自由空间光通信中大气光束传输数值模拟研究

Simulation Research of Laser Beam Atmospheric Propagation in Free-Space Optical Communication

相对于理论研究和实验研究,数值模拟研究具有独特的优越性,包括参数可控和可实现系综平均等。因此,对于大仰角链路大气湍流影响研究等实验系统无法搭建的研究,可以采用光束传输的数值模拟方法来进行研究。在Zernike多项式展开法和多相位屏理论的基础上,建立了基于Zernike多项式的大气湍流多相位屏数值模型,实现了高斯光束水平链路(0°)和大仰角典型链路(30°、60°)大气传输的数值模拟,并利用水平链路到达角(AOA)起伏方差经验计算公式对3组900次水平链路数值仿真结果进行了分析。结果表明,数值模拟到达角起伏方差和实验值误差在5%以内,多相位屏数值模型是有效的。该工作对自由空间光通信系统中大气湍流影响研究具有重要意义。

Numerical simulation has advantages over theoretical and experimental research of controllable parameters and realizing ensemble average. Therefore, numerical simulation can be used to study the influence of atmospheric turbulence in big elevation link and other fields which can＇t be built in experimental system. Using Zernike polynomial method and multi-layer phase screen theory, the atmospheric multi-layer phase screen model is established. The numerical simulations of Gaussian beam propagating in horizontal link （0°） and big elevation link （30°,60°） are achieved. Using the empirical formula for the variance of angle of arrival （AOA） fluctuations in horizontal link, the results of three groups of 900 times numerical simulation in horizontal link are analyzed. The results show that the error of variances of AOA fluctuations between simulation and experimental values is within 5 %, and this model is effective. This work is important for studying the influence of atmospheric turbulence in free- space optical communication system.