利用光子追踪法建立了大气直视信道模型,仿真分析了信噪比(SNR)、比特率和能见度三者对自由空间光通信误码率的影响。选用1.55μm和10.6μm两个波长作对比分析,结果显示两种波长的误码率随SNR的增大而减小,随比特率的增大而增大。在能见度较低时,10.6μm激光的误码性能优于1.55μm激光,并且在低SNR和高比特率的情况下,这种优势越发明显。在能见度较高时,两种波长的误码性能相差无几。 The atmospheric direct-view channel model was established by photon tracing method. The effects of SNR, bit rate and visibility on the bit error rate of free space optical communication were analyzed. The comparative analysis of two wavelengths of 1.55μm and 10.6μm shows that the error rates of the two wavelengths decrease with the increase of SNR and increase with the increase of bitrate. At lower visibility, the error performance of 10.6μm lasers is superior to 1.55μm lasers, and this advantage becomes more apparent at low SNR and high bit rates. At higher levels of visibility, the error performance of the two wavelengths is almost the same.