trends in future communicationsinternational workshop - renato rabelo

Trends in Future Communications

International WorkshopCPqD - Campinas

Renato Cunha Rabelo, PhD – IEAv-DCTA24/02/2014

Outline

• IEAv/DCTA

• Lithium Niobate Filters

IEAv

EAH ENU EFA EFO ESTEGI

IEAv

EAH ENU EFA EFO ESTEGI

Institute for Advanced Studies

IEAv

EAH ENU EFA EFO ESTEGI

Institute for Advanced Studies

Mission: Build scientific knowledge and develop strategic technology capableof strengthening Brazilian aerospace competence.

IEAv

EAH ENU EFA EFO ESTEGI

Photonics Division

IEAv

EAH ENU EFA EFO ESTEGI

Photonics Division

Generate, control and detect light

IEAv

EAH ENU EFA EFO ESTEGI

EFO-LEFO-SEFO-O

PhDs Masters Graduates Technicians

EFO-L 07 03 03 04

EFO-O  04 02 0 03

EFO-S  05  05  0  03

Total EFO  17  10  03  10

MANPOWER

40

Collaborators

Postdocs MSc / PhD Students

Graduates / MSc

Students

UndergradStudents

EFO-L 01 10 04 06

EFO-O  1 0 0 10

EFO-S  02 0  2  02

Total EFO  04  10  06  1838

Spectral Slicing Filters in Titanium Diffused Lithium Niobate (Ti:LiNbO3)

Waveguides

WDMFiber Optic Communication link

1ReceiverTransmitter1

Optical Fiber

Transmitter2

Transmittern-1

Transmittern

2Receiver

n-1Receiver

nReceiver

. .

. . .

.

MU

XD

EM

UX

DWDM Channels

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0+6-6 -5 -4 -3 -2 -1 +10 +3+2 +5+4

Am

plitu

de (

a.u.

)

Normalized Frequency (-0) X 100 GHz)

TE-TM Mode Conversion:

LiNbO3

Ti diffused Waveguide

x y

z

TE

TM

L

SiO2 Strain inducing grating

TE-TM Mode Conversion:

unconvconv

conv

PP

PPCE

)0(

)0(

sin2

cossin

sinsin2

cos

)(

)(

2/2/

2/2/

B

A

yjyeyje

yjeyjye

yB

yA

yjyj

yjyj

)()(0

0 TMTETMTE nnnnv

c

0

2)(2

c

nnv TMTE

2)(2

c

nnv TMTE

)0(

)0(

cossin

sincos

)(

)(

B

A

LLj

LjL

LB

LA

LL

L

22

2

cossin

sin

L2sin

TE-TM Mode Conversion:

-12 -8 -4 0 4 8 120.0

0.2

0.4

0.6

0.8

1.0P

ola

riza

tion

Co

nve

rsio

n E

ffici

en

cy

Normalized Frequency (() x 100 GHz)

Fabrication Steps

Titanium Deposition(DC sputtering)

LiNbO3

Ti t Patterning(Photolithography)

DiffusionLiNbO3

Ti t

LiNbO3

Ti

LiNbO3

Heatand Time

LiNbO3

SiO2

Silica Deposition(E-beam evaporation)

@ High Temp

Cool-down toRoom Temp.LiNbO3

SiO2

Surface Strainbuild-up

SiO2 < LiNbO3

Patterning(Photolithography)LiNbO3

SiO2

(Side view) LiNbO3

SiO2SiO2SiO2SiO2 SiO2 SiO2

Conversion EfficiencyTest Setup

Er+ doped fiber

Laser DiodePump @ 980 nm

OSA

Sample under test

Objective

WDM 980/1550coupler

PZ fiber

Objective

Polarizer

Amplified Spontaneous Emission light source

Isolator

Conversion EfficiencyTest Setup

Conversion EfficiencyTest Results (Uniform Grating)

TM TM

TM TE

TE TE

TE TM

Conversion EfficiencyTest Results (Uniform Grating)

22

2

)()(

)(

zBzA

zB

utputr at the oTotal powe

ion power polarizat ConvertedPCE

1528 1530 1532 1534 1536 1538 15400.0

0.2

0.4

0.6

0.8

1.0

W/G 5 - Linear ScaleRoom Temperature500 elements

TE input/TM output TM input/TE output Theoretical Response

Pol

ariz

atio

n C

onve

rsio

n E

ffici

ency

Wavelength (nm)

