EFFECTS OF PROCESSING STRESSES ON RESIDUAL DEGRADATION IN LONG-LIVED GA1-XALXAS LASERS

Oxide-insulated stripe-geometry double-heterostructure lasers have been lifetested continuously for periods up to 25 000 h. Degradation occurred in two stages, an initial stage lasting several thousand hours and a final stage, characterized by rates of threshold increase of 0-6 and 1-2%/kh, respectively. The dominant stress in these lasers is caused by the insulating oxide film. The magnitude of the stress was found to vary considerably depending on the detailed shape of the oxide profile and thickness. Good correlation was found between stress magnitude and initial residual degradation rate. It is concluded that for reliable laser performance processing stresses must not exceed 1×10 8 dyn cm-2 in the active region.