表征稳频半导体激光器频率特性的方法  

Method for characterizing frequency of frequency-stabilized semiconductor lasers

作　　者：李珊珊 杨介伟 杨天新[1] 王肇颖[1] 张恒康 Li Shanshan;Yang Jiewei;Yang Tianxin;Wang Zhaoying;Zhang Hengkang(Key Laboratory of the Ministry of Education on Optoelectronic Information Technology,School of Precision Instrument and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China;Beijing Institute of Control Engineering,Beijing 100190,China)

机构地区：[1]天津大学精密仪器与光电子工程学院光电信息技术教育部重点实验室,天津300072 [2]北京控制工程研究所,北京100190

出　　处：《红外与激光工程》2023年第10期42-48,共7页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(62075164);天津市自然科学基金项目(19 JCZDJC32500);空间光电测量与感知实验室开放基金课题资助项目(WZYY-04002·21)。

摘　　要：对稳频半导体激光器的频率进行在线实时监测的需求量和迫切性一直在不断增长。特别是近几年发展起来的连续波激光雷达通常以单频半导体激光器为种子源,并通过相干检测方式获得雷达信号的频率,从而获得目标物的距离信息,这就使得种子光源的频率精度直接与测距精度密切相关,因此,对光源的频率稳定性的表征也提出了新的要求:更关注短期(在相干时间内,亚微秒~数毫秒)的频率变化模式,对长时段内(数分钟~24 h)的绝对频率高精度监测的需求减弱;同时要求频率监测系统具有在线实时监测能力。针对这些需求,基于延时自外差原理,提出了一种表征稳频激光器的频率变化的方法,经过严谨的原理推导和算法编程,使得监测系统不仅结构简单,还实现了在线实时监测功能,并测量了一台利用氰化氢(H13C14N)气体吸收谱线基于边频锁定技术的稳频分布反馈式半导体激光器(DFB-LD)频率变化曲线。测量结果是:在10 ms内稳频激光器的最大频率变化约为25 MHz,并且清楚地观察到激光器的频率变化不是单向的漂移模式。为了进一步验证该方法的精度,采用主流的飞秒光频梳拍频法离线测量了同一台稳频DFB-LD的频率变化,实验结果是:在50 min内频率变化约为30 MHz。两种测量方法的测量结果均在相同的MHz量级,证明了该方法是一个快速可靠的光频率分析手段,可应用于实时调节稳频激光器的伺服回路系统。Objective The demand for on-line and real-time monitoring of frequency-stabilized semiconductor laser is very high and urgent.Especially,the continuous wave lidar developed in recent years usually takes a single frequency semiconductor laser as a seed source,and obtains the frequency of the radar signal through coherent detection,so as to obtain the distance of the target.It results in the frequency accuracy of the seed light source directly determing the ranging accuracy.Therefore,new requirements are proposed for the characterization of the frequency stabilization of the light source.More attention is paid to short-term(in coherent time of submicrosecond up to milliseconds)frequency change patterns,rather than the absolute frequency accuracy in a long duration of minutes,even up to 24 hours;At the same time,the frequency monitoring system is required to have functions of on-line and real-time monitoring.Methods Aiming at these requirements,based on the principle of delay self-heterodyne,this paper proposes a method for characterizing the frequency of frequency stabilized laser.By deriving the principle rigorously and programming the algorithm,the monitoring system not only has a simple structure(Fig.1),but also realizes the functions of online and real-time monitoring.Results and Discussions The frequency variation curve of a frequency-stabilized distributed feedback semiconductor laser(DFB-LD)using hydrogen cyanide(H13C14N)gas absorption spectrum based on side frequency locking technique is measured.The result is that the maximum frequency range of the stabilized laser is about 25 MHz in 10 ms,and it is clearly observed that the frequency changes of the laser are not in one-way drift pattern(Fig.2).In order to further verify the accuracy of this method,the mainstream femtosecond optical frequency comb beat method is adopted to measure the frequency change of the same frequency-stabilized DFBLD offline(Fig.3-4).The experimental results show that the frequency range is about 30 MHz within 50 minutes(Fig.5).Concl

关 键 词：半导体激光器 自外差探测 频率测量 稳频 

分 类 号：O436[机械工程—光学工程]