Research on optimum local oscillator laser power of the space coherent laser communication

The space coherent laser communication is a very potential and attractive mean as it allows higher speed communication between satellites. The space coherent laser communication makes use of local oscillator laser power to improve the power of received optical signal by mixing local oscillator laser and optical signal together. However, the power of the local laser oscillator can not be increased infinitely, too large but reduces the detection sensitivity. In this paper, starting from the principle of the signal-to-noise ratio of the space coherent laser communication, we found the optimum local oscillator laser power was 28.174mw, under the condition of the selected photodetector specific parameters. It is a great significant for high detection sensitivity and low data error of the actual coherent detection system.