time walk compensation of a spad with a linear photodetection · 2002-10-30 · etienne samain...
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Time walk compensation of a SPADwith a linear photodetection
Etienne SAMAINRobert Dalla
Observatoire de la Côte d’Azur - CERGA France
Ivan Prochazka
Czech Techinal University Czech Republic
Specifications
Multi-photons mode with a dynamic of 104
Time stability below 1 ps over 1000 s
Precision better than 20 ps rms
Insensitive to the laser pulse width (20 - 200 ps)
Asynchronous detection mode
Silicon Sensor ADH230 SPADTime walk and precision
-600
-500
-400
-300
-200
-100
0
0.01 0.1 1 10 100 1000 10000 100000
N & <N>
Tim
e W
alk
(ps)
0
5
10
15
20
25
30
35
40
45
Rm
s (p
s)
Time WalkDiode Rms = f(<N>)Statistic RmsDiode Rms = f(N)
Photon statistic
( )LiniGei N,Npr
34,0
10lnN ⋅⋅
τ≈σ
LinGei Nr
r1N
−=
GeiN
LinN
iN
( ) linlinilin
i
NNNNNlini r)r1(CN,Np −−=
Photon statistic
Time walk : 100 ps/decader = 0.5
0
5
10
15
20
25
30
35
40
45
1 10 100 1000 10000 100000
Photon number Ni
Rm
s(p
s)
Statistic RmsDiode Rms = f(N)
Synoptic of T2L2 Space detection
Synoptic of Ground detection
Space segment prototype
Linear Photodetection
Avalanche photodiode in GainMode (RCA 902S)
Low noise integrator amplifier
Min threshold level < 100 hυ e-
Dynamic: 1040
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 5 10 15 20 25 30 35 40 45t (ns)
Am
plit
ud
e (V
)
Analog to digital converter
Resolution: 16 bits
Input bandwidth: 200 MHz
Linearity error: 1.3 bits rms
Precision: 1.3 bits rms-20
-15
-10
-5
0
5
10
15
20
-2 -1 0 1 2Input (Volts)
Lin
eari
ty (
bit
s)
Non linear photodetectionSPAD: Silicon Sensor AD230
0
20
40
60
80
100
120
140
0 200 400 600 800 1000t (ps)
Co
un
ts
SSOAD230 N°7Rms: 39 ps rms532 nm FWHM: 20 ps<N> = 0.08 hv
Precision and time walkOverall instrument
0
50
100
150
200
250
300
350
10 100 1000 10000 100000 1000000 10000000
< Photon number >
Tim
e w
alk
(ps)
.
0
2
4
6
8
10
12
14
16
Pre
cisi
on
rm
s (p
s)
.
Time walk
precision
Time stability @ 532 nm 10 HzOverall instrument
0.1
1
10
0.1 1 10 100 1000τ (s)
σx
(ps)
<N> = 1000 hvT0 = 0,1 s532 nm, FWHM = 20 ps
Time stability @ 778n nm 1 kHz Overall instrument
0.01
0.1
1
10
100
0.001 0.01 0.1 1 10 100τ (s)
σx
(ps)
<N> = 1000 hvT0 = 0,001 s778 nm, FWHM = 20 ps
SPAD K14 100 µmPrecision - Single photon mode
0
50
100
150
200
250
300
350
400
450
500
0 200 400 600 800 1000t (ps)
Co
un
ts
K14 100 µmRms: 21 ps rmsFWHM: 55ps532 nm FWHM: 20 ps<N> = 0.16 hv
0
40
80
120
160
200
240
-80 -60 -40 -20 0 20 40 60 80
Position (µm)
Tim
e w
alk/
rm
s (p
s)
0.01
0.1
1
Rel
ativ
e ef
fici
ency
Time walk
Rms
Relative Efficiency
SPAD K14 100 µmCenter-edge effect
SPAD K14 100 µmPrecision & TW - Multi photon mode
0
50
100
150
200
250
300
0 1 10 100 1000 10000 100000
< Photon number>
Tim
e w
alk
(ps)
0
5
10
15
20
25
30
Pre
cisi
on
rm
s (p
s)
Time walk
precision
Conclusions
Time walk compensatedPrecision: 15 - 3 ps over the whole dynamicTime stability better than 1 ps over 1000 s Insensitive to the laser pulse width (20 - 200 ps)Asynchronous detection mode
SPAD K14: the performances will be 2 times better
Chronograph
Light pulse
Linear photo detection
Integrator
Excess bias voltage
Light pulse SPAD
Output signal