5 kW近单模光纤激光振荡器的光子暗化效应  

Photodarkening Effect of 5 kW Near-Single-Mode Fiber Laser Oscillator

作　　者：王鹏[1,2,3,4] 杨保来 张汉伟[1,2,3] 奚小明 史尘[1,2,3] 王小林 许晓军 吕品 Wang Peng;Yang Baolai;Zhang Hanwei;Xi Xiaoming;Shi Chen;Wang Xiaolin;Xu Xiaojun;Lü Pin(College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,Hunan,China;State Key Laboratory of Pulsed Laser Technology,National University of Defense Technology,Changsha 410073,Hunan,China;Hunan Provincial Key Laboratory of High Energy Laser Technology,Changsha 410073,Hunan,China;Institute of Automation,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]国防科技大学前沿交叉学科学院,湖南长沙410073 [2]脉冲功率激光技术国家重点实验室,湖南长沙410073 [3]高能激光技术湖南省重点实验室,湖南长沙410073 [4]中国科学院自动化研究所,北京100190

出　　处：《光学学报》2022年第23期1-10,共10页Acta Optica Sinica

基　　金：国家自然科学基金(62005315);长沙市杰出创新青年培养计划(kq2009004)。

摘　　要：为研究掺镱光纤(YDF)光子暗化效应对高功率高亮度光纤激光器的影响,利用25/400μm大模场YDF和915 nm半导体泵浦源搭建了光纤激光振荡器,输出功率可达5 kW,输出激光为近单模。对该光纤激光振荡器进行满功率拷机时出现了光子暗化现象,激光器输出功率急剧下降,输出激光时域中呈现出强烈的横向模式不稳定性(TMI)现象。经过多次测试后发现:后向泵浦时该光纤激光振荡器的TMI效应对应的泵浦功率阈值和输出功率阈值均出现一定程度的下降(约为14%),与传统理论相符;前向泵浦时TMI效应对应的泵浦功率阈值和输出功率阈值出现一定程度的上升(约为15%),这与传统理论不相符,需进一步开展研究。最终,该光纤激光振荡器输出功率受到光子暗化效应的影响无法维持在5 kW功率水平。In order to investigate the influence of the photodarkening effect of ytterbium-doped fiber(YDF)on high-power and high-brightness fiber lasers,a fiber laser oscillator is established by using 25/400μm large-mode-area YDF and 915 nm laser diodes.The maximum output power is up to 5 kW,and the output laser is near single mode.When the fiber laser oscillator is operated at full power,the photodarkening effect appears.The output power of the oscillator drops sharply,and strong transverse mode instability(TMI)occurs in the time domain of the output laser.After many tests,it is found that the pump power and output power thresholds corresponding to the TMI effect of the oscillator under the backward pump has a certain decline(about 14%),which is consistent with the traditional theory.However,the pump power and output power thresholds corresponding to the TMI effect of the oscillator under the forward pump shows a certain increase(about 15%),which is inconsistent with the traditional theory.Therefore,further investigation is required.Finally,the output power of the fiber laser oscillator fails to be maintained at 5 kW due to the photodarkening effect.

关 键 词：光纤光学 掺镱光纤 光子暗化 光纤激光振荡器 横向模式不稳定 

分 类 号：O436[机械工程—光学工程]