Multiple polarization modulation (MPLM) system for coherent optical space communication

For a future multirate, multichannel and multimedia transmission with high capacity and high flexibility, this paper proposes a multiple polarization modulation (MPLM) system using polarization multiplexing, which is an optical hybrid transmission technique to transmit modulated subcarriers and baseband signals simultaneously and independently. It is clarified that the MPLM system can remove laser phase noise and the polarization axis mismatch between transmitter and receiver and its theoretical performance is sufficiently high.