Patent ID: 7391798

Claim:
A semiconductor laser device, comprising: an active layer formed on a substrate of a first conductivity type and including an AlGaAs layer; an Al a Ga b In 1-a-b P (where 0≦a≦1, 0≦b≦1 and 0≦a+b≦1) layer formed at least one of above and below the active layer, a first reflector of a second conductivity type formed above the active layer; a second reflector of the first conductivity type formed below the active layer; a first spacer layer formed between the first reflector and the active layer; and a second spacer layer formed between the second reflector and the active layer, wherein each of the first spacer layer and the second spacer layer has a thickness enough to obtain a desired laser oscillation wavelength, wherein the Al a Ga b In 1-a-b P layer has a composition enough to serve as a barrier layer against electrons injected into the active layer, and is located at least one of a position between the first reflector and the active layer and a position between the second reflector and the active layer, and forms part of at least one of the first spacer layer and the second spacer layer, wherein at least part of the first reflector is an AlGaAs layer, and a buffer layer including an Al c Ga d In 1-c-d P (where 0≦c≦1, 0≦d≦1 and 0≦c+d≦1) layer is further provided between the Al a Ga b In 1-a-b P layer and the AlGaAs layer.