Performance comparison study of modulation in atmospheric laser communication system

There were many ways of modulation in the laser communication system. In order to verify that PolSK modulation was the most suitable technology for space laser communication system, we analyzed the implementation principle of several signal modulation ways in this paper. By combing the theoretical analysis and software simulation, we make an analysis and comparative study through five aspects in the function of the PolSK modulation and the traditional modulation ways, including transmission rate in the unit, bandwidth requirements, transmission capacity, the average power utilization and error performance. The results indicated that PolSK modulation possess a higher transmission rate in the unit, a lower bandwidth requirements, and a larger transmission capacity. The most important thing was that PolSK modulation mode had a superior performance and a strong anti-air channel interference activity compared with the traditional modulation in a weak turbulence conditions. So PolSK modulation mode was suitable for laser communication system.