新型全光腔内负反馈单频光纤激光器抑噪技术研究

Low noise and narrow linewidth single frequency fiber lasers have wide applications in the fields of optical communication, microwave photonics, space gravitational wave detection and etc. In order to meet the urgent demand of ultralow noise laser in the application of the next generation long distance coherent detection and solve the key problem of traditional noise reduction technique, including the limited bandwidth of photoelectric feedback technology, design of complex structure of optical filter outside the laser cavity and etc., novel noise reduction technology of single frequency fiber via intracavity all optical negative feedback is researched. The related research contents including: building the theoretical model of fiber laser and the noise transfer-function to improve the performance of the laser; The influence of laser output power, wavelength, noise spectrum on the heat distribution of the grating area is studied experimentally, and the optical negative feedback mechanism is established; The noise level of the laser is greatly suppressed by all optical negative feedback in the cavity and the mechanism simulation and experimental study are carried out. This research will provide a large amount of data and experimental confirmation which will also be useful for the improvement of Low noise and narrow linewidth fiber lasers.

低噪声窄线宽的单频光纤激光器在激光通信、光学传感、空间引力波探测、光频传递等领域中有着广泛的应用前景。本项目针对下一代长距离、相干探测等应用中对超窄线宽单频激光光源的迫切需求以及目前传统噪声抑制手段的瓶颈，如光电反馈技术中补偿带宽的限制、腔外光滤波器复杂结构的设计等，拟开展基于腔内全光负反馈效应的新型单频光纤激光器抑噪技术及相关机理问题的研究。项目旨在利用热光效应实现激光谐振腔内折射率的调制，进而形成激光工作点的改变并建立腔内全光负反馈效应，最终实现光纤激光器的噪声抑制。研究内容包括：建立光学负反馈耦合的光纤激光器理论模型，获得激光器噪声性能优化的关键参数；实验详细研究光纤激光器的出射功率、波长，噪声谱等激光器关键数据随栅区热分布变化的影响，实现负反馈机制的建立；利用腔内全光负反馈效应大幅抑制激光器的噪声水平并进行深入的机理仿真和实验研究，为下一代激光器性能提升提供理论依据和技术支撑。

根据项目计划书的要求，针对下一代长距离、相干探测等应用中对超窄线宽单频激光光源的迫切需求以及目前传统噪声抑制手段的瓶颈，本项目开展基于腔内全光负反馈效应的新型单频光纤激光器抑噪技术及相关机理问题的研究。利用热光效应实现激光谐振腔内折射率的调制，进而形成激光工作点的改变并建立腔内全光负反馈效应，最终实现光纤激光器的噪声抑制。项目总共发表SCI论文8篇，国内期刊文章5篇，进行国际会议报告2次(其中一次为邀请报告)，国内会议邀请报告2次，申请发明专利3项，超过了项目计划书的要求，取得了较好结果；项目同时协助培养了2位博士研究生。