Bill Ahern
Axsun Technologies, Inc.
Bio Opto Japan 2013
Tailoring Lasers for Specific Swept
Source OCT Applications
Outline
• Axsun Overview
• Axsun Technology and Manufacturing
• OCT Laser Platform
• Imaging Subsystems
• Laser Operation
• Advanced System Development
• Summary
Axsun Technologies Inc.
• A wholly owned subsidiary of Volcano
Corporation (Nasdaq: VOLC)
• Founded in 1998, located in Billerica, MA
• Producing more than ten thousand
optical engines annually into Telecom,
Industrial Spectroscopy and Medical
Imaging applications
• Unique tunable MEMS and optical
integration technology
• Telecom and Industrial products have
strong synergy with Medical Imaging
• 115 employees
• 110 Issued Patents
AXSUN MODULE ASSEMBLY FACILITY
Optical Engine
MEMs Technology and
Manufacturing Platform
High Capacity, Automated
Manufacturing
The Axsun Platform – Unique Devices,
Assembly, and Products
Unique Devices Optical Bench Optical Engine
Module
Complete Subsystem
The Axsun Platform – Unique Devices,
Assembly, and Products
Unique Devices Optical Bench Optical Engine
Module
Complete Subsystem
The Axsun Platform – Unique Devices,
Assembly, and Products
Unique Devices Optical Bench Optical Engine
Module
Complete Subsystem
The Axsun Platform – Unique Devices,
Assembly, and Products
Unique Devices Optical Bench Optical Engine
Module
Complete Subsystem
Swept Source OCT
Axsun Swept Laser Technology
and Performance
Optical Coherence TomographyOCT Techniques
1. Time-domain OCT
2.Frequency-domain OCT• Spectral-domain OCT
• Swept-source OCT
Swept-Source OCT advantages
– Enables balanced and polarization diverse detection
schemes
– Longer Wavelengths, such as 1060nm and 1300nm, enable
deeper penetration into tissue
– Increased imaging depth range from slower signal roll-off
– High SNR and Resolution in a compact, rugged package
SSOCT
Axsun MEMs External Cavity Tunable Laser
14 mm
SOA
Tunable FP Filter
Laser Cavity
GainOutput
Optical
Fiber
Fiber
Reflector
Lens Lens
Micro-Electro-Mechanical System
(MEMS) Tunable Filter
Tethered
Membrane
Filter Assembly
Wafer Scale Processing
HR Coated
Flat Mirror
Electrode Gap
Optical Cavity
HR Coated Curved
Mirror on Tethered
Membrane
Si
MEMS Fabry-Perot Filter Structure
V
Micro-Optical Bench Packaging Platform
SOA gain chip
Output Fiber pigtail
LIGA alignment structure
Si micro lens
MEMS tunable filter
Micro-optical bench
x
y
z
Micro-
lens
fiber
Enables the most compact, highest
speed tunable laser for OCT
Axsun Swept Laser
Performance
Axsun Laser Tuning Range (Bandwidth)
BW >110 nmBW >100 nm
Axsun Laser Coherence Length
0 2 4 6 8 10 12 14 16 18 20 22-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
Full Length (mm)
Sig
nal F
FT
(dB
=20*l
og10)
<Down Tune Wavelength> <oct 0243 CohLen 1mm.dat>
Coherence Length = 13.5 mm
Operating conditions:
– l ~ 1060nm
– 110nm tuning
range
– 100kHz scan rate
Axsun’s slow signal rolloff enables longer imaging depth
range than competitive swept lasers and Spectral Domain
OCT systems
SNR over Imaging Depth
Slow SNR rolloff enables
longer imaging depth
range
Ref:
Benjamin Potsaid, Bernhard Baumann,
David Huang, Scott Barry, Alex E. Cable,
Joel S. Schuman, Jay S. Duker, and
James G. Fujimoto, "Ultrahigh speed
1050nm swept source / Fourier domain
OCT retinal and anterior segment imaging
at 100,000 to 400,000 axial scans per
