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Direct-detection Free-space Laser Transceiver Test-bedNASA Goddard Space Flight Center is developing a direct-detection free-space laser communications transceiver test bed. The laser transmitter is a master-oscillator power amplifier (MOPA) configuration using a 1060 nm wavelength laser-diode with a two-stage multi-watt Ytterbium fiber amplifier. Dual Mach-Zehnder electro-optic modulators provide an extinction ratio greater than 40 dB. The MOPA design delivered 10-W average power with low-duty-cycle PPM waveforms and achieved 1.7 kW peak power. We use pulse-position modulation format with a pseudo-noise code header to assist clock recovery and frame boundary identification. We are examining the use of low-density-parity-check (LDPC) codes for forward error correction. Our receiver uses an InGaAsP 1 mm diameter photocathode hybrid photomultiplier tube (HPMT) cooled with a thermo-electric cooler. The HPMT has 25% single-photon detection efficiency at 1064 nm wavelength with a dark count rate of 60,000/s at -22 degrees Celsius and a single-photon impulse response of 0.9 ns. We report on progress toward demonstrating a combined laser communications and ranging field experiment.
Document ID
20080032735
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Krainak, Michael A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Chen, Jeffrey R. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Dabney, Philip W. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Ferrara, Jeffrey F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Fong, Wai H. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Martino, Anthony J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
McGarry Jan. F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Merkowitz, Stephen M. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Principe, Caleb M. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Sun, Siaoli (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Zagwodzki, Thomas W. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 24, 2013
Publication Date
January 19, 2008
Subject Category
Lasers And Masers
Meeting Information
Meeting: Photonics West 2008
Location: San Jose, CA
Country: United States
Start Date: January 19, 2008
End Date: January 25, 2008
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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