摘要
在高功率激光运转条件下,掺杂稀土离子的量子亏损和玻璃材料的本征吸收均会造成光纤放大器中增益光纤温度的整体上升与梯度分布。在热平衡状态下,光纤材料的热光效应将会诱导光纤横向折射率的再分布,引发高功率激光运转条件下增益光纤模式特性的改变。为此,利用多物理场有限元建模的数值计算方法对高功率激光运转条件下大模场掺镱石英光纤的热致模式特性展开系统研究,分析总结大模场增益光纤的模式特性在不同激光运转功率、增益光纤设计参数(纤芯直径、数值孔径、热光系数)和光纤弯曲使用条件下的变化规律。结果表明,随着激光运转功率的增加,纤芯和包层之间的温差会变大,从而导致光纤的归一化参数V值增大,最终使模式的传输损耗系数减小,模式在纤芯区域的功率因子增大。
Under the condition of high power laser operation,the quantum defect of rare earth ions and the intrinsic absorption of glass materials will lead to the overall increase and gradient distribution of the temperature of the gain fiber in the optical fiber amplifier.In the state of thermal equilibrium,the thermo-optic effect of optical fiber materials will induce the redistribution of transverse refractive index of optical fiber and cause the change of mode characteristics of gain fiber under the condition of high power laser operation.For this reason,the numerical calculation method of multi-physical field finite element modeling is used to systematically study the thermally induced mode characteristics of large mode field ytterbium doped quartz fiber under the condition of high power laser operation.The changes of mode characteristics of large mode field gain fiber under different laser operating power,gain fiber design parameters(core diameter,numerical aperture,thermo-optical coefficient)and fiber bending are analyzed and summarized.The results show that with the increase of laser power,the temperature difference between the core and the cladding will increase,which leads to the increase of the parameter V of the fiber,the decrease of the transmission loss coefficient of the mode and the increase of the power factor of the mode in the core region.
作者
沈超超
于飞
于春雷
胡丽丽
Shen Chaochao;Yu Fei;Yu Chunlei;Hu Lili(Key Laboratory of Materials for High Power Laser,Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences,Shauglicd 201800,China;Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences,Hangzhou 310024,Zhejiang,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2022年第10期107-114,共8页
Acta Optica Sinica
基金
国家自然科学基金(61935002,61775224,61875216)
中国科学院基金(ZDBS-LY-JSC020)
国家重点研发计划(2020YFB1805900)。
关键词
激光光学
大功率激光光纤放大器
有限元仿真
大模场掺镱石英光纤
模式特性
热光效应
laser optics
high-power laser fiber amplifiers
finite-element simulation
large-mode-area Yb-doped optical fiber
modal properties
thermo-optical effect
