Theoretical analyses on improved beam properties of GaSb-based 2.X-μm quantum-well diode lasers with no degradation in laser parameters

Asymmetric laser heterostructure is developed to improve beam properties of GaSb-based diode lasers with no degradation in laser parameters. Employing the semivectorial finite difference method, the dependences of beam divergence and optical confinement factor on waveguide width and refractive index step are investigated theoretically. After carefully designing, a particular asymmetric laser structure is proposed. Its beam divergence in the fast axis is reduced from 61° to 34°compared with that of the broad-waveguide structure. The optical confinement factor is approximately equal to 0.0362 and comparable to that of the conventional broad-waveguide structure.