基于光学锁相环的编码合成孔径激光雷达系统设计与实验验证  

Design and Experimental Verification of Coded Synthetic Aperture Lidar System Based on Optical Phase-Locked Loop

作　　者：方付平 胡恒 鄢朋朋 李兆洋 吕银环[2,3] 徐卫明 舒嵘[1,2,3] Fang Fuping;Hu Heng;Yan Pengpeng;Li Zhaoyang;Lü Yinhuan;Xu Weiming;Shu Rong(Key Laboratory of Space Active Optical-Electro Technology,Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200080,China;Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200080,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海技术物理研究所空间主动光电技术重点实验室,上海200080 [2]中国科学院上海技术物理研究所,上海200080 [3]中国科学院大学,北京100049

出　　处：《光学学报》2022年第6期128-135,共8页Acta Optica Sinica

基　　金：中科院国家重点实验室基金(CXJJ-20S019)。

摘　　要：合成孔径激光雷达具有成像分辨率与探测距离无关的特点。与微波相比,激光波长至少小3个数量级,因此能实现更高分辨率的成像,但是波长更短时成像更容易受系统自身引入的相位误差的影响,从而导致成像模糊。为了消除该误差对成像的影响,提出采用光学锁相环(OPLL)技术抑制编码合成孔径激光雷达的系统随机相位噪声。在发射端,激光信号经编码信号驱动的电光调制器调制后用于探测目标;在接收端,对接收到的回波信号与本振光进行正交解调。所提出的基于OPLL的编码合成孔径激光雷达工作在1550 nm波段,调制带宽为1.25 GHz,脉冲重复频率最高可达1.2 MHz/s。实验结果表明,在没有OPLL时,系统随机相位波动大于100 rad,采用OPLL后,系统内部相位稳定度优于0.1 rad,大幅度提高了系统自身的相位稳定度和方位向合成成像精度。Synthetic aperture lidar has the advantage that the imaging resolution is independent of the detection distance.Compared with microwave,laser has a wavelength at least 3 orders of magnitude smaller.Thus,synthetic aperture lidar can achieve imaging with a higher resolution.However,due to the shorter wavelength,it is also more vulnerable to the phase error introduced by the system itself,which results in imaging blur.To eliminate the influence of this error on imaging,the paper adopts an optical phase-locked loop(OPLL)technology to suppress the random phase noise of the coded synthetic aperture lidar system.At the transmitting end,the laser signal is modulated by an electro-optic modulator driven by the coded signal for detecting the target.At the receiving end,the received echo signal and the local oscillation light are subjected to orthogonal demodulation.The proposed coded synthetic aperture lidar based on OPLL works at the 1550 nm band.Its modulation bandwidth is 1.25 GHz,and the pulse repetition frequency is up to 1.2 MHz/s.The experimental results show that the random phase fluctuation of the system is greater than 100 rad without OPLL.In the presence of OPLL,the phase fluctuation of the internal system is smaller than 0.1 rad.To sum up,the OPLL technology greatly improves the phase stability of the system and the synthetic imaging accuracy in the azimuth direction.

关 键 词：相干光学 合成孔径雷达 光学锁相环 误差传递函数 相位稳定度 

分 类 号：O436[机械工程—光学工程]