弱海洋湍流中高斯光束的到达角起伏特性  

Angle-of-arrival Fluctuation Characteristics of Gaussian Beams in Weak Oceanic Turbulence

作　　者：易湘[1] 班堃 刘欢欢 程明建 YI Xiang;BAN Kun;LIU Huan-huan;CHENG Ming-jian(State Key Laboratory of ISN,Xidian University,Xi’an 710071,China;School of Physics,Xidian University,Xi’an 710071,China)

机构地区：[1]西安电子科技大学,综合业务网理论与关键技术国家重点实验室,西安710071 [2]西安电子科技大学物理学院,西安710071

出　　处：《光通信研究》2023年第4期34-41,共8页Study on Optical Communications

基　　金：国家重点研发计划资助项目(2022YFC2808101)。

摘　　要：海洋湍流引起的到达角(AOA)起伏是影响水下通信和成像系统性能的关键因素。基于通用的海洋湍流光功率谱(OTOPS),文章采用适用于弱湍流条件的Rytov近似方法推导出高斯光束的波结构函数(WSF)以及AOA起伏方差的全区间解析解,并就上述物理量及空间相干半径(SCR)在大间距(ρ?η,其中,ρ为间距,η为Kolmogorov微尺度)和小间距(ρ?η)渐近区间内的近似解进行了讨论。数值结果表明,当ρ?η时,现有结果在菲涅尔比Λ0=1附近存在较大偏差。在此基础上还分析了AOA起伏方差与ρ/η的关系。在渐近区间ρ?η内,AOA起伏方差几乎不变;当处于区间ρ≈η时,AOA起伏方差急剧减小;当处于渐近区间ρ?η时,AOA起伏方差的下降速度变得逐渐平缓。文章推导得到的结果更加准确并且适用范围更广,利用这些结果可以更好地研究高斯光束在弱海洋湍流中的传播特性。The Angle of Arrival(AOA)fluctuation caused by oceanic turbulence is the critical factor affecting the performance of underwater communication and imaging systems.Based on the general Oceanic Turbulence Optical Power Spectrum(OTOPS),this paper derives analytical solutions for the full interval of the Wave Structure Function(WSF)and the AOA fluctuation variance of the Gaussian beam using the Rytov approximation method applicable to weak turbulence conditions.The approximate solutions of the above physical quantities and the Spatial Coherence Radius(SCR)in the asymptotic intervals of large spacing(ρη,whereρdenotes spacing andηdenotes Kolmogorov microscale)and small spacing(ρη)are also discussed.The numerical results show that the existing results have a large deviation around the Fresnel ratioΛ0=1 whenρη.On the basis of this,the relationship between AOA fluctuation variance andρ/ηis also analyzed.In the asymptotic intervalρη,the AOA fluctuation variance is almost constant.When in the intervalρ≈η,the AOA fluctuation variance decreases sharply.When in the asymptotic intervalρη,the decline of the AOA fluctuation variance becomes gradually flat.The results derived in this paper are more accurate and applicable to a wider range.These results will enable a better study of the propagation properties of Gaussian beams in weak oceanic turbulence.

关 键 词：到达角起伏 海洋湍流 高斯光束 Rytov近似 

分 类 号：TN929[电子电信—通信与信息系统]