Device degradation of GaAs-based AlGaAs/GaInP/GaInAs ridge waveguide (RW) l
aser diodes is found to lead to peculiarities in the longitudinal mode spec
trum. These features give information on the position of inhomogeneities al
ong the laser stripe. Using monochromatic cathodoluminescence (CL), transmi
ssion electron microscopy (TEM) and energy dispersive X-ray analysis (EDX)
these inhomogeneities are found to be located in the region of the quantum
well (QW) and to be caused by interdiffusion of the lattice constituents. T
his interdiffusion extends over the active region from the interfaces of th
e GaInP waveguides to the GaAs spacer layers. It is triggered by nonradiati
ve recombination under laser operation. (C) 2000 Elsevier Science B.V. Al r
ights reserved.