Abstract: Because a laser device is constructed in such a way that the laser device includes a solid-state laser element 3 that has gains for plural different wavelengths in plural different axial directions, and an optical element that has a characteristic of making an optical loss increase with increase in light intensity for each of light beams with the wavelengths, and the solid-state laser element 3 and the optical element are constructed in such a way as to be included in a resonator for fundamental waves which are generated by the solid-state laser element 3, and the laser device oscillates at two or more wavelengths, outputted light beams with the plural different wavelengths can be acquired by using the single solid-state laser element 3. As a result, a small, cheap, and easy to produce laser device can be acquired.

Abstract: An end surface 3b of a solid-state laser element 3 is sloped in such a way that, assuming that laser light is incident upon air from the end surface, an angle of incidence which a normal to an inner side of the end surface forms with a traveling direction of the laser light substantially matches the Brewster angle at the incidence plane, an end surface 4a of a wavelength conversion element 4 is sloped in such a way that, assuming that the laser light is incident upon air from the end surface, an angle of incidence which a normal to an inner side of the end surface forms with a traveling direction of the laser light substantially matches the Brewster angle at the incidence plane, and the end surface 3b and the end surface 4b are arranged in such a way as to be opposite to each other.

Abstract: To provide an optical module and optical transmission method that reduce tracking errors caused by position shifting of the focal point of light related to the optical axis direction, using a simpler method. A lens 1 causes light emitted from an emission point to be focused at a focal point. A lens cap 2 is provided on a stem 6 and supports the lens 1. A semiconductor laser 3 is provided on the stem 6 and emits light from a position corresponding to the emission point. A control member 7 controls position shifting of the focal point generated by thermal expansion of the lens cap 2, through thermal expansion in the direction of the optical axis of the lens 1.

Abstract: A semiconductor device includes a submount; a semiconductor laser mounted on the submount via solder in a junction-down manner. The semiconductor laser includes a semiconductor substrate, a semiconductor laminated structure containing a p-n junction, on the semiconductor substrate, and an electrode on the semiconductor laminated structure and joined to the submount via the solder. A high-melting-point metal or dielectric film is located between the submount and the semiconductor laminated structure and surrounds the electrode.

Abstract: A semiconductor light-emitting diode includes an electrically conductive substrate transmissive to light-emitting wavelengths, and semiconductor layers including a light-emitting layer, on the substrate. A principal-surface electrode is located on the semiconductor layers and a rear-surface electrode having an opening is located on the rear surface of the substrate. The width of the opening is L, the distance between the rear-surface electrode and the light-emitting layer is t, L?2 t, and the rear-surface electrode covers no more than 40% of the rear surface of the substrate.

Abstract: A method for manufacturing a semiconductor device includes forming a semiconductor laminated structure on a substrate as a wafer including semiconductor laser structures; forming a first groove between the semiconductor laser structures on a major surface of the wafer; separating the wafer to laser bars including at least two of the semiconductor laser structures arrayed in a bar shape, after forming the first groove; forming a second groove in the first groove of the laser bars, the second groove having a width no wider than the first groove; and separating one of the laser bars into respective semiconductor lasers along the second groove.

Abstract: A nitride semiconductor light-emitting device includes a p-type contact layer, a p-type intermediate layer below the p-type contact layer, and a p-type cladding layer below the p-type intermediate layer. Band gap energy differences between the p-type contact layer and the p-type intermediate layer and also between the p-type intermediate layer and the p-type cladding layer are, respectively, 200 meV or below.

Abstract: A semiconductor device includes a submount; a semiconductor laser mounted on the submount via solder in a junction-down manner. The semiconductor laser includes a semiconductor substrate, a semiconductor laminated structure containing a p-n junction, on the semiconductor substrate, and an electrode on the semiconductor laminated structure and joined to the submount via the solder. A high-melting-point metal or dielectric film is located between the submount and the semiconductor laminated structure and surrounds the electrode.

Abstract: A method for manufacturing a semiconductor device includes forming a semiconductor laminated structure on a substrate as a wafer including semiconductor laser structures; forming a first groove between the semiconductor laser structures on a major surface of the wafer; separating the wafer to laser bars including at least two of the semiconductor laser structures arrayed in a bar shape, after forming the first groove; forming a second groove in the first groove of the laser bars, the second groove having a width no wider than the first groove; and separating one of the laser bars into respective semiconductor lasers along the second groove.

Abstract: A semiconductor laser having a high electrostatic withstand voltage, resistant to a power supply surge, and having improved long-term reliability is obtained by reducing current leakage through a threading dislocation portion. The semiconductor laser includes a substrate having a high dislocation region having a dislocation density of 1×105 cm?2 or more, a crystalline semiconductor structure located on the substrate and having an active layer, an insulating film located on the semiconductors structure, a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer, and a back electrode located on a rear surface of the substrate. The semiconductor laser has a laser resonator with a length L, and the area of the surface electrode is 120×L ?m2 or less.

Abstract: A GaN laser, includes a coating film on a front end surface through which laser light is emitted. The coating film includes a first insulating film in contact with the front end surface and a second insulating film on the first insulating film. The optical film thickness of the second insulating film is an odd multiple of ?/4 with respect to the wavelength ? of laser light produced by the semiconductor laser. The adhesion of the first insulating film to GaN is stronger than the adhesion of the second insulating film to GaN. The refractive index of the second insulating film is 2 to 2.3 thick. The first insulating film is 10 nm or less. The first insulating film is an oxide film having a stoichiometric composition.

