We analyze the degradation process of proton‐implanted, top‐emitting vertical cavity surface emitting lasers using cross‐sectional cathodoluminescence. The spatially resolved luminescence characteristics of the active regions, andp‐ andn‐distributed Bragg reflector (DBR) mirrors before and after degradation of the devices are presented. Degradation has been observed not only in the active regions, but also remarkably in thep‐DBR mirror stacks. We show that a significant minority carrier population is present in thepmirror under normal operating conditions to drive the degradation observed in thepmirror. ©1995 American Institute of Physics.