Abstract: In a semiconductor laser device: a lower cladding layer; a lower optical waveguide layer; a compressive strain quantum well active layer made of Inx3Ga1−x3As1−y3Py3, where 0<x3≦0.4, 0≦y3≦0.1; an upper optical waveguide layer; a first upper cladding layer made of Inx8Ga1−x8P of a second conductive type, and formed on the upper optical waveguide layer; an etching stop layer made of Inx1Ga1−x1As1−y1Py1 of the second conductive type, where 0≦x1≦0.3, 0≦y1≦0.3; a current confinement layer made of Inx8Ga1−x8P of the first conductive type, where x8=0.49±0.01; a second upper cladding layer made of Alz4Ga1−z4As of the second conductive type, where 0.20≦z4≦0.50; and a contact layer of the second conductive type are formed on a GaAs substrate of a first conductive type in this order.

Abstract: In a semiconductor laser device: a p-type AlzGa1-zAs cladding layer is formed above an active layer, where z≧0.3; a p-type GaAs contact layer is formed on the cladding layer except for at least one near-edge portion of the cladding layer; and an electrode is formed on at least the contact layer. The upper surface of each of the at least one near-edge portion of the cladding layer is insulated, where each of the at least one near-edge portion of the cladding layer is located in a vicinity of one of opposite end facets perpendicular to the direction of laser emission.

Abstract: In a process for producing a substrate for use in a semiconductor element: a porous anodic alumina film having a great number of minute pores is formed on a surface of a base substrate; the surface of the base substrate is etched by using the porous anodic alumina film as a mask so as to form a great number of pits on the surface of the base substrate; the porous anodic alumina film is removed; and a GaN layer is formed on the surface of the base substrate by crystal growth.

Abstract: In a semiconductor laser device: an n-type In0.49Ga0.51P cladding layer, an undoped or n-type Inx1Ga1-x1As1-y1Py1 optical waveguide layer, an Inx3Ga1-x3As1-y3Py3 compressive-strain quantum-well active layer, an undoped or p-type Inx1Ga1-x1As1-y1Py1 optical waveguide layer, a p-type In0.49Ga0.51P cladding layer, and a p-type GaAs etching stop layer are formed on an n-type GaAs substrate; a p-type Inx8Ga1-x8P etching stop layer and an n-type GaAs current confinement layer are formed corresponding to high-refractive-index regions which realize an ARROW structure; a p-type Inx9Ga1-x9P etching stop layer is formed over the n-type GaAs current confinement layer and exposed areas of the first etching stop layer; a p-type GaAs etching stop layer and an n-type In0.49Ga0.51P current confinement layer are formed in regions other than a current injection region; and a p-type In0.49Ga0.51P cladding layer and a p-type GaAs contact layer are formed over the entire upper surface.

Abstract: A semiconductor laser device is disclosed that improves reliability during high-power oscillation. On a plane of an n-type GaAs substrate, grown are an n-type GaAs buffer layer, an n-type In0.48Ga0.52P lower cladding layer, an n-type or i-type Inx1Ga1-x1As1-y1Py1 optical waveguide layer, an i-type GaAs1-y2Py2 tensile-strain barrier layer, an Inx3Ga1-x3As1-y3Py3 compressive-strain quantum-well active layer, an i-type GaAs1-y2Py2 tensile-strain barrier layer, a p-type or i-type Inx1Ga1-x1As1-y1Py1 upper optical waveguide layer, a p-type In0.48Ga0.52P first upper cladding layer, a GaAs etching stop layer, a p-type In0.48Ga0.52P second upper cladding layer and a p-type GaAs contact layer. Two ridge trenches are formed on the resultant structure, and current non-injection regions are formed by removing the p-type GaAs contact layer in portions extending inwardly by 30 &mgr;m from cleavage positions of edge facets of the resonator on a top face of a ridge portion between the ridge trenches.

