结合光学反馈以及光学锁相环的量子级联激光器线宽压窄和频率控制技术研究  

Research on linewidth narrowing and frequency control technology of quantum cascade lasers based on optical feedback and optical phase-locked loops

作　　者：高健 焦康 赵刚 尹润涛 杨家琪 闫晓娟[1,2] 陈宛宁 马维光 贾锁堂[1,2] GAO Jian;JIAO Kang;ZHAO Gang;YIN Runtao;YANG Jiaqi;YAN Xiaojuan;CHEN Wanning;MA Weiguang;JIA Suotang(State Key Laboratory of Quantum Optics and Quantum Optics Devices,Shanxi University,Taiyuan 030006,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China;Silesian College of Intelligent Science and Engineering,Yanshan University,Qinhuangdao 066000,China)

机构地区：[1]山西大学,量子光学与光量子器件国家重点实验室,太原030006 [2]山西大学,极端光学协同创新中心,太原030006 [3]燕山大学西里西亚智能科学与工程学院,秦皇岛066000

出　　处：《物理学报》2025年第1期159-167,共9页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2023YFF0614000,2022YFC3703900);国家自然科学基金(批准号:62327813,62175139,62375161,61975103);山西省留学人员科技活动择优资助项目(批准号:20220001);江淮前沿技术协同创新中心追梦基金(批准号:2023-ZM01C007)资助的课题.

摘　　要：中红外波段缺乏窄线宽、可精确调谐的激光源,限制了中红外精密光谱的发展.本文介绍了一种结合强光学反馈和光学锁相环技术的量子级联激光器(QCL)频率控制技术,通过强光学反馈先抑制QCL频率噪声中的高频成分,再使用光学锁相环将激光频率偏频锁定到另外一个超稳中红外激光源上.通过相位超前电路拓展锁定带宽,系统锁定后,将功率谱中心窄拍频信号提高66 dBm,低频区域相位噪声抑制到-81 dBc/Hz@2 kHz,高频区域相位噪声抑制到101 dBc/Hz@2 MHz,激光器线宽从3.8 MHz被压窄到3 Hz.最终,利用该激光器进行腔衰荡光谱信号的测量,相较于未锁定激光,信号的信噪比提升了5倍.The mid-infrared(MIR)spectral region,which corresponds to molecular vibrational and rotational energy level transitions,contains a wealth of molecular energy level information.By employing techniques such as cavity ring-down spectroscopy(CRDS),the MIR spectra can be precisely measured,thereby validating fundamental physical laws,the inversion of fundamental physical constants,and the detection of trace gases.However,technical noise from temperature fluctuations,mechanical vibrations,and current noise causes free-running quantum cascade laser(QCL)to suffer high-frequency noise,typically broadening the linewidth to the MHz range,thus reducing spectral resolution.Moreover,long-term drift in the laser frequency due to temperature and current fluctuations hinders high-precision spectroscopy,particularly for narrow-linewidth nonlinear spectroscopy,such as saturated absorption and multiphoton absorption spectroscopy.This work presents a method of combining optical feedback with an optical phase-locked loop(OPLL)for offset frequency locking,aiming to generate a mid-infrared(MIR)laser with excellent frequency characteristics.Strong optical feedback is employed to narrow the linewidth of the quantum cascade laser(QCL)acting as a slave laser,thereby alleviating the challenges associated with phase locking.The OPLL uses frequency-offset to lock the slave laser to the ultra-narrow laser.By adjusting the offset frequency,fine control of the slave laser is achieved.To ensure tight phase locking,the OPLL is based on the ADF4007,and combines a phase lead circuit to compensate for phase lag,effectively expanding the loop bandwidth of the system.In this work,the fundamental principles of the optical phase-locked loop are theoretically analyzed,and a basic model is established.The influence of loop bandwidth on locking performance is also investigated.Upon achieving phase locking using the combined optical feedback and OPLL system,the magnitude of the beat note of the two lasers is improved by 66 dBm,with phase noise suppressed to-8

关 键 词：量子级联激光器 光学锁相环 光学反馈 

分 类 号：TN248[电子电信—物理电子学]