Broadband Coherent Communication System

摘要

During the last few years, there has been an increasing demand for high-speed data transmission. Although, fiber optics technology has matured already for high data transport, however, for spaces lacking the fiber infrastructure, wireless technologies are becoming the medium of choice for broadband networking. The first investigations on optoelectronic satellite link were based on intensity modulation of the laser beam and the system is still very bulky and heavy. Thus, it becomes rapidly evident that optical coherent communication is the only way to achieve the requirement of space communication. Coherent communication also has advantages over the intensity modulation system in terms of quantum noise, it also allows better packing of the channel in frequency domain. In the present paper an outline of the coherent communication system pertaining to fiber optics and free space communications is discussed.