采用无胶键合(AFB)技术制备的晶体波导具有良好的模式限制作用。在考虑模式竞争的情况下,对晶体波导的单横模条件进行计算,得出在芯层材料为原子数分数为 1%的Yb∶YAG,内包层材料为原子数分数为0.5%的Er∶YAG中,芯层和内包层的单横模厚度范围。计算结果表明芯层厚度上限可以增大为传统计算结果的1.79倍,为同时实现大模场面积和单横模输出提供了理论支持。通过实验制备出芯层尺寸为320 μm×400 μm的大芯层尺寸Yb∶YAG晶体波导,并将该晶体波导作为增益介质搭建了晶体波导激光器,得到了1030 nm激光输出,其最高输出功率为26 W,斜率效率为31.5%,此时光束质量因子为 Mx2=1.22, My2=1.05。实验结果证明该晶体波导能够实现近衍射极限输出,引入模式竞争来实现大芯层尺寸晶体波导单横模输出的设计方法可靠。

Crystal waveguides prepared by adhesive-free bonding techniques demonstrate strong mode-limiting effects. In this paper, the crystal waveguide's single transverse mode condition is calculated in the context of mode competition. The single transverse mode thickness range of the core and inner cladding is obtained when the core material is Yb∶YAG with atomic number fraction of 1% and the inner cladding material is Er:YAG with atomic number fraction of 0.5%. Results from these calculations show that the maximum core thickness can be increased to approximately 1.79 times of the traditional calculation results obtained without mode competition. This finding provides theoretical support for the possibility of simultaneous large-mode area and single transverse mode output. A large-core Yb∶YAG crystal waveguide with a core size of 320 μm×400 μm is prepared in the experiment. The crystal waveguide is used as a gain medium to build a crystal waveguide laser that could output a 1030-nm laser. The laser's maximum output power is 26 W, with a slope efficiency of 31.5% and beam quality factors of Mx2=1.22 and My2=1.05. These experimental results demonstrate that the crystal waveguide can achieve an output that approaches the diffraction limit. The introduction of mode competition is a reliable design method for achieving single transverse mode output in a large-core crystal waveguide.