在分析光波偏振特性的基础上，提出了偏振移位键控(PolSK)技术，即对激光偏振态参数进行调制/解调的技术。构建了基于圆偏振移位键控(CPolSK)的平衡探测大气激光通信系统，利用圆偏振光的两种旋态(左旋和右旋)进行编码通信。并对开关键控(OOK)系统与单路接收PolSK系统、平衡探测CPolSK系统进行计算机仿真，对比、分析各通信系统性能。结果表明,PolSK技术在自由空间光通信领域具有独特的优越性。平衡探测CPolSK的大气激光通信系统接收信号波形的幅值为OOK系统和单路接收PolSK系统的2倍。且在相同仿真参数条件下，平衡探测CPolSK系统的眼图也远优于OOK系统。由此可以看出，基于PolSK的大气激光通信技术可有效提高通信系统性能，在未来的自由空间光通信领域有广阔的发展空间和应用前景。

Polarization shift keying (PolSK) technology is proposed based on the analysis of the polarization characteristics of the optical wave. Atmospheric laser communication system based on circular polarization shift keying (CPolSK) with balanced detection is constructed, in which the left and right circularly polarization states of optical wave are used to encode signal. OOK system and PolSK system are simulated and contrasted with single receiver and CPolSK system with balance detection, and the performance of various communication systems is analyzed. The results show that PolSK has a unique advantage in the field of free-space optical communication. Waveform amplitude of signal received by CPolSK system with balance detection is two times than that of the OOK system and the PolSK system with single receiver. And in the same simulation parameters, eye diagram of CPolSK system with balance detection is far superior to the OOK system. From this, we can see that atmospheric laser communication system based on PolSK can effectively improve the performance of the communication system, and it has broad space for development and application in the free space optical communication field in the future.