
1
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
2
Block Diagram
BLOCK DIAGRAM
The id800 contains an ASIC which time-tags events on 8 input channels and multiplexes them together. An FPGA takes these tags, sorts and compresses them for output. The FPGA also counts coincidences between channels, allowing accurate real-time reporting of coincidences at high signal rates.
PRINCIPLE OF OPERATION
APPLICATION #1: Time Interval Analyzer
The id800 is supplied with software for building histograms of time differences between time-tags. This is useful for analysing timing jitter or after-pulsing probabilities of detectors. For example, a function generator can be used to generate pulses from an id300 short-pulse laser source, which are then attenuated and detected by an id220 free-running single photon detection module. The time differences can be measured by the id800, and investigated with the id800's provided software. In this example, the start of the measurement is triggered with a pulse from the user. The id800 can also p e r f o r m c o n t i n u o u s t i m i n g measurements without requiring an external trigger.
SortingSignalComp-ression
Test Signal Generator
FPGAASIC
USB Output
Output is limited only by the speed of the USB 2.0 connection: up to 2.5 million events per second.
id300: laser
function generator
id220:SPDM id800:TDC
200 MHz 40 MHz 2.5 MEvents/s
Start
Stop
PC
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
3
APPLICATION #2: Coincidence Counter
The id800 can be used as a real-time coincidence counter. This mode of operation is especially useful in applications such as the optimization of coupling paired photons from a spontaneous parametric down-conversion (SPDC) source, where it is necessary to simultaneously optimize coupling of individual photons as well as the number of pairs.
Direct Measurement Indirect Measurement (Post-Processing)
Using a supplied LabView program, real-time plots of singles and coincidence rates can be generated, useful for real-time experiment optimization. Histograms and raw time-tags can also be displayed.
The supplied software can write time-tags to file, and from this file coincidences can be counted after detection.
INTERFACES WITH THE id800There are four provided ways of interfacing with the id800:
Graphical User Interface SoftwareCommand Line InterfaceLabView sub-VIs and sample programC user libraries
Laser BBO crystal
Detectors id800:TDCPC
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
4
REDEFINING PRECISION
id800-TDCSPECIFICATIONS
ORDERING INFORMATION
Part number: id800-TDC
DisclaimerThe information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2006-2012 ID Quantique SA - All rights reserved - id800 v20121105 - Specifications as of November 2012
id100 Single-photon detector for the visible spectral range
id101 Miniature single-photon detector for the visible spectral range (see above)
id110 Single-photon detection system for visible wavelength operating in gated mode
id150 Monolithic linear array of single-photon detectors for the visible range
id210 Single-photon detection system for telecom wavelengths
id220 Free-running single photon detection module - Near infrared range
id300 Short pulse laser source
id400 Single photon counting module for the 900-1150nm spectral range
Quantis Quantum Random Number Generator2Clavis Quantum Key Distribution System for R&D
Cerberis Layer 2 encryptor with Quantum Key Distribution
Centauris Layer 2 encryptor
Arcis Adjustable bandwidth encryptors which offer multi-layer (L3, L4) encryption
OTHER PRODUCTS
Parameter
Bin size, timing resolution 81 ps
Channels 8
Input Connectors BNC
Input levels LVTTL (5V tolerant)
PC Interface USB 2.0
Dimensions 25cm x 10cm x 30cm (width, height, depth)
Power supply 110 - 230 VAC
Maximum Count Rate, Total 12.5 Mhz
Data Transfer Rate 2.5 MHz
Minimum Pulse Interval 5.5 ns
Minimum Pulse Width 4 ns
Maximum Count Rate per Channel 10 MHz
IDQ Partner
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
REDEFINING RANDOMNESS
WHEN RANDOM NUMBERS CANNOT BE LEFT TO CHANCE
QUANTIS
Cryptography
Gambling, lotteries
Secure printing
PIN number generation
Mobile prepaid system
Statistical research
Numerical simulations
True quantum randomness
Certified by Swiss National Laboratory
High bit rate up to 16 Mbits/s
Low cost
Compact and reliable
Continuous status check
Easy integration in applications
APPLICATIONS MAIN FEATURES
PCI Express (PCIe)USB PCI
TRUE RANDOM NUMBER GENERATORBASED ON QUANTUM PHYSICS
Tested and certified by METASSwiss Federal Office of Metrology
METAS
Passes NIST and Diehard randomness tests
Although random numbers are required in many applications, their generation is often overlooked.
Being deterministic, computers are not capable of producing random numbers. A physical source of
randomness is necessary.
Quantum physics being intrinsically random, it is natural to exploit a quantum process for such a
source. Quantum random number generators have the advantage over conventional randomness
sources of being invulnerable to environmental perturbations and of allowing live status verification.
Quantis is a physical random number generator exploiting an elementary quantum optics process.
