Lateral waveguide mode selection for the development of single-mode ridge lasers with a distributed Bragg mirror

Abstract: The possibility of mode selection in lateral mesa-stripe waveguides for the implementation of single-mode lasers with a surface distributed Bragg reflector (DBR) is studied theoretically. The dependence of mode discrimination of TE₀₀ and TE₀₁ lateral modes on such laser crystal parameters as the mesa-stripe width, the mesa-groove depth, and the DBR depth is analysed. An algorithm is presented for choosing the value of these parameters depending on the required generation spectrum width for a given heterostructure design. The possibility of increasing the width of the emitting aperture while maintaining the single-mode generation regime is demonstrated, while the selection of lateral modes in narrow mesa-stripe waveguides is achieved due to different DBR reflection coefficients for TE₀₀ and TE₀₁ modes at a given DBR length. The resulting mesa-stripe broadening can be used to increase the optical power of a single-mode laser.

Keywords: single-mode diode lasers, distributed Bragg reflector, lateral waveguide, mode selection, heterostructure.