对具有高光束质量输出的晶体波导激光器的芯径增大方法进行了理论计算和实验验证。通过模拟计算各个导模的相对增益,在考虑模式竞争的情况下,采用Yb原子数分数为1.0% 的Yb∶YAG作为芯层材料,Er原子数分数为0.5%的 Er∶YAG作为内包层材料,芯层的基模截止厚度可以达到360 μm,相当于传统计算方法的两倍。采用扩散键合技术,制备了芯层尺寸为400 μm×320 μm×77 mm的晶体波导,并搭建了波导激光器,得到了最大输出功率为31 W,光-光转换效率为55.3%,光束质量为1.2×1.05的近衍射极限激光输出。实验结果证实了利用模式竞争计算晶体波导基模芯径的可靠性。

The method to increase the core diameter of a crystal waveguide laser with high beam quality is theoretically investigated and experimentally verified. Through the simulation calculation of the relative gain of each guiding mode and considering the mode competition, the fundamental mode cut-off thickness of the core layer can reach 360 μm, twice of that by the traditional calculation method, when 1.0% Yb∶YAG is used as the core material and 0.5% Er∶YAG is used as the inner cladding material. A crystal waveguide with a core size of 400 μm×320 μm×77 mm is fabricated by diffusion bonding, and a waveguide laser is constructed. The maximum output power of this waveguide laser is 31 W, the conversion efficiency from light to light is 55.3%, and the near-diffraction-limited laser output with beam quality of 1.2×1.05 is obtained. The experimental results show that it is reliable to calculate the core diameter of the fundamental mode of a crystal waveguide by mode competition.