Photons - light particles - are sent one by one onto a semi-transparent mirror and detected. The
exclusive events (reflection - transmission) are associated to "0" - "1" bit values. The operation of
Quantis is continuously monitored. If a failure is detected the random bit stream is immediately
disabled.
Quantis is available as a PCI and PCI Express card, as well as a USB device and integrates easily
in existing applications. It is compatible with the most commonly used operating systems. A library
which allows easy access and a demonstration application are provided.
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
GENERAL SPECIFICATIONS
Random bit rate 4 Mbit/s ± 10% (Quantis-PCIe-4M)
REDEFINING RANDOMNESS
QUANTIS PCI CARD
GENERAL SPECIFICATIONS
Random bit rate
Thermal noise contribution
Storage temperature
Dimensions
PCI local bus specification
Requirements
4 Mbit/s ± 10% (Quantis-PCI-1)
16 Mbit/s ± 10% (Quantis-PCI-4)
< 1% (Fraction of random bits arising from thermal noise)
-25 to +85°C
167.6 mm x 106.7 mm
2.2
IBM-compatible PC with available PCI slot
167.6mm
106.7mm
167.6mm
106.7mm
Quantis-PCI-1 (4Mbits/s) Quantis-PCI-4 (16Mbits/s)
QUANTIS PCI EXPRESS (PCIe) CARD
Thermal noise contribution
Storage temperature
Dimensions
PCI Express specification
Requirements
< 1% (Fraction of random bits arising from thermal noise)
-25 to +85°C
120 mm x 64.4 mm
PCI Express Base 1.0a compliant
IBM-compatible PC with available PCI Express slot
120.0mm
64.4mm
(supplied with low profile and standard height brackets)
Quantis-PCIe-4M (4Mbits/s) Quantis-PCIe-4M (4Mbits/s)
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
REDEFINING RANDOMNESS
QUANTIS USB DEVICE
GENERAL SPECIFICATIONS
Random bit rate
Thermal noise contribution
Storage temperature
Dimensions
USB specification Requirements Power
4 Mbit/s ± 10% (Quantis-USB-4M)
< 1% (Fraction of random bits arising from thermal noise)
-25 to +85°C
61mm x 31mm x 114mm
2.0IBM-compatible PC with available USB connectorvia USB port
61.0mm
114.0mm
61.0mm
31.0mm
Quantum RandomNumber Generator
QuantisTM
www.idquantique.comSerial n°: 090615A410
Model n°: Quantis USB
Made in Switzerland
Quantis software (drivers, Quantis library and application) available for the following operating systems:
Notes:1 : Quantis-PCI-1, Quantis-PCI-42 : Quantis-PCIe-4M3 : Quantis-USB-4M4 : FreeBSD support for PCI/PCIe from FreeBSD 7.05 : FreeBSD support for USB from FreeBSD 8.1 6 : Available subsequently. Contact IDQ for more
information
SUPPORTED OPERATING SYSTEMS RANDOMNESS CERTIFICATION
1 2 3PCI / PCIe USB
Windows XP (32-bit)
Windows XP (64-bit)
Windows Server 2003 (32-bit)
Windows Vista (32-, 64-bit)
Windows Server 2008 (32-, 64-bit)
Windows 7 (32-, 64-bit)
Linux 2.6 (32-, 64-bit)
Solaris / OpenSolaris
FreeBSD
NetBSD
OpenBSD
Max OS X
ü
üüüüüüüüüü
4 5üü
ü
üûû
6 6ûû
6 6ûû6 6ûû6û
Tested and certified by METASSwiss Federal Office of Metrology
METAS
ID Quantique SAChemin de la Marbrerie 3
1227 Carouge/GenevaSwitzerland
T +41 22 301 83 71F +41 22 301 83 79
DisclaimerThe information and specification set forth in this document are subject to change at any time by ID Quantique without prior notice. Copyright© 2006-2011 ID Quantique SA - All rights reserved - Quantis v4.1 - Specifications as of May 2011
Quantis-PCIe-4M PCI Express card with 1 module generating a random bit stream of 4 Mbits/s
Wrappers, allowing to access the Quantis library, as well as sample source code are provided for the following programming languages:
REDEFINING RANDOMNESS
SOFTWARE
ORDERING INFORMATION
Quantis-USB-4M
Quantis-PCI-1
Quantis-PCI-4
USB device with 1 module generating a random bit stream of 4 Mbits/s
PCI card with 1 module generating a random bit stream of 4 Mbits/s
PCI card with 4 modules generating a random bit stream of 16 Mbits/s
Quantis comes with a truly invaluable cross operating system application called EasyQuantis allowing to read random numbers, which can be stored in a file or displayed.Random number can be generated in the following formats:
The application including a scaling functionality and can be used to access multiple Quantis generators.
