Holc, KatarzynaKatarzynaHolcJakob, A.A.JakobWeig, T.T.WeigKöhler, KlausKlausKöhlerAmbacher, OliverOliverAmbacherSchwarz, U.T.U.T.Schwarz2022-03-122022-03-122014https://publica.fraunhofer.de/handle/publica/38410110.1117/12.2037336We investigate the influence of the epitaxial layer roughness on the far-field profile of the optical mode in gallium nitride-based, c-plane ridge waveguide laser diodes. Occasionally, we observe long-range growth instabilities leading to a periodical modulation of the surface. Amplitude and period of this surface roughness is typically on the order of a few 10nm and 20 µm, respectively. Using different characterization techniques, we investigate the influence of the surface roughness on the vertical mode profile along the fast axis in the far-field, in particular the contribution of light scattering at the rough waveguide interfaces, as well as that of substrate modes.enGaNlaser diodesurface roughnessfar fieldwaveguide scatteringsubstrate modes667conference paper