与半导体激光Bar条相比, 单管半导体激光器具有光束质量好, 寿命长等优点, 但由于其输出功率小, 故在激光加工等领域的应用受到限制。为提高单管半导体激光器的输出功率, 提出了基于偏振复用技术对多个单管半导体激光器进行光纤耦合的方法。首先, 将16只808 nm单管半导体激光器分成两个单元, 通过空间合束将每个单元上的激光器发出的光合成一路; 然后, 利用偏振复用技术将两个单元发出的光束再次合束, 通过自行设计的聚焦系统将合束后的光束耦合进光纤实现光纤输出, 从而提高了半导体激光器光纤耦合模块的功率水平。实验显示, 当工作电流为5.8 A时, 通过芯径为200 μm、数值孔径(NA)为0.2的光纤的输出功率为67 W, 耦合效率达到84%。此模块在功率和光束质量方面满足激光塑料焊接等应用的要求。

Single emitter diode laser has better beam quality and longer lifetime as compared with a diode laser bar. However, its application to the material processing is limited by its lower output powers. To improve the output power of the single emitter diode laser, this paper proposed an optical fiber coupling method for single emitter diode lasers based on the polarization multiplexing. Firstly, 16 single emitters were divided into two laser groups, and the laser beam from the two groups was combined into one by spacial multiplexing technology. Then the beam was combined by polarization multiplexing again. Finally, a focusing system developed by ourselves was used to couple the combined beam into an optical fiber to improve the output power of the optical fiber coupling module. Experimental results show that the laser output of the module can reach 67 W from a fiber with a fiber core of 200 μm and a Numerical Aperture (NA) of 0.2 when the working current is 5.8 A. Moreover, the coupling efficiency of the module has reached 84%. This high power LD module can meet the requirements of plastic processing in power and beam quality.