光学学报, 2011, 31 (s1): s100204, 网络出版: 2011-06-23
光纤弯曲缠绕方式对模式激发的影响
Effect of Fiber Coiling Mode on Modes Excitation
摘要
模式耦合、弯曲畸变、弯曲损耗是大模场光纤激光中重要的考虑因素。为了研究模场畸变对于大模场光纤光束质量的影响,理论研究了阶跃光纤的模式耦合和模场畸变的特性。计算了有效弯曲半径经历渐变和突变情况下,模式功率随传播距离和有效弯曲半径的关系。数值计算结果显示,弯曲半径经历匀滑的变化过渡到直光纤,当最小有效弯曲半径大于3 cm时,畸变基模激发的高阶模就可以忽略。而弯曲半径经历突然的变化过渡到直光纤,这个最小弯曲半径需大于20 cm时,畸变基模激发的高阶模才可以忽略。
Abstract
Mode coupling, bend distortion and bend loss are important considerations in large mode area (LMA) fiber laser. Both mode coupling and mode distortion in the step-index fiber are studied theoretically in order to gain the effect of mode distortion on the beam quality. The dependences of mode power on propagation distance, effective bend radius are calculated with the bend radius experiencing sudden and gradual transition. Numerical simulations show that, if the distorted fundamental mode experiences smooth transition from bend fiber to straight fiber, the excitation of higher order modes could be ignored when the bend radius is larger than 3 cm. But the bend radius must be larger than 20 cm when the mode experiences sudden transition.
李晶, 王建军, 邓颖, 许党朋, 林宏奂, 景峰. 光纤弯曲缠绕方式对模式激发的影响[J]. 光学学报, 2011, 31(s1): s100204. Li Jing, Wang Jianjun, Ding Ying, Xu Dangpeng, Lin Honghuan, Jing Feng. Effect of Fiber Coiling Mode on Modes Excitation[J]. Acta Optica Sinica, 2011, 31(s1): s100204.