基于光谱滤波的宽谱激光相干合成光程与相位同步控制研究  

Research on Optical Path and Phase Simultaneous Control in Coherent Beam Combining of Broadband Laser Based on Spectral Filtering

作　　者：常洪祥 靳凯凯 张雨秋 张嘉怡 金坤 李灿 粟荣涛 冷进勇 周朴[1] Chang Hongxiang;Jin Kaikai;Zhang Yuqiu;Zhang Jiayi;Jin Kun;Li Can;Su Rongtao;Leng Jinyong;Zhou Pu(College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,Hunan,China;Nanhu Laser Laboratory,National University of Defense Technology,Changsha 410073,Hunan,China;Hunan Provincial Key Laboratory of High Energy Laser Technology,National University of Defense Technology,Changsha 410073,Hunan,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：《光学学报》2023年第17期179-187,共9页Acta Optica Sinica

基　　金：国家自然科学基金(62275272)。

摘　　要：高精度光程控制是宽谱激光相干合成中的关键技术之一,是在一定光谱宽度条件下保持多路激光相干性的重要手段。为了保持各路激光之间的时间相干性,对于光谱宽度为10 nm量级的激光,光程差一般要控制在十几个波长以内。因此,为了实现宽谱激光的相干合成,除了对多束激光进行相位控制,还需要同步地对各路激光之间的光程差进行有效控制。本文研究了基于光谱滤波的相位与光程同步控制技术,利用放大自发辐射光源和中心波长为1064 nm的光纤带通滤波器产生光谱宽度为10 nm的光纤激光,通过光谱滤波的方式实现相位和光程的同步探测与控制,光程控制范围优于0.1 ps,相位控制残差<λ/16。该方法在高平均功率光纤激光相干合成中具有重要的应用价值。Objectives Fiber laser has the advantages of high conversion efficiency,compact structure,and easy maintenance,and it has been widely used in industrial processing,material treatment,radar detection,and other fields.In some specific fields,requirements for the output power of fiber lasers have been further proposed,such as using high-power femtosecond laser filament principle to realize atmospheric multi-component detection,using narrow linewidth fiber lasers to achieve long-distance Doppler wind speed measurement,and using 532 nm green laser for copper material processing and 3D printing applications.By increasing the output power of fiber lasers,the detection distance and processing efficiency can be improved.However,due to the presence of nonlinear effects such as stimulated Brillouin scattering and mode instability in fibers,the output power of a single fiber is limited.Coherent beam combining(CBC)with multiple lasers is one of the effective ways to obtain high average output power fiber lasers.In a pulse fiber laser CBC system,a shorter pulse indicates wider spectral width.In a high-power continuous fiber laser CBC system,it is often necessary to apply phase modulation,so as to appropriately broaden the seed linewidth and suppress nonlinear effects in the fiber amplifier.A wider spectral width poses higher requirements on the optical path control of each laser in a CBC system.Meanwhile,there exists a coupling between the phase and the optical path.Therefore,simultaneous control of the optical path and phase in the CBC system is needed.Methods We investigated CBC of broadband light sources based on spectral filtering.Numerical simulations of phase and optical path simultaneous control in broadband laser interferometry were performed using a stochastic parallel gradient descent algorithm.A rectangular spectral light source with a 3 dB spectral width of 10 nm was obtained by using an amplification of spontaneous emission(ASE)light source and a fiber bandpass filter with a center wavelength of 1064 nm.Phase modu

关 键 词：相干合成 超短脉冲 光谱滤波 光程控制 

分 类 号：TN249[电子电信—物理电子学]