基于偏振复用技术的激光二极管光纤耦合方法

光纤耦合输出的高功率激光二极管(LD)模块作为光纤激光器的抽运源已经得到了广泛应用。为了进一步提高光纤耦合激光二极管输出功率,提出了利用激光二极管输出光束的线偏振特性,采用偏振复用技术,将两只高功率激光二极管输出光束经准直、复合、聚焦的光纤耦合方法。利用光线追迹法,分析了圆柱透镜对激光二极管发散光束的准直特性,并讨论了柱透镜的安装距离对准直性能的影响。根据激光二极管和光纤的相关参数设计了聚焦透镜组。采用这种方法将两只输出波长为980 nm的高功率激光二极管输出光束耦合进数值孔径0.22,芯径100μm的多模光纤中,当工作电流为4.5 A时,光纤激光连续输出功率为6.36 W,耦合效率大于78%。

Fiber-Coupled High Power Laser Diode by Polarization Multiplexing

High power fiber-coupled-output laser diode (LD) modules have been widely used for end-pumping fiber laser. For increasing output power of fiber-coupled LD modules, a new method was developed. Based on the linear polarization of laser from LD using polarization multiplexing, beams from two high power laser diodes are coupled into a single multi-mode fiber via collimating, combining, focusing and coupling. Based on ray-tracing method, the collimating characteristic of the cylindrical lens for the divergent beam from LD is analyzed. The influence of the location of the cylindrical lens on beam collimating is discussed. The focusing lens set is designed with the related technical data of fiber and LD. In experiments, beams of two 980 nm high power laser diodes are coupled into a multi-mode fiber, with a core diameter of 100 μm and a numerical aperture (NA) of 0.22. The fiber output power is 6.36 W at current 4.5 A with coupling efficiency more than 78%.