Design and experimental verification of near diffraction-limited output of a large core size Yb:YAG crystalline waveguide laser

Crystalline waveguide prepared by adhesive-free bonding technique (AFB) has good mode limiting effect. In this paper, considering the mode competition, the waveguide core size under the single mode condition is calculated, which can increase the core size 1.79 times comparing with the traditional result. A 400 mu m x 320 mu m large core size Yb:YAG crystalline waveguide is used to build a crystalline waveguide laser, and output the beam quality is achieved with M-2 = 1.22 x 1.05. The experimental results of near diffraction-limited output verify that the calculating method is reliable.