光纤激光器反馈耦合损耗分析

Analysis on Coupling Loss of Fiber Lasers

将双包层光纤基模LP01模近似表示为拉盖尔-高斯光束的线性叠加,前六阶的拉盖尔-高斯光束包含了LP01模能量的99.99%.利用拉盖尔-高斯光束的传输特性计算了腔镜分别为球面镜和透镜加平面反射镜时的反馈耦合损耗.结果表明,腔镜为球面镜时,只有当球面镜和到达球面镜光束的曲率半径匹配时才能获得最小的耦合损耗,特别是当平面镜紧贴光纤端面时,耦合损耗为0;当腔镜为透镜加平面反射镜时,将平面镜放置在透镜焦平面时获得最小反馈耦合损耗为0.25%.

The fundamental mode LP01 mode in double-clad fiber is approximated by a linear combination of Laguerre-Gauss beams. The first six Laguerre-Gauss modes contain 99.99% of energy of the LP01 mode. The coupling loss in fiber lasers whose reflectors are calculated respectively. The numerical results show that a curvature mirror and a lens and flat mirror are the coupling loss is low when the cavity mirror is a phase-matched mirror. The coupling loss is zero when a flat mirror is placed closed to the fiber end face. When a plane mirror is placed at the focal plane of a lens,the coupling loss is 0.25%.