For group III nitride‐based lasers a new approach to realise DFB lasers and arrays is presented. Laterally coupled DFB (LC‐DFB) lasers are realised to minimise processing‐induced damage and to enable post‐processing adjustment of DFB laser parameters according to the material parameters achieved after epitaxial growth. These DFB laser arrays enable one to measure the threshold and the refractive index of electrically pumped DFB lasers over a wavelength emission range of 6 nm. DFB emission is demonstrated up to 70 °C and simultaneously a small temperature shift of the DFB mode. A significantly smaller tuning range is observed compared to optically pumped DFB lasers as well as a significantly red‐shifted gain region. Furthermore, the dispersion relation gradient determined, dneff/dλ, appears significantly steeper (by a factor of six) than in the optically pumped case. These effects are attributed to incompletely screened polarisation fields in electrically pumped InGaN/GaN lasers.
Laterally Coupled InGaN/GaN DFB Laser Diodes - Schweizer - 2002 - physica status solidi (a) - Wiley Online Library