Gain spectra and current-induced change of refractice index in (In/Al)GaN diode lasers

Abstract

Adapting the Hakki-Paoli method for blue laser diodes we measure gain spectra for (In/Al)GaN on SiC substrate laser diodes in the low carrier density regime. From the measured longitudinal mode spacing we calculate the effective refractive index and can exclude a mode spacing anomaly. We demonstrate that the substrate has a considerable influence on the modal gain.