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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.