Catastrophic failure in GaAs double-heterostructure injection lasers

Abstract

Catastrophic failure in GaAs double-heterostructure (DH) injection lasers is shown to manifest itself in two ways concurrently: rupture of one or both laser mirrors, and internal damage to the laser active region. When the electroluminescent emission is observed in a direction normal to the plane of the junction, internal damage takes the form of a dark line which starts from the damaged mirror and extends normal to it into the active region. The increase in lasing threshold and decrease of external efficiency of a catastrophically damaged laser are due to (i) decrease in reflectivity of the damaged mirror, (ii) reduction of electronic gain (and possible conversion into loss) of the active region immediately adjacent to the dark line, and (iii) optical scattering due to internal crystal damage associated with the dark line. It is shown that catastrophic damage in GaAs is consistent with a model whereby failure occurs when the optical electric field intensity at the GaAs mirror exceeds a certain critical value. In the best-quality GaAs material available, this critical optical field intensity is ≈120 kV/cm for 100-ns pulse lengths.