EasyQuantis Application
Quantis Library
Library Wrappers
C++
C#
Java
VB.NET
Binary
Integers
Floating point
The Quantis library can be used to access the Quantis Quantum Random NumberGenerator. The library API is identical for the PCI, PCIe and USB library and isavailable on all supported operating systems.The library offers the possiblity to produce random binary data, integers and floating point numbers. It
can be used to access multiple Quantis generators and includes advanced functionalities such as
random data scaling.
Quantis-OEM-4M OEM component generating a random stream of 4 Mbits/s
RELATED PRODUCTS
Page 2
Table of contents1. Introduction .............................................................................................................................................................. 3
2. Cryptography ............................................................................................................................................................. 3
Box 1: Quantum Random Number Generator (RNG) .............................................................................................. 4
3. Key Distribution ......................................................................................................................................................... 5
Box 2: One-way Functions ....................................................................................................................................... 5
4. Quantum Cryptography ............................................................................................................................................ 6
4.1. Principle.................................................................................................................................................................. 6
4.2 Quantum Communications ..................................................................................................................................... 6
4.3. Quantum Key Distribution Protocols ..................................................................................................................... 7
Box 3: The Polarization of Photons .......................................................................................................................... 7
4.4. Key Distillation ....................................................................................................................................................... 8
Box 4: Quantum Key Distribution Protocol ............................................................................................................. 8
Box 5: Rudimentary Privacy Amplification Protocol ................................................................................................ 9
4.5. Real World Quantum Key Distribution ................................................................................................................. 10
4.6. State-of-the-Art QKD ............................................................................................................................................ 11
4.7. Perspectives for Future Developments ................................................................................................................ 11
5. Conclusion ............................................................................................................................................................... 12
ID Quantique SA Tel: +41 (0)22 301 83 71
Ch. de la Marbrerie, 3 Fax: +41 (0)22 301 83 79
1227 Carouge www.idquantique.com
Switzerland [email protected]
Information in this document is subject to change without notice.
Copyright © 2012 ID Quantique SA. Printed in Switzerland.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means – electronic, mechanical,
photocopying, recording or otherwise – without the permission of ID Quantique.
Trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products. ID
Quantique SA disclaims any proprietary interest in the trademarks and trade names other than its own.
Page 3
1. Introduction
Classical physics is adequate for the description of
macroscopic objects. It applies to systems larger than
one micron (1 micron = 1 millionth of a meter). It was
developed gradually and was basically complete by the
end of the 19th
century.
At that time, the fact that classical physics did not
always provide an adequate description of physical
phenomena became clear. A radically new set of
theories - quantum physics - was then developed by
physicists such as Max Planck and Albert Einstein
during the first thirty years of the 20th
century.
Quantum physics describes the microscopic world
(molecules, atoms, elementary particles), while
classical physics remains accurate for macroscopic
objects. The predictions of quantum physics drastically
differ from those of classical physics. For example,
quantum physics features intrinsic randomness, while
classical physics is deterministic. It also imposes a
limitation on the accuracy of the measurements that
can be performed on a system (Heisenberg's
uncertainty principle).
Although quantum physics had a strong influence on
the technological development of the 20th
century – it
allowed for example the invention of the transistor or
the laser – its impact on the processing of information
has only been understood more recently. “Quantum
information processing” is a new and dynamic
research field at the crossroads of quantum physics
and computer science. It looks at the consequence of
encoding digital bits – the elementary units of
information – on quantum objects. Does it make a
difference if a bit is written on a piece of paper, stored
in an electronic chip, or encoded on a single electron?
Applying quantum physics to information processing
yields revolutionary properties and possibilities
without any equivalent in conventional information
theory. In order to emphasize this difference, in this
context a digital bit is called a quantum bit or a "qubit"
With the miniaturization of microprocessors, which
will reach the quantum limit in the next ten or so
years, this new field will gain in importance. Its
ultimate goal is the development of a fully quantum
computer, possessing massively parallel processing
capabilities.
Despite great progress in recent years this goal is still a
challenge. However the first applications of quantum
information processing have already been
commercialized by ID Quantique (IDQ). The first one,
the generation of random numbers, will only be briefly
mentioned in this paper. It exploits the fundamentally
random nature of quantum physics to produce high
quality random numbers. IDQ’s Quantis random
number generator was the first commercial product
based on this principle. It has been used in security,
online gaming and other applications since 2001.
The second application – the main focus of this paper
– is called quantum cryptography. It exploits
Heisenberg's uncertainty principle to allow two
remote parties to exchange a cryptographic key in a
provably secure manner.
