中文摘要：

在几何光学的基础上,采用解析的方法分析了双包层光纤激光器的泵浦问题,讨论了内包层中泵光的传输行为。推导了传输过程中不同的光线与纤芯中心轴的距离,由此确定了能够产生泵浦作用的光线;之后,又进一步分析了对泵浦有贡献的光线在纤芯中走过的长度。

英文摘要：

The pump radiations launched into the double - clad fiber laser （DCF） have been traced with the geometric optics and the propagation of the pump light within the inner clad has been analytically analyzed. The expression for the distance between different rays in the process of propagation and the central axis of fiber core has been derived. As a result, the optical rays which can actually pump the fiber core can be determined. In addition, the traversing distance of the pump rays inside the fiber core has also been quantified.