Theoretical analysis of optical transverse-mode control on GaN-based laserdiodes

Optical transverse-mode properties of the GaN-based semiconductor laser-dio de is characterized by effective refractive index method. In order to stabi lize a transverse-mode in the conventional ridge-waveguide structure, very precise control of ridge-height is found to be necessary. On the contrary, a novel 2-step grown structure with 2-dimensional index guiding has wide fe asibility for device parameter, excellent stability of large confinement fa ctor in transverse-mode, and small aspect ratio of beam divergence, under t he condition that AlN molar fraction of 0.08 in AlGaN current blocking laye r and stripe width of 1.5 mu m are used.