2. Cryptography
Cryptography is the art of rendering information
exchanged between two parties unintelligible to any
unauthorized person. Although it is an old science, its
scope of applications remained mainly restricted to
military and diplomatic purposes until the
development of electronic and optical
telecommunications. In the past twenty-five years,
cryptography evolved out of its status of "classified"
science, and it is now increasingly mandated by
regulations governing data protection for commercial
and public institutions. Although confidentiality is the
traditional application of cryptography, it is also used
nowadays to achieve broader objectives, such as data
authentication, digital signatures and non-
repudiation1.
The way cryptography works is illustrated in Fig. 1.
Before transmitting sensitive information, the sender
1 For a comprehensive discussion of cryptography, refer to “Applied
Cryptography”, Bruce Schneier, Wiley. “The Codebook”, Simon
Singh, Fourth Estate, presents an excellent non-technical
introduction and historical perspective on cryptography.
Page 4
combines the plain text with a secret key, using some
encryption algorithm, to obtain the cipher text. This
scrambled message is then sent to the recipient who
reverses the process, recovering the plain text by
combining the cipher text with the secret key using
the decryption algorithm. An eavesdropper cannot
deduce the plain message from the scrambled one
without knowing the key. To illustrate this principle,
imagine that the sender puts his message in a safe and
locks it with a key. The recipient uses in turn a copy of
the key, which he must have in his possession, to
unlock the safe. The scheme relies on the fact that
both sender and receiver have symmetric keys, and
that these keys are known only to the authorized
persons (also referred to as secret or symmetric key
cryptography)
Figure 1: Principle of Cryptography
Numerous encryption algorithms exist. Their relative
strengths essentially depend on the length of the key
they use. The more bits the key contains, the better
the security. The DES algorithm – Data Encryption
Standard – played an important role in the security of
electronic communications. It was adopted as a
standard by the US federal administration in 1976. The
length of its keys is however only 56 bits. Nowadays
traditional DES can be cracked in a few hours. It has
been replaced by the Advanced Encryption Standard –
AES – which has a minimum key length of 128 bits2.
In addition to its length, the amount of information
encrypted with a given key also influences the
strength of the scheme. In general, the more often a
2 For recommendations on minimum key lengths and the longevity of
protection provided by each key scheme refer to
http://www.keylength.com/
key is changed, the better the security. In the very
special case where the key is as long as the plain text
and used only once – a “one-time pad” – it can be
proven that decryption is impossible and that the
scheme is absolutely secure.
In commercial applications the encryption algorithm is
normally public – with the effectiveness of the
encryption deriving from the fact that the key is
secret.
This means firstly, that the key generation process
must be appropriate, in the sense that it must not be
possible for a third party to guess or deduce it. Truly
random numbers must thus be used for the key. Box 1
describes a quantum random number generator.
Box 1: Quantum Random Number
Generator (RNG)
Classical physics is deterministic. If the state of a
system is known, physical laws can be used to
predict its evolution. On the contrary, the outcome
of certain phenomena is, according to quantum
physics, fundamentally random. One example is the
reflection or transmission of an elementary light
“particle” – a photon – on a semi-transparent
mirror. In such a case, the photon is transmitted or
reflected by the mirror with a probability of 50%. It
is thus impossible for an observer to predict the
outcome. Because of this intrinsic randomness, it is
natural to use this to generate strings of high-
quality random numbers. IDQ’s Quantis is a
quantum RNG exploiting this principle.
Page 5
Secondly, it must not be possible for a third party to
intercept the secret key during its exchange between the
sender and the recipient. This so-called “key distribution
problem” is absolutely central in cryptography.
3. Key Distribution
For years, it was believed that the only possibility to solve
the key distribution problem was to send some physical
medium – a disk for example – containing the key. In the
digital era, this requirement is clearly unpractical. In
addition it is impossible to check whether this medium
has been intercepted and its content copied.
In the late sixties and early seventies, researchers of the
British "Government Communication Headquarters"
(GCHQ) invented an algorithm to solve this key
distribution problem. To take an image, it is as if they
replaced the safe mentioned above by a padlock. Before
the communication, the intended recipient sends an open
padlock to the party who will be sending valuable
information. The recipient keeps the key to the padlock.
Before transmitting the information the sender closes the
padlock, thus protecting the data he sends. The recipient
is then the only person who can unlock the data with the
key he kept. “Public key cryptography” was born. This
invention however remained classified and was
independently rediscovered in the mid-seventies by
American researchers. Formally, these padlocks are
mathematical expressions of so-called “one-way
functions”, because they are easy to compute but difficult
to reverse (see Box 2). As public key cryptography
algorithms require complex calculations, they are slow.
For this reason they are not used to encrypt large amount
of data but instead to exchange short session keys for
secret-key algorithms such as AES.
In spite of the fact that it is extremely practical, the
exchange of keys using public key cryptography suffers
from two major flaws. First, it is vulnerable to
technological progress. Reversing a one-way function can
be done, provided one has sufficient computing power or
time available. The resources necessary to crack an
algorithm depend on the length of the key, which must
therefore be carefully selected.
