Facet degradation and passivation of InGaAsP/InP lasers

Abstract
Formation of oxide on mirror facets was observed by Auger electron spectroscopy in InGaAsP/ InP buried heterostructure lasers. The oxide on the mirror facets caused increase of threshold current and leakage current, and decrease of differential quantum efficiency. Such phenomena were observed under nonlasing high current density operation as well as under high optical output power operation. The degradation of lasers due to the mirror facet oxidation is shown to be suppressed by coating the mirror facet with Al2O3.