第７回可視赤外線観測装置技術ワークショップ
２０１７年１１月１７日（金）１３：００〜１３：４０
京都大学 北部キャンパス 益川ホール（北部総合教育研究棟）

ＭＥＭＳ光制御技術の研究動向（静電マイクロアクチュエータの光学応用）
年吉洋

Hiroshi TOSHIYOSHI
東京大学 先端科学技術研究センター
Research Center for Advanced Science and Technology (RCAST)The University of Tokyo

東京大学 生産技術研究所
マイクロナノメカトロニクス国際研究センター
Center for International Research on Micronano Mechatronics
Institute of Industrial Science
The University of Tokyo

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 1

Contents Today

1. MEMS = Micro Electro Mechanical Systems
2. µ-Actuator for Astronomy
3. MEMS at the Beginning = Fiber Telecom
4. Theory of Electrostatic Force
5. More Added Values
6. Summary

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 2

ケータイ／スマホの部品、実世界とのＩ／ＯはＭＥＭＳ
センサ

圧力センサ

アクチュエータ

小型スピーカー（高度計）

加速度センサ

タッチパネル

方位センサ

画像ディスプレィ

指紋センサ

距離計

マイクロフォン

画像プロジェクタHiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 5

ＣＭＯＳ­ＭＥＭＳマイクロミラーはじめました

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 8

Projection Display in 1975
R. N. Thomas, J. Guldberg, H. C. Nathanson, P. R. Malmberg, IEEE Trans. ED vol. 22,
1975, Westinghouse Research Labs & Philips

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 9

A True Micro Motor, Diameter 120 microns

Y.Tai et al. Sensors & Actuators 1989
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 10

Quantum Photonics
Emission
Absorption

Electromagnetism

Polarization
Absorption

Near Field Optics, Plasmon Resonance, Metamaterial

Wave Optics

Wave Front
Control

Diffraction

Coupling

ShieldInterference
Delay

Ray Optics

T.I.R
Reflection
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Refraction
Page 13MEMS Micro Actuators

K. Isamoto, Santec Corp.,

K. Takahashi, 2007

K. Takahashi, IIS, Univ. of Tokyo 2005

T. Takahashi, IIS, Univ. of Tokyo 2006

MEMS = Micro Electro Mechanical Systems

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 14MEMS Actuators for Optical Applications
Interactive Image Displays

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 15

Contents Today

1. MEMS = Micro Electro Mechanical Systems
2. µ-Actuator for Astronomy
3. MEMS at the Beginning = Fiber Telecom
4. Theory of Electrostatic Force
5. Faster !
6. Summary

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 16

Multi-Slit Array for Observatory
TAO in Atacama（5639 m）

Incident Light
from Galaxies

MEMS Shutter Array(Multi Slits)

Gratings / Prism

SpectraHiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 18

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 19

Electromagnetic MEMS Shutter for NASA JWST
Li et al., "Microshutter array development for the James Webb space telescope,”(2005) SPIE 5650 9

•
•
•
•
•

For satellite mountOpen Electromagnetically
Latch Electrostatically
Matrix 64 × 128
Size 100 µm × 200 µm

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 21単位面積あたり発生力
静電駆動

電磁駆動

単位面積
あたりの
発生力
(N/m2)

