基于辅助棱镜增强回音壁模式微腔光反馈自注入锁定方案  

Whispering⁃Gallery⁃Mode Resonator Self⁃Injection Locking MethodBased on Enhanced Optical Feedback with Auxiliary Prism

作　　者：吴佳军 钟山 康松柏 Wu Jiajun;Zhong Shan;Kang Songbai(Key Laboratory of Atomic Frequency Standards,Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430071,Hubei,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院精密测量科学与技术创新研究院中国科学院原子频标重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049

出　　处：《中国激光》2024年第13期73-78,共6页Chinese Journal of Lasers

摘　　要：光反馈强度是微腔自注入锁定技术中实现激光线宽压窄的重要参数。设计了一种仅通过单个镀膜辅助棱镜实现晶体回音壁模式微腔(WGMR)内反馈光幅度增强的方案。实验结果显示,与腔体自身的瑞利散射相比,该方案获得的反馈光强提高了100倍以上。将该方案应用于微腔自注入锁定激光器后,激光瞬时线宽降低至~7 Hz,锁定宽度增大到8 GHz,相对强度噪声降低到-152 dBc/Hz@10 MHz。该设计结构紧凑、易操控,且能与晶体WGMR实现一体化集成,为自注入锁定技术中的反馈光强度控制提供了解决方案。Objective Narrow linewidth lasers based on whispering-gallery-mode resonator (WGMR) self-injection locking (SIL) have the potential for use in fields such as coherent optical communication,optical atomic clocks,high-resolution spectroscopy,and precision frequency measurement.The intensity of SIL optical feedback is a crucial parameter that determines the performance of locked lasers,including instantaneous linewidth,locking range,and relative intensity noise (RIN).At present,the SIL technique commonly uses WGMR Rayleigh backscattering to create optical feedback.However,the optical feedback intensity is uncontrollable.Investigations have been successfully conducted on the feedback control of on-chip WGMRs such as Si_(3)N_4,and Al N using micro-cavity refectors.However,there are few studies on how to control the feedback intensity for high-Q fluoride crystalline WGMRs.Liang et al.proposed a feedback-intensity enhancement scheme for crystalline WGMRs using a set of optical components,including a coupling prism,collimation lenses,and a mirror reflector.However,the additional components increased the complexity and instability of the system.In this study,we propose a compact and easy-to-operate feedback-enhancement approach for crystalline WGMRs that replaces the set of feedback-enhanced components with a designed auxiliary prism,which can be integrated with the WGMR.It provides a compact solution for controlling feedback intensity in WGMR SIL technology.Methods We design an auxiliary prism to enhance the counterclockwise (CCW) light amplitude inside the WGMR (Fig.1).The auxiliary prism first extracts the clockwise (CW) light from the WGMR with a specific angleΦthat is determined by the coupling phase-matching condition.The coupled output beam travels over an optical length d in the prism and is then vertically reflected by highly reflective film coated on the prism.Finally,it is coupled back into the WGMR along the original trace to enhance the CCW light amplitude with any additional optical components.The bottom an

关 键 词：激光器 自注入锁定 窄线宽 增强光反馈 回音壁模式微腔 

分 类 号：O436[机械工程—光学工程]