J. Kubby, UC Santa Cruz

K. German,J. Chen, J. Diehl, K. Feinberg, P. Gulvin, L. Herko, N. Jia, P.

Lin, X. Liu, J. Ma, J. Meyers, P. Nystrom, Y. R. Wang, Xerox

Plasma Etch Users Group (PEUG)

Plasma Etch Users Group (PEUG)

Plasma Etch Users Group (PEUG)

October 12

October 12

October 12thth th, 2006

, 2006

, 2006

Optical MEMS platform

for low

Optical MEMS platform

for low

Optical MEMS platform

for low

cost on

cost on

cost on-- - chip integration of planar

chip integration of planar

chip integration of planar

light circuits and optical switching

light circuits and optical switching

light circuits and optical switching

PLC and M

EMS W

aveguide Switch Integration

Why Integrate: New

technology for a new

market

Elements of compact affordable integration

�Silicon on Insulator (SOI) PLC Optics

�Latching M

EMS waveguide sw

itches

�PLC and M

EMS System

Integration

�Component reconfiguration

Exam

ple Prototypes: ROADM andλ−Router

Next Steps and Extensions

�InfotonicsTechnology Center

�Hybrid integration and active elem

ents

Summary

Acknowledgem

ents-Outline -

Metro Networks

Optical Devices

Affordable enabling components for

wavelength services (~10x cost reduction)

Optical Add/Drop M

ultiplexer at each

on ram

p and off ram

p

Additional network functions (V

OA,

DGE,…

.)

Wavelength Services

Provide bandwidth on dem

and at the

wavelength granularity

Dem

ocratize bandwidth through

affordable provisioning

Enables new

services (SAN, PWS,

GigE) using existing W

DM

infrastructure

Elements of compact affordable integration

Latching

Optical

Switches

Mux

De-Mux

SOI for integrated M

EMS and PLCs

SOI Optical Design Space

Intrinsic Trade-offs

Insertion Loss/Length

Cross Talk (single m

ode)

Polarization Dependent Loss

Minim

um Bending Radius

Coupling Loss

Chip Size

Extrinsic Factors

Process uniform

ity

Waveguide Roughness

SiO

2n 2n 1n 0

air

Si

2bλ

2aλ

2brλ

SiO

2n 2n 1n 0

air

Si

2bλ

2aλ

2brλ

Single M

ode Condition

)1(

/3.

02r

rb

a−

+≤

Rib W

aveguide param

eters

Shower curtain

Compact Planar Light Circuits

Silicon waveguides

can have bending radii 3 to 4 tim

es

smaller than silica waveguides

Silicon: n = 3.42, absorption ~ 0.1 dB/cm

Silica : n ~ 1.45

SiO

2cladding 2

SiO

2cladding 1

SOI wafer

5µm

SCS

Waveguide fabrication comparison

SiO

2Ge

WG channels

Si wafer

Example SOI ROADM

1.7 cm x 1.0 cm chip

(MEMS switches)

Silica

on

Silicon

Silicon

on

Insulator

Dry reactive

ion etch rib

WGs in SCS

Lightwave Microsystems

6”wafer (TO switches)

More de

vice

s an

d high

er yield per w

afer

Total max

thickness

~ 45 µm

Coupling fibers to SOI waveguides

SOI v

ertically ta

pered mod

e ad

aptor

Com

puted SOI W

G m

ode

Measurements on prototypes project 0.7 dB coupling

loss/facet when AR coatings are applied

Mode matching and adiabatic transform

ation help m

inim

ize

losses associated with coupling

Latching M

EMS W

aveguide Switch

Anchored

AnchoredWaveguides

Waveguides

Drive

Drive

Latch

Latch

Out

Out

Add

Add

InIn

Drop

Drop

Quenc

h

Quenc

h

Released

Released

Waveguides

Waveguides

(cantilever)

(cantilever)

Switch Operation

Fabricated

in Add/Drop

State

Apply

latching

sequence

Pulse

s symmetric

wrt

volta

ge com

mon

:-

minim

izes

pulldow

n an

d po

tential

diffe

renc

e at la

tch

contac

t points

Latch in

Through

State

latc

h

dri

ve

IN

ADD

DROP

OUT

Latching M

EMS W

aveguide Switch States

Thru State

Add/D

rop State

OUT IN

•Power is required to change state

•No power is required to hold either state (failsafe)

Released

waveguides

Anchored

waveguides

QUENCH

LatchDROP

Heatuatordesigns for robust alignment

Tensile

Stress

•Variations in beam

width and doping

produce thermal

gradients

•Thermal gradients

induce predictable

displacement

direction

•Straight beams

enable stability

under tensile

stress

Joule

Heating

misalignment

No m

echanical bias

(straight beams)

?

