为充分证明偏振移位键控可有效抑制大气湍流等因素的影响这一观点，对目前大气激光通信系统中广泛采用的几种强度调制和偏振移位键控技术进行详细的分析研究，从各调制方式的功率利用率、带宽需求、传输容量以及差错性能几个方面进行对比。研究结果表明，各调制方式各有千秋，不能一概而论。综合各方面性能考虑，偏振移位键控较其他几种强度调制方式更具优越性，其具有最大传输容量、最小的带宽需求和接收误码率。由此可见，偏振调制方式更适合应用于大气激光通信。

To fully demonstrate the view that polarization modulation can effectively suppress the influence of atmospheric turbulence，this paper analyzes polarization shift keying and several kinds of intensity modulation which are widely used in atmospheric laser communication systems. The comparative study of various modulation modes contains of power utilization, bandwidth requirement, transmission capacity and error performance. The results show that PolSK is more superior to any other kinds of intensity modulation mode when we consider all aspects of the performance. It has the maximum transmission capacity, the smallest bandwidth and receiving bit error rate. Thus, the polarization modulation is more suitable to be used in atmospheric laser communication.