针对高功率光纤激光器在实际应用过程中所面临的高效耦合及激光输出质量问题，自行设计了大模场微结构光纤的波导结构，采用集束拉丝技术制备了纤芯直径41 μm、内包层数值孔径0.62、纤芯数值孔径0.05、有效模场面积约530 μm2的掺镱微结构光纤。在抽运功率为35.0 W的条件下，获得的单模激光输出功率为19.1 W，斜率效率为55.2%，光束质量因子M2小于1.01。

The waveguide structure of the large-mode microstructure fiber is designed in view of the efficient coupling and laser output quality during the practical application of the high-power fiber laser. It employs the bundle drawing technology to prepare the ytterbium-doped microstructure fibre with the core diameter of 41 μm, inner-cladding numerical aperture of 0.62, core numerical aperture of 0.05 and effective mode area of 530 μm2. The output power of the single-mode laser is 19.1 W, the slope efficiency is 55.2% and the beam quality factor of M2 is less than 1.01, on the condition that the pump power is 35.0 W.