径向部分相干光束在各向异性非Kolmogorov湍流中的传输  

Propagation of Radial Partially Coherent Beams in Anisotropic Non-Kolmogorov Turbulence

作　　者：王铭淏 元秀华[1] 李军 周小歆 李奇[1] 周泽宇 Wang Minghao, Yuan Xiuhua, Li Jun, Zhou Xiaoxin, Li Qi, Zhou Zeyu(School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, Chin)

机构地区：[1]华中科技大学光学与电子信息学院,湖北武汉430074

出　　处：《光学学报》2018年第3期272-282,共11页Acta Optica Sinica

基　　金：国家自然科学基金(61275081)

摘　　要：具有中心对称相干度分布的非均匀部分相干光,即径向部分相干光束(RPCB),可以有效降低大气湍流引起的光束闪烁,改善接收质量。应用波动光学仿真方法,比较研究了相干高斯光束、高斯谢尔模光束和具有凸型高斯型、超高斯型相干度分布的径向部分相干光束在各向异性的非Kolmogorov湍流中的传输特性,从远场光强分布和孔径平均闪烁指数等方面分析了湍流的各向异性参数和非Kolmogorov功率谱指数对远场光束质量的影响。仿真结果显示,光束的接收质量随功率谱指数的增大而持续劣化;同时,各向异性湍流会导致远场光斑呈椭圆形分布,因而在接收端使用等面积的椭圆接收孔径替代圆形孔径,可以显著降低接收机的孔径平均闪烁指数。总体而言,径向部分相干光束在各向异性非Kolmogorov湍流中,特别是在接收孔径较小的情况下,具有优于完全相干光和高斯谢尔模光束的传输性质。Nonuniformly correlated partially coherent beams with radially symmetric coherence distributions, i.e., the radial partially coherent beams （RPCBs）, can alleviate the scintillation induced by atmospheric turbulence and thus benefit the reception performance. We use wave optics simulation to study the propagation characteristics of coherent Gaussian beams, Gaussian Schell-mode beams, and RPCBs with convex Gaussian and super-Gaussian coherence distributions through anisotropic non-Kolmogorov turbulence. The effects of anisotropic parameters as well as non-Kolmogorov power spectrum index on far-field beam quality are analyzed in terms of far-field intensity profile and aperture-averaged scintillation index. The simulation results indicate that, the beam quality continues to deteriorate as the non-Kolmogorov spectrum index increases. On the other hand, the anisotropy will result in elliptical irradiance distribution in the far field. Therefore, instead of using a circular aperture with an equal-area elliptical aperture at the receiving end, the aperture-averaged scintillation index can be substantially reduced. Generally speaking, the propagation properties of RPCBs in anisotropic non-Kolmogorov turbulence remain superior to fully coherent beams as well as Gaussian Schell-model beams, especially for relatively small receiving apertures.

关 键 词：光通信 自由空间光通信 光场调控 波动光学仿真 大气湍流 光场传播 

分 类 号：O438[机械工程—光学工程]