Abstract: In a method for predicting the lifetime of a photo-semiconductor device that has a maximum light output value restricted by thermal saturation, the maximum light output value is extracted by measuring the characteristic of light output from the photo-semiconductor device with respect to drive current. The decrease tendency of the maximum output values with respect to drive time is predicted to predict the lifetime of the photo-semiconductor. Further, the predicted lifetime is updated as time passes. Therefore, in this method, even if drive condition changes, or an individual difference of the photo-semiconductor per se is present, it is possible to substantially accurately predict the lifetime of the photo-semiconductor.

Abstract: An end face emission type semiconductor light emitting device which include: a substrate; a first conductive type clad layer stacked on the substrate; an active region layer including an active layer stacked on the first conductive type clad layer; a second conductive type clad layer stacked on the active region layer such that a thickness of a portion thereof at least over an emission region of the active region layer in an emission end face adjacent area is thinner than a thickness of the other portion; and a second conductive type regrowth layer stacked on the second conductive type clad layer, which has a higher refractive index than the second conductive type clad layer.

Abstract: In a method for predicting the lifetime of a photo-semiconductor device that has a maximum light output value restricted by thermal saturation, the maximum light output value is extracted by measuring the characteristic of light output from the photo-semiconductor device with respect to drive current. The decrease tendency of the maximum output values with respect to drive time is predicted to predict the lifetime of the photo-semiconductor. Further, the predicted lifetime is updated as time passes. Therefore, in this method, even if drive condition changes, or an individual difference of the photo-semiconductor per se is present, it is possible to substantially accurately predict the lifetime of the photo-semiconductor.

Abstract: An end face emission type semiconductor light emitting device which include: a substrate; a first conductive type clad layer stacked on the substrate; an active region layer including an active layer stacked on the first conductive type clad layer; a second conductive type clad layer stacked on the active region layer such that a thickness of a portion thereof at least over an emission region of the active region layer in an emission end face adjacent area is thinner than a thickness of the other portion; and a second conductive type regrowth layer stacked on the second conductive type clad layer, which has a higher refractive index than the second conductive type clad layer.

Abstract: A semiconductor laser element having a structure in which at least one AlGaInP or GaInP layer is formed above a GaAs substrate. The crystal orientation of the principal plane of the GaAs substrate is tilted from (100) toward (111). When the total thickness of the at least one AlGaInP or GaInP layer is 1 micrometer or smaller, the tilt angle of the crystal orientation of the principal face is 8 to 54.7 degrees. When the total thickness of the at least one AlGaInP or GaInP layer is 1 micrometer or greater, the tilt angle of the crystal orientation of the principal face is 13 to 54.7 degrees.

Abstract: In a semiconductor laser element: a lower cladding layer of In0.49(Alx1Ga1-x1)0.51(x2<x1<1) of a first conductive type which lattice-matches with GaAs; a lower optical waveguide layer of In0.49(Alx2Ga1-x2)0.51P (0<x2<x1) which lattice-matches with GaAs; an active layer; an upper optical waveguide layer of In0.49(Alx2Ga1-x2)0.51P (0<x2<x1) which lattice-matches with GaAs; and an upper cladding layer of In0.49(Alx1Ga1-x1)0.51P (x2<x1<1) of a second conductive type which lattice-matches with GaAs are formed in this order on a substrate of GaAs. The total thickness of the lower optical waveguide layer, the active layer, and the upper optical waveguide layer is 0.30 micrometers or greater.

Abstract: In a semiconductor laser element: a lower cladding layer of a first conductivity type, a quantum-well active layer, an upper cladding layer of a second conductivity type, a contact layer of the second conductivity type, and a first electrode of the second conductivity type are formed in this order above a surface of a semiconductor substrate of the first conductivity type, and a second electrode of the first conductivity type is formed below the lower cladding layer. An optical guide layer is arranged between the quantum-well active layer and one or each of the lower cladding layer and the upper cladding layer. The whole or a portion of the optical guide layer contains a dopant so as to realize a carrier concentration of 3.0×1017 cm?3 or higher.

Abstract: A red semiconductor laser including a first type GaAs substrate having a set of layers sequentially formed on the substrate, which includes at least: a first conductivity type AlInGaP clad layer; an AlInGaP lower optical guide layer; a quantum well active layer made of GaInP or AlInGaP; an AlInGaP upper optical guide layer; a second conductivity type AlInGaP first upper clad layer including a non-doped region formed on the side of the upper clad layer facing the upper optical guide layer; a second conductivity type GaInP heterobuffer layer; and a second conductivity type GaAs cap layer. The second conductivity type carrier concentration at the interface between the first upper clad layer and upper optical guide layer is kept at a value which is less than or equal to 4×1016 cm?3.

