千瓦级窄线宽掺铥光纤放大器激光线宽对SBS阈值的影响(特邀)  

Effect of Laser Linewidth of Kilowatt Narrow-Linewidth Thulium-Doped Fiber Amplifier on SBS Threshold(Invited)

作　　者：任传永 韩耀聪 栾心雨 江浩 王昊天 王飞 沈德元 Ren Chuanyong;Han Yaocong;Luan Xinyu;Jiang Hao;Wang Haotian;Wan Fei;Shen Deyuan(School of Physics and Electronic Engineering,Jiangsu Normal University,Xuzhou 221116,Jiangsu,China;Jiangsu Institute of Mid-Infrared Laser Technology&Applications,Xuzhou 225261,Jiangsu,China)

机构地区：[1]江苏师范大学物理与电子工程学院,江苏徐州221116 [2]江苏中红外激光应用技术产业研究院,江苏徐州225261

出　　处：《中国激光》2024年第19期230-236,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(62035007,62105130)。

摘　　要：2μm波段高功率窄线宽激光在超远距离相干光通信、下一代引力波探测及激光雷达等前沿应用领域中有着重大需求。受激布里渊散射(SBS)效应是制约窄线宽光纤激光功率提升的关键问题之一。基于多热点设计构建了全光纤掺铥主振荡功率放大(MOPA)系统,利用伪随机二进制序列(PRBS)驱动电光相位调制器,实现了单频种子源激光线宽的连续调谐。理论与实验研究了种子源激光线宽对千瓦级窄线宽掺铥光纤放大器中SBS阈值的影响规律。实验结果表明,当单频种子源的调制线宽为480 MHz时,此掺铥光纤MOPA系统可实现>1025 W的激光输出,激光中心波长为1998 nm,信噪比>46 dB。该激光线宽比目前已报道的千瓦级掺铥光纤激光窄线宽(~5 GHz)窄一个数量级,可用于相干光通信等应用领域的光源研发。Objective 2μm high-power narrow-linewidth fiber lasers have a wide range of application demands in frontier applications and scientific research fields,such as coherent optical communications,Lidar,remote sensing,and next-generation gravitational wave detection,owing to their favorable spatiotemporal coherence.Generally,the power scaling of narrow-linewidth fiber lasers is limited by the stimulated Brillouin scattering effect.Using phase modulation to broaden the linewidth of a single-frequency seed source to reduce the SBS gain peak,researchers achieved>1 kW narrow-linewidth laser output for high-power fiber amplifiers in the 1.0‒1.5μm band,thus proving that phase modulation is the most promising technical path currently to achieve kilowattlevel narrow-linewidth fiber-laser operations.Compared with 1.0‒1.5μm Yb-or Er-doped fiber lasers,2μm-band Tm-doped fibers with a larger mode field area can effectively increase the SBS threshold,thus demonstrating significant potential in achieving high-power single-frequency laser operations.Thus far,2μm Tm-doped fiber lasers have achieved 316 W singlefrequency outputs and 1.1 kW laser powers with a narrow linewidth of~5 GHz.However,the effect of the laser linewidth on the SBS suppression capability of kilowatt-level narrow-linewidth thulium-doped fiber amplifiers has not been investigated comprehensively.In this study,we constructed a thulium-doped fiber laser system with>1 kW power and a linewidth of<500 MHZ based on pseudo-random binary sequence phase modulation and a multihotspot pumping scheme.Additionally,we investigated the effect of the seed-source linewidth on the SBS threshold in thulium doped fiber amplifier(TDFA),both theoretically and experimentally.Methods First,based on the theoretical model of the SBS threshold enhancement factor after filtered pseudo-random binary sequence(PRBS)signal modulation,the effects of the PRBS7 signal modulation frequency and seed linewidth on the SBS threshold enhancement factor of a thulium-doped fiber amplifier were anal

关 键 词：光纤激光 千瓦级 2μm窄线宽激光 受激布里渊散射效应 相位调制 

分 类 号：O438[机械工程—光学工程]