Comparisons of Cn 2 measurements and power-in-fiber data from two long-path free-space optical communication experiments
Name
Parenti-2010-Comparisons of Cn 2 measurements and power-in-fiber data from two long-path free-space optical communication experiments.pdf
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2.27 MB
Format
Adobe PDF
Checksum (MD5)
ce1d6d78152c0e44b3f2584c1726c737
Author(s)
Parenti, Ronald R.
Michael, Steven
Roth, Jeffrey M.
Yarnall, Timothy M.
Date Issued
August 2010
Journal
Proceedings of SPIE--the International Society for Optical Engineering; v. 7814
Publisher
SPIE
Citation
Ronald R. Parenti, Steven Michael, Jeffrey M. Roth and Timothy M. Yarnall, "Comparisons of Cn2 measurements and power-in-fiber data from two long-path free-space optical communication experiments", Proc. SPIE 7814, 78140Z (2010); doi:10.1117/12.864256 © 2010 SPIE
Version
Final published version
Abstract
Over a two-year period beginning in early 2008, MIT Lincoln Laboratory conducted two free-space optical communication experiments designed to test the ability of spatial beam diversity, symbol encoding, and interleaving to reduce the effects of turbulence-induced scintillation. The first of these exercises demonstrated a 2.7 Gb/s link over a ground-level 5.4 km horizontal path. Signal detection was accomplished through the use of four spatially-separated 12 mm apertures that coupled the received light into pre-amplified single-mode fiber detectors. Similar equipment was used in a second experiment performed in the fall of 2009, which demonstrated an error-free air-to-ground link at propagation ranges up to 60 km. In both of these tests power levels at all fiber outputs were sampled at 1 msec intervals, which enabled a high-rate characterization of the received signal fluctuations. The database developed from these experiments encompasses a wide range of propagation geometries and turbulence conditions. This information has subsequently been analyzed in an attempt to correlate estimates of the turbulence profile with measurements of the scintillation index, characteristic fading time constant, scintillation patch size, and the shape parameters of the statistical distributions of the received signals. Significant findings include observations of rapid changes in the scintillation index driven by solar flux variations, consistent similarities in the values of the alpha and beta shape parameters of the gamma-gamma distribution function, and strong evidence of channel reciprocity. This work was sponsored by the Department of Defense, RRCO DDR&E, under Air Force Contract FA8721-05-C-0002. Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the United States Government.
MIT Department
Lincoln Laboratory
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DOI of Published Version
https://doi.org/10.1117/12.864256
