掺镱光纤激光器粒子数空间分布研究

Study on Spatial Distribution of Population for an Yb^(3+)-doped Double-clad Fiber Laser

针对基于重叠因子模型的速率方程不能分析粒子数空间分布的情况,依据双包层掺Yb3+光纤激光器中,内包层光强近似于均匀分布、而纤芯中光场近似于高斯分布的特点,建立了基于光强分布的速率方程。依据该方程,分析了正向、反向和双向泵浦方式下,Yb3+上能级粒子数的空间分布。结果表明:沿光纤轴向,不同的泵浦方式导致上能级粒子数呈现不同的分布特征;而沿光纤径向,无论采用何种泵浦方式,上能级粒子数都呈现中间低、两端高的抛物线分布结构。

For the rate equation based on overlapping factor model could not analyze the spatial distribution of population in a laser,the rate equation is improved by mean of the different distributions of laser intensity in both inner cladding and the core of an Yb 3＋-doped double-cladding laser.Based on the improved rate equation,spatial distributions of population are studied for an Yb 3＋-doped double-clad fiber laser at different pumping configuration.The results show that the population in center of the core is lower than that in edge of the core along the fiber diameter direction,and spatial distribution of normalized population presents different characteristics along the fiber length direction.