Research On The Technology Of Plorization Shift Keying In Free Space Optical Communication System

Space optical communications utilizes laser beam as the carrier to transfer the information. With the emergence of lasers in the beginning of the1960s, laser communication has been rapidly developed. Compared with other wireless communication mode, laser communication reserves the advantages of a larger information capacity, higher security, no needing to receive authorization license, small sized equipment, and flexible construction. So laser communication plays important role in the communication between satellite links, the ground stations, and underwater.Modulation technique is one of the key technologies in wireless laser communications. Modulation mode utilized in laser communication system at home and abroad is always the intensity modulation mode. The present study discussed the polarization modulation mode, a new intensity modulation mode that received a widespread concern in recent years. And it also studied the modulation principle, system implementation and the variation of polarization properties of polarized light transmitted in the atmospheric channel. The study showed that polarization modulated space laser communication systems had a better communication performance, and inhibited the interference of atmospheric channel. So polarization modulation is the most suitable modulation mode for space laser communication field.