单锥形掺镱光纤在纳秒脉冲放大器中的激光性能  

Laser Performance of Single Tapered Ytterbium⁃Doped Fiber in Nanosecond Pulsed Amplifier

作　　者：刘韦志 王晓亮 林贤峰 张志伦 罗涛 肖润珩 邢颍滨 彭景刚 李海清 戴能利 李进延 Liu Weizhi;Wang Xiaoliang;Lin Xianfeng;Zhang Zhilun;Luo Tao;Xiao Runheng;Xing Yingbin;Peng Jinggang;Li Haiqing;Dai Nengli;Li Jinyan(Wuhan National Laboratory for Optoelectronics,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China;Wuhan Changjin Laser Technology Co.,Ltd.,Wuhan 430206,Hubei,China)

机构地区：[1]华中科技大学武汉光电国家研究中心,湖北武汉430074 [2]武汉长进光子技术股份有限公司,湖北武汉430206

出　　处：《中国激光》2024年第13期1-8,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(61975061)。

摘　　要：为了抑制高平均功率、高单脉冲能量纳秒脉冲激光放大器中的受激拉曼散射效应与光束质量退化,制备了纤芯直径为31~62μm、内包层直径为250~500μm的单锥形掺镱光纤。基于自行研制的单锥形掺镱光纤搭建了全光纤结构的纳秒脉冲激光放大器,在重复频率为100 kHz的条件下,实现了平均功率为832 W、单脉冲能量为8.32 mJ、峰值功率为24.8 kW的纳秒脉冲激光输出。在相近输出功率下,与纤芯/内包层直径为50μm/400μm的均匀光纤相比,单锥形掺镱光纤将受激拉曼散射效应出现的阈值功率提升了约31%,光束质量因子由约4.8减小至约3.5。实验验证了单锥形掺镱光纤对受激拉曼散射效应与光束质量退化的抑制效果。Objective A pulsed fiber laser with high power,high energy,and good beam quality has significant application value in laser cleaning,deep penetration welding,and other fields.The development of double-cladding fiber,laser diodes,and passive devices has allowed the unprecedented improvement of the output power of nanosecond pulsed fiber lasers.A master oscillation power amplification(MOPA)structure is commonly used to achieve a nanosecond pulsed laser output with high average power,high singlepulse energy,and excellent beam quality,which expands the range of applications.However,this laser output improvement is limited by the parasitic oscillation caused by amplified spontaneous emission(ASE)and the stimulated Raman scattering(SRS)caused by a high peak power.Large-mode-area gain fiber is commonly used to suppress the SRS and achieve a laser output with high average power and high pulse energy.However,this also leads to serious deterioration of the beam quality.Commercial 30μm/250μm fibers can achieve nanosecond pulsed laser output near the diffraction limitation,but cannot simultaneously achieve high average power and high pulse energy.With the longitudinal variation of the core cladding structure,tapered ytterbium-doped fiber(T-YDF)can suppress SRS and beam-quality deterioration,realizing a laser output with high average power,high single-pulse energy,and excellent beam quality.This provides a suitable method for improving the output performance of pulsed lasers.Herein,a T-YDF with a total length of 4 m and tapered region length of 1.5 m is proposed,which experimentally provides obvious suppression effects of the SRS and beam quality deterioration.Methods The T-YDF shown in Fig.1 is fabricated by modified chemical vapor deposition(MCVD)process with solution doping technology(SDT).This T-YDF can be divided into two regions along the longitudinal direction.The first is a tapered region with a gradual variation in the diameters of the core and cladding at a fixed ratio of 0.124.The diameter of the core varies from

关 键 词：单锥形光纤 纳秒脉冲激光 受激拉曼散射效应 光束质量 

分 类 号：TN248[电子电信—物理电子学]