Non-Kolmogorov湍流对光强影响的模拟实验  

Simulated Experiment of the Light Intensity Influenced by Non-Kolmogorov Turbulence

作　　者：张娜娜[1] 单欣[1] 张燕革[1] 冯阳 郭松[2] ZHANG Na-na;SHAN Xin;ZHANG Yan-ge;FENG Yang;GUO Song(College of Electronic Information, Wuhan University, Wuhan 430079, China;Shanghai Academy of Spaceflight Technology, Shanghai 201109, China)

机构地区：[1]武汉大学电子信息学院,武汉430072 [2]上海航天技术研究院,上海201109

出　　处：《光子学报》2018年第6期102-110,共9页Acta Photonica Sinica

基　　金：国家自然科学基金(No.11204220);上海航天科技创新基金(No.SAST2017-103)资助~~

摘　　要：基于液晶空间光调制器进行了Non-Kolmogorov湍流的室内模拟实验,并对光强概率密度分布、光强闪烁指数及光强时间频谱进行了分析,完成了模拟实验结果与相关湍流理论之间的对比验证.实验结果显示:在弱湍流下,归一化对数光强近似服从正态分布,且随着湍流强度的减小,正态分布拟合系数增大;光强时间频谱高频段的幂律随着湍流功率谱幂律的减小呈减小趋势,与理论分析一致,但具体数值小于理论预测;闪烁指数则随着大气相干长度的增大而减小,在大气相干长度小于0.05 m的范围内闪烁指数急剧变化,在大气相干长度大于0.2 m之后趋近平缓,这一变化趋势与湍流幂律无关,与理论预测一致,表明湍流模拟实验能较好地再现湍流对无线光通信中接收光强的影响.模拟实验的误差分析表明,不同强度湍流的模拟实验其误差主要来源不同,可为实验的进一步改进提供针对性建议.A Non-Kolmogorov turbulence simulation experiment was carried out in the laboratory,based on the liquid crystal spatial light modulator. The probability density distribution,the scintillation index and the temporal powerspectrum were analyzed,and the experimental results were compared with the the turbulence theory. The results show that the probability density distribution of the normalized logarithmic intensity is more close to the normal distribution under weak turbulence,and the fitting coefficient becomes larger with the decrease of the turbulence strength. In the high frequency band of the intensity temporal power spectrum,the power law reduces as the turbulence spectral power law decreases. Although its value is less than the theoretical analysis,the variation trend does match the theory. The scintillation index decreases with the increase of the atmosphere coherence length. It changes abruptly when the atmosphere coherence length is less than 0. 05 m,while it tends to change flattenedly when the atmosphere coherence length is greater than 0. 2 m. This changing trend remains the same under different Non-Kolmogorov turbulence spectrum, which is also consistent with the theoretical prediction. The results illustrates that the turbulence simulation experiment can reproduce the turbulence effect on the received light intensity in wireless optical communications. Moreover,the error analysis of the simulation experiment illustrates that the main sources of the experimental error are different under different turbulence strength. It can provides some effective advices for the improvement of further experiments.

关 键 词：大气湍流 Non-Kolmogorov谱 液晶空间光调制器 概率密度分布 闪烁指数 时间频谱 

分 类 号：TN929.12[电子电信—通信与信息系统]