Conversion Efficiency = 99.8%

@ 1533 nm

Device Fabrication

Conversion Efficiency

•Coupling coefficient had to be adjusted

dxdzEE TMpert

TE

Critical Parameters:1. Titanium film thickness Mode Profiles2. Titanium in-diffusion time and temperature Mode Profiles3. SiO2 strain film thickness and deposition temperature Strain field

Conversion Mechanism (index modulation) Static strain-optic (elastooptic) effect

Conversion EfficiencyUniform Grating ( 500 spatial periods)

• 1250 Å Ti film deposition• Photolithography to define Waveguides (Ti-strips)• 13 h diffusion @ 1035

oC and wet atmosphere

• 1.7 m SiO2 strain film deposited @ 389 oC

• Photolithography to define strain grating (500 periods) @ room temperature

After many trials:

Conversion EfficiencyTemperature Tuning (Uniform Grating)

1524 1526 1528 1530 1532 1534 1536 1538 1540 1542 1544 1546 15480.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

24.5 oC 22.5 oC 20.0 oC

17.7 oC 16.6 oC 15.2 oC

14.4 oC

Temperature tuning

Pol

ariz

atio

n C

onve

rison

Effi

cien

cy

Wavelength (nm)14 16 18 20 22 24 26

1528

1530

1532

1534

1536

1538

1540

1542

1544

Peak wavelengths vs Temperatureand

Linear Regression

d/dT = - 1.3419 nm / oC

Co

nve

rte

d P

ea

k w

ave

len

gth

(n

m)

Temperature (oC)

Sparse Grating:

L1L2 L3 L4 L5 L6

L L L LL LiNbO3

Ti diffused Waveguide

x y

z

Sparse Grating:Propagation Matrix

inTE

inTMLnn

cj

outTE

outTM

E

EeE

E gTEgTM

10

0

inTE

inTM

outTE

outTM

E

Ez

E

E

10

01

Combining Effects (Coupling and Propagation)

inTE

inTM

R

R

inTE

inTMnn

outTE

outTM

E

E

zAzjB

zjBzA

E

EPCPCPPCC

E

E

)()(

)()(121

c

nnLT gTMgTE )(

Tjez

Z Transform

s-plane

j

sTez

z-plane

)Re(z

1

)Im(z

s-plane

j

j

sTez

z-plane

)Re(z

1

)Im(z

Z Transform

n

ii zzzP

1

1)1()(

-1 -0.5 0 0.5 1

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Roots of B5(z)

Re(z)

Im(z

)

Filter Theoretical Frequency Response

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 70.0

0.2

0.4

0.6

0.8

1.0

Pol

ariz

atio

n C

onve

rsio

n E

ffici

ency

Normalized Frequency (-0) X 100 GHz)

FSR

DWDM Channels

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0+6-6 -5 -4 -3 -2 -1 +10 +3+2 +5+4

Am

plitu

de (

a.u.

)

Normalized Frequency (-0) X 100 GHz)

Filtered DWDM Channels

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 70.0

0.2

0.4

0.6

0.8

1.0-6 +60

Am

plitu

de (

a.u.

)

Normalized Frequency ((-0) X 100 GHz)

Filter Theoretical Frequency Response

-4 -3 -2 -1 0 1 2 3 40.0

0.2

0.4

0.6

0.8

1.0P

olar

izat

ion

Con

vers

ion

Effi

cien

cy

Normalized Frequency ((-v0)/FSR)

Electrooptically Tunable Sparse Grating Filter

L1 L2 L3 L4 L5 L6

L L L LL LiNbO3

Ti diffused Waveguide

x y

z

Electrodes

L1 L2 L3 L4 L5 L6

L L L LL LiNbO3

Ti diffused Waveguide

x y

z

L1 L2 L3 L4 L5 L6

L L L LL LiNbO3

Ti diffused Waveguide

x y

z

Electrodes

Device Fabrication / Electrodes

Fabrication StepsTitanium Deposition

(DC sputtering)

LiNbO3

Ti t Patterning(Litho and Etching)

DiffusionLiNbO3

Ti t

LiNbO3

Ti

LiNbO3

Heatand Time

LiNbO3

Photolithography(Image Reversal)

E-Beam3 metalsLiNbO3

Lift-OffLiNbO3

Silica Deposition(E-beam evaporation)

@ High Temp

Cool-down toRoom Temp.

