基于APD自适应增益控制的近地无线激光通信信道大气湍流抑制方法研究  

Atmospheric Turbulence Suppression Methods for Near the Earth Wireless Laser Communication Channels Based on Avalanche Photodiode Adaptive Gain Control

作　　者：周畅 于笑楠[2] 姜会林 王潼[2] 安宁 Zhou Chang;Yu Xiaonan;Jiang Huilin;Wang Tong;An Ning(School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun,Jilin 130022,China;National and Local Engineering Research Center of Space Optoelectronic Technology,Changchun University of Science and Technology,Changchun,Jilin 130022,China;Changchun Observatory,National Astronomical Observatories,Chinese Academy of Sciences,Changchun,Jilin 130117,China)

机构地区：[1]长春理工大学光电工程学院,吉林长春130022 [2]长春理工大学空间光电技术国家地方联合工程研究中心,吉林长春130022 [3]中国科学院国家天文台长春人造卫星观测站,吉林长春130117

出　　处：《中国激光》2022年第4期70-78,共9页Chinese Journal of Lasers

基　　金：吉林省科技发展计划项目(20200801050GH)。

摘　　要：随着5G时代的到来,自由空间光通信成为无线通信领域的研究热点,限制激光通信系统在大气信道下发展的主要因素是湍流闪烁效应。为了提高激光通信系统在大气信道下的通信性能,本文提出了一种基于雪崩光电二极管自适应增益控制的激光传输终端大气湍流的抑制方法,建立了大气湍流信道时域频域模型,编写了一套闭环调节算法并在湍流条件下搭建了具有自适应增益控制算法的无线激光通信实验。结果表明:在弱湍流条件下,光强闪烁方差由0.057降低至0.023,开启自动增益控制的功率谱曲线更加符合5/3次幂律谱,系统误码率降低两个数量级。经多次试验证明,自适应增益控制算法有效地抑制了湍流引起的信号功率波动,实现了高抗干扰能力的无线激光通信。Objective Owing to 5G,free-space optical communication(FSO)has high communication rate,long communication distance,strong anti-interference and low power consumption.It does not require laying fibre optic cables and has become the current research hot spot in wireless communication.For wireless free-space laser communication,the most severe problem is the impact of the atmospheric channel.The light intensity scintillation effect caused by atmospheric turbulence causes the communication data received by the receiver to be superimposed with jitter and fading,inevitably leading to degradation in communication quality.The front-end avalanche photodiode avalanche photodiode(APD)method is used in this study.In this technique,the reverse bias voltage is changed to control the multiplication factor of APD,which is essential in suppressing atmospheric turbulence and extending the dynamic range.Methods In order to improve the communication performance of laser communication systems under atmospheric channels,this study proposes a laser transmission terminal atmospheric turbulence suppression algorithm based on APD adaptive gain control(AGC).Additionally,we design an APD current feedback and bias control circuit and write a set of closed-loop regulation schemes.Furthermore,a wireless laser communication experiment with an adaptive gain control algorithm under medium and weak turbulence is developed.Results and Discussions A laser communication test with a 500 m communication distance was conducted at Huawei's Songshan Lake base in Dongguan,Guangdong Province.The average temperature was 25℃and weather was cloudy and breezy weather on the experiment day.The experimental system consists of an APD receiver and laser diode(LD)transmitter(Fig.5).The probability distributions and power spectra were tested under 500 m of weak turbulence,with fixed APD gain and adaptive APD gain control,respectively.The results show that the optical power distribution ranges from 1000 to 40,000 nA(Fig.6)under weak turbulence conditions,with a log-

关 键 词：光通信 自由空间光通信 大气湍流 雪崩光电二极管 自适应增益控制 

分 类 号：TN929.1[电子电信—通信与信息系统]