In principle, an eavesdropper could indeed record
communications and wait until he can afford a computer
powerful enough to crack them. This assessment is
straightforward when the lifetime of the information is
one or two years, as in the case of credit card numbers,
but quite difficult when it spans a decade. In 1977, the
three inventors of RSA – the most common public key
cryptography algorithm – issued a challenge in an article
entitled “A new kind of cipher that would take million of
years to break”. The challenge was to crack a cipher
encrypted with a 428-bits key. They predicted at the time
that this would take 40 quadrillion years. However the
$100 prize was claimed in 1994 after 6 months of work by
a group of scientists using parallel computing over the
Internet, and the resulting solution “The magic words are
squeamish ossifrage” has gone down in the history of
cryptanalysis.
Other public-key cryptography schemes based on the
intractability of certain mathematical problems are now in
use, such as elliptic curve cryptography. For elliptic-curve-
based protocols, it is assumed that finding the discrete
logarithm of a random elliptic curve element with respect
to a publicly-known base point is infeasible. The
minimum recommended length for asymmetric keys
continues to grow in response to threats from
Box 2: One-way Functions
The most common example of a one-way function is
factorization. The RSA public key system is actually
based on this mathematical problem. It is relatively
easy to compute the product of two prime integers –
say for example 37 * 53 = 1961, because a practical
method exists. On the other hand, reversing this
calculation – finding the prime factors of 1961 – is
tedious and time-consuming, especially with key
lengths of 2048 or more bits. No efficient algorithm
for factorization has ever been disclosed. It is
important to stress however that there is no formal
proof that such an algorithm does not exist. It may
not have been discovered yet or… it may have been
kept secret.
Page 6
improvements in technology and increased computing
power.
In addition in 1994 there was an attack on another front -
Peter Shor, professor of Applied Mathematics at MIT,
proposed an algorithm for integer factorization which
would run on a quantum computer and allow to reverse
one-way functions - in other words to crack some versions
of public key cryptography. The development of the first
quantum computer will immediately make the exchange
of a key with current public key algorithms insecure.
The second major flaw with public key cryptography is
that it is vulnerable to progress in mathematics. In spite of
tremendous efforts, mathematicians have not yet been
able to prove that public key cryptography is secure. It has
not been possible to rule out the existence of algorithms
that allow the reversal of one-way functions. The
discovery of such an algorithm would make public key
cryptography insecure overnight. It is even more difficult
to assess the rate of theoretical progress than that of
technological advances. There are examples in the history
of mathematics where one person was able to solve a
problem, which kept other researchers busy for years or
decades. It is even possible that an algorithm for reversing
some one-way functions has already been discovered, but
kept secret. These threats simply mean that public key
cryptography cannot guarantee future-proof key
distribution.
4. Quantum Cryptography
4.1. Principle
Quantum cryptography solves the problem of key
distribution by allowing the exchange of a cryptographic
key between two remote parties with absolute security,
guaranteed by the fundamental laws of physics. This key
can then be used securely with conventional
cryptographic algorithms. The more correct name for
quantum cryptography is therefore Quantum key
Distribution.
The basic principle of quantum key distribution (QKD) is
quite straightforward. It exploits the fact that, according
to quantum physics, the mere fact of observing a
quantum object perturbs it in an irreparable way. For
example, when you read this white paper, the sheet of
paper must be illuminated. The impact of the light
particles will slightly heat it up and hence change it. This
effect is very small on a piece of paper, which is a
macroscopic object. However, the situation is radically
different with a microscopic object. If one encodes the
value of a digital bit on a single quantum object, its
interception will necessarily translate into a perturbation
because the eavesdropper is forced to observe it. This
perturbation causes errors in the sequence of bits
exchanged by the sender and recipient. By checking for
the presence of such errors, the two parties can verify
whether an eavesdropper was able to gain information
on their key. It is important to stress that since this
verification takes place after the exchange of bits, one
finds out a posteriori whether the communication was
intercepted or not. This is why the technology is used to
exchange a key and not valuable information. Once the
key exchange is validated, and the key is provably secure,
it can be used to encrypt data. Quantum physics allows
to formally prove that interception of the key without
perturbation is impossible.
4.2 Quantum Communications
What does it mean in practice to encode the value of a
digital bit on a quantum object? In telecommunication
networks, light is routinely used to exchange information.