Surface Strainbuild-up

SiO2 < LiNbO3

Patterning(Litho and Etching)LiNbO3

SiO2

LiNbO3

SiO2

LiNbO3

SiO2

Device Fabrication / Electrodes

(Side view) LiNbO3

SiO2

SiO2 SiO2 SiO2

Electrodes

Conversion EfficiencyTest Setup

Er+ doped fiber

Laser DiodePump @ 980 nm

OSA

Sample under test

Objective

WDM 980/1550coupler

PZ fiber

Objective

Polarizer

Amplified Spontaneous Emission light source

Isolator

Conversion EfficiencyTest Results (Sparse Grating)

TE TE

TE TM TM TE

TM TM

Conversion EfficiencyTest Results (Sparse Grating)

) 9.131( 044.13 GHznmdB

1515 1518 1521 1524 1527 1530 1533 1536 1539 1542-30

-28

-26

-24

-22

-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

TE input/TM output T= 25.0 oC

TM input/TE output Theoretical Response

Pol

ariz

atio

n C

onve

rsio

n E

ffici

ency

(dB

)

Wavelength (nm)

%96PCE

Test Results (Sparse Grating)Thermal Tuning

1515 1520 1525 1530 1535 1540 1545 1550 15550.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

14oC

25oC

Po

lari

zatio

n C

on

vers

ion

Effi

cie

ncy

Wavelength (nm)

12 14 16 18 20 22 24 26 28 301524

1526

1528

1530

1532

1534

1536

1538

1540

1542

TM to TE conversion TM to TE data linear regression TE to TM conversion TE to TM data linear regression

Ce

nte

r P

ea

k W

ave

len

gth

(n

m)

Temperature (oC)

CdTd onm/ 0.1

Test Results (Sparse Grating)Voltage Tuning

input) (TM nm/V 045.0dVd

1520 1530 15400.0

0.2

0.4

0.6

0.8

1.070 V

-70 V

Pol

ari

zatio

n C

on

vers

ion

Effi

cie

ncy

Wavelength (nm)

-80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80

1528

1529

1530

1531

1532

1533

1534

1535

1536

1537

TM input/TE output Linear fit TM input data TE input/TM output Linear fit TE input data

Wa

vele

ng

th (

nm

)

Applied Voltage (V)

input) (TE nm/V 039.0dVd99.4%91.7%

Polarization Independent Sparse Grating Filter

InputInput

No Output

...

...

2

2

......

......

2

2

InputInputOutput

2

Polarization Independent Sparse Grating Filter

Polarization Independent Sparse Grating

L1 L2 L3

L L L L L

L3 L2 L1

LiNbO32

L1 L2 L3

L L L L L

L3 L2 L1

LiNbO3

L1 L2 L3

L L L L L

L3 L2 L1

LiNbO32

Test Results - Polarization Independent Sparse Grating

Er+ doped fiberLaser DiodePump @ 980 nm

WDM 980/1550coupler

Er ASE light source

PZ fiberOpticalPowerMeter

Ge PhotodetectorSampleUnder Test

CurrentSource

Output Fiber

Isolator

Er+ doped fiberLaser DiodePump @ 980 nm

WDM 980/1550coupler

Er ASE light source

PZ fiberOpticalPowerMeter

Ge PhotodetectorSampleUnder Test

CurrentSource

Output Fiber

Isolator

Test Results - Polarization Independent Sparse Grating

Test Results - Polarization Independent Sparse Grating

1518 1521 1524 1527 1530 1533 1536 1539 1542-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

TM input TE input Theoretical Response

No

rma

lize

d O

utp

ut S

pe

ctru

m (

dB

)

Wavelength (nm)

Test Results - Polarization Independent Sparse GratingThermal Tuning

1515 1520 1525 1530 1535 1540 1545 1550 15550.0

0.2

0.4

0.6

0.8

1.0

TE input @ 14oC

TE input @ 27oC

No

rma

lize

d F

ilte

r R

esp

onse

Wavelength (nm)

10 12 14 16 18 20 22 24 26 28 301524

1526

1528

1530

1532

1534

1536

1538

1540

1542

1544 TM input Linear Fit of TM data TE input Linear Fit of TE data

Wav

elen

gth

(nm

)

Temperature (oC)

CdTd onm/ 0.1

Future Work

• 4-Port Asymmetric MZI

L1 L2 L3

L L L L L

L3 L2 L1

LiNbO32

L1 L2 L3

L L L L L

L3 L2 L1

LiNbO32

Future Work

• Generic “all-zero” synthesis

L1 L2 L3 L4 L5 L6

B C D EA LiNbO3

Ti diffused Waveguide

x y

z

Electrodes

L1 L2 L3 L4 L5 L6

B C D EA LiNbO3

Ti diffused Waveguide

x y

z

L1 L2 L3 L4 L5 L6

B C D EA LiNbO3

Ti diffused Waveguide

x y

z

Electrodes

Thank you !rcrabelo@ieav.cta.br