同带泵浦千瓦级掺铥光纤激光器输出特性理论模拟  

Modeling In-band Pumped kW Level High-Power Tm-Doped Fiber Lasers via Simulations

作　　者：陶蒙蒙 叶锡生[1] 叶景峰[2] 余婷[1] 全昭[1] 漆云凤[1] 冯国斌[2] 陈卫标[1] Tao Mengmeng;Ye Xisheng;Ye Jingfeng;Yu Ting;Quan Zhao;Qi Yunfeng;Feng Guobin;Chen Weibiao(Shaihai Key Laboratory of All Solid-State Laser and Applied Techniques,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;State Key Laboratory of Laser Interaction with Matter,Northwest Institute of Nuclear Technology,Xi'an,Shaanxi 710024,China)

机构地区：[1]中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室,上海201800 [2]西北核技术研究所激光与物质相互作用国家重点实验室,陕西西安710024

出　　处：《中国激光》2022年第1期203-213,共11页Chinese Journal of Lasers

基　　金：国家自然科学基金(62105268,62005300);激光与物质相互作用国家重点实验室基金(SKLLIM1801Z)。

摘　　要：对793 nm、1.6μm和1.9μm三种不同泵浦波段下千瓦级掺铥光纤激光器的输出特性开展了数值模拟研究。在1 kW输出功率下,对不同泵浦波段的输出效率和热特性进行了对比分析。结果表明,在793 nm泵浦下,受益于交叉弛豫过程,量子效率可超过100%,但是其整体斜率效率依然不高,导致激光器产热严重,废热与输出功率比达80.8%,光纤端面温度也相对较高。在同带泵浦下,激光器效率得到明显提升,尤其是在1.9μm同带泵浦下,激光器斜率效率达90%以上,废热也得到显著抑制,使用低掺杂光纤时,增益光纤温度整体在50℃以内。对同带泵浦下掺铥光纤激光器的功率提升开展了初步估算和数值模拟,估算表明在同带泵浦下,掺铥光纤激光器的功率提升主要受限于受激布里渊散射、模式不稳定、外包层损伤以及光损伤等四个因素。数值模拟结果表明,同带泵浦下热载显著降低,掺铥光纤激光器的功率提升不会受到模式不稳定的影响,而外包层损伤和受激布里渊散射成为主要的限制因素。对于1.6μm和1.9μm同带泵浦,在25μm芯径尺寸下,激光器最高输出功率可分别达5.9 kW和12.7 kW。Objective Until now,high-power Tm-doped fiber systems at the kW-level output are all laser diode(LD)pumped at 793 nm.However,even with the cross-relaxation process,the operation efficiency at the high-power output for a 793 nm pump is~50%,leading to a heat waste comparable with the output and posing severe challenges on heat management and power scaling.In high-power fiber systems,in-band pumping is an effective way to reduce the quantum defect and improve the energy conversion efficiency.For Tm-doped fiber systems,1.6μm and 1.9μm are the two major resonant pump bands.With the 1.6μm pump,systems with an output >400 W have been demonstrated.However,with a quantum defect of 20%,the operation efficiency of the 1.6μm pump is~60%,indicating that it is not an ideal pump choice for high-power Tm-doped fiber systems.The 1.9μm pump is recently developed in high-power Tm-doped fiber systems;the extremely high efficiency of this pumping scheme has been experimentally demonstrated with 100-W-level output,manifesting the huge potential for power scaling of Tmdoped fiber systems to high output levels.In this study,the output and thermal characteristics of kW-level Tmdoped fiber amplifiers(TDFAs)are investigated for different pump bands.Moreover,the power scalability of inband pumped TDFAs is explored under several conditions.Methods Numerical simulations were performed to investigate the output and thermal characteristics.Different laser configurations featuring different pump schemes and active fibers were compared.Active fiber lengths for different laser configurations were optimized before comparison.For power scaling,a rough estimation was made at first.Then,a numerical algorithm with iterative loops for heat load profile and temperature distribution was developed for further investigations.In the simulation,the overall absorption was set as a constant to ensure sufficient absorption of the pump,whereas the doping concentration and the fiber length were varying parameters.Results and Discussions Simulations show that,

关 键 词：激光器 光纤激光器 同带泵浦 热效应 热载 功率提升 

分 类 号：TN244[电子电信—物理电子学]