Development of a Simulation Tool for Free-Space Coherent Laser Communications

摘要

Over the last few years, there has been a renewed interest in free-space coherent laser communications due to the fabrication of terminals for satellite communication links which are using a homodyne binary phase-shift keying (BPSK). A general model for an optical coherent communications atmospheric channel is still missing although several approaches have been undertaken in the past. In order to evaluate the channel model, a simulation tool is being developed. It is shall be assistant to measured data with the aim to find a general theory. In this paper, two models are being applied and compared. The bit-error rate (BER) is calculated and it is found that horizontal links near the ground at low altitudes will provide a sufficient BER for high-speed data communications up to a few km under normal conditions. The simulation is intended to be further extended by higher order spatial modal compensation as well as a slant and ground-to-satellite atmospheric propagation path model.