A Study on Atmospheric Turbulence Effects in Full-Optical Free-Space Communication Systems

Next generation free-space optical communication systems have used fiber-optic technology as the seamless connection between free-space and optical fiber. The full-optical free-space optical communication systems use optical fiber as the receiver to get faster communication speed. The atmospheric turbulence deeply influenced on the optical wave propagated in terrestrial application. As the active receiving area of the full-optical free-space optical communication systems is very small, it is important to research on the atmospheric turbulence effects on the full-optical free-space optical communication system. In this paper, we discuss about both the turbulence-induced intensity fluctuations and the angle-of-arrival effects in full-optical free-space optical communication systems which are used in a few kilometers communication. We gave the numerical results of the atmosphere turbulence effects on the free-space optical communication systems. In order to minimize the atmospheric turbulence influence on the full-optical free-space optical communications system, we also investigate the use of fine tracking system in the communication system. We have set up a full-optical free-space communication system in Tokyo and received useful data from the experiment. We compared the receiving power of the experiment, when the fine tracking system is On and Off. From the experiment results, we can see that the fine tracking system effectively mitigates the atmospheric turbulence and increases the receiving power of the communication system.