LATTICE DISORDER, FACET HEATING AND CATASTROPHIC OPTICAL MIRROR DAMAGE OF ALGAAS QUANTUM-WELL LASERS

Raman microprobe spectra from dry-etched, coated (110) AlGaAs single quantum well laser mirrors show, apart from the allowed phonon modes, a series of symmetry forbidden modes whose strength is dependent on the mirror treatment prior to coating. A particularly strong mode at 193 cm-1 can be attributed to disorder activated longitudinal acoustic phonon scattering in addition to-and this is new-the E(g)-mode of elemental arsenic. The existence of lattice disorder and arsenic clusters is confirmed by Rayleigh scattering and energy dispersive x-ray spectroscopy. The optical power level at catastrophic optical mirror damage and the local mirror temperatures of the biased laser are found to have a strong dependence on mirror disorder.