紧凑型光谱组束系统中光纤阵列扰动对光束质量的影响分析  

Effects of Fiber Array Disturbance on Beam Quality in Compact Spectral Beam Combining System

作　　者：王勇能 李福建 饶大幸 崔勇[2] 赵晓晖 贺瑞敬 季来林[2] 高妍琦[2] 隋展 陈华才 Wang Yongneng;Li Fujian;Rao Daxing;Cui Yong;Zhao Xiaohui;He Ruijing;Ji Lailin;Gao Yanqi;Sui Zhan;Chen Huacai(Insititute of Optics and Electronics,China Jiliang University,Hangzhou 310018,Zhejiang,China;Shanghai Institute of Laser Plasma,China Academy of Engineering Physics,Shanghai 201800,China)

机构地区：[1]中国计量大学光学与电子科技学院,浙江杭州310018 [2]中国工程物理研究院上海激光等离子体研究所,上海201800

出　　处：《中国激光》2023年第7期196-206,共11页Chinese Journal of Lasers

摘　　要：定量分析光纤阵列位移及指向扰动偏差对合束激光光束质量因子M^(2)的影响规律是实现合束激光光束质量有效控制的前提。根据衍射积分推导了紧凑型光谱组束系统中光纤阵列存在不同位移、指向扰动时合束激光的远场光强分布,利用Heisenberg不确定性原理推导出了合束激光光束质量因子M^(2)的表达式。在恒定的子束数目下,分析了单路/多路光束分别存在位移、指向扰动偏差时合束激光光束质量因子M^(2)的变化情况,并在一定的随机位移、指向扰动偏差下对不同子束数量的合束激光的光束质量因子M^(2)进行了误差分析。结果显示:合束激光光束质量因子M^(2)对沿光纤端面水平(x轴)方向的扰动量最为敏感,需要控制在微米量级;确定了光纤阵列的不同扰动量与合束激光光束质量因子M^(2)之间的定量关系,给出了光纤阵列位移、指向精度控制要求;当参与合束的子束数量超过23束时,在特定的随机扰动量下,合束激光的光束质量因子M^(2)的统计均值分别趋向各自的稳定值1.37、1.34、1.25,而标准差分别趋于0.05、0.06、0.04。Objective High power,high beam quality,and compact miniaturization are the development goals of fiber lasers.Spectral beam combination is an effective means to overcome the bottleneck of single-fiber output power and can achieve a high power output of fiber lasers.In most existing spectral beam combining systems,the gap between adjacent subfibers is generally of the order of millimeters or even larger;consequently,the entire system occupies a large space.Therefore,a compact spectral beam combining system based on a precision fiber array is proposed in this study.Many factors affect the beam quality of a combined laser in a spectral beam combining system,including lens aberration,laser line width,grating thermal distortion,and fiber array disturbance,which degrade the beam quality of the combined laser.Research on the influence of fiber array disturbance deviation on beam quality is relatively scarce.Therefore,this study focused on the effects of fiber array disturbance on beam quality factor of a combined laser.Quantitative analysis of the effects of fiber array displacement and pointing disturbance deviation on beam quality factor of the combined laser provides a means of realizing effective control of combined laser beam quality.Unlike in similar studies,this study conducted error analysis of the axial displacement deviation of the fiber array by the M^(2) factor of the combined laser,which makes the theoretical model more practical.Methods Diffraction propagation theory enables us to derive the light field distribution at each position of a subbeam affected by displacement and pointing deviation.In the observation plane where the combined laser is formed,the near-and far-field light intensities of each subbeam are incoherently superimposed based on the incoherent superposition principle.The traditional intensity second-moment method is used to caclulate beam quality factor of the beam by fitting the relationship between the beam width and propagation distance.Due to the limitations of computer memory and perfo

关 键 词：光纤光学 光纤阵列 光束质量 光谱组束 紧凑型组束系统 

分 类 号：TN241[电子电信—物理电子学]