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Proceedings Paper

Coherent optical receiver for PPM signals under atmospheric turbulence
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Paper Abstract

In free-space optical communications, atmospheric turbulence causes fluctuations in both the intensity and the phase of the received signal. We propose to use focal-plane arrays to collect optical signals from different spatial modes simultaneously, and then recombine them optimally. Experimental setup for proof-of-concept coherent adaptive array detection experiment using 32-Pulse Position Modulated (PPM) signals under atmospheric turbulence has been completed. Adaptive combining of experimentally obtained heterodyned PPM signals with pulse-to-pulse coherence, in the presence of simulated atmospheric turbulence is demonstrated. The adaptively combined PPM signals are phased up via a Least-Mean-Square (LMS) algorithm suitably optimized to operate with PPM in the presence of additive shot-noise, and detected via a maximum likelihood software receiver. Convergence study of the algorithm is presented and results with simulated PPM signals and real PPM signals experimentally obtained at the laboratory are presented.

Paper Details

Date Published: 18 April 2005
PDF: 12 pages
Proc. SPIE 5712, Free-Space Laser Communication Technologies XVII, (18 April 2005); doi: 10.1117/12.591269
Show Author Affiliations
Michela Munyoz Fernandez, California Institute of Technology (United States)
Jet Propulsion Lab. (United States)
Victor A. Vilnrotter, Jet Propulsion Lab. (United States)


Published in SPIE Proceedings Vol. 5712:
Free-Space Laser Communication Technologies XVII
G. Stephen Mecherle, Editor(s)

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