Buried convex waveguide structure (GaAl)As injection lasers

The fabrication technique, analysis of the waveguide property, and lasing characteristics of buried convex waveguide structure (BCS) lasers are described. An improved BCS laser structure having a truncated convex active region was produced by using a novel selective etching technique. It was found that the truncated convex waveguide is very effective in suppressing higher order mode lasing when compared with a convex waveguide. The improved BCS lasers showed stable fundamental transverse mode lasing up to 20 mW/facet, typical threshold current of 20 mA, and an external differential quantum efficiency of 28 percent/facet.