Abstract: In a semiconductor laser element: a lower cladding layer of a first conductivity type, a quantum-well active layer, an upper cladding layer of a second conductivity type, a contact layer of the second conductivity type, and a first electrode of the second conductivity type are formed in this order above a surface of a semiconductor substrate of the first conductivity type, and a second electrode of the first conductivity type is formed below the lower cladding layer. An optical guide layer is arranged between the quantum-well active layer and one or each of the lower cladding layer and the upper cladding layer. The whole or a portion of the optical guide layer contains a dopant so as to realize a carrier concentration of 3.0×1017 cm?3 or higher.

Abstract: In a semiconductor laser element: a lower cladding layer of In0.49(Alx1Ga1-x1)0.51(x2<x1<1) of a first conductive type which lattice-matches with GaAs; a lower optical waveguide layer of In0.49(Alx2Ga1-x2)0.51P (0<x2<x1) which lattice-matches with GaAs; an active layer; an upper optical waveguide layer of In0.49(Alx2Ga1-x2)0.51P (0<x2<x1) which lattice-matches with GaAs; and an upper cladding layer of In0.49(Alx1Ga1-x1)0.51P (x2<x1<1) of a second conductive type which lattice-matches with GaAs are formed in this order on a substrate of GaAs. The total thickness of the lower optical waveguide layer, the active layer, and the upper optical waveguide layer is 0.30 micrometers or greater.

Abstract: A semiconductor laser element having a structure in which at least one AlGaInP or GaInP layer is formed above a GaAs substrate. The crystal orientation of the principal plane of the GaAs substrate is tilted from (100) toward (111). When the total thickness of the at least one AlGaInP or GaInP layer is 1 micrometer or smaller, the tilt angle of the crystal orientation of the principal face is 8 to 54.7 degrees. When the total thickness of the at least one AlGaInP or GaInP layer is 1 micrometer or greater, the tilt angle of the crystal orientation of the principal face is 13 to 54.7 degrees.

Abstract: An n-GaAs buffer layer, an n-Alz1Ga1?z1As cladding layer, an n- or i-In0.49Ga0.51P waveguide layer, an i-Inx3Ga1?x3As1?y3Py3 barrier layer, a compressive strain Inx1Ga1?x1As1?y1Py1 quantum well active layer, an i-Inx3Ga1?x3As1?y3Py3 upper barrier layer, and an In0.49Ga0.51P cap layer are laminated on an n-GaAs substrate. Regions near facets of the barrier layer to the cap layer are removed, and a p- or i-type In0.49Ga0.51P upper optical waveguide layer is laminated on the cap layer to fill in the removed portions. A p-GaAs etching stop layer, an n-In0.49(Alz2Ga1?z2)0.51P current confinement layer having an opening, an n-In0.49Ga0.51P second cap layer, a p-In0.49Ga0.51P second upper optical waveguide layer 34 and a p-Alz1Ga1?z1As upper cladding layer are laminated thereon, and a p-GaAs contact layer is formed inwardly except near the facets on the laminated surface, and an insulation film is formed on the regions near the facets, and a p-side electrode is provided as an uppermost layer.

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: An n-GaAs buffer layer, an n-Alz1Ga1-z1As cladding layer, an n- or i-In0.49Ga0.51P waveguide layer, an i-Inx3Ga1-x3As1-y3Py3 barrier layer, a compressive strain Inx1Ga1-x3As1-y3Py3 quantum well active layer, an i-Inx3Ga1-x3As1-y3Py3 upper barrier layer, and an In0.49Ga0.51P cap layer are laminated on an n-GaAs substrate. Regions near facets of the barrier layer to the cap layer are removed, and a p- or i-type In0.49Ga0.51P upper optical waveguide layer is laminated on the cap layer to fill in the removed portions. A p-GaAs etching stop layer, an n-In0.49(Alz2Ga1-z2)0.51P current confinement layer having an opening, an n-In0.49Ga0.51P second cap layer, a p-In0.49Ga0.51P second upper optical waveguide layer 34 and a p-Alz1Ga1-z1As upper cladding layer are laminated thereon, and a p-GaAs contact layer is formed inwardly except near the facets on the laminated surface, and an insulation film is formed on the regions near the facets, and a p-side electrode is provided as an uppermost layer.

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.