Compensation technology of Doppler frequency shift in space coherent optical communication using DSP
空间相干光通信中基于DSP的多普勒频移补偿技术

Optical phase-locked loop(OPLL) is often used in space coherent optical communication as the traditional way to achieve the phase synchronous. But the OPLL is affected by the Doppler frequency shift, so in this paper, we use an open-loop compensation technology based on DSP to compensate the Doppler frequency shift, and apply it to a recursive demodulate system, demodulating the next data according to the previous data information. Simulation results show that the open-loop compensation technology based on DSP is able to compensate the Doppler frequency shift, and allow the space coherent optical communication system to demodulate without any optical phase-locked loop, and the performance of the system can approach the ideal status which Doppler frequency shift is completely compensated.