Abstract: A semiconductor laser device with window regions according to the present invention is provided, in which a double hetero structure including cladding layers and an active layer sandwiched by the cladding layers is formed on a semiconductor substrate, the double hetero structure is buried in burying layers with a bandgap larger than that of the active layer, and the burying layers form window regions situated at both end facets of the double hetero structure, wherein the window regions have a waveguide structure including a plurality of semiconductor layers with different bandgaps.

Abstract: A distributed feedback semiconductor laser device comprising a current blocking structure having a stripe groove, and a diffraction grating formed in the bottom of the stripe groove. The current blocking structure is formed over an active layer for laser oscillation, and it includes an etch stop layer against a groove etching in a lower potion of the current blocking structure. The refractive index distribution in transverse directions inside the stripe groove is controlled by the thickness of the optical guiding layer, enabling oscillation of the fundamental transverse mode.

Abstract: In a first crystal growth step, a first cladding layer, an active layer, and an optical wave-guide layer are sequentially grown on a semiconductor substrate. A diffraction grating is formed at a surface of the optical waveguide layer. In a second crystal growth step, a current block layer is grown on the optical waveguide layer having the diffraction grating. The current block layer is selectively etched to expose the diffraction grating and thus to form a stripe groove. In a third crystal growth step, a second cladding layer is grown on the diffraction grating inside the stripe groove and on the current block layer.

Abstract: A semiconductor laser device having a mesa stripe whose side faces are facets of {111} planes is disclosed. In the laser device, a current blocking layer is formed on a semiconductor substrate whose main surface is a (100) plane, and a channel which is oriented along the <011> direction is formed in the current blocking layer. The mesa stripe is formed on the substrate within the channel by a selective growth technique. The mesa stripe has a multilayer structure including an active layer and is covered by a burying layer.