Abstract: A semiconductor laser device contains a pair of electrodes; a conductive substrate connected to one of the pair of electrodes; a lower cladding layer formed on the conductive substrate; a lower optical waveguide layer formed on the lower cladding layer; a quantum well active layer formed on the lower optical waveguide layer; an upper optical waveguide layer formed on the quantum well active layer; an upper cladding layer formed on the upper optical waveguide layer; and a contact layer formed on the upper cladding layer. The other of the pair of electrodes is formed on the contact layer, and the conductive substrate is made of InGa material. The lower cladding layer is made of one of InGaN and InGaAlN material and has a composition which causes a strain not less than −0.01 and not greater than 0.01 between the lower cladding layer and the conductive substrate.

Abstract: In a semiconductor laser device: an active layer; a first upper cladding layer of a first conductive type; a current confinement layer of a second conductive type; a second upper cladding layer of the first conductive type; and a contact layer of the first conductive type are formed above a GaN layer of the second conductive type. In the semiconductor laser device: a groove is formed through the full thickness of the current confinement layer so as to form an index-guided structure; the active layer is a single or multiple quantum well active layer formed by alternately forming at least one Inx1Ga1−x1N well and a plurality of Inx2Ga1−x2N barriers, where 0≦x2<x1<0.

Abstract: In a semiconductor-laser device: a compressive-strain quantum-well active layer is made of Inx3Ga1. x3As1−y3Py3 (0<x3≦0.4 and 0≦y3≦0.1); tensile-strain barrier layers made of Inx2Ga1−2AS1−y2P1−y2 (0≦x2<0.49y2 and 0<y2≦0.4)are formed above and under the compressive-strain quantum-well active layer; and optical waveguide layers being made of either p-type or i-type In0.49Ga0.51P are formed above the upper tensile-strain barrier layer and under the lower tensile-strain barrier layer. Preferably, the absolute value of a sum of a first product and a second product is less than or equal to 0.25 nm, where the first product is a product of a strain and a thickness of said compressive-strain active layer, and the second product is a product of a strain of said lower and upper tensile-strain barrier layers and a total thickness of the lower and upper tensile-strain barrier layers.

Abstract: In a semiconductor laser device: an n-type lower cladding layer; a lower optical waveguide layer; a compressive strain quantum well active layer made of Inx3Ga1-x3As1-y3Py3, where 0<x3≦0.4 and 0≦y3≦0.1; an upper optical waveguide layer; a p-type In0.49Ga0.51P first upper cladding layer; an etching stop layer made of Inx1Ga1-x1As1-y3Py1, where 0≦x1≦0.3 and 0≦y1≦0.6; an n-type In0.49Ga0.51P current confinement layer; a p-type second upper cladding layer made of Inx4Ga1-x4As1-y4Py4, where x4=(0.49±0.01)y4 and 0.4≦x4≦0.46; and a p-type contact layer are formed on an n-type GaAs substrate in this order. At least the current confinement layer has a stripe-shape opening realizing a current injection window filled with the second upper cladding layer. The absolute value of the product of the strain and the thickness of the compressive strain quantum well active layer is equal to or smaller than 0.

Abstract: In a semiconductor laser device: an n-type lower cladding layer; a lower optical waveguide layer; a compressive strain quantum well active layer made of Inx3Ga1−x3As1−y3Py3, where 0<x3≦0.4 and 0≦y3≦0.1; an upper optical waveguide layer; a p-type In0.49Ga0.51P first upper cladding layer; an etching stop layer made of Inx1Ga1−x1As1−y1Py1, where 0≦x1≦0.3 and 0≦y1≦0.6; an n-type current confinement layer made of In0.49(Alz1Ga1−z1)0.51P, where 0≦z1≦0.1; an In0.49Ga0.51P cap layer; a p-type second upper cladding layer made of Inx4Ga1−x4As1−y4Py4, where x4=(0.49±0.01)y4 and 0.9≦y4≦1; and a p-type contact layer are formed on an n-type GaAs substrate in this order. Each of the etching stop layer, the current confinement layer, and the cap layer has a stripe-shape opening realizing a current injection window filled with the second upper cladding layer.

