A Composite Cavity for Mode Control in Broad-Area Diode Laser

A unstable cavity structure composed of the arc-shaped cavity, Fabry-Perot cavity, and sidewall saw-tooth microstructure is proposed to achieve mode selection in high-power broad-area diode laser with 980nm wavelength. In this cavity, the loss difference between the higher-order modes and the fundamental mode is increased to suppress the lasing of higher-order modes. The lateral divergence is reduced by about 28%. The number of modes in the near-field spot is reduced and the light intensity is concentrated towards the center of the Near-field profile. Also, the lateral beam parameter product decreases by 15%.