For each bit of information, a pulse is emitted and sent
down an optical fiber – a thin fiber of glass used to carry
light signals – to the receiver, where it is registered and
transformed back into an electronic signal. These pulses
typically contain millions of particles of light, called
photons. In quantum key distribution the same approach
is followed with the difference that the pulses contain
only a single photon. A single photon represents a very
tiny amount of light (when reading this white paper your
eyes register billions of photons every second) and it
follows the laws of quantum physics. In particular, it
cannot be split into halves. This means that an
eavesdropper cannot take half of a photon to measure
the value of the bit it carries, while letting the other half
continue its course. If he wants to obtain the value of the
bit, he must observe the photon and will thus interrupt
the communication and reveal his presence. A better
Page 7
strategy is for the eavesdropper to detect the photon,
register the value of the bit and prepare a new photon
according to the obtained result to send it to the receiver.
In QKD the two legitimate parties cooperate to prevent
the eavesdropper from doing so, by forcing him to
introduce errors. Protocols have been devised to achieve
this goal.
4.3. Quantum Key Distribution
Protocols
Although several QKD protocols exist, only one
protocol will be discussed here to illustrate the
principle of quantum key distribution. The BB84
protocol was the first to be invented in 1984 by
Charles Bennett of IBM Research and Gilles Brassard
of the University of Montreal. It is still widely used and
has become a de facto standard.
An emitter and a receiver can implement it by
exchanging single-photons, whose polarization states
are used to encode bit values over an optical fiber
(refer to Box 3 for an explanation of polarization). This
fiber, and the transmission equipment, is called the
quantum channel. They use four different polarization
states and agree, for example, that a 0-bit value can
be encoded either as a horizontal state or a –45°
diagonal one (see Box 4). For a 1-bit value, they will
use either a vertical state or a +45° diagonal one.
Filters exist to distinguish horizontal states from
vertical ones. When passing through such a filter,
the course of a vertically polarized photon is
deflected to the right, while that of a horizontally
polarized photon is deflected to the left. In order
to distinguish between diagonally polarized
photons, one must rotate the filter by 45°.
If a photon is sent through a filter with the
incorrect orientation – diagonally polarized
photon through the non-rotated filter for
example – it will be randomly deflected in one of
the two directions. In this process, the photon
also undergoes a transformation of its
polarization state, so that it is impossible to know
its orientation before the filter.
Linear polarization states
Filters
50%
50%
Box 3: The Polarization of Photons The polarization of light is the direction of oscillation
of the electromagnetic field associated with its
wave. It is perpendicular to the direction of its
propagation. Linear polarization states can be
defined by the direction of oscillation of the field.
Horizontal and vertical orientations are examples of
linear polarization states.
Diagonal states (+ and – 45°) are also linear
polarization states. Linear states can point in any
direction. The polarization of a photon can be
prepared in any of these states.
Page 8
• For each bit, the emitter sends a photon whose
polarization is randomly selected among the four
states. He records the orientation in a list.
• The photon is sent along the quantum channel.
• For each incoming photon, the receiver randomly
chooses the orientation – horizontal or diagonal –
of a filter allowing to distinguish between two
polarization states. He records these orientations,
as well as the outcome of the detections – photon
deflected to the right or the left.
After the exchange of a large number of photons, the
receiver reveals the sequence of filter orientations he
has used, without disclosing the actual results of his
measurements. This information is exchanged over a
so-called classical channel, such as the internet or the
phone. The emitter uses this information to compare
the orientation of the photons he has sent with the
corresponding filter orientation. He announces to the
receiver in which cases the orientations where
compatible and in which they were not. The emitter
and the receiver now discard from their lists all the
bits corresponding to a photon for which the
orientations were not compatible. This phase is called
the sifting of the key. By doing so, they obtain a
sequence of bits which, in the absence of an
eavesdropper, is identical and is half the length of the
raw sequence. They can use it as a key.
It is thus sufficient for the emitter and the receiver to
check for the presence of errors in the sequence, by
comparing over the classical channel a sample of the
bits, to verify the integrity of the key. Note that the
bits revealed during this comparison are discarded as
they could have been intercepted by the
eavesdropper.
It is important to realize that the interception of the
communications over the classical channel by the
eavesdropper does not constitute a vulnerability, as
they take place after the transmission of the photons.
4.4. Key Distillation The description of the BB84 QKD protocol assumed
that the only source of errors in the sequence
exchanged by the emitter and the receiver was the
action of the eavesdropper. All practical QKD will
Box 4: Quantum Key Distribution Protocol
0 1 1 0 1 0 0 1Emitter bit value
Emitter photon source
Receiver filter orientation
1 0 1 0 0 1 1 0 Receiver bit value
Receiver photon detector
Sifted key - - 1 - 0 - 1 0
Page 9
however feature an intrinsic error rate caused by
component imperfections or environmental
perturbations of the quantum channel.
In order to avoid jeopardizing the security of the key,
these errors are all attributed to the eavesdropper. A
post processing phase, also known as key distillation,
is then performed. It takes place after the sifting of the
key and consists of two steps. The first step corrects all
the errors in the key, by using a classical error
correction protocol. This step also allows to precisely
estimate the actual error rate. With this error rate, it is
possible to accurately calculate the amount of
information the eavesdropper may have on the key.