second," Opt. Express 18, 20029-20048
(2010)
1060nm 47kHz
InGaAs Camera 850nm 91kHz
CMOS CameraAxsun 1060nm
100kHz Engine
-60
-40
-20
0
20
40
60
80
100
120
0.001 0.01 0.1 1 10 100 1000 10000
dB
Reference Power (uW)
Sensitivity for 2.5 mW sample power
Noise
Signal
SNR
SNR + Loss
OCT System Performance
Operating conditions:
– l ~ 1060nm
– 110nm tuning range
– 100kHz scan rate
– System includes
Axsun BD and DAQ
Shot Noise Limited
sensitivity of 102dB
Axsun OCT Engine
Current products
Axsun OCT Imaging Products• OCT Engines
– Enabling element for next generation Frequency Domain
OCT systems
– Industry leading speed, imaging depth and resolution
– Small, rugged and reliable
Swept Laser Swept Laser with Integrated Optics Complete OCT Engine
OCT system with Axsun SS Laser &
Axsun Data Acquisition Board
Swept Laser
20
80
50
50
Balanced
Receiver
Variable Delay
10
90
Clock
Clock interferometerDAQ Board
Sweep
Trigger
Signal
1060 nm OCT “Engine”
Probe
Axsun OCT products
Axsun Swept Laser OEM EngineAxsun Camera Link DAQ Board
Axsun Swept Laser Benchtop
EngineAxsun Swept Laser Engine with
integrated DAQ
New 2 Channel DAQ Overview
500MS/s PCIe DAQ
x8 PCIe
Bra
cket
Cut
out
regi
on (
end
view
)4
GTXs
8 GTXs
DSP
TI ADC
TI ADC
BracketMtg Hole
MaximADC
Virtex-6Xilinx
XC6VLX130T-1FFG784C
+ Aavid374324B60023G(27x27x10mm)
spring-clip
anchor
Flash
FRAM
LED
StandoffMtg Hole
(on Engineand heatsink)
Engine PCB Outline
PHY
1Gb
PHY
PHY
JTAG1 J6
QSFP cageMolex 0747500021
Module
AvagoAFBR-79Q4Z
PCB Bracket
Strut
Mtg HoleStrut
CLOCK LOGIC
12V SUPPLY FILTER,
DIGITAL VOLTAGE REGULATORS
(5VD, 3.3VD, 2.5V, 1V)
ANALOGVOLTAGE
REGULATORS(6V, 5VA, 3.3VA
-5V)
SATA
J1
SATAJ2
PowerJ3
USBJ4
MBJ5
0.124
SDRAM
SMA J10
Hand-pieceJ11
RJ-45J9
(R/A)
COMJ7
7.000”
4.376”
FAN J16
AUX
J15
F/O
J8
JTAG J12J14
J13
• 2 Channel PCIe based DAQ Board
– Specifically designed to work
seamlessly with Axsun 100kHz and
future 200kHz sources
– 2 Channel 500MS/s 12-bit DAQ– 1024-2048 samples per A-scan
– Xilinx Virtex-6 FPGA gives added
signal processing capability– Image processing (FFT, Pol. Mixing,
Windowing)
– Image compression
– Multiple high speed data interfaces– PCIe x 8, Ethernet, GBE, RS232,
– In-house expertise to provide custom
algorithms
– Quick turn customization capability
will be a differentiator and speed
TTM for our customers
New Wide Bandwidth 1310nm Engine> 40% Wider Tuning BW
150nm Axsun 1310nm Source
Axsun Proprietary and Confidential Information
• 140nm 1310nm Engine– 50 or 100kHz Sweep Rate
– High Output Power (20mW Average)
– Wide (>140nm) Tuning Range
– >12 mm Coherence Length
– Enables 10um Axial Resolution and High
Signal to Noise Ratio
– Compact OEM Module design
– USB Interface
– Optional MZI Clock output
Axsun OCT Real World
Imaging Examples
Axsun SS-OCT engines used in broad range of
clinical applications
World Class Retinal Imaging
Image Courtesy of
Topcon
(Healthy Subject)
1,050 nm 840 nm
Courtesy of Topcon, healthy Subject
Comparison of 1060nm SSOCT vs 840nm
SDOCT
Scan length : 12 mm
1,050nm
High Myopia
強度近視 High Myopia Patient
脂肪組織
硝子体
強膜 脈絡膜
Scan length : 12 mm
Scan length : 12 mm
中心性漿液性脈絡網膜症(central serous
chorioretinopathy:CSC)
Enhanced Depth Imaging with Axsun SL
Engine
• SSOCT Imaging of the
entire Anterior Segment,
Kitasato University
showing dynamic
accommodation 1
• Full Anterior Segment
Imaging using fast
Optical Switching – Univ.
