Abstract: A semiconductor laser device and a method for the production of the semiconductor laser device are provided, which semiconductor laser device includes a striped channel formed in a semiconductor substrate through a current blocking layer on the substrate and at least two dummy grooves formed in the current blocking layer on each side of the striped channel. Also provided are a semiconductor wafer prepared for the purpose of producing optical devices with an optical waveguide, and a method for the production of the semiconductor wafer. The semiconductor wafer includes a semiconductor substrate, the surface of which has an orientation inclined from the [100] direction to one of the [011] and [011] directions of an angle .theta. satisfying the relationship 0.1.degree.<.vertline..theta..vertline.<4.degree.

Abstract: A semiconductor device comprising a (111)B single-crystalline semiconductor substrate which is misoriented toward (110), and epitaxial layers grown on the substrate by molecular beam epitaxy, whereby the crystallinity and luminescence efficiency of epitaxial layers are significantly improved.

Abstract: A semiconductor laser device is disclosed which comprises a semiconductor substrate and a multi-layered crystal structure disposed on the substrate, the multi-layered crystal structure containing a first cladding layer, a quantum-well active layer for laser oscillation, and a second cladding layer with a striped ridge portion for current injection, wherein the difference in the effective refractive index between the region underneath the striped ridge portion and the adjacent regions thereto is greater in the vicinity of at least one of the facets than inside of the facets.

Abstract: An optical semiconductor device is disclosed that comprises a quantum-well structure as an active region and exhibits a nonlinear optical effect with regard to light of energy near the band gap between the allowed band edges in the active region. The quantum-well structure of this device is composed of alternate layers consisting of at least one first semiconductor layer with a thickness smaller than the de Broglie wavelength of carriers and at least two second semiconductor layers with a band gap greater than that of the first semiconductor layer, the alternate layers being formed along a crystal orientation in the zinc-blende structure. The second semiconductor layers mentioned above are of an indirect transition type.

Abstract: A semiconductor laser device is disclosed which comprises a semiconductor substrate, a striped mesa disposed on the substrate and having an active layer for laser oscillation, a current injection layer disposed on the striped mesa and having a width smaller than that of the striped mesa, and a burying layer disposed on both sides of the current injection layer so as to come into contact with the side walls of the current injection layer, the burying layer being capable of absorbing laser light produce in the active layer and of preventing current from flowing through the outside of the striped mesa.

Abstract: A semiconductor laser device comprising a substrate of a first conductivity type having a mesa; a first semiconductor layer of a second conductivity type which is formed on the upper surface of the substrate other than the mesa to form a flat plane including the top face of the mesa; a laser oscillation region which is formed on the flat plane and includes an active area for laser oscillation; and a multi-layer structure burying the laser oscillation region, the multi-layer structure comprising a high resistance layer formed on the first semiconductor layer and burying both sides of the laser oscillation region, and a second semiconductor layer of the first conductivity type formed on the high resistance layer.

Abstract: A semiconductor laser device containing a laser oscillation-operating area which comprises a Ga.sub.1-x Al.sub.x As (0.ltoreq.x.ltoreq.1) quantum well active layer, Ga.sub.1-y Al.sub.y As optical guiding layers interposing the quantum well active layer therebetween, and Ga.sub.1-z Al.sub.z As cladding layers superposed on the optical guiding layers, respectively, wherein the AlAs mole fraction y at the area of each of the optical guiding layers positioned in the vicinity of the interface of the optical guiding layers and the quantum well active layer meets the relationships y-z.gtoreq.0.3 and z-y.ltoreq.0.25.

Abstract: A semiconductor laser device of this invention comprises a plurality of semiconductor epitaxial layers grown on a semiconductor substrate, wherein the growth plane of said substrate is substantially the (111) plane.

Abstract: A double-heterostructure multilayered crystal structure in a semiconductor laser device contains an active layer for laser oscillation. A striped etching-protective thin layer is formed on the double-heterostructure multilayered crystal. A striped-mesa multilayered crystal is formed on the striped etching-protective thin layer. A burying layer is formed on the double-heterostructure multilayered crystal outside of both the striped thin layer and striped-mesa multilayered crystal. This provides refractive index distributions within the active layer corresponding to the inside and the outside of the striped-mesa multilayered crystal. Further, it provides a striped structure which functions as a current path composed of the striped-mesa multilayered crystal.

Abstract: A semiconductor device using the quantum effect of one dimension that arises in the direction vertical to the plane of a substrate on which the device structure is disposed, wherein the plane of the substrate is substantially the (111) plane.

