Analog coherent optical space communication system using polarization ellipticity angle modulation

It is expected that analog coherent optical communication systems will become an important system for future space communications, in which an optical carrier is coherently modulated by frequency‐multiplexed radio signals and optically transmitted. In this paper, the fundamental of the analog coherent optical space communication system are investigated, and a new analog optical communication scheme suitable for the space communication is proposed and analyzed. In the proposed analog scheme, the polarization ellipticity angle is selected as the modulation parameter, and the insensitiveness to the phase noise of the high‐power laser and to the polarization axis mismatch are obtained as well as the high detection gain due to the use of a wideband FM signal during the demodulation of the polarization ellipticity angle.