用焦散面半径方法计算双包层光纤的吸收效率  

Calculation of Absorption Efficiency for Double-Clad Optical Fiber by Using Radius of Caustic Surface

作　　者：张辉[1] 王子华[1] 

机构地区：[1]上海大学通信与信息工程学院,上海200072

出　　处：《上海大学学报（自然科学版）》2002年第5期396-399,共4页Journal of Shanghai University:Natural Science Edition

基　　金：国家自然科学基金面上项目资助 (60 2 770 2 5 )

摘　　要：采用一种基于射线理论和模式理论相结合的方法 ,用模式理论计算焦散面半径 ,以此半径为判据用射线方法确定穿过纤芯的模式 ,即能被吸收的模式 .该模式的总数与总模数的比值即为泵浦吸收效率 .用此方法计算了两种圆形内包层截面的双包层光纤的纤芯对内包层中泵浦光的吸收效率与纤芯半径和偏芯距离的关系 .计算结果表明 :圆形内包层截面的双包层光纤激光器和放大器可以通过将纤芯偏离中心位置来提高吸收效率 .该结果与用 2维几何光学射线法的结果一致 .Combining the mode analysis and ray optic theory, a new method to calculate absorption efficiency for double clad optical fibers is presented. The caustic surface is determined by using mode analysis. Taking the radius of caustic surface as a threshold, one can estimate whether or not an individual mode is absorbable. The ratio of the number of solvable modes to the total number of guided modes is then taken as absorption efficiency. Numerical examples are given, and compared with results of 2 D ray optics analysis. Dependence of absorption efficiency on core size and off set distance has also been investigated.

关 键 词：焦散面半径方法 吸收效率 双包层光纤 射线理论 模式理论 纤芯半径 偏芯距离 

分 类 号：TN253[电子电信—物理电子学]