代表的
設計値

g

熱膨張
（通電加熱）

w

V

原理図

圧電駆動
（磁歪・電歪駆動）IB(1/2) ε0 E 2

IB/w

Eε

E α ΔT

E : 電場
ε0 : 誘電率

I : 駆動電流
B : 磁束密度w : 線幅E : ヤング率ε:歪E : ヤング率
α : 線膨張系数
ΔT : 温度変化

101〜104 N/m2

101〜103 N/m2

圧電 107〜108 N/m2
電歪 107〜109 N/m2

106〜108 N/m2

永久磁石
Hc ~ 10 kOe

ヤング率
E ~ 100 GPa

ヤング率
E ~ 100 GPa

駆動電流
I = 1 mA ~ 1 A

圧電の機械歪ε = 0.01 ~ 0.1 %

線膨張係数
α ~ 10 ppm

配線幅w ~ 10 µm

磁歪、電歪の機械歪ε = 0.01 ~ 1 %温度変化
ΔT = 1 ~ 100 ℃

静電ギャップg = 1 ~ 10 µm
駆動電圧
V = 1 ~ 100 V

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 22

Optical MEMS Shutter Array at UTokyo
W 100 um x L 1000 um

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 23

Contents Today

1. MEMS = Micro Electro Mechanical Systems
2. µ-Actuator for Astronomy
3. MEMS at the Beginning = Fiber Telecom
4. Theory of Electrostatic Force
5. More Added Values
6. Summary

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 27

MEMS Variable Optical Attenuator

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 28

MEMS VOA Application in Fiber Telecom Network
Optical Coupling
ReceiverTransmitter
MOD

VOA

LD l2

WL

MOD

VOA

LD l3

WL

MOD

VOA

LD l4

WL

MOD

VOA

Rerouting
MUX

WL

VOA

Fiber
Amp

Sw

Sw

DEMUX

LD l1

WF

VOA

PD l1

WF

VOA

PD l2

WF

VOA

PD l3

WF

VOA

PD l4

WF

VOA

PD lN

VOA
LD lN

WL

MOD

VOA

Wavelength Tuning

Wavelength
Equalizer /Dispersion
Compensator

Intensity Modulation

OADM /OXC

Wavelength
Filtering /Tracking

VOA

Wavelength Equalizer

Rx

Tx

現在このイメージを表示できません。
現在このイメージを表示できません。

現在このイメージを表示できません。

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 29

Simple Structures and Process for VOA

Suspension

Mirrorf

A
Release
Hole

La

q

A’

Electrostatic Actuator Plate

Wa

B

g

B’
Substrate

Suspensionht
wtVAnchorHiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 30

SOI Bulk Micromachining by DRIE
Deep Reactive Ion Etching (DRIE)
Photoresist
Aluminum 100 nm
Silicon-on-Insulator 30 µm

SOI Wafer(1)

Buried Oxide (BOX) 2 µm
Silicon Substrate 500 µm
Aluminum 100 nm
Passivation
Photoresist(2)

Deep Reactive Ion Etching (DRIE)
Sacrificial Release in HF
Electrostatic Electrodes
MirrorGold 100 nm on
Chromium 50 nm

(3)

Chip

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 31

Attenuation Control and Complete Block-out
Normally-Bright Mode
Insertion Loss - 0.8 dB

Optical Attenuation dB

0-10
Attenuation
range 40 dB

Resolution
0.1 dB

-20

-30

-40

5-V Operation

0

1

2

3

4

5

Driving Voltage V dc
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 32

Contents Today

1. MEMS = Micro Electro Mechanical Systems
2. µ-Actuator for Astronomy
3. MEMS at the Beginning = Fiber Telecom
4. Theory of Electrostatic Force
5. More Added Values
6. Summary

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 33

静電駆動マイクロアクチュエータ
電圧印加 → 静電引力 → 機械的変形
Mechanical Anchor

GND

Springk
Constant

c Viscosity

Voltage VA

Displacement(VA = 0)Initial Gap

g - x
Voltage VB

e

0

Mass

m

QA

Plate Area

QB

S

i

x

R

Electrical
ResistanceV

Drive Voltage

Electrostatic micro actuator (bi-directional)

1
S
2(VA - VB )F = e02
2 (g - x )GND

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 34

第１問

電極間を接続するとどうなるでしょう？

1
S
2(VA - VB )F = e02
2 (g - x )Ａ
動くHiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Ｂ
動かないPage 35

正解と解説Ｂ
動かない

電極間が等電位であれば、静電引力は発生しない。
→よって、等電位の電極どうしは動かない。

この原理の応用例：
可動構造と基板を等電位に接地して、下向きの動きを防止。

バネ、可動電極

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 36第２問

等電位なのに、なぜ動くのでしょうか？
箔（はく）検電器
電極（金属箔に接続）

絶縁体のキャップ

金属箔

金属箔

紙（絶縁体）
http://www.kenis.co.jp/
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 37

