光纤激光相干合成中偏振-相位主动控制技术(特邀)  

Active polarization-phase control in fiber laser coherent beam combining(invited)

作　　者：周宏冰 陶汝茂 辛雄 张昊宇[1] 刘辰旭 王信宇 舒强 楚秋慧 林宏奂[1] 王建军[1] 颜立新[2] 景峰[1] ZHOU Hongbing;TAO Rumao;XIN Xiong;ZHANG Haoyu;LIU Chenxu;WANG Xinyu;SHU Qiang;CHU Qiuhui;LIN Honghuan;WANG Jianjun;YAN Lixin;JING Feng(Laser Fusion Research Center,China Academy of Engineering Physics,Mianyang 621900,China;Department of Engineering Physics,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国工程物理研究院激光聚变研究中心,四川绵阳621900 [2]清华大学工程物理系,北京100084

出　　处：《红外与激光工程》2024年第12期8-22,共15页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(62205317)。

摘　　要：建立了光纤激光相干合成多通道偏振-相位主动控制数理模型,首次仿真研究了合成路数、初始状态、相位残差、动态噪声等对不同控制方案的性能影响。结果表明,基于随机并行梯度下降算法的光束同时取样方案的收敛步数随路数增多而增大,约为路数的4.5倍,而光束独立取样和基于多抖动法的光束同时取样方案的收敛速度均不随路数变化。在光束同时取样方案中,相位残差会影响偏振控制从而导致合成效率下降,基于多抖动法的光束同时取样方案可通过增大参考光振幅来改善,当参考光振幅与合振幅之比大于10时,0.1 rad相位残差导致的合成效率下降低于5%,然而在动态噪声条件下控制效果不佳,需要开发更好的方法来提升偏振误差信号的可靠性。Objective Coherent beam combining(CBC)can improve laser brightness while maintaining beam quality,which is one of the most promising techniques to break through the power limitation of a single fiber laser.CBC requires high-purity linearly-polarized lasers,which are usually obtained from all-polarization-maintained fiber lasers.Unfortunately,nonlinear effect thresholds of all-polarization-maintained fiber lasers are lower than that of non-polarization-maintained ones,and the system cost is higher.Non-polarization-maintained fiber laser system with active polarization control technology is one of the alternatives for achieving linearly-polarized laser sources.However,there is little research on the theory of active polarization-phase control,and no comprehensive analysis of different control schemes has been reported.In this paper,active polarization-phase control of multi-channel CBC system with different control schemes is modeled.The convergence and feasibility of the control schemes are verified,and the channel scalabilities as well as the effect of extra residual phase and dynamic noise on combining efficiency have been studied.Methods Based on the structure of filled-aperture CBC,active polarization-phase control model is constructed,where phase control adopts multi-dithering method while the polarization control adopts SPGD algorithm to ensure fair comparison.According to the sampling scheme of laser beams,the polarization-phase control schemes is divided into individual sampling and simultaneous sampling categories.The latter ones are further divided into SPGD-based schemes and multi-dithering-based schemes.CBC performance based on the above three kinds of control schemes has been simulated with their convergence and feasibility being verified.The channel scalabilities of different schemes are compared,and the effect of the extra residual phase on combining efficiency of simultaneous sampling schemes is analyzed.Moreover,dynamic noise is modeled with emphasis on either lowfrequency or high-frequency contri

关 键 词：光纤激光 偏振控制 多抖动法 相干合成 

分 类 号：O436[机械工程—光学工程]