Nonabsorbing mirrors for AlGaAs quantum well lasers by impurity-free interdiffusion

Impurity-free vacancy disordering (IFVD) was used to elaborate AlGaAs quantum-well (QW) laser diodes with non-absorbing mirror (NAM) facets to rise the catastrophic optical mirror degradation (COMD) threshold. Prior to laser processing, blueshifted emission windows were formed by rapid thermal annealing at 930 degrees Celsius below SiO 2 cap layers. The photoluminescence (PL) energy blueshift measured between active and window regions is around 30 meV, with no degradation on the PL signal. Active region, free of SiO 2 encapsulation, exhibits however a non-negligible PL blueshift which is attributed to an internal interdiffusion process. This effect seems to be related to the silicon doping of the n-type AlGaAs cladding layer. 120-micrometer-aperture broad area lasers were fabricated both with and without 25 micrometer NAM sections on both sides. COMD was measured under pulsed operation (50 microsecond(s) - 100 Hz) using an epi-side-up mounting configuration. Uncoated NAM facets exhibit, on the average, a COMD threshold 1.5 times higher than that of standard ones: we achieved by this way a maximum peak power of 2 W from a 782-nm emitting laser.