全光纤结构拉曼振荡器实现近1.8 kW激光输出  

All-fiber Raman oscillator with 1.8 kW output power

作　　者：范晨晨 付敏 郝修路 黄善旻 李阳[1] 陈子伦 冷进勇 姚天甫 周朴[1] Fan Chenchen;Fu Min;Hao Xiulu;Huang Shanmin;Li Yang;Chen Zilun;Leng Jinyong;Yao Tianfu;Zhou Pu(College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,China;Nanhu Laser Laboratory,National University of Defense Technology,Changsha 410073,China;Hunan Provincial Key Laboratory of High Energy Laser Technology,Changsha 410073,China)

机构地区：[1]国防科技大学前沿交叉学科学院,湖南长沙410073 [2]国防科技大学南湖之光实验室,湖南长沙410073 [3]国防科技大学高能激光技术湖南省重点实验室,湖南长沙410073

出　　处：《红外与激光工程》2024年第5期268-270,共3页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(12174445,62061136013)。

摘　　要：拉曼光纤激光器在实现高功率特殊波长激光方面具有独特优势,受到了广泛关注和研究。近年来,随着渐变折射率多模光纤在拉曼激光器中的运用,不仅提高了可注入的泵浦功率,还通过光束净化特性实现了激光亮度增强。Objective Raman fiber lasers are distinguished by their exceptional capabilities in generating high-power lasers at specific wavelengths,attracting considerable interest and research efforts.In recent years,the utilization of graded-index multimode fibers in Raman lasers has not only increased the injectable pump power but also enhanced laser brightness through beam cleaning characteristics.Currently,significant breakthroughs have been made in Raman fiber lasers based on large-core graded-index multimode fibers,with researchers successfully achieving kilowatt-level near-single-mode output.Methods An all-fiber Raman laser system was built based on the oscillator structure.Extensive design optimization of passive fiber components,including fiber refractive index,core diameter,mode field area,as well as combiners and fiber gratings,was conducted to effectively suppress higher-order Raman effects and prevent degradation of beam quality.The system utilized multiple 1080 nm lasers as the pump source,which were combined by a custom-designed fiber combiner.The Raman gain medium was a piece of graded-index fiber with a length of 18 m and a core diameter of 150μm.The resonator cavity was constructed using a pair of specially designed fiber gratings with mode-selecting characteristics,featuring a central reflection wavelength of 1130 nm.Results and Discussions The power evolution of the laser system,illustrated in Fig.1(a),demonstrated that with pump power injection of 2392 W,the signal laser output reached 1780W with residual pump power of 340 W,corresponding to a Raman conversion efficiency of 74.4%.Figures 1(b)and(c)indicated that as the power increased,a discernible broadening of the output spectrum and degradation in beam quality were observed,attributed to heightened nonlinear effects.Specifically,as the signal power increased from 200 W to 1780 W,the 3 dB linewidth of the output spectrum widened from 0.7nm to 1.9 nm,and the output beam quality factor M²degraded from 2.5 to 3.5(average values derived from multiple m

关 键 词：光纤激光 拉曼振荡器 受激拉曼散射 渐变折射率光纤 

分 类 号：TN248[电子电信—物理电子学]