Patent ID: 7173273

Claim:
A semiconductor laser device comprising: an active layer; a lower cladding layer located on a first side of said active layer; a first upper cladding layer located on a second side of said active layer, the second side being opposite the first side of the active layer; an etching stopper layer located at said first upper cladding layer on the second side of said active layer; and a second upper cladding layer located opposite said etching stopper layer, on the second side of said active layer, and including a stripe protrusion, in which a stripe light-guiding channel is located between said protrusion and said etching stopper layer, wherein said etching stopper layer is a single layer of a material including a chemical element different from the chemical elements of each of said lower, first upper, and second upper cladding layers, and has a refractive index within a range that is Â±5% of refractive index of each of said lower, first upper, and second upper cladding layers.