Research on the effect of key system parameters on linewidth tolerance of space coherent optical communication

Abstract

In order to investigate the influence of different system parameters on linewidth tolerance in space coherent optical communication system, we give the ensemble average bit error rate (BER) model of binary phase-shift keying (BPSK) modulation and homodyne detection space coherent optical communication system. The BER model also considers the laser linewidth induced phase noise and pointing error. Based on the BER model, the numerical simulation is conducted to investigate the relationship between linewidth tolerance and different system parameters of divergence angle, receiving aperture, zenith angle, and transmitted optical power. Through our numerical simulation, it is found that the linewidth tolerance will change from several kHz to several hundred kHz. Besides, linewidth tolerance will decrease with the increase of divergence angle and zenith angle. While with the increase of receiving aperture and transmitted optical power, the linewidth tolerance will increase. Also, we find that the linewidth tolerance changes more obviously with the variation of the zenith angle. This paper has a good reference value for the selection of laser linewidth of the space coherent optical communication system under different system parameters.