Abstract: A Semiconductor laser device comprising a quantum well region with a superlattice structure that functions as an active region, wherein the superlattice quantum well region is composed of alternate layers consisting of a plurality of first Al.sub.x Ga.sub.1-x As thin films and a plurality of second Al.sub.y Ga.sub.1-y As thin films (0<x<y.ltoreq.1).

Abstract: A semiconductor laser device comprising an active layer, optical guiding layers sandwiching the active layer therebetween, and a cladding layer disposed on each of the optical guiding layers, wherein the refractive index of each of the optical guiding layers gradually varies in the direction of the thickness of the optical guiding layer, and the thickness of each of the cladding layers is 0.5 um or less.

Abstract: In a semiconductor laser device comprising In(Ga.sub.1-x Al.sub.x)P cladding layers and an active region which has one or more In(Ga.sub.1-y Al.sub.y)P (y<x) quantum well layers and which is sandwiched by said cladding layers, superlatticed structures having an altervative lamination of In(Ga.sub.1-x Al.sub.x)P layers and In(Ga.sub.1-y Al.sub.y)P layers are disposed in contact with said cladding layers and/or said quantum well layers.

Abstract: A semiconductor laser device comprising a substrate of a first conductivity type having a mesa; a first semiconductor layer of a second conductivity type which is formed on the upper surface of the substrate other than the mesa to form a flat plane including the top face of the mesa; a laser oscillation region which is formed on the flat plane and includes an active area for laser oscillation; and a multi-layer structure burying the laser oscillation region, the multi-layer structure comprising a high resistance layer formed on the first semiconductor layer and burying both sides of the laser oscillation region, and a second semiconductor layer of the first conductivity type formed on the high resistance layer.

Abstract: A semiconductor laser device comprising a double-heterostructure that is composed of an active layer and a pair of cladding layers sandwiching the active layer therebetween, a striped structure in which current injected into the laser device is confined, the striped structure being constituted by a part of the double-heterostructure, and optical guiding layers positioned between one cladding layer and the active layer and between the active layer and the other cladding layer, wherein the resistance of one optical guiding layer positioned at the striped structure side is higher than that of the other optical guiding layer positioned opposite to the striped structure side.

Abstract: A semiconductor laser device containing a laser oscillation-operating area comprising a superlatticed quantum well region which is composed of layers of GaAs alternating with layers of Al.sub.x Ga.sub.1-x As (0<x.ltoreq.1), where each of the layers has a thickness of several molecular layers or less;optical guiding layers consisting of Al.sub.y Ga.sub.1-y As (x.ltoreq.y.ltoreq.1) sandwiching the quantum well region, where the AlAs mole fraction varies continuously; andcladding layers covering the optical guiding layers.

Abstract: A semiconductor device is formed by sequentially forming a first clad layer, active layer, second clad layer, and cap layer from, for example, an AlGaAs layer with an AlAs mixing ratio of .gtoreq.0.4, on a substrate made of GaAs or the like by MBE, MOCVD or another high precision growth process. Then AlGaAs layer is selectively removed only in the vicinity of formed ridges, and in this part, grooves on two stripes are formed from the cap layer surface, leaving the second clad layer with an intact thickness of, for example, only 3000 .ANG.. An insulation layer made of, for example, SiN is then formed in the groove area and the AlGaAs layer region, thereby creating a current stripe structure, in which only two grooves provide for current passages, that is, the light-emitting regions.

Abstract: A semiconductor laser device comprising a multi-layered semiconductor crystal containing an active region for laser oscillation, wherein the extended portions of said active region which are adjacent to both sides of one facet having the width of a selected value of said device constitute light-absorbing regions by which light in a high-order transverse mode is absorbed to a greater extent than that in a fundamental transverse mode, thereby achieving laser oscillation in a stable fundamental transverse mode up to a high output power.

Abstract: A semiconductor laser device comprising a single or a plurality of quantum well regions formed by a superlatticed structure which is composed of alternate layers consisting of thin GaAs layers and thin Al.sub.x Ga.sub.1-x As (0<x<1) layers, each of said layers having a thickness of five molecular layers or less and each of said quantum well regions having a thickness in the range of 100 .ANG. to 150 .ANG..

Abstract: A semiconductor laser device comprising a laser oscillation-operating area containing a first cladding layer, an active layer, an optical guiding layer and a second cladding layer in that order, wherein a striped impurity-diffusion region is formed into said second cladding layer from one facet to the other facet and a plurality of narrow strips of GaAs with a spaced pitch are formed in parallel with both facets in the region, except for the region corresponding to said striped diffusion region, which is positioned at the interface between the optical guiding layer and the second cladding layer.