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Proceedings Paper

Electronics design of a multi-rate DPSK modem for free-space optical communications
Author(s): H. G. Rao; C. A. Browne; D. O. Caplan; J. J. Carney; M. L. Chavez; A. S. Fletcher; J. J. Fitzgerald; R. D. Kaminsky; G. Lund; S. A. Hamilton; R. J. Magliocco; O. V. Mikulina; R. J. Murphy; M. M. Seaver; M. S. Scheinbart; N. W. Spellmeyer; J. P. Wang
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Paper Abstract

We have designed and experimentally demonstrated a radiation-hardened modem suitable for NASA’s Laser Communications Relay Demonstration. The modem supports free-space DPSK communication over a wide range of channel rates, from 72 Mb/s up to 2.88 Gb/s. The modem transmitter electronics generate a bursty DPSK waveform, such that only one optical modulator is required. The receiver clock recovery is capable of operating over all channel rates at average optical signal levels below -70 dBm. The modem incorporates a radiation-hardened Xilinx Virtex 5 FPGA and a radiation-hardened Aeroflex UT699 CPU. The design leverages unique capabilities of each device, such as the FPGA’s multi-gigabit transceivers. The modem scrubs itself against radiation events, but does not require pervasive triple-mode redundant logic. The modem electronics include automatic stabilization functions for its optical components, and software to control its initialization and operation. The design allows the modem to be put into a low-power standby mode.

Paper Details

Date Published: 25 March 2014
PDF: 16 pages
Proc. SPIE 8971, Free-Space Laser Communication and Atmospheric Propagation XXVI, 89710Y (25 March 2014); doi: 10.1117/12.2057574
Show Author Affiliations
H. G. Rao, MIT Lincoln Lab. (United States)
C. A. Browne, MIT Lincoln Lab. (United States)
D. O. Caplan, MIT Lincoln Lab. (United States)
J. J. Carney, MIT Lincoln Lab. (United States)
M. L. Chavez, MIT Lincoln Lab. (United States)
A. S. Fletcher, MIT Lincoln Lab. (United States)
J. J. Fitzgerald, MIT Lincoln Lab. (United States)
R. D. Kaminsky, MIT Lincoln Lab. (United States)
G. Lund, MIT Lincoln Lab. (United States)
S. A. Hamilton, MIT Lincoln Lab. (United States)
R. J. Magliocco, MIT Lincoln Lab. (United States)
O. V. Mikulina, MIT Lincoln Lab. (United States)
R. J. Murphy, MIT Lincoln Lab. (United States)
M. M. Seaver, MIT Lincoln Lab. (United States)
M. S. Scheinbart, MIT Lincoln Lab. (United States)
N. W. Spellmeyer, MIT Lincoln Lab. (United States)
J. P. Wang, MIT Lincoln Lab. (United States)

Published in SPIE Proceedings Vol. 8971:
Free-Space Laser Communication and Atmospheric Propagation XXVI
Hamid Hemmati; Don M. Boroson, Editor(s)

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