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ADVANCED MEMS SPATIAL LIGHT
MODULATOR FOR COMMUNICATIONS,IMAGING, AND TARGETING
Microsystems and Nanotechnolgy ResearchBell Labs Lucent Technologies
Murray Hill, NJ
Warren Lai, C.S. Pai, Fred Klemens, John Miner, Ray Cirelli, Ed Ferry, Ashley Taylor,Tom Sorsh, Avi Kornblit , Bill Mansfield, Eric Bower, Bob Fullowan
Rae McLellan, Nagesh Basavanhally, Dave RamseyMara Elina Simon, Vladimir Aksyuk, Cristian Bolle, Csar Chialvo, Harold Dyson, ArmanGasparyan, Susanne Arney
This material is based on work supported in partby DARPAs CCIT program under contract NumberHR0011-04-C-0048
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Optical, secure, free-spacecommunications
Advanced pixelated SLMs:Applications
Imaging Complex Mirror Array
LARGE Tip-tilt, Piston motionFAST Tip-tilt, Piston response time.
FLAT, smooth, reflectiveHIGH Fill factor
Collimating optics
SLM
Wavefront Sensor
camera
control
* Reference starWith AO Without AO
Segmented: Trackingtargetingscanning
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Breaking out of the traditional MEMS spaceMEMS arrays complexity map
Actuator density
Array
Linear
2D
120 m mirror (system,chips size) Integrable with electronics,scalable ( 100V) 642, 2562 and beyond High fill factor (>98%) Flat (30nm, 2nm Roughness)
Large Mechanical Power
-3 m x2 ( -3
2 )
Fast Large displacement
Flat (thick) mirror
100
101
102
103
104
105
10-3
10-2
10-1
100
101
102
103
104
105
Polychromator
BostonMM
Lucent CCIT SLM
Si Light Machines GLV
IBM Millipede
Lucent LRouter
Lucent WSS
Early DMD
Lucent M
Micronics
TI DMD
TT 2D
MARS
IRIS
MEMEXEXC
C
OMPLEXITY
Mechani
calPower/D
OF(nanowat
ts)
DOF / mm2
(1/mm2)
R ~ Log (Array Size * bits/pix) Goal
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Design principleDual, in-plane, rotational comb-drives
arm / springlayer
V=0
V
In-plane
combs
Routing
layer
Combs side view
4 actuators in parallel One control signal per actuator
2 comb drives per actuator
Piston motion results from
two opposite actuators or all fouractuators together
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Design principleDual, in-plane, rotational comb-drives
arm / springlayer
V=0
V
In-plane
combs
Routing
layer
Combs side view
4 actuators in parallel One control signal per actuator
2 comb drives per actuator
Tilt motion results from
single actuators or two adjacentactuators together
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Design principle andfabrication
In-planecombs
V=0
V
arm / springlayer
Routinglayer
Combs side view
Combs front viewTotal: 17-28 mwith 100nm registration accuracy between all layers
1-2 m PolySi-3 Mirror CD .5 m
1-2 m PolySi-2 Spring/Arm CD .5 m
6-12 m PolySi-1 Combs CD .5 m
2.5 m Routing (PolySi-0 +) CD .5 m
2-4.5 m Sacrificial layers (each)
20
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SE
MI
mag
es10 mask levels 248nm4X stepper lithography
Reinforcing struts (back of the mirror)
120 m
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Mono
lithicM
irror
Strut-reinforced, 1.5 mthick mirror with
40 Ti / 400 Au
Excluding thatregion and the
overall curvature theRMS roughness is~1.85nm
Mirror, front side
Even with thisdeposition/polishingartifact the peak tovalley variation is
~50nm
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Test Vehicle
CORE
PERIPHERY
(A)
(B)(C)
Packaged 64x64 256x256 on 8 wafer
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0 10 20 30 40 50 60 70 80 90 100 110
0
1
2
3
4
5
6
displcement(m)
angle(degrees)
Voltage (V)
1AT
2AT
4AP
Mechanical Response: Angle-Piston vs. Voltage
2-Actuator Tilt
1-Actuator Tilt
4-Actuator Piston12
34
Continuous, smoothvarying, stable,controllable Motion
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Combined X-tilt and Piston:
0 1 2 3 4 5 6-5
0
5
Piston motion (um)
Tiltangle
()
X-tilt
Y-tilt
1
23
V1=V2 in range 0 to 80V (SQRT spaced)V3=V4 in range 0 to 80V (SQRT spaced)
+/-0.1 degrees totalaccumulated Y-tilt(open loop)
4
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0 1 2 3 4 50
1
2
3
4
Combined Diagonal Tilt and Piston:
Piston motion (um)
X-tilt
Y-tilt
Tiltangle
()
1
23
V1=V3 in range 0 to 80V (SQRT spaced)V2 in range 0 to 100V (SQRT spaced)
V4=0
4
V4 > 0
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5 10 15 20 25 30 35 40
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Normalized
Amplitude
Frequency (KHz)
Mode F0
Tilt 1 29.6KHz
Tilt 2 29.6KHz
Piston 30.9KHz
next mode 140KHz
Mechanical Response: Resonance
2-Actuator Tilt
1-Actuator Tilt
4-Actuator Piston
Simulated Resonancefrequencies in Vacuum F0~30Kz from fitting
Polytec Vibrometer Measurement
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-20 0 20 40 60 80 100 120 140 160 180 200 220
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
P
iston(m)
time (s)
X-angleTilt(deg)
Pr=9.5s
Tr=23.4s
Pf =7.4s
Tf =18.6s
-20 0 20 40 60 80 100 120 140 160 180 200 220
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
P
iston(m)
time (s)
X-angleTilt(deg)
Pr=9.5s
Tr=23.4s
Pf =7.4s
Tf =18.6s
Atmospheric pressure,0-60V step
Me
chanic
alResp
onse:StepFun
ction
Interferometerstroboscopicmeasurement
Video frame rate:6000X slower thanactual motion
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We have Implementedhigh-force actuatordesign in a 10-lithography-step MEMS
process
5.4m, 10s piston4.3, 20s tilt
MEMS fabricationapproach scalable to2562 and beyond
Integration-ready with
high-voltage electronics
Design andfabrication tour de
force100 101 102 103 104 105
10-3
10-2
10-1
100
101
102
103
104
105
Polychromator
BostonMM
Lucent CCIT SLM
Si Light Machines GLV
IBM Millipede
Lucent LRouter
Lucent WSS
Early DMD
Lucent M
Micronics
TI DMD
TT 2D
MARS
IRIS
MEMEX
LT CCIT TV
EXC
COMPLEXIT
Y
Mecha
nicalPower/
DOF(nanow
atts)
DOF / mm2
(1/mm2)
R ~ Log (Array Size * bits/pix)
Summary
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Pure Tilt Dynamics
Time (us)
Pistonmo
tion(um)
Tiltangle()
X-tilt
Y-tilt
Piston
0 100 200 300 400-4
-3
-2
-1
0
1
2
3
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8 inch
12um deep combs
Future: faster response
Deeper combs, stiffer springsDamping TuningTailor for different applications within this
platformContinue to work on integration / packaging
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