The second step is called privacy amplification and
consists in compressing the key by an appropriate
factor to reduce the information of the eavesdropper.
A rudimentary privacy amplification protocol is
described in Box 5. The compression factor depends
on the error rate. The higher it is, the more
information an eavesdropper might have on the key
and the more it must be compressed to be secure. Fig.
2 schematically shows the impact of the sifting and
distillation steps on the key size. This procedure works
up to a maximum error rate. Above this threshold, the
eavesdropper can have too much information on the
sequence to allow the legitimate parties to produce a
key. Because of this, it is essential for a quantum
cryptography system to have an intrinsic error rate
that is well below this threshold – this can be achieved
through the system design and the choice of
components.
Figure 2: Impact of the sifting and distillation steps on the key size
Key distillation is then complemented by an
authentication step in order to prevent a “man in the
middle attack”. In this case the eavesdropper would
cut the communication channels and pretend to the
emitter that he is the receiver and vice versa.
Such an attack is prevented thanks to the use of a pre-
established secret key in the emitter and the receiver,
which is used to authenticate the communications on
the classical channel. This initial secret key serves only
to authenticate the first quantum cryptography
session. After each session, part of the key produced is
used to replace the previous authentication key.
Box 5: Rudimentary Privacy
Amplification Protocol
Let us consider a two-bit key shared by the emitter
and the receiver and let us assume that it is 01. Let us
further assume that the eavesdropper knows the first
bit of the key but not the second one: 0?.
The simplest privacy amplification protocol consists in
calculating the sum, without carry, of the two bits and
to use the resulting bit as the final key. The legitimate
users obtain 0 + 1 = 1. The eavesdropper does not
know the second bit. For him, this operation could be
either 0 + 0 = 0 or 0 + 1 = 1. He has no way to decide
which one is the correct one. Consequently, he does
not have any knowledge on the final key. There is a
cost. This privacy amplification protocol shortens the
key by 50%. In practice, more efficient protocols have
obviously been developed.
Page 10
4.5. Real World Quantum Key
Distribution The first experimental demonstration of quantum
cryptography took place in 1989 and was performed
by Bennett and Brassard. A key was exchanged over
30 cm of air. Although its practical interest was
certainly limited, this experiment proved that QKD was
possible and motivated other research groups to enter
the field. The first demonstration over optical fiber
took place in 1993 at the University of Geneva.
The performance of a QKD system is described by the
rate at which a key is exchanged over a certain
distance – or equivalently for a given loss budget.
When a photon propagates in an optical fiber, it has,
in spite of the high transparency of the glass used, a
certain probability of getting absorbed. If the distance
between the two QKD stations increases, the
probability that a given photon will reach the receiver
decreases. Imperfect single-photon source and
detectors further contribute to the reduction of the
number of photons detected by the receiver. The fact
that only a fraction of the photons reaches the
detectors does not however constitute a vulnerability,
as these do not contribute to the final key. It only
amounts to a reduction of the key exchange rate.
When the distance between the two stations
increases, two effects reinforce each other to reduce
the effective key exchange rate. First, the probability
that a given photon reaches the receiver decreases.
This effect causes a reduction of the raw exchange
rate. Second, the signal-to-noise ratio decreases – the
signal decreases with the detection probability, while
the noise probability remains constant – which means
that the error rate increases. A higher error rate
implies a more costly key distillation, in terms of the
number of bits consumed, and in turn a lower
effective key creation rate. Fig. 3 summarizes this
phenomenon.
Figure 3: Key creation rate as a function of distance.
Typical key exchange rates for existing QKD systems
range from hundreds of kilobits per second for short
distances to hundreds of bits per second for greater
distances. Since the bits exchanged by the QKD
systems are used for the creation of relatively short
encryption keys (128 or 256-bits), the bit exchange
rate is sufficient to create a regular refresh rate of
provably secret and absolutely random keys. Data is
then encrypted with these keys at transmission rates
up to 10Gbps.
The span of current QKD systems is limited by the
transparency of optical fibers and typically reaches
100 kilometers (60 miles). In conventional
telecommunications, one deals with this problem by
using optical repeaters. They are located
approximately every 80 kilometers (50 miles) to
amplify and regenerate the optical signal. In QKD it is
not possible to do this as repeaters would have the
same effect as an eavesdropper and corrupt the key
by introducing perturbations.
Note that if it were possible to use repeaters, an
eavesdropper could exploit them. The laws of
quantum physics forbid this. However it is possible to
set up a network of trusted QKD repeaters to increase
the distance3.
