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Proceedings Paper

Free-space optical communication link performance enhancement via modified receiver geometric characteristics
Author(s): Narasimha S. Prasad; Patrick T Kratovil; Sara C. Tucker; Neil J. Vallestero; Mark Khusid
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Paper Abstract

A free-space, line-of-sight, ground-based optical link at 1.5 microns is attractive for tactical communications because it would provide eye-safety, covertness and jam-proof operation. However, the effects of atmospheric turbulence have to be appropriately mitigated for achieving acceptable bit-error-rate (BER) for reliable dissemination of information. Models to predict achievable BER at 1.5 microns for several beam propagation schemes that include beam scanning have been developed for various turbulence conditions. In this paper, we report performance characterization of free-space, high-data (>1Gb/s) rate beam propagation parameters at 1.5 microns for achieving BER reduction under the presence of turbulence. For standard free-space optical links, the mean SNR limits the achievable BER to lesser than 10-6 for Cn2 (structure constant of refractive index fluctuations) around 10-12 m-2/3. To validate these models, simultaneous measurements of structure constant of refractive index fluctuations, Cn2, and coherence diameter over tactical ranges have been carried out and analyzed. The effect of input beam conditioning to reduce BER levels have been explored. Furthermore, single and multiple transmit beams in conjunction with single and multiple detector arrangements have been examined. Based on these measurements, it is shown that the advantages of input beam conditioning coupled with modified receiver geometric characteristics would provide a path for BER reduction and hence, appreciable enhancements in data link reliability.

Paper Details

Date Published: 27 January 2004
PDF: 12 pages
Proc. SPIE 5160, Free-Space Laser Communication and Active Laser Illumination III, (27 January 2004); doi: 10.1117/12.510630
Show Author Affiliations
Narasimha S. Prasad, Coherent Technologies, Inc. (United States)
Patrick T Kratovil, Coherent Technologies, Inc. (United States)
Sara C. Tucker, Coherent Technologies, Inc. (United States)
Neil J. Vallestero, U.S. Army Communications Electronics Command (United States)
Mark Khusid, U.S. Army Communications Electronics Command (United States)


Published in SPIE Proceedings Vol. 5160:
Free-Space Laser Communication and Active Laser Illumination III
David G. Voelz; Jennifer C. Ricklin, Editor(s)

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