Industrial Affiliates Workshop, March 2004 Planar Ion-Exchanged Glass Waveguide Devices Seppo Honkanen, Brian West and Sanna Yliniemi Optical Sciences.

Industrial Affiliates Workshop, March

2004

Planar Ion-Exchanged Glass Waveguide Devices

Seppo Honkanen, Brian West and Sanna Yliniemi

Optical Sciences Center

University of Arizona

Collaborators:

Nasser Peyghambarian, Ray Kostuk, David Geraghty,

Axel Schulzgen, Mike Morrell (University of Arizona)

Industrial Affiliates Workshop, March

2004

Outline

• Introduction• Ion Exchange Glass Waveguide

Technology– Molten Salt Process

– Extensive Process -and Device Modeling– Study on Waveguide Birefringence

– Dry Ag-Film Process– MM-diode pumped Er-doped Waveguide Lasers

• Outlook and Conclusion

2

Industrial Affiliates Workshop, March

2004

Ti MaskDeposition

Na+

Ag+

MaskPatterning

IonExchange

MaskRemoval

Field-Assisted

Burial

• Waveguides Defined by Standard Photolithography

• Simple Processing

• Potential for Adjustment Through Annealing

Molten Salt Ion Exchange

3

Industrial Affiliates Workshop, March

2004

Binary Ion Exchange

Diffusion Equation

kT

CEq

C

CC

C

D

t

C Aext

A

AA

A

AA .

1

)(

1

22

• CA = normalized concentration of in-diffusing ions

• DA = self-diffusion coefficient of in-diffusing ions

• DB = self-diffusion coefficient of out-diffusing ions

• α = 1 - DA/DB

• q = electron charge

• k = Boltzmann’s constant

• T = absolute temperature

• Eext = externally applied electric field

4

Industrial Affiliates Workshop, March

2004

Example: Process Modeling for a Directional Coupler

The common procedure in device modeling: 1. Model the fabrication process of an isolated waveguide

2. Determine the device geometry

3. For each waveguide within the device, use the modeling results of (1)

This procedure is inaccurate when modeling ion exchanged devices

5

Industrial Affiliates Workshop, March

2004

Concentration and Mode Profiles

3 μm mask opening 9 μm mask opening

6

Industrial Affiliates Workshop, March

2004

Burial Depth vs. Waveguide Width

-7.5

-7

-6.5

-6

-5.5

-5

-4.5

-4

0 1 2 3 4 5 6 7 8 9 10Mask opening width (µm)

Bu

ria

l de

pth

(µ

m)

Experimental

Modeling(M=0.2)

Modeling(M=0.5)

Modeling(M=1)

Linear f it(Exp)

Linear f it(M=0.2)

Lineat f it(M=0.5)

Linear f it(M=1)

Opt. Lett. 28 (13), 2003

7

Industrial Affiliates Workshop, March

2004

Waveguide Birefringence

8

Industrial Affiliates Workshop, March

2004

Selectively Buried Waveguides

Glass

Polymer

Polymer-Glass Modulator

Masking During Burial:

9

Industrial Affiliates Workshop, March

2004

Adiabatic VerticalWaveguide Transition

10

Industrial Affiliates Workshop, March

2004

Calculated Cross Section Profile in the Middle of the Transition:

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

0

2

4

6

8

10

x [m]

y [

m]

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

0

2

4

6

8

10

x [m]

y [

m]

Concentration Intensity

11

Industrial Affiliates Workshop, March

2004

Device Example:Add/Drop Wavelength Filter

12

34

12

4

3 3'

3'

Add/Drop FilterIn 1 Fiber

• Add/Drop Provides Access to Signal

• Common Configuration• Fiber Bragg grating• Two circulators

FBGCIRC CIRC

12

Industrial Affiliates Workshop, March

2004

Asymmetric Y-BranchAdd/Drop Filter

Output

AddDrop

Input

OutputInput

On Resonance

Off Resonance

• Asymmetric Y branches• Wide guide excites even mode• Narrow guide excites odd mode• Bi-directional

• Tilted Grating• Breaks orthogonality of 2 modes

• Benefits• Ion-Exchanged Waveguides• Single component• Structures defined photolithographically• Possible mass integration

13

Industrial Affiliates Workshop, March

2004

Adiabatic 4-Port Coupler

14

Industrial Affiliates Workshop, March

2004

Add/Drop Performance

• 20 dB Extinction

• 0.4 nm 3 dB Bandwidth

Electron. Lett. 37(13), 2001

1562 1564 1566 1568-20

-15

-10

-5

0

Rel

ativ

e P

ower

(dB

)

Wavelength (nm)

1562 1564 1566 1568-20

-15

-10

-5

0

Rel

ativ

e P

ower

(dB

)Wavelength (nm)

1562 1564 1566 1568-20

-15

-10

-5

0

Rel

ativ

e P

ower

(dB

)

Wavelength (nm)

PASS ADDDROP

Pass

AddDrop

Input

15

Industrial Affiliates Workshop, March

2004

Ag-Film Ion-Exchange

+V

GND

a) Spin-coat Photo Resist b) Mask Patterning c) Ag film deposition

d) Electric Field Assisted Ion-Exchange f) Thermal Diffusione) Ag Removal

PR

Er-Doped Phosphate Glass

Ag

Ag

Surface Waveguide

16

Industrial Affiliates Workshop, March

2004

Pumping with aBroad Area Laser Diode

Erbium/Ytterbium codoped glass

Ion exchanged waveguide

Undoped glass

Single mode waveguide

Multimode section (100 µm)

Dielectric mirror (R>99%)

10 mm 30 mm 10 mm

Surface Relief Bragg grating (R = 72 %)

965 nmpump

Appl. Phys. Lett. 82(9), 2003

17

Industrial Affiliates Workshop, March

2004

Output vs. Pump Power

0

10

20

30

40

50

60

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Pump power (W)

Out

put p

ower

(mW

) Wavelength = 1538 nm

Slope = 4.9 %

Threshold = 280 mW

Output power = 54 mW

18

Industrial Affiliates Workshop, March

2004

Outlook

• New device innovations– Mode-locked waveguide lasers– MMI-Waveguide lasers – Tunable dispersion compensators– All-optical header recognition chip

• Exotic host glasses

• Integration with other materials

19

Industrial Affiliates Workshop, March

2004

Conclusion

• Ion-Exchange in Glass

– A Proven Low-Cost Integrated Optics Technology

– Offers Unique Advantages for Various Passive and Active Waveguide Devices

20