of Luebeck 2
1. Biomedical Optics Express Vol. 1, Issue 5, Nov. 2010
2. ARVO Meeting, May 2011
12mm
OCT Assisted Micro-Surgery
• The use of OCT as
guidance for Micro-
surgery in the eye or
elsewhere in the body
makes the procedure
faster with better
outcomes
Biomedical Optics Express, Vol. 4, Issue 7, pp. 1045-1050 (2013)
Corneal Prosthesis Imaging
• 1060nm OCT Precisely
measures the anterior
segment and can be
used to assess the
integrity of the
keratoprosthesis (KPRO)
implant
• The speed and depth
range of SSOCT minimize
motion artifacts and
provide a more complete
image than SDOCT
systems
JBO 18(8) 086002 August 2013, Zawadzki et al
Doppler Imaging with Axsun SL Engine
• Retinal Blood flow with Axsun 200kHz SSOCT demonstrated by MIT 1
• Doppler OCT blood flow measurement data from Duke University 2
– Axsun 1060nm SSOCT demonstrated a more than 60% improvement in Doppler dynamic range over SDOCT
MIT Retinal Blood Flow with 200kHz Doppler OCT
1. Biomedical Optics Express Vol. 2, Issue 6, May 2011
2. Biomedical Optics Express Vol. 2, Issue 8, August 2011
High Velocity Doppler OCT retinal blood flow
comparison of Axsun 1060nm SSOCT vs 830nm
SDOCT
Non-Ophthalmic 1310 images
J. de Boer group, "High speed miniature motorized endoscopic probe for optical frequency domain imaging," Opt. Express 20, 24132-24138 (2012);
D. Sampson group, "High-sensitivity anastigmatic imaging needle for optical coherence tomography," Opt. Letters 37, 5247-9 (2012);
Non-Ophthalmic 1310 images
J. de Boer group, "High speed miniature motorized endoscopic probe for optical frequency domain imaging," Opt. Express 20, 24132-24138 (2012);
D. Sampson group, "High-sensitivity anastigmatic imaging needle for optical coherence tomography," Opt. Letters 37, 5247-9 (2012);
Speed of SSOCT Enables Dynamic Measurement
• OCT Doppler Imaging of
Vibrating porcine Vocal
Chords – UC Irvine (1)
38
1. June 2011 / Vol. 19, No. 12 / OPTICS
EXPRESS 2010
OCT in Dermatology
Images courtesy of Michelson Diagnostics
20kHz 1310-Wideband with K-Clock
OCT in Dentistry• OCT offers dentists a
new high resolution
modality enabling
earlier detection of
decay and true
preventive dentistry
Images generated by Axsun 1310 Engine
Biometric Measurement with OCT
• OCT can be used for
Spoof Proof fingerprint
detection, displaying
the fingerprint,
detecting vascular
pattern and blood
flow, scars and
scratches and sweat
duct patterns for a fast
ultra secure image with
many unique attributes
Flexible laser platform
14 mm
SOA
Tunable FP Filter
Laser Cavity
GainOutput
Optical
Fiber
Fiber
Reflector
Lens Lens
Tailoring of tunable filter finesse, FSR and cavity length optimizes
our laser to image a range of depth, resolution, and sweep speed
Extended Coherence Length• High speed extended depth
imaging
• 1060nm SS-OCT
• 30nm tuning BW
• 30kHz Speed
• Designs up to 100mm Lc
have been demonstrated Lc = ~70mm
Enables new applications such as whole eye imaging
Current Axsun SS-OCT lasers
A-line rate (kHz)
Tunin
g B
andw
idth
(nm
)
20 2001005030
140
110
30
1310
1060 long Lc
1060
Ping-Pong
Laser Operation and Advanced
System Development
Basic Operation
Laser tuning driven by non-
linear phase shift
Fig. 7CitationAl-Hafeez Dhalla, Derek Nankivil, Joseph A. Izatt, "Complex conjugate resolved heterodyne swept source optical coherence tomography using coherence revival," Biomed. Opt. Express 3, 633-649 (2012); http://www.opticsinfobase.org/boe/abstract.cfm?uri=boe-3-3-633
Coherence Revival
Fig. 8
Laser Operation Summary
• Axsun laser is passively mode-locked
• Non-linear tuning mechanisms promote short to
long tuning (blue -> red)
• Cavity modes do not have to build up from
spontaneous emission
• Enables high-speed tuning
• Coherence revival shown both theoretically and
experimentally
Approaches for increased A-line
rate
52
• Faster filter drive
• Utilize both up and down wavelength tuning
• New fast tunable laser regime (FDML)
• Multi-spot imaging
• Time-delayed optical buffering
Time-delayed optical buffering
increases A-line rate
53
Huber et al., Optics Letters 2006
2x buffering (370 kHz) Huber et al., Optics Letters 2007
2x buffering (236 kHz)
Long fiber lengths required: ~1km
4/8/16x buffering has also been demonstrated
Booster amplifier typical
Proposed buffering alternative –
Dual source “Ping Pong” approach
54
• Two lasers are time-multiplexed into one output
• Output A-line rate is twice the rate of individual
lasers
Drive Electronics
Laser 1
Laser 2
50/50
95/5
Output 2
Imaging
k-Clock MZI
Ping-Pong Timing
Ping
Pong
Trigger
Output 200kHz 1060 SS-Engine
1060-200kHz PP Images
Finger Tip Tape Roll Kiwi Fruit
Sweat Gland 60 um Layers
Integrated design: Dual Source
“Ping-Pong” Laser
• Shared laser cavity = “1.5 cavities”
• Ping/Pong orthogonal output polarization
SOA
SOAPBC
HWPOutput
Optical
Fiber
Fiber
Reflector
Filter Lens Lens
Lens
Ping-Pong vs. Buffering
Summary
• Axsun’s Core Technology provides distinct
advantages in size, speed, imaging depth range
and reliability for our OCT Engine Products
• Axsun’s Swept Laser OCT Engine products are
leading the way in the next generation of OCT
imaging systems
• The Axsun OCT Swept Laser platform is flexible and can be configured to meet requirements for a wide range of imaging applications
Acknowledgements
Dale Flanders, PhD
Randy Murdza
Peter Whitney, PhD
Walid Atia, PhD
Mark Kuznetsov, PhD
Bart Johnson, PhD
Brian Goldberg, PhD
Chris Cook
Vaibhav Mathur
Ranko Galeb
Bill Wells
Noble Larson
Eric McKenzie
Ed Mallon
Steve Conover
Carlos Melendez
Tom Williams
Seungbum Woo
Axsun Team
Systems engineering booth B-165
Thank you!
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