3 For reference to secure key agreements over trusted repeater QKD
networks see http://arxiv.org/pdf/0904.4072.pdf developed within
framework of SECOQC project www.secoqc.net/
Page 11
4.6. State-of-the-Art QKD In 2002, IDQ launched the first industrialised QKD
system called Clavis, designed for research and
development applications, and in 2008 the next-
generation Clavis24 was launched. Clavis2 uses a
proprietary auto-compensating optical platform,
which features outstanding stability and interference
contrast, guaranteeing low quantum bit error rate.
Secure key exchange becomes possible up to 100 km.
This optical platform is well documented in scientific
publications and has been extensively tested and
characterized. The Clavis2 system is the most flexible
product of its kind on the market. It consists of two
stations controlled by one or two external computers.
A comprehensive software suite implements
automated hardware operation and complete key
distillation. Two quantum cryptography protocols
(BB84 and SARG) are implemented. The exchanged
keys can be used in an encrypted file transfer
application, which allows secure communications
between two stations.
In 2007, IDQ launched Cerberis5, a QKD server
designed for commercial applications. This has been
deployed and extensively field tested since its
installation that same year for use in elections by the
government of Geneva, Switzerland6. In addition, the
robustness and reliability of IDQ’s QKD technology in a
real-time telecommunications network was
unequivocally proven in the Swissquantum project7.
This documents the longest ever uninterrupted
deployment of a QKD network, running from end
March 2009 until the project was dismantled in
January 2011.
The Cerberis QKD system provides fully automated,
provably secure key exchange for Layer 2 link
4 http://www.idquantique.com/scientific-instrumentation/clavis2-qkd-
platform.html 5 http://www.idquantique.com/network-encryption/cerberis-layer2-
encryption-and-qkd.html 6 http://www.idquantique.com/images/stories/PDF/cerberis-
encryptor/user-case-gva-gov.pdf 7 www.swissquantum.ch
encryptors over standard optical fibers in an existing
network. Future-proof confidentiality of the data is
guaranteed by the use of QKD.
Real-life implementations now reach up to distances
of 100 kilometers (60 miles) over a dedicated fiber.
QKD is primarily used to secure the critical backbone
or data recovery center links for financial institutions8,
large companies and defence & government
organizations. However it has also been deployed in
sporting events such as the 2010 South African World
Cup9.
IDQ’s Cerberis QKD server is also compatible with
wavelength division multiplexing (WDM). Quantum
keys can be multiplexed with data over a single fiber
for distances up to 30 km in Metropolitan Area
Networks (MAN). In addition, in 2011 IDQ and Colt
launched the world’s first QKD-as-a-Service10
for
enterprises and financial institutions.
4.7. Perspectives for Future
Developments Future developments in QKD will certainly focus on
increasing the range of the systems. The first option is
to get rid of the optical fiber. It is possible to exchange
a key using quantum cryptography between a
terrestrial station and a low orbit satellite (absorption
in the atmosphere takes place mainly over the first
few kilometers. It can be low, if an adequate
wavelength is selected and…if the weather is clear.)
Such a satellite moves with respect to the earth’s
surface. When passing over a second station, located
thousands of kilometers away from the first one, it can
retransmit the key. The satellite is implicitly
considered as a secure intermediary station. This
technology is less mature than that based on optical
fibers. Research groups have already performed
8 http://www.idquantique.com/images/stories/PDF/cerberis-
encryptor/user-case-drc.pdf 9 http://www.idquantique.com/news/press-release-worldcup.html
10 http://www.idquantique.com/images/stories/PDF/cerberis-
encryptor/user-case-colt-qaas.pdf
Page 12
preliminary tests of such a system, but an actual key
exchange with a satellite remains to be demonstrated.
There are also several theoretical proposals for
building quantum repeaters11
. They would relay
quantum bits without measuring and thus perturbing
them. They could, in principle, be used to extend the
key exchange range over arbitrarily long distances. In
practice, such quantum repeaters do not exist yet
although they are the subject of intensive research.
It is interesting to note that a quantum repeater is a
rudimentary quantum computer. At the same time as
making current public key cryptography obsolete, the
development of quantum computers will also allow
the implementation of quantum cryptography over
transcontinental distances.
5. Conclusion For the first time in history, the security of
cryptography is dependent neither on the computing
resources of the adversary nor on mathematical
progress. Quantum cryptography, and specifically
QKD, allows the exchange of encryption keys whose
secrecy is future-proof and guaranteed by the laws of
quantum physics. Its combination with conventional
secret-key cryptographic algorithms raises the
confidentiality of data transmissions to an
unprecedented level. Despite being written in 2003,
the MIT Technology Review and Newsweek magazine
were prescient when they identified quantum
cryptography as one of the “ten technologies that will
change the world”.
11 For more information on quantum repeaters see
http://quantumrepeaters.eu/index.php/qcomm/quantum-repeaters