In the atmosphere laser communication, scintillation caused by atmospheric turbulence could seriously affect the performance of communication system and increase bit error rate. Multi-beam transmission is an effective method to overcome this effect. We analyze the intensity probability distribution when transmitting with different numbers of beams and analyze the intensity probability distribution with different aperture diameters when transmitting multi-beam. The results show that when the transmitting beam and the aperture diameter increase, intensity probability distribution more likely tend to normal distribution and the mean intensity probability density also increases. This article also analyzes the relationship between the normalized correlation coefficient of multi-beam transmission and the intensity variance. Besides, the bit error rate of multi-beam transmission in different turbulent environment is analyzed. Analysis results show that multi-beam transmission system can improve the intensity fluctuation on receiving surface well and reduce bit error rate%在大气激光通信中,大气湍流所引起的光强闪烁会严重影响通信系统的性能,导致系统误码率的增加,多光束发射是克服这种影响的有效方法,本文分析了用不同数目光束发射时的光强概率分布；以及多束光发射时接收端用不同直径的接收透镜进行接收时的光强概率分布,结果表明随着发射光束的增加、孔径直径的增大,光强概率分布更加趋于正态分布,光强概率的均值增大.文中还分析了多光束发射的归一化相关系数和光强方差的关系以及多光束发射在不同湍流环境下的误码率性能,分析结果表明多光束发射系统可以很好地改善接收面的光强起伏,降低系统的误码率.
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