High power broad ridge (Al,In)GaN laser diodes: Spatial and spectral stability

To improve the output power of (Al,In)GaN laser diodes (LDs), the ridge width has to be increased, but beam quality of GaN‐based broad area lasers is still a critical point. We present a multidimensional characterization of the optical laser mode, propagating from the near‐into the far‐field, and show that the formation of the characteristic multi‐lobed lateral far‐field pattern of broad ridge (Al,In)GaN LDs is the result of interfering, phase locked filaments, that build up the laser mode. In this context we show that variation of driving current or temperature may have an significant impact on the spectral and spatial stability of the laser beam. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)