A 7-k W narrow-linewidth fiber amplifier assisted by optimizing the refractive index of the large-mode-area active fiber  

作　　者：Pengfei Ma Tianfu Yao Wei Liu Zhiyong Pan Yisha Chen Huan Yang Zilun Chen Zefeng Wang Pu Zhou Jinbao Chen 

机构地区：[1]College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha,China [2]Nanhu Laser Laboratory,National University of Defense Technology,Changsha,China [3]Hunan Provincial Key Laboratory of High Energy Laser Technology,National University of Defense Technology,Changsha,China

出　　处：《High Power Laser Science and Engineering》2024年第5期115-122,共8页高功率激光科学与工程(英文版)

基　　金：supported by the National Key Research and Development Program of China (No. 2022YFB3606400);the National Natural Science Foundation of China (No. U22A6003)。

摘　　要：The high-power narrow-linewidth fiber laser has become the most widely used high-power laser source nowadays Further breakthroughs of the output power depend on comprehensive optimization of stimulated Brillouin scattering(SBS),stimulated Raman scattering (SRS) and transverse mode instability (TMI).In this work,we aim to further surpass the power record of all-fiberized and narrow-linewidth fiber amplifiers with near-diffraction-limited (NDL) beam quality SBS is suppressed by white-noise-signal modulation of a single-frequency seed.In particular,the refractive index of the large-mode-area active fiber in the main amplifier is controlled and fabricated,which could simultaneously increase the effective mode field area of the fundamental mode and the loss coefficient of higher-order modes for balancing SRS and TMI.Subsequent experimental measurements demonstrate a 7.03 kW narrow-linewidth fiber laser with a signal-to-noise ratio of 31.4 dB and beam quality factors of M_(x)^(2)=1.26,M_(y)^(2)=1.25.To the best of our knowledge,this is the highest reported power with NDL beam quality based on a directly laser-diode-pumped and all-fiberized format,especially with narrow-linewidth spectral emission.

关 键 词：fiber amplifier fiber evaluation high power narrow linewidth 

分 类 号：TN2[电子电信—物理电子学]