面向大气激光通信的空间光到少模光纤耦合特性研究  

Analyses of Coupling Characteristics of Space Light to Few-Mode Fiber for Atmospheric Laser Communication

作　　者：何爽 张鹏[1,2] 魏佳 伍文韬 宫喜宇 王超[1,2] 佟首峰[1,2] He Shuang;Zhang Peng;Wei Jia;Wu Wentao;Gong Xiyu;Wang Chao;Tong Shoufeng(Institute of Space Optoelectronics Technology,College of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun,Jilin 130022,China;National and Local Joint Engineering Research Center of Space Optoelectronics Technology,Changchun University of Science and Technology,Changchun,Jilin 130022,China)

机构地区：[1]长春理工大学光电工程学院空间光电技术研究所,吉林长春130022 [2]长春理工大学空间光电技术国家与地方联合工程中心,吉林长春130022

出　　处：《中国激光》2021年第23期81-92,共12页Chinese Journal of Lasers

基　　金：国家自然科学基金(61705019,61805028);吉林省科技发展计划项目(20200201010JC);吉林省科技厅自然基金(20180101338JC,20190201271JC);吉林省国际科技合作项目(20200801053GH);吉林省教育厅基金(JJKH20200752KJ,JJKH20190563KG)。

摘　　要：少模前置光放大加分集接收的模式可有效提高接收灵敏度和大气激光通信抗湍流能力,为此有必要研究空间光到少模光纤耦合特性。首先,基于捕获跟踪对准模型、Von Karman湍流谱模型推导了大气湍流及跟瞄误差条件下空间光到少模光纤的耦合模型。其次,基于推导模型分析得到耦合效率与少模光纤参数、湍流强度、跟瞄误差存在凸曲线关系。受到大气湍流强度(大气折射率常量C_(n)^(2)为10^(-15)到10^(-14))影响,光纤归一化频率(V值)在5附近可实现最优耦合性能,最优V值随着湍流强度增加而增加。而受到跟瞄误差(0~4μrad)影响,光纤V值也存在最优值,并随着V值增加其抗跟瞄误差能力也增加。最后,搭建了模拟大气湍流条件下的少模光纤耦合性能实验平台,实验研究了V值分别为3.8、4.6、4.9、5.1的少模光纤在不同模拟湍流强度下的耦合特性,测试结果初步验证了理论研究结果。研究结果为大气激光通信前置放大器设计等研究提供技术参考。Objective Free-space optical communication has attracted wide attention due to its advantages,such as large information capacity,high transmission rate,strong anti-interference ability,small system size and low power consumption.Being an important part of the free-space optical communication,atmospheric laser communication is facing technical bottlenecks,such as unsatisfactory reception efficiencies and large energy jitters.Fiber coupling can effectively solve these technical bottlenecks.Coupling with optical fiber is the most common method;however,multi-mode fiber limits the usage of coherent communication reception.Using a single-mode fiber will definitelyreduce the coupling efficiency under atmospheric turbulence conditions.Recently,pre-amplification of few-mode fiber or few-mode multi-core fiber has become essential to improve the reception performance of atmospheric laser communication.However,a turbulent atmosphere will have effects,such as spot distortion,arrival angle fluctuation,beam expansion and light intensity flicker.These effects seriously affect the coupling efficiency between the space light and few-mode fiber.In this study,we first studied the relationship between few-mode fiber parameters,turbulence intensity,tracking error and the coupling efficiency of space light to the few-mode fiber under the conditions of atmospheric turbulence and tracking error.Then,we established a coupling model of the space light to the few-mode fiber under the conditions of atmospheric turbulence and tracking error.Finally,we established an experimental platform under this condition to verify the coupling performance of the few-mode fiber.We hope our results can provide a technical reference for the design of the atmospheric laser communication preamplifiers.Methods Based on the coupling model of space light to few-mode fiber,an approximate calculation of step-type fewmode fiber optical field was performed using the Laguerre-Gaussian(LG)distribution and LG beam as the free-space light.We obtained the optical field di

关 键 词：光通信 空间激光通信 耦合效率 光纤耦合 少模光纤 

分 类 号：O439[机械工程—光学工程]