Abstract: An n-GaAs buffer layer, an n-AlGaAs lower cladding layer, an n- or i-InGaP lower optical waveguide layer, an InGaAsP quantum cell active layer, a p- or i-InGaP upper optical waveguide layer, a p-AlGaAs first upper cladding layer, a p- or i-InGaP etch-stopping layer, a p-AlGaAs second upper cladding layer, and a p-GaAs contact layer, are grown upon an n-GaAs substrate. A photoresist is coated on the wafer, and two grooves are formed by etching. Then, the photoresist on the perimeter of the device is removed and the contact layer is selectively etched. Next, the photoresist is lifted off. A Sio2 film is formed on the entire surface. After a window is formed in a portion of the SiO2 film corresponding to a ridge portion, a p-electrode is formed on a region of the Sio2 film other than the device perimeter.

Abstract: In a process for producing a semiconductor laser device, an n-type cladding layer, an n-type or i-type Inx2Ga1−x2As1−y2Py2 first lower optical waveguide layer, an i-type Inx5Ga1−x5P intermediate layer, an i-type Inx2Ga1−x2As1−y2Py2 second lower optical waveguide layer, an Inx1Ga1−x1As1−y1Py1 compressive strain active layer, a p-type or i-type Inx2Ga1−x2As1−y2Py2 first upper optical waveguide layer, and an Inx5Ga1−x5P cap layer are formed on an n-type GaAs substrate. Then, near-edge portions of the cap layer are etched off with a hydrochloric acid etchant, and near-edge portions of the active region above the intermediate layer are etched off with a sulfuric acid etchant so as to produce spaces in vicinities of end facets. Next, the spaces are filled with a p-type Inx2Ga1−x2As1−y2Py2 second upper optical waveguide layer formed over the cap layer, and a p-type upper cladding layer is formed on the second upper optical waveguide layer.

Abstract: In a semiconductor laser device having a substrate and an active region, the active region includes an active layer between tensile strain optical waveguide layers. The active layer includes at least one compressive strain quantum well sublayer. When the active layer includes more than one compressive strain quantum well sublayer, the active layer further includes at least one barrier sublayer being formed between the more than one quantum well sublayer and having an identical amount of tensile strain to that of the optical waveguide layers. The absolute value of a sum of a product of the strain and the total thickness of the at least one quantum well sublayer and a product of the strain and the total thickness of the optical waveguide layers and the at least one barrier sublayer (if any) is equal to or smaller than 0.05 nm.

Abstract: In a semiconductor laser device having an InGaAsP compressive strain quantum well active layer, an InGaAsP first upper optical waveguide layer formed on the active layer, and a current confinement layer which is formed above the first upper optical waveguide layer and includes a stripe groove. An AlGaAs second upper optical waveguide layer having an approximately identical refractive index to that of the first upper optical waveguide layer covers the current confinement layer and the stripe groove. The product of the strain and the thickness of the active layer does not exceed 0.25 nm. All the layers other than the compressive strain quantum well active layer lattice-match with GaAs. An AlGaAs or InGaAsP upper cladding layer formed above the second upper optical waveguide layer has an approximately identical refractive index to that of a lower cladding layer formed under the active layer.

Abstract: In a semiconductor laser element having a plurality of semiconductor layers formed on a substrate, a groove-form concave portion is formed on the surface of the substrate opposite to the surface having the semiconductor layers. The concave portion is filled with metal having a higher heat conductivity higher than the substrate. The semiconductor laser element achieves improved heat dissipation characteristics and high reliability even under high-output operation.

Abstract: Heating at the end face while operating in a high output is prevented and reliability improves in a semiconductor laser device. On an n-GaAs substrate, laminated are n-Alz1Ga1−z1As lower cladding layer, an n- or i-In0.49Ga0.51P lower optical waveguide layer, an Inx3Ga1−x3As1−y3Py3 quantum well active layer, a p- or i-In0.49Ga0.51P upper first optical waveguide layer, a GaAs cap layer and SiO2 film. Then a width of about 20 &mgr;m of the SiO2 film is removed inwardly from the cleaved surface. Using the SiO2 film as a mask, the cap layer near the end face and the upper first optical waveguide layer are removed. Then the SiO2 film, the quantum well active layer near the end face and the remaining cap layer are removed. A p- or i-In0.49Ga0.51P upper second optical waveguide layer, a p-Alz1Ga1−z1As upper cladding layer and a p-GaAs contact layer are deposited thereon.