解説
等電位であっても、クーロン反発力は働きます1
1
U = E D = e 0E222

http://www.kenis.co.jp/
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 38

だまされてませんでしたか？
Ｂ
動かない

電極間が等電位であれば、静電引力は発生しない。
→よって、等電位の電極どうしは動かない。

ただし、等電位であっても静電反発力は働く。

バネ、可動電極

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 39

第３問

静電反発力を使わない理由は？

どっちもクーロン力、電荷の量は同じ、符号が違うだけ

Q1 × Q2
F=×
4 p e0
r2
1

-Q

+Q

+Q

+Q

静電引力アクチュエータ

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

静電反発力アクチュエータ

Page 41

解説

駆動電圧が高いのは損

電場に逆らって電荷を移動した仕事が「電位」

s
V = En × r =
×r
2 e0

-Q

+Q
+Q

r

+Q
Vrepulsive

Vattractiver ®¥Vattractive << Vrepulsive

静電引力アクチュエータ
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

静電反発力アクチュエータ
Page 42Contents Today

1. MEMS = Micro Electro Mechanical Systems
2. µ-Actuator for Astronomy
3. MEMS at the Beginning = Fiber Telecom
4. Theory of Electrostatic Force
5. More Added Values
6. Summary

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 45

Optically Powered Fiber Endoscope
Tissue under Test

■ Powering at 1.5 um■ OCT measurement at 1.3 um

OCT Probe
λ 1.3 µm

OCT Probe In(λ 1.3 µm)

Power Supply(λ 1.5 µm, 500 Hz)

OCT Probe Out(λ 1.3 µm)

Photovoltaic Cell

MEMS Scanner

10 mW, λ 1.5 µm ! max. 11 V

7 ~ 10 V, 250 Hz

GRIN Lens (Collimator)

Beam Splitter

Focusing Lens

Sheath
φ 6 mm5 mm
Single Mode
Fiber
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Photovoltaic
Cell

MEMS ScannerPage 48

Application of WDM Technology
λ 1.3 um

■ Power 1.5μｍ■ OCT Probe 1.3μｍ

φ 5 mmFocus Lens
Collimator
SheathMEMS Scanner
Optical Fiber

Beam Splitter
Photovoltaic Cell

Optical Coupling

λ 1.5 um

FerruleReceiverTransmitter
MOD

VOA

LD l2

WL

MOD

VOA

LD l3

WL

MOD

VOA

LD l4

WL

MOD

VOA

Rerouting
MUX

WL

VOA

Fiber
Amp

Sw

Sw

DEMUX

LD l1

WF

VOA

PD l1

WF

VOA

PD l2

WF

VOA

PD l3

WF

VOA

PD l4

WF

VOA

PD lN

VOA
LD lN

WL

MOD

VOA

Wavelength Tuning

Wavelength
Equalizer /Dispersion
Compensator

Intensity Modulation
Wavelength Equalizer

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

OADM /OXC
VOARx

Wavelength
Filtering /Tracking

Tx
Page 49

Electrostatic MEMS Optical Scanner 2 mm x 3 mm
Comb-Drive Electrodes

Suspensions

Mirror Plate
1.5 mm x 1.5 mm

3 mm

2 mm

Chip-Handle

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 50

Assembly of MEMS Endoscope Head
Beam Splitter

Focusing Lens

MEMS Scanner

GRIN Lens

GRIN Lens(Collimator)

Photovoltaic Cell

Beam Splitter

Focusing Lens

Sheathf 6 mmSingle Mode
Fiber

Photovoltaic
Cell l = 1.55 mm

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

MEMS Scannerl = 1.3 mm

Page 52

Detail View of Optically Powered OCTß Fast Scanner

Slow Scanner àEndoscopePowering Light 1.5 um
WDM Coupler
Optical Circulator
Attenuator

