Single filament semiconductor laser with large emitting area

DETAILED DESCRIPTION A semiconductor laser includes a body of semiconductor material having a substrate with a pair of spaced, substantially parallel grooves in a surface thereof.
A first confinement epitaxial layer is over the surface of the substrate and the surfaces of the grooves, the first confinement layer having a flat surface portion over the portion of the substrate surface between the grooves.
A guide epitaxial layer is over the first confinement layer, a thin active epitaxial layer is over the guide layer and a second confinement epitaxial layer is over the active layer.
The active layer is of a material which has an index of refraction larger than that of the materials of each of the first and second confinement layers and the guide layer is of a material having an index of refraction less than that of the active layer but larger than that of each of the first and second confinement layers.
The first confinement layer and guide layer are of the same conductivity type and the second confinement layer is of the opposite conductivity type.
The active layer is the active recombination region of the laser with the light being generated therein in the vicinity of the portion which is over the flat surface portion of the first confinement layer.