Influence of the vertical structure on the mirror facet temperatures of visible GaInP quantum well lasers

Reflectance modulation measurements on red‐emitting GaInP quantum well ridge lasers show a sensitive dependence of the laser mirror temperatures on the number of quantum wells, the type of cladding layers, the configuration of a heat spreader layer covering the ridge waveguide, and on how the laser is mounted on a heat sink. The temperature versus injection current curves also demonstrate the contribution of laser radiation heating even in single quantum well lasers. The temperatures decay rapidly from the mirror into the cavity within about 6 μm (1/e‐point) as found from spatially resolved electroluminescence spectra detected along the laser cavity.