OpticalDelay Line

OCT Probe 1.3 um

Delay Line Equalizer

Synchronizer

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Polarization
Controller

Balanced
Detector

PreAmplifier

PC
DAQ
I/O Interface
Page 53

OCT (Optical Coherence Tomography) Image
Skin

Sweat
Gland

M. Nakada, et al., "Optical Coherence Tomography based on Power-overfiber MEMS Scanner," APCOT 2008, Jun. 22-25 2008.

2.3 mmCuticleDermisScan Range(mm)

Resolution(um)

Lateral

1.6

40

Depth

1.0 ~ 2.58
2 mm

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 54

Wavelength-Tunable Laser for OT
Finesse (= Bandwidth / FWHM)

1400

Higher Resolution, Faster Imaging
2nd Gen.

3rd Gen.

1200
Ophthalmology
Axial Length1000

l = 1 um
Dl = 20~40 nm
dl = 0.02~0.03 nm
f = 1~5 kHz

800

MEMS
Scanner
Anterior Segment

l = 1 um, Dl = 100 nm
dl = 0.1 nm, f = 20~100 kHz

600

Industrial
Endoscope

400

PolygonScanner

DentalDl = 80~100 nm
dl = 0.12 nm
f = 40~100 kHz

l = 1.3 um
Dl = 100 nm
dl = 0.15 nm
f = 30~100 kHz

Retina Inspection

200
0

Vascular Inspection

Target : Over 100 kHz

l = 1 um, Dl = 100 nm
dl = 0.1 nm, f = 50~140 kHz

0

20

40

60

80

100

120

Scan Speed kHz

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

140

160
Page 55

Two OCT Operation Principles
Time-Domain OCT (TD-OCT)

Swept-Source OCT (SS-OCT)

A-ScanReference Arm

Reference ArmDLDL

A-ScanLow Coherence
SourceDl

High Coherence
SourceSample Arm

Sample Arm

l

l

Dl
dz

DL

dz

OCT
SignalOCT
Signalc / 2DLZ

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

t

FFT

DL

Page 56

Advantages of SS-OCT
Time-Domain OCT (TD-OCT)

Swept-Source OCT (SS-OCT)

Time-Domain Zeiss Visante OCTThis work

Reference

A ScancorneaHigh-Coherent
Measurement
Spatial Scan
(B Scan)

TD-OCT

SS-OCT

Sensitivity dB~ 90 dB~ 110

Frame Rate fps

1

54

Resolution µm

10~15

5~10

A ScanWavelength Scan
(A-Scan)

FFT
Keiji Isamoto, Kohki Totsuka, Tooru Sakai, Takuya Suzuki, Atsushi Morosawa,
Changho Chong, Hiroyuki Fujita, Hiroshi Toshiyoshi, "A High Speed MEMS
Scanner for 140-kHz SS-OCT," IEEE Int. Conf. on Optical MEMS andNanophotonics, Istanbul, Turkey, Aug. 8-11, 2011.

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 57MEMS Scanner to Replace Polygon Mirrors
Fast Operation Speed at 70 kHz

3cm

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 59External Cavity Laser for Wavelength Tuning
External Cavity Laser
Scanner
OutputBeam
ExpanderGain Chip

MEMS Scanner

Diffraction
Grating

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 61

Wavelength Scan Performance
Mechanical 70 kHz x round-trip scan à 140 kHz Sweep
Band Width ~ 100 nm
1410

20

15

1360

10

5

1310

W avelength(nm ) nm
Wavelength

OpticalPower
O pticalpow er (m W ) mW

25

0

-5
0.0

1260
2.0

4.0

6.0

8.0
tim e(μsec)

10.0

12.0

14.0

16.0

Time µs
Intensity calibration required for OCT imaging
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 62

Virtually Slicing Alive

TadpoleHigher resolution, less invasive, and less expensive than
X-ray CT or Ultrasonic Imagers

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 63

Benefits of Fast OCT Scan
Higher Resolution & Faster Frame Rate

This research is supported by Optoelectronic Industry and Technology Development Association (OITDA), subsidized by JKA through its Promotion
funds from KEIRIN RACE.
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 64

Wavelength-Tunable Laser for OT
Finesse (= Bandwidth / FWHM)

1400

Higher Resolution, Faster Imaging
2nd Gen.

