Degradation processes in high power broad-area InGaAs-AlGaAs strained quantum well lasers were studied using electron beam-induced current (EBIC) techniques, time-resolved electroluminescence (TR-EL) techniques, and deep-level transient spectroscopy (DLTS). Accelerated lifetests of the broad-area lasers yielded catastrophic failures at the front facet and also in the bulk. EBIC was employed to study dark line defects generated in degraded lasers stressed under different test conditions. TR-EL was employed to study the intra-cavity intensity distribution in real time as devices were aged. DLTS was employed to study deep electron traps in both pristine and degraded laser diodes. Lastly, we present a possible scenario for the initiation of bulk degradation in the broad-area lasers.