High single-mode selectivity V-cavity tunable semiconductor laser based on GaAs

With the progress of integrated optoelectronic devices over recent decades, the semiconductor research has increasingly focused on tunable semiconductor lasers featuring a compact structure and simplified fabrication. In this manuscript, we present a proposal for a V-Cavity tunable semiconductor Laser (VCL) at a center wavelength of 940 nm. The theoretical analysis encompasses the threshold conditions of the laser, considering various cavity length differences within the waveguide layer structure. Moreover, we showcase a VCL with a waveguide width of 3 μm and a channel interval of 0.6 nm. Through the optimization of polynomial parameters associated with the curved waveguide, the VCL attains a transmittance exceeding 99.4 %. Additionally, we address the determination of optimal parameter ranges and solve the optical field distribution within the half-wave coupler. The simulation results exhibit that the half-wave coupler, employing optimized parameters, achieves remarkable single-mode selectivity when operating at a central wavelength of 940 nm. Notably, a maximum side mode suppression ratio (SMSR) of 47.9 dB is attainable with a half-wave coupler length of 45 μm and a waveguide gap of 1.7 μm.