3rd Gen.

1200
Ophthalmology
Axial Length1000

l = 1 um
Dl = 20~40 nm
dl = 0.02~0.03 nm
f = 1~5 kHz

800

MEMS
Scanner
Anterior Segment
l = 1 um, Dl = 100 nm
dl = 0.1 nm, f = 20~100 kHz

600

Industrial
Endoscope

400

PolygonScanner

Dl = 80~100 nm
dl = 0.12 nm
f = 40~100 kHz

l = 1.3 um
Dl = 100 nm
dl = 0.15 nm
f = 30~100 kHz

Retina Inspection

200
0

Vascular Inspection

Dentall = 1 um, Dl = 100 nm
dl = 0.1 nm, f = 50~140 kHz

0

20

40

60

80

100

120

Scan Speed kHz

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Target : Over 100 kHz
140160Page 65MEMS-based Tunable VCSEL
1060 nm wavelength range with InGaAs/GaAs
Active layer
InGaAs / GaAs
VGND

Laser cavity
Vanode

DBR
Half
VCSEL

VcathodeV+

Diaphragm
MEMS
SiO2

SiliconKeiji Isamoto, Kiyotaka Yamashita, Mohammed Saad Khan, Nicolas Lafitte, Kouki Totsuka, Changho Chong,Nobuhiko Nishiyama, and Hiroshi Toshiyoshi, "A MEMS based electrically pumped tunable VCSEL operating
at 1060nm for SS-OCT," SPIE Photonics West 2015 -- MOEMS and Miniaturized Systems XIV --, Feb. 9-12,
2015, The Moscone Center, San Francisco, CA.
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Page 67

MEMS-based Tunable VCSEL
Device Package (Front / Rear)

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

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Wavelength Tuning Performance
Coherence Length > 100 nm to probe deep insideSpec.

TypicalScan Speed

10 - 200 kHz

Coherence
Length>100 mm

Output Power

40 mW average(2 mW w/o amp)

Wavelength
Range

80 nm

Output Intensity(Time = Wavelength)

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

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Benefits of Long Coherence Length
Visualizing Long Distance … in particular for ophthalmologic examination
Anterior Chamber

Lens

RetinaHiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

20kHz operation

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Imaging Depth Scaling

Imaging Depth d (mm)At 500 MHz data sampling with a 50% duty cycle
Wide Tuning Range (40 nm)
For High Resolution
Small Depth (40 mm)

Short Tuning Range (4 nm)
For Course Resolution
Large Depth (> 100 mm)

Tunable Bandwidth Dl (nm)Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

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OCT over a Distance (~ 1 m)
Dl = 4 nm à d ~ 10 cm

4nm
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

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OCT over a Distance (~ 1 m)
Dl = 4 nm à d ~ 10 cm

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

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Overall OCT System Performance
Experimental Results

Note

Scan Speed

140 kHz

Round-Trip Scan

Band Width

100 nmOCT Resolution

9 µm

Spectrum Width

0.25 nm

Coherence Length

3 mmMaximum Power

20 mW

Dynamic Range

60 dB

FAST MEMS Scanner

1310 nm(in Air)

Wavelength Tunable Laser

ＯＣＴImaging
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

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Contents Today

1. MEMS = Micro Electro Mechanical Systems
2. µ-Actuator for Astronomy
3. MEMS at the Beginning = Fiber Telecom
4. Theory of Electrostatic Force
5. More Added Values
6. Summary

Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

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Quantum Photonics
Emission
Absorption

Electromagnetism

Polarization
Absorption

Near Field Optics, Plasmon Resonance, Metamaterial

Wave Optics

Wave Front
Control

Diffraction

Coupling

ShieldInterference
Delay

Ray Optics

T.I.R
Reflection
Hiroshi Toshiyoshi © 2017, hiro@iis.u-tokyo.ac.jp, Univ. of Tokyo, http://toshi.iis.u-tokyo.ac.jp/

Refraction
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