光纤随机激光赋能功率提升和谱域拓展(特邀)  

Power Scaling and Wavelength Extension Enabled by Random Fiber Laser(Invited)

作　　者：肖起榕[1,2] 齐天澄 李丹 杜山山[1,2] 王乐乐 符国浩 阳优司 李冠中 张逸杰 闫平 巩马理 柳强[1,2] Xiao Qirong;Qi Tiancheng;Li Dan;Du Shanshan;Wang Lele;Fu Guohao;Yang Yousi;Li Guanzhong;Zhang Yijie;Yan Ping;Gong Mali;Liu Qiang(Department of Precision Instrument,Tsinghua University,Beijing 100084,China;State Key Laboratory of Precision Space-Time Information Sensing Technology,Beijing 100084,China)

机构地区：[1]清华大学精密仪器系,北京100084 [2]时空信息精密感知技术全国重点实验室,北京100084

出　　处：《中国激光》2024年第19期66-85,共20页Chinese Journal of Lasers

基　　金：国家自然科学基金(62122040,62075113);国家重点研发计划(2023YFB4604501)。

摘　　要：光纤随机激光器结合了光纤波导和随机激光器的特有优势,近年来快速发展成为获得高时域稳定性、高空间亮度、低相干性、高功率激光光束的重要途径。不同于点反馈机制的传统固定腔长光纤激光器,光纤随机激光器为高性能光纤激光的输出功率提升和谱段拓展开辟了全新的道路。本文总结回顾了光纤随机激光器以其时域稳定和波长灵活的特性赋能高功率、新波长光纤激光产生的最新研究进展,介绍了光纤随机激光器以其高亮度和低相干特性在当前的实际应用情况,并展望了其未来的发展方向和可能面临的挑战。Significance Random fiber lasers(RFLs)utilize the distributed feedback in optical fibers to form resonant cavities of random lengths.They combine the low coherence of random lasers with the high brightness of fiber lasers.Therefore,RFLs have been widely used in fields such as environmental sensing and optical communications.Because all-fiber-integrated RFLs were proposed using Rayleigh backscattering as a feedback mechanism,RFLs have attracted significant attention in the power scaling and wavelength extension of fiber lasers.Rayleigh backscattering occurs in silicon fibers owing to disordered fluctuations in the refractive index,which provides randomly distributed feedback for RFLs.Because the output of an RFL is the sum of the resonant cavities with random lengths,the RFL is free of the self-pulsing effect,unlike traditional fiber laser generated in a fixed cavity.Amplifying the RFL through the master oscillator power amplification(MOPA)configuration can suppress spectral broadening because no peak power from the RFL seed is enhanced during this process.Control experiments were conducted in a 10 kW-level MOPA system by adopting an RFL and a fiber laser with a fixed cavity as the seed.The results demonstrate a suppression effect.Rayleigh backscattering provides broadband reflection in optical fibers,which can replace the reflection component in wavelengthtunable fiber-laser systems and supercontinuum(SC)sources.Therefore,RFLs can easily achieve wavelength tunability using a single-frequency selection component.By taking advantage of cascaded Raman scattering,the operating wavelength of the RFL can cover the transmission band of the silicon fiber.Research on 1.1‒2.0μm RFLs proves the flexibility of their output wavelength.In addition,the modulation instability provides a wide band gain for light waves near the zero-dispersion wavelength of the optical fiber.This type of light wave can be generated by cascaded Raman scattering in the RFLs.In addition,the nonlinear effect is enhanced by Rayleigh backscattering b

关 键 词：高功率光纤激光 光纤随机激光 受激拉曼散射 超连续谱产生 无散斑成像 

分 类 号：O436[机械工程—光学工程]