Hybrid Organic-Inorganic for Integrated Optics:

Electro-Optic Filters and Modulators

Support: NSF-STC CMDITR

Mahmoud FallahiCollege of Optical Sciences, Universit

y of Arizonafallahi@optics.arizona.edu

Group Research Activities

Semiconductor Lasers and Integrated Photonics

High Power SemiconductorLasers

Integrated Opticsand WDM

High Power Optically Pumped VECSEL

1300-1560 nmInGaAsP/InP

Sol-gel Integrated Optics

EO sol-gel/polymerSLM

High Power Tunable VECSEL and SHG

400 500 600 700 800 900 1000 1100-100

-80

-60

-40

-20Fundamental (~976 nm) and SHG (~488 nm)

Sp

ectr

um

(lo

g s

ca

le)

Wavelength (nm)

Fundamental~976nm SHG~488 nm (1.3 W)

EO Hybrids and Applications

Objective: Development of High-Speed, Low-Voltage, low-Cost Special Light Modulators, Tunable Filters and Switches arrays.

Applications:• Optical Communications and Network security• Optical Correlators and recognition system• Optical Cross-Bar Switching• Real-time beam steering• Holographic Data Storage• 3-D Imaging

Competing Technologies and our approach

• Liquid Crystal: Issues: Slow, retain image, variable contrast and sensitivity across device

• Semiconductor EA in MQW Stark effect: Fast, Issues: difficult to make in large array, poor contrast and high voltage, high loss

• Magneto-optic of Aluminum Garnet: Low efficiency, High powered drive current

• Deformable mirrors (MEMS): Expensive, non-flat, slow (ms)

• EO Polymers/Hybrids-based strtucture: Our approach

Combine high chromophores with Improved hybrid poling method

Polymers or hybrid organic-inorganic sol-gel as the host

Fabry-Perot Etalon with high finesse and sensitivity

Transparent electrodes inside the cavity for low voltage

2-D Pixelation of SLM

Hybrid Organically-Modified Sol-Gel

Sol-gel: Chemical route for production of glass material from Metallorganic precursor.Advantages:• Low Temperature Processing (<250 C)• Crack Free Thick Film Deposition • Refractive Index Tuning• Low Loss Waveguides• Photo-Patternable• High Tg and High Stability • Low Cost• Electro-Optic Components by Chromophore Doping

Sol-gel Synthesis of organoaluminosilicate

1.480

1.485

1.490

1.495

1.500

0 5 10 15 20 25

Molar Ratio Zr/Si, %

Re

fra

ctiv

e I

nd

ex

UV+HB(2 h)

H 2C= C(CH3)CO2(CH2 )3Si(OCH3 )3

+ 0.01M HCl (R=1) Stir 30

minStir 30 min Al(C

4H

9O)

3

H2O (R=2)Stir 30 min

StirAge 24 hrs

C10H12O2

Spin coatBake at 100o

C

UV/Develop

(MAPTMS)

metal-alkoxides

organically modifiedsilicon-alkoxide

Hydrolysis & Cross-linking

photoinitiator

Hard Bake

Nonlinear Chromophores

NOO

Si Si

S

O

NC

NC

NC

CF3 AJL833 pm/V in APC

S

NC

NC

NC

CN

O

OH

NOHHO

TCBD36 pm/V in sol-gel

AJLs10278 pm/V in APC

DR1 DR13 DR19

Fabry-Pérot Étalon: Design

Glass

Epoxy

ITO

DBR

EO Polymer

In2O3

V

VStructure 1

Structure 2

VStructure 3

Better TCO

Light Path

Review: EO Sol-gel Tunable Filter

-10 -5 0 5 10

-8

-6

-4

-2

0

2

4

6

8

Wav

elen

gth

Shi

ft (n

m)

Applied Voltage (V)

1530 1540 1550 1560

0.0

0.2

0.4

0.6

0.8

1.0

-10V10V

Inte

nsity

(a.

u.)

Wavelength (nm)

0 2 4 6 8 10

0

5

10

15

20

25

30

35

Isol

atio

n R

atio

(dB

)

Applied Voltage (V)

-10 -5 0 5 10

0.0

0.2

0.4

0.6

0.8

1.0

Nor

mal

ized

Inte

nsity

(a.

u.)

Applied Voltage (V)

1520 1540 1560 1580

0

2

4

6

8

-30V

-20V-10V

0V10V

20V

30V

Inte

nsi

ty (

a.u

.)

Wavelength (nm)

Source

Appl. Phys. Lett. 89 (2006), 041127.

EO polymer: TCBD coupled hybrid sol-gel Étalon structure 1 with ITO electrodes Large tunability (0.75 nm/V), high finesse (~235), wide tunable range (>50 nm) 35 dB isolation ratio with10 V

Review: Hybrid Fabry-Pérot Étalon

-10 -8 -6 -4 -2 0 2 4 6 8 10

1540

1542

1544

1546

1548

1550/V = -0.3946 nm/V

Wav

elen

gth

(nm

)

Voltage (V)

-10 -8 -6 -4 -2 0 2 4 6 8 10

0.0

0.2

0.4

0.6

0.8

1.0

Applied Voltage (V)No

rma

lize

d In

ten

sity

(a

.u.)

0

4

8

12

16

20

Iso

latio

n R

atio

(d

B)

Drive voltage Vp=5V

Modulation depth = 10%

Appl. Phys. Lett. 89 (2006), 141113.

154015421544154615481550

10V -10V

Inte

nsity

(a.

u.)

Wavelength (nm)

EO polymer: AJL8/APC Étalon structure 2 with ITO & In2O3

Large tunability (0.4 nm/V), high finesse (~234), low insertion loss (~4 dB) 10 dB isolation ratio with 5 V 10 % modulation with 5 V at 200 kHz

SLM - Photomask Design

* Applicable pattern ranges from 4×4 to 16×16 each 1cm × 1cm.

SLM - Substrate Fabrication

Patterned 8×8 ITO substrate Patterned 16×16 ITO substrate

Patterned 4×4 ITO substrate w/DBR coated & wires attached

Patterned 8×8 ITO substrate w/EO polymer AJL8/APC spin-coated

SLM - Integration & Testing

Patterned 8×8 ITO/DBR SubstrateElectrically poled

In-house fabricated 8×4 SLM

Optical testing set-up

4x8 SLM - Testing Results

Transmission through part of SLM (part of 4 pixels) with a broadband source (~1550 nm ± 25 nm)

Resonance transmission through 4 pixels with a 1558 nm laser with no applied voltage.

Modulated image under biased voltage

Field applied to all pixels

4 x 8 SLM with ITO outside electrodes