相移光纤光栅耦合强度对分布式反馈光纤激光器输出性能的影响  

Effect of Phase-Shifted Fiber Grating Coupling Strength on Output Performance of Distributed Feedback Fiber Laser

作　　者：邹萌 鲁强 肖翔鹏 代雨泽 沈凯 孙琪真[1,2] 闫志君 Zou Meng;Lu Qiang;Xiao Xiangpeng;Dai Yuze;Shen Kai;Sun Qizhen;Yan Zhijun(School of Optical and Electronic Information,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China;Wuxi Research Institute,Huazhong University of Science and Technology,Wuxi 214174,Jiangsu,China)

机构地区：[1]华中科技大学光学与电子信息学院,湖北武汉430074 [2]华中科技大学无锡研究院,江苏无锡214174

出　　处：《中国激光》2025年第2期1-10,共10页Chinese Journal of Lasers

基　　金：国家重点研发计划(2022YFC2203904);湖北省重点研发计划(2022BAA004)。

摘　　要：研究了相移光纤光栅(PS-FBG)耦合强度对分布式反馈光纤激光器(DFB-FL)输出性能的影响。基于传输矩阵理论和粒子能级速率方程建立了DFB-FL的传输模型,仿真结果表明:PS-FBG透射狭缝带宽随着耦合强度的增大而减小;DFB-FL的泵浦效率随着PS-FBG耦合强度的增大先增大后降低;DFB-FL的输出偏振态与光纤内部双折射、PS-FBG的耦合强度相关,降低PS-FBG耦合强度或增大光纤内部双折射有利于DFB-FL单偏振态输出;DFB-FL的弛豫振荡频率(ROF)随着PS-FBG耦合强度增大向高频方向移动,同时相对强度噪声(RIN)下降。在实验室制备了不同PS-FBG耦合系数和光栅长度的DFB-FL,性能测试结果与理论分析结果相吻合。最终通过封装结构设计获得了输出激光线宽为4.1 kHz,RIN峰值<-120 dB/Hz,偏振消光比(PER)为23 dB,泵浦效率为0.17%的窄线宽光纤激光器。本研究对研制高效率、窄线宽、低噪声、单偏振输出的种子源激光器具有一定参考价值。Objective Distributed feedback(DFB)fiber lasers(DFB-FLs)are the seed source of high-power narrow linewidth fiber lasers,which are widely employed in LIDAR,gravitational wave detection,beam combination,and other applications.Phase-shifted fiber gratings(PS-FBG)are the key devices of DFB-FLs,whose coupling strength has a direct impact on the output performance of DFBFLs.Therefore,it is essential to study the coupling strength of the PS-FBG to obtain the best DFB-FL output performance.Methods Using the transmission matrix theory and the energy level rate equation,a transmission model of the DFB-FL was established,and the output characteristics of the DFB-FL were analyzed by simulation.Experimentally,PS-FBGs with varying coupling coefficients and grating lengths were fabricated using the light scanning method of a phase mask.Based on PS-FBGs,DFBFLs were constructed and tested.Finally,to introduce additional birefringence in the PS-FBG phase-shift region,a stress point was applied during the packaging process.This approach was aimed at suppressing dual-polarization states and enhancing the polarization extinction ratio of the laser.Results and Discussions The simulation results indicate that the transmission slit bandwidth of the PS-FBG decreases with an increase in the coupling strength.The pumping efficiency of the DFB-FL first increases and then decreases with an increase in the PSFBG coupling strength.The output polarization state of the DFB-FL is influenced by the coupling strength of the PS-FBG and birefringence within the fiber.Thus,reducing the coupling strength of the PS-FBG or increasing the internal birefringence of the PSFBG is advantageous for achieving the single polarization state output of the DFB-FL.The relaxation oscillation frequency of the DFB-FL increases as the PS-FBG coupling strength increases while the relative intensity noise(RIN)decreases.The experimental results show that the output performance of DFB-FL is closely related to PS-FBG coupling strengthκL.First,the output laser linewidth of D

关 键 词：相移光纤光栅 分布式反馈光纤激光器 窄线宽 单偏振 相对强度噪声 

分 类 号：TN247[电子电信—物理电子学]