双通道符合计数光子外差探测系统仿真构建与研究  

Simulation Construction and Study of Photon Heterodyne Detection System with Two-Channel Coincidence Counting

作　　者：蒲梦瑶 胡以华 杨博 董骁 张鑫源 Pu Mengyao;Hu Yihua;Yang Bo;Dong Xiao;Zhang Xinyuan(State Key Laboratory of Pulsed Power Laser Technology,College of Electronic Engineering,National University of Defense Technology,Hefei 230037,Anhui,China;Anhui Provincial Key Laboratory of Electronic Restriction,College of Electronic Engineering,National University of Defense Technology,Hefei 230037,Anhui,China;Unit 95793 of PLA,Guiyang 550000,Guizhou,China)

机构地区：[1]国防科技大学电子对抗学院脉冲功率激光技术国家重点实验室,安徽合肥230037 [2]国防科技大学电子对抗学院安徽省电子制约技术重点实验室,安徽合肥230037 [3]95793部队,贵州贵阳550000

出　　处：《光学学报》2023年第14期22-31,共10页Acta Optica Sinica

基　　金：国防科技大学科研计划项目(ZK18-01-02,ZK-35);国防科技大学自主科研创新基金(22-ZZCX-07);国家自然科学基金(62201597)。

摘　　要：本文提出将符合测量方法用于光子外差测速技术中,将光子符合计数模式应用于光子外差测速系统,能够在一定程度上减少背景噪声、暗噪声和后脉冲带来的光子误计数,提高信噪比等测速性能。基于外差原理与单光子探测的泊松响应,以及光子符合计数原理,本文仿真研究了双通道符合计数光子外差系统的性能,利用1550 nm连续波激光器探测匀速运动目标,结果表明,双通道符合计数模式下中频信号功率谱的信噪比明显高于单通道自由运行模式和一阶滤波下的功率谱信噪比。随着信号光子数增加,两种计数模式的信噪比能够相差2~3 dB。针对该方法,又进一步通过仿真研究了本振光强、背景噪声、中频频率、探测时长四个因素对双通道符合计数光子外差测速系统性能的影响。结果表明,随着本振光强与信号光强的比值逐渐增大,系统信噪比先增大后减小,在k_(L)=3附近时达到最大;背景噪声越大,饱和信号光子数越大,饱和信噪比越低;探测时长越长,饱和信噪比提高幅度越大;而在探测带宽之内,中频频率也即运动目标的速度对结果影响较小。本文从改变前端光子计数模式的角度提高光子外差探测系统的性能,为提高光子外差测速的信噪比拓宽了思路。Objectives Due to the high sensitivity of the singlephoton detector,an ultranarrow band filter is needed to ensure the normal operation of the detector under the influence of strong background light noise in the daytime.Therefore,the antibackground noise ability of photon heterodyne detection is crucial.In addition,the dark count and postpulse effect of the singlephoton detector will lead to a false count and thus reduce the signaltonoise ratio(SNR).Therefore,new methods are required to improve the SNR of photon heterodyne detection.In the earlier research on photon heterodyne detection,most scholars focused on signal processing for denoising.They proposed new signal processing methods to denoise echo signals and rarely made an effort to improve the detection system or change the photon counting mode.As current signal processing has limited ability to improve the SNR of photon heterodyne detection,this study applies the coincidence counting mode to photon heterodyne detection.This mode relies on multichannel detection and filters out random optical noise at the photon counting terminal to improve the SNR.Methods In this study,a photon heterodyne velocity measurement system with twochannel coincidence counting is constructed by simulation.After frequency beating,light waves of heterodyne signals are evenly divided into two parts and sent into two singlephoton detection channels separately.A twochannel coincidence counting mode is adopted at the singlephoton detection end,and different coincidence gate widths are set for the system according to different situations.The twochannel coincidence counting system will automatically select the channel 1 as the main channel and the other channel as the slave channel and create a time window(the size of which can be set)centered on the main channel.When both channels have photon counting in this window,an effective coincidence will be generated,and the coincidence counting results within a certain collection time will be given at last.When the signal photon is detected in b

关 键 词：探测器 光子外差 单光子探测 符合计数 测速性能 影响因素 

分 类 号：O439[机械工程—光学工程]