Novel techniques for stabilizing transverse mode in AlGaInN-based laser diodes

We report on a novel laser structure for stabilizing transverse mode in AlGaInN-based high power laser diodes (LDs). AlGaInN-based laser structures were grown on epitaxially laterally overgrown GaN (ELO-GaN) by MOCVD. We have developed a novel ridge structure with a new current-blocking layer consisting of spin-on-glass, which shows absorption of the emitted light to some extent. With this structure, there was no kink in the light output versus current curve up to 150 mW under cw operation, and the full width at half-maximum angle of far-field pattern in the direction parallel to the epitaxial layers was 9.1°. This large beam divergence was kept stable up to 150 mW, which indicates that our novel structure realized a stable lateral optical confinement.