Patent ID: 7382814

Claim:
A semiconductor laser device comprising: a substrate of a first conductivity type; a first semiconductor laser structure located on said substrate and comprising a first first cladding layer of the first conductivity type on said substrate, a first active layer located on the first first cladding layer, and including a quantum well layer, a first second cladding layer of a second conductivity type located on the first active layer, an etching end detecting layer of the second conductivity type located on the first second cladding layer, and having the same constituent elements as those of the first second cladding layer, and a first third cladding layer of the second conductivity type, having a stripe mesa-like shape, located on the etching end detecting layer, having the same constituent elements as those of the etching end detecting layer, and having composition ratios of two constituent elements in a complementary relation, different from those composition ratios of the etching end detecting layer; and a second semiconductor laser structure located on said substrate independently of said first semiconductor laser structure, the second semiconductor laser structure comprising a second first cladding layer of the first conductivity type located on said substrate, a second active layer located on the second first cladding layer, and including a quantum well layer, and a second second cladding layer of the second conductivity type located on the second active layer, having the same material constitution as that of said first third cladding layer, and having a part projecting in a stripe mesa-like shape.