Mechanical bias

(v-beams)

System

Advantages of HeatuatorDrive and Latch

Low voltage (< 10 V)

Small footprint (length < 1 m

m)

Good m

echanical suspension

(Lowest natural frequency ~ 30 kHz)

FEM ANALYSIS

suspended components

1stlatched m

ode

30 kHz

2ndlatched m

ode

76 kHz

1stunlatched m

ode

30 kHz

2ndunlatched m

ode

50 kHz

(arbitrary depicted amplitudes)

Latching waveguide sw

itch in action

Life tested to over 17 m

illion changes of state

1550.60

1563.40

1557.00

1.28 nm/div

nm

-79.00

-67.00

-55.00

-43.00

-31.00

-19.00

6.00

dB/div

dBm

REF: -25.00 dBm

08:38AM

13 Dec 2002

Mkr 2(A)

Mkr(2-1)

Mkr 3(A)

Mkr 4(A)

Mkr(4-3)

1554.54 nm

3.14 nm

1557.86 nm

1561.06 nm

3.20 nm

-35.262 dBm

1.827 dB

-34.231 dBm

-36.373 dBm

-2.142 dB

In�

Out output spectrum

Reconfigurable OADM Perform

ance

1545.60

1558.40

1552.00

1.28 nm/div

nm

REF: -25.00 dBm

11:58AM

13 Dec 2002

1545.60

1558.40

1552.00

1.28 nm/div

nm

REF: -25.00 dBm

12:23PM

13 Dec 2002

1545.60

1558.40

1552.00

1.28 nm/div

nm

REF: -30.00 dBm

11:59AM

12 Dec 2002

1 2 3 4 5 6 7 8

Drop

Out

Drop:

Odd Channels

Pass:

Even Channels

Pass:

All Channels

All Switches

Unlatched

Switches

1, 3, 5, 7

Latched

Switches

2, 4, 6, 8

Unlatched

Out

Reconfigurable λ-Router Perform

ance

Real time sw

itching of R-O

ADM

Exam

ples of component reuse

B: Demultiplexed

WADM In

Add

Drop

Out

M 2x2

Switch Fabric

E: Node Bypass

InBypass

M 1x2

Switch Fabric

Out

C: Partial Drop WADMs

In

Add

Drop

Out

2x2

Switch

Fabric

In

Add

Drop

Out

2x2

Switch

Fabric

InOut-1

M 1x2

Switch Fabric

Out-2

D: Multiplexed WADM

A:Wavelength

OpticalRouter

In-1

Out-1

In-2

Out-2

M 2x2

Switch Fabric

Prototype Specs and Product Targets

�40 dB

Extinction Ratio

�>17 M

Lifetim

e (state changes)

�Yes

Latching

10

12

Speed (msec)

~ 500 pulsed

~ 800 pulsed

Power (mW)

0.5dB

??Polarization (PDL)

50 dB

??Return Loss (RL)

�>30 dB

AdjacentCross Talk (AXT)

�>25 dB

Adjacent Cross Talk (AXT)

2 dB

4 dB

IL Uniform

ity (ILU)

12 dB

19 dB

Insertion Loss (IL)

Target

Achieved

R-O

ADM System

Fabrication Process

Process developed under the auspice of the NIST

Advanced TechologyProgram (ATP)

Broadly enabling in the area of free space and

guided wave MicroOptoElectroMechanical

System

s (M

OEMS)

Hybrid integration capabilities included for active

optical elem

ents

Developed in partnership with Coventor, Corning

IntelliSense Corp., and M

icroScanSystem

s

Prototypes employed a subset of the full process

for quick proof of concept dem

onstration

Hybrid SOI MicromachineProcess

For details see:

www.infotonics.org

→fabrication →

device technologies →foundation process

Extensibility to higher levels of integration

Process is extensible to hybrid integration

techniques such as flip chip bonding (NIST ATP)

�Photodetectors

�Power amplifiers

Silicon enables further m

onolithic integration

�VOA for equalization

�GHz modulation

�On chip electronics, controls, logic

�Silicon laser on the horizon

Next Steps

�Decrease IL (sidew

all roughness, AR coatings on facets)

�Pursue higher levels of integration, device optimization,

reconfiguration and/or packaging pending customer

traction

�Not for profit organization

�Promote photonics and m

icrosystem

s

�Cooperative sponsorship of industry,

academ

ia, and government

�MEMS prototype, pilot plant, packaging

capabilities under development

Summary

On chip integration of SOI MEMS latching optical

waveguide sw

itches with PLCscan reduce size

and cost of optical network devices

Prototypes have dem

onstrated the feasibility of

this approach to compact affordable integration

Switches and PLC components can be

reconfigured to m

ake many network devices

Hybrid integration can further extend the SOI

MEMS platform

to devices that require active

optical components

Advances in adiabatic m

ode coupling technology

address issues of low loss fiber attachment

Acknowledgem

ents

Process work perform

ed under Cooperative Agreem

ent

#70NANB8H4014, National Institute for Standards and

Technology Advanced Technology Program, ATP Project

Managers Thomas

Lettieriand CarlosGrinspon.