Performance Testing of a Risk Reduction Space Winds Lidar Laser Transmitter

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• Performance Testing of a Risk Reduction Space
  Winds Lidar Laser Transmitter
• Floyd Hovis, Fibertek, Inc.
• Jinxue Wang, Raytheon Space and Airborne Systems
• February 8, 2006

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Approach to Developing Space-Qualified 355 nm
Lasers
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Status of Related Laser Development Programs
Single frequency laser development has a broad
support base
Customer Application Required 1 mm
Performance Program Status Univ. of
NH Doppler Wind Lidar 150 mJ at 50
Hz Delivery complete NASA Langley Ozone
DIAL 1000 mJ/pulse at 50 Hz Delivery
complete Raytheon Doppler Wind Lidar 1000
mJ at 50 Hz Delivery complete Air
Force Remote Imaging Lidar 500 mJ at 100
Hz Testing in progress NASA Langley Phase II
SBIR Seed Metrology Laser 50 mW single
frequency Prototype demonstrated NASA
Langley High Spectral Res. Lidar IIP 200 mJ at
200 Hz Final build in progress NASA
Langley Mars exploration 40 mJ at 20
Hz Delivery complete Navy SBIR Rangefinder/
Designator 300 mJ at 25 Hz Final build in
progress NASA GSFC Doppler Wind Lidar
IIP 100 mJ at 200 Hz Final build in progress
Single frequency pump head resonator technology
will support a significant number of next
generation lidar applications
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Summary of Technical Approach

An all solid-state diode-pumped laser transmitter
featuring ? Injection seeded ring
laser Improves emission brightness (M2) ?
Diode-pumped zigzag slab amplifiers Robust and
efficient design for use in space ? Advanced
E-O phase modulator material Allows high
frequency cavity modulation for
improved stability injection seeding ?
Alignment insensitive / boresight Stable and
reliable operation over stable 1.0 mm cavity
and optical bench environment ? Conduction
cooled Eliminates circulating liquids w/in
cavity ? High efficiency third harmonic
generation Reduces on orbit power
requirements ? Space-qualifiable electrical
design Reduces cost and schedule risk for a
future space-based mission
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Raytheon 1 J Risk Reduction Laser Optical Layout
Final System Optical Configuration
Both the original NASA Ozone amplifiers and the
power amplifier have been shown to be capable of
100 Hz operation
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Raytheon 1 J Risk Reduction Laser Optical Layout
Final System Optical Configuration
Both the original NASA Ozone amplifiers and the
power amplifier have been shown to be capable of
100 Hz operation
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Solid Model of Integrated LaserTop View -
Electrical Connection End
LEU cooling plates
Laser Electronics Unit (LEU)
LOM/LEU electrical interconnections
28 VDC terminals
Laser Optics Module (LOM)
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Solid Model of Integrated LaserTop View -
Optical Output End
LEU cooling plates
Laser Electronics Unit (LEU)
Output windows
Laser Optics Module (LOM)
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Solid Model of Integrated LaserBottom View
LOM cooling plates
Mounting foot
Laser Optics Module (LOM)
Mounting foot
Mounting foot
Laser Electronics Unit (LEU)
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Acceptance Testing of Space Winds Lidar Laser
Transmitter Is Complete
Design uses all three amplifiers Autonomous
operation controlled through RS232 serial
interface Nominal 28 VDC primary
power Space-qualifiable electrical
design Thermal control through conductive
cooling to liquid cooled plates bolted to bottom
of laser module 355 nm single frequency output
of over 460 mJ/pulse _at_ 50 Hz (23 W) Delivered
system will undergo extended life testing at
Raytheon
Electronics module
Laser module
Space-Winds Lidar Laser Transmitter
Final acceptance testing was completed in
November 2006
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Acceptance Testing1064 nm Power Energy Test
Results
50 Hz operation Final 1064 nm power - 44.4 W
(888 mJ/pulse) Input electrical power -
684W Wall plug efficiency - 6.5 77 of final
power is reached in 1 min 99 of final power is
reached in 2 minutes Short term (20 s) shot to
shot energy stability is 0.8 (3?) Long term (30
min) energy stability is 3.7 (3?) Pulse width -
14 ns
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Acceptance Testing355 nm Power Energy Test
Results
50 Hz operation Final 355 nm power - 23.9 W (478
mJ/pulse) Input electrical power - 684W 355 nm
conversion efficiency - 53.8 Wall plug
efficiency - 3.5 74 of final power is reached
in 1 min 93 of final power is reached in 2
minutes Short term (20 s) shot to shot energy
stability is 3.5 (3?) Long term (30 min) energy
stability is 4.3 (3?) Pulse width - 14 ns
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Acceptance Testing 1064 nm M2
Beam quality data
Near field profile
M2x 2.2 M2y 2.3
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Acceptance Testing 355 nm M2
Beam quality data
Near field profile
M2x 4.0 M2y 5.7
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Acceptance Testing Pointing Stability
355 nm data
1064 nm data
Circle containing 90 of centroid values
Circle containing 90 of centroid values
1064 nm pointing stability lt 64 µrad (lt5 of raw
beam divergence) 355 nm pointing stability lt 71
µrad (lt10 of raw beam divergence)
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Acceptance Testing 1064 nm Frequency Stability
Frequency drift is lt 1 MHz/min and appears to
be dominated by seed laser frequency drift
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Acknowledgements

• BalloonWinds laser transmitter was funded by
  NOAA BalloonWinds
• Program through UNH and MAC
• Space Doppler Winds LIDAR risk-reduction laser
  transmitter was funded by
• Raytheon Internal Research and Development
  (IRAD)
• NASA support through the SBIR and Advanced
  Technology Initiative
• programs
• Air Force SBIR funding for 100 Hz laser
  development