Abstract: A first resist layer (21) and a second resist layer (22) are formed on a base material (11) in the recited order, the first resist layer (21) being removable by etching and the second resist layer (22) being a photosensitive resist layer in which either exposed or unexposed regions become soluble in a developing solvent upon emission of light. Near-field light is then emitted to the second resist layer (22) by means (24) for emitting near-field light (27) according to a diffraction grating pattern upon reception of the light. Next, the diffraction grating pattern is formed in the second resist layer (22) by developing the second resist layer (22). The first resist layer (21) is etched with the pattern in the second resist layer (22) as an etching mask, and a diffraction grating pattern consisting of the first and second resist layers (21, 22) is formed.

Abstract: In a semiconductor laser device, a lower cladding layer, a lower optical waveguide layer, an active layer, an upper optical waveguide layer, an upper cladding layer, and a contact layer are formed in this order on a GaAs substrate. The semiconductor laser device has at least one of first and second resistance reduction layers. The first resistance reduction layer is arranged between the substrate and the lower cladding layer, and made of an InGaAsP material having an energy gap which is greater than the energy gap of the substrate, and smaller than the energy gap of the lower cladding layer. The second resistance reduction layer is arranged between the upper cladding layer and the contact layer, and made of an InGaAsP material having an energy gap which is greater than the energy gap of the contact layer, and smaller than the energy gap of the upper cladding layer.

Abstract: In a semiconductor-laser device: an n-type cladding layer, an optical-waveguide layer, an Inx3Ga1−x3As1−y3Py3 compressive-strain quantum-well active layer (0<x3≦0.4, 0≦y3≦0.1), an optical-waveguide layer, a p-Inx6Ga1−x6P etching-stop layer (0≦x6≦1), a p-Inx1Ga1−x1As1−y1Py1 etching-stop layer (0≦x1≦0.4, 0≦y1≦0.5), a p-InxGa1−xP layer (x=0.49±0.01), and an n-InxGa1−xP current-confinement layer are formed on an n-GaAs substrate. A stripe groove is formed down to the depth of the upper surface of the p-Inx6Ga1−x6P etching-stop layer. A p-Inx4Ga1−x4As1−y4Py4 cladding layer (x4=0.49y4±0.01, x−0.04≦x4≦x−0.01) is formed over the current-confinement layer and the stripe groove. A p-type contact layer is formed on the p-Inx4Ga1−x4As1−y4PY4 cladding layer. The absolute value of the product of the strain and the thickness of the active layer does not exceed 0.

Abstract: A semiconductor laser element capable of reducing an element resistance and producing a beam of high quality includes: an n-Ga1-Z4AlZ4N composition gradient layer provided between an n-GaN contact layer and an n-Ga1-Z1AlZ1N/GaN superlattice clad layer; an n-Ga1-Z5AlZ5N composition gradient layer provided between the n-Ga1-Z1AlZ1N/GaN superlattice clad layer and an nor i-Ga1-Z2AlZ2N optical waveguide layer; a p-Ga1-Z5AlZ5N composition gradient layer provided between a p- or i-Ga1-Z2AlZ2N optical waveguide layer and a p-Ga1-Z1AlZ1N superlattice gradient layer; and a p-Ga1-Z4AlZ4N composition gradient layer provided between a p-Ga1-Z1AlZ1N/GaN superlattice upper clad layer and a p-GaN contact layer. Z4 of the n-Ga1-Z4AlZ4N composition gradient layer is continuously changed from 0 to a composition corresponding to the band gap of the Ga1-Z1AlZ1N/GaN superlattice clad layer.