Semiconductor laser device

Abstract From the Canadian patent

A BTRS (Buried Twin-Ridge Substrate) structure laser wherein an, oblong protrusion is provided on a substrate of a first conductivity type and two ridges divided by a groove therebetween are provided on a second layer of a second conductivity type. A plurality of further layers including an active layer are provided. The protrusion is shortened so as to have both of its ends spaced inside the cavity facets of the substrate and the width of each, ridge may be narrowed at both ends thereof thereby forming narrowed end parts so that excessive current injection to the active layer near the cavity facet is eliminated, and increased service life is obtained.