Performance analysis of a fiber-bundle based FSO link

A transmitter and receiver design based on the use of fiber optic bundles have been proposed and studied both experimentally in the laboratory and theoretically through simulation, and have shown promise for providing enhanced functionality in mitigating the effects of turbulence and weather on the pointing, acquisition and tracking problem. In this paper, the operation of an FSO link constructed from these designs is analyzed under varying environmental conditions. A transmitter with a linear fiber array transmitted at 1550 nm to a receiver constructed using a hexagonal array of 19 fibers located 4.6 meters away. Transmissions occurred for different weather conditions over grass, concrete, and brick surfaces at different locations on campus. Data at 100 kb/s was transmitted across the link and the collected signal was recorded for off-line statistical analysis, including achieved bit-error rate. The investigation showed that the system performance was only slightly sensitive to temperature and terrain. The largest contributing factor to high BER time periods was when the receiver optics were blown out of the path of the transmitted beam due to instabilities in the construction of the mounting unit of the receiver. Improvements in the mounting structure are expected to eliminate this effect and allow a more accurate assessment of the receiver´s capabilities.