Abstract: A first and second semiconductor laser, which comprise buffer layers, cladding layers, quantum well active layers, and cladding layers integrated on the substrate and have a stripe geometry, are integrated on a common substrate, with the quantum well active layers in the vicinity of the cavity facets disordered by impurity diffusion. Relationships ?1>?b1, ?2>?b2, ?1>?2, and E1?E2 are satisfied, where ?1 and ?2 are defined, respectively, as the emission wavelengths of the active layers of the first and second semiconductor lasers, E1 and E2, respectively, as the forbidden band energies of the buffer layers of the first and second semiconductor lasers, and ?b1 and ?b2 respectively as the wavelengths corresponding to the forbidden band energies of the buffer layers of the first and second semiconductor lasers.

Abstract: A semiconductor laser device includes a red-light-emission portion and an infrared-light-emission portion on a single substrate. The red-light-emission portion has a structure in which an AlGaInP-based active layer is sandwiched by a first cladding layer of a first conductivity type having a striped portion and a second cladding layer of a second conductivity type. The infrared-light-emission portion has a structure in which an AlGaAs-based active layer is sandwiched by a third cladding layer of the first conductivity type having a striped portion and a fourth cladding layer of the second conductivity type. The first, second, third, and fourth cladding layers are all made of an AlGaInP-based material. When in these layers, the Al:Ga contents are represented by X1:1-X1, X2:1-X2, X3:1-X3, and X4:1-X4, respectively, X1?X2 and X3?X4 are satisfied.