Impact of filamentation on the far-field of high power broad ridge (Al,In)GaN laser diodes

摘要

For broad ridge (Al,In)GaN laser diodes, which are inevitable for high output power applications in the near-UV to blue spectral region, filaments appear, which influence the far-field beam quality. We present an extensive study of the optical mode profile of conventional c-plane LD test structures with ridge widths from 1.5 to 10 micrometers. The broad ridge samples are optimized to reach several hundred milliwatt of cw output power. Spectral and spatial resolved near- and far-field measurements show, that the characteristic lateral multi-lobed far-field pattern can be interpreted as superposition of interfering phase-locked filaments in the ridge waveguide.