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Proceedings Paper

Impact of atmospheric effects in free-space optics transmission systems
Author(s): Erich Leitgeb; M. Gebhart; Peter Fasser; Josef Bregenzer; J. Tanczos
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Paper Abstract

The coherent wave propagation is affected by the atmosphere in many ways. Several theoretical models for propagation of light through the atmosphere are well known. To predict link availability in different climate zones it is necessary to do field tests for data acquisition. Therefore we have done reliability- and availability-tests on commercial available and also on self-developed optical point-to-point and point-to-multipoint systems. We sent test data at 155 Mbps (STM-1) from one FSO-unit to a distant (2.7 km) FSO-unit. The received data were sent back (loop) to the first unit. Our primary interest in this long-time investigation was the time of link failure, because it turned out that BERs be low in general, less than 10-8 at very bad weather conditions in winter and less than 10-12 at clear sky. In a second measurement campaign we investigated the influence of turbulences in the air. The measurements clearly show variations in the fluctuation of the incoming optical power during a day. In principle there are two periods with strong variations, during the day and during the night, and two periods of rather stable air, these are around sunset and sunrise. The power variations have the highest amplitude and show the fastest changes at noon and they are less distinct and show slower changes in the night. As a medium value we got power variations of 4 dB over the distance of 2.7 km in summer. The duration of fades/scintillations was in the order of 4 to 60 milliseconds at daytime and about 10 to 150 ms in the night.

Paper Details

Date Published: 30 April 2003
PDF: 12 pages
Proc. SPIE 4976, Atmospheric Propagation, (30 April 2003); doi: 10.1117/12.483802
Show Author Affiliations
Erich Leitgeb, Technical Univ. Graz (Austria)
M. Gebhart, Technical Univ. Graz (Austria)
Peter Fasser, Technical Univ. Graz (Austria)
Josef Bregenzer, Technical Univ. Graz (Austria)
J. Tanczos, Technical Univ. Graz (Austria)

Published in SPIE Proceedings Vol. 4976:
Atmospheric Propagation
Cynthia Y. Young; John S. Stryjewski, Editor(s)

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