窄线宽脉冲光纤激光的自相位调制预补偿研究  

Self-phase modulation pre-compensation of narrowlinewidth pulsed fiber lasers

作　　者：粟荣涛 肖虎 周朴[2,3] 王小林 马阎星[2,3] 段磊 吕品 许晓军[2,3] Su Rong-Tao1,2,3,Xiao Hu1,2,3,Zhou Pu2,3, Wang Xiao-Lin2,3, Ma Yan-Xing2,3,Duan Lei1. Lii Pin1. Xu Xiao-Jun2,3. 1.(Institute of Software, Chinese Academy of Sciences, Beijing 100190, China） 2. （College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China） 3. （ Hunan Provincial Collaborative Innovation Center of High Power Fiber Laser, Changsha 410073, China)

机构地区：[1]中国科学院软件研究所,北京100190 [2]国防科技大学前沿交叉学科学院,长沙410073 [3]大功率光纤激光湖南省协同创新中心,长沙410073

出　　处：《物理学报》2018年第16期233-240,共8页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017YFF0104603);中国博士后科学基金(批准号:2017M620070);国家自然科学基金(批准号:61705265;61705264)资助的课题~~

摘　　要：自相位调制(SPM)效应会展宽窄线宽脉冲光纤激光的光谱宽度,降低其相干性.通过相位调制对SPM引起的非线性相移进行预补偿,能够使脉冲激光在光纤中进行放大和传输后保持种子激光的光谱特性.基于三波耦合方程开展数值仿真,研究了在对SPM进行"欠补偿","完全补偿"和"过补偿"的情况下,SPM预补偿对受激布里渊散射阈值和激光光谱特性的影响.开展了SPM预补偿实验研究,将脉冲激光的光谱宽度从1.4 GHz压缩到120 MHz.研究内容可以为窄线宽脉冲光纤激光系统的设计搭建提供参考.High peak power, single frequency nanosecond fiber lasers have aroused the intense interest in their applications such as nonlinear frequency generation, LIDAR, and remote sensing. However, self-phase modulation（SPM） will induce a temporally dependent phase shift φNL（L, t） = ｜Ap（0, t）｜^2γLeff, where Ap is the amplitude of pump wave, γ is the nonlinear parameter, and Leffis the effective fiber length. The nonlinear phase shift will broaden the spectral linewidth of pulsed laser, which degrades the coherence of the laser and influences the performance of the laser. In order to obtain laser pulses with narrower linewidth, we can phase-modulate the pulsed laser with a value of-φNL（L, t）. Thus, the SPM induced the nonlinear phase shift can be eliminated, and the spectra of pulsed laser can remain during the amplification and transmission in the fiber. Stimulated Brillouin scattering（SBS） has very low threshold and should be taken into consideration in narrow linewidth fiber lasers. The SBS threshold, which is dependent on the linewidth of laser, will be changed at the same time when the SPM is pre-compensated for. Because the SPM pre-compensation will change the linewidth of the pulsed laser. According to three coupled amplitude equations, we numerically analyze the influence of SPM pre-compensation on SBS threshold and spectral characteristics. The stimulation results show that in a master oscillator power amplifier structured fiber laser system, when SPM is completely compensated for φM（t） = φNL（L, t））,the spectrum of the output pulsed laser can be maintained as that of the laser seed, but the SBS threshold usually decreases. When the SPM is compensated for incompletelyφM（t）〈φNL（L, t））, the spectral linewidth of the output laser cannot be compressed to that of the laser seed, and the SBS threshold in this situation is lower than the SBS threshold obtained when φM（t） = φNL（L, t）. When the SPM is overcompensated for φM（t）〉φNL（L, t））, the spe

关 键 词：光纤激光 非线性效应 自相位调制 受激布里渊散射 

分 类 号：TN248[电子电信—物理电子学]