Patent ID: 7561609

Claim:
A semiconductor laser device comprising: a first cavity and a second cavity formed apart from each other over a semiconductor substrate, wherein the first cavity includes a first buffer layer and a first semiconductor layer on the first buffer layer, the first semiconductor layer including a first lower cladding layer, a first active layer, and a first upper cladding layer, and the first semiconductor layer being formed with a stripe structure, the second cavity includes a second buffer layer and a second semiconductor layer on the second buffer layer, the second semiconductor layer including a second lower cladding layer, a second active layer, and a second upper cladding layer, and the second semiconductor layer being formed with a stripe structure, a window structure is provided in a region near an end face of each of the first semiconductor layer and the second semiconductor layer, the window structure being formed by diffusing an impurity, a band gap of the first buffer layer is greater than that of the first active layer, a band gap of the second buffer layer is greater than that of the second active layer, and each of the first buffer layer and the second buffer layer is a layered element formed by alternately stacked n-type AlGaInAs layers and n-type AlGaInP layers.