Electron microscopic techniques have been applied to the characterization of degraded single quantum well separate-confinement heterostructure (SQW SCH) stripe geometry lasers. Scanning electron microscopy (SEM) investigations have revealed changes at the lasers mirrors, an anomalous behavior of their junctions and a partial lack of the electron beam-induced luminescence in the active stripe areas of the devices. Cross-sectional transmission electron microscopy (XTEM) has revealed the presence of many crystallographic defects located in the active and cladding layers in the stripe area. (C) 2003 Elsevier Science B.V. All rights reserved.