Abstract: A nitride semiconductor device with a p electrode having no resistance between itself and other electrodes, and a method of manufacturing the same are provided. A p electrode is formed of a first Pd film, a Ta film, and a second Pd film, and on a p-type contact layer of a nitride semiconductor. On the second Pd film, a pad electrode is formed. The second Pd film is formed on the entire upper surface of the Ta film which forms part of the p electrode, and serves as an antioxidant film that prevents oxidation of the Ta film. Preventing oxidation of the Ta film, the second Pd film can reduce the resistance that may exist between the p electrode and the pad electrode, thereby preventing a failure in contact between the p electrode and the pad electrode and providing the p electrode with low resistance.

Abstract: A semiconductor light-emitting element s includes a semiconductor substrate; a semiconductor laminate structure having a first conductivity-type cladding layer, an active layer, a second conductivity-type cladding layer, and a second conductivity-type contact layer sequentially arranged on the semiconductor substrate; a stripe-shaped waveguide region on an upper surface of the semiconductor laminate structure; and recessed portions on the upper surface, spaced from the waveguide region; a first electrode electrically connected to the semiconductor substrate; a second electrode electrically connected to the contact layer; a pad electrode on the second electrode; and an inner recessed portion electrode in the recessed portions, on an insulating film.

Abstract: A semiconductor light emitting device has an active layer of a gallium nitride compound semiconductor material, a first semiconductor layer of Inx1Aly1Ga1?x1?y1N (0?x1?1, 0?y1?1), on a p-layer side of the active layer, and which is subjected to tensile strain, a second semiconductor layer of Inx2Aly2Ga1?x2?y2N, wherein (0?x2?1, 0 ?y2?1), and which has a bandgap energy smaller than the bandgap energy of the first semiconductor layer, and a third semiconductor layer between the first semiconductor layer and the second semiconductor layer, of Inx3Aly3Ga1?x3?y3N, wherein (0?x3?1, 0?y3?1), and which has a bandgap energy smaller than the bandgap energy of the first semiconductor layer and larger than the bandgap energy of the second semiconductor layer.

Abstract: A semiconductor laser, having an active layer with a double-quantum-well structure, includes two InGaN well layers, each of which has a thickness of 5 nm. The threshold current deteriorates to a relatively small degree while differential efficiency is improved considerably in a region having a light confinement coefficient ? of 3.0% or less. The light confinement coefficient indicates the proportion of light in the well layers with respect to light in the light emitting device, during light emission. When the light confinement coefficient ? is less than 1.5%, the threshold current increases considerably and the improvement in differential efficiency becomes small. It is therefore preferable that the lower limit of the light confinement coefficient ? be about 1.5%. A differential efficiency of 1.6 W/A or more is obtained when light the confinement coefficient ? is 3.0% or less, and a differential efficiency of 1.7 W/A or more is obtained when the light confinement coefficient ? is 2.6% or less.

Abstract: A semiconductor light-emitting device which exhibits small threshold current, high differential efficiency, and good characteristics, by reducing electrons that overflow an electron barrier, trapping the electrons in an active layer. Of the barrier layers of an active layer, a final barrier layer, which is a barrier layer closest to a p side, is smaller in band gap energy than other barrier layers. Thus, as compared with a case where the final barrier layer has the same band gap energy as that of the other barrier layer, an energy band discontinuity (electron barrier) with an electron blocking layer can be made larger. As a result, overflow of electrons is reduced.

Abstract: A semiconductor laser having a high electrostatic withstand voltage, resistant to a power supply surge, and having improved long-term reliability is obtained by reducing current leakage through a threading dislocation portion. The semiconductor laser includes a substrate having a high dislocation region having a dislocation density of 1×105 cm?2 or more, a crystalline semiconductor structure located on the substrate and having an active layer, an insulating film located on the semiconductor structure, a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer, and a back electrode located on a rear surface of the substrate. The semiconductor laser has a laser resonator with a length L, and the area of the surface electrode is 120×L ?m2 or less.

Abstract: A semiconductor laser having a high electrostatic withstand voltage, resistant to a power supply surge, and having improved long-term reliability is obtained by reducing current leakage through a threading dislocation portion. The semiconductor laser includes a substrate having a high dislocation region having a dislocation density of 1×105 cm?2 or more, a crystalline semiconductor structure located on the substrate and having an active layer, an insulating film located on the semiconductor structure, a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer, and a back electrode located on a rear surface of the substrate. The semiconductor laser has a laser resonator with a length L, and the area of the surface electrode is 120×L ?m2 or less.

Abstract: A GaN semiconductor laser, includes a coating film on a front end surface through which laser light is emitted. The coating film includes a first insulating film in contact with the front end surface and a second insulating film on the first insulating film. The sum of the optical film thicknesses of the first insulating film and the second insulating film is an odd multiple of ?/4 with respect to the wavelength ? of laser light produced by the semiconductor laser. The adhesion of the first insulating film to GaN is stronger than that of the second insulating film to GaN. The refractive index of the first insulating film is 1.9 or less and the refractive index of the second insulating film is 2 to 2.3.

Abstract: A GaN laser, includes a coating film on a front end surface through which laser light is emitted. The coating film includes a first insulating film in contact with the front end surface and a second insulating film on the first insulating film. The optical film thickness of the second insulating film is an odd multiple of ?/4 with respect to the wavelength ? of laser light produced by the semiconductor laser. The adhesion of the first insulating film to GaN is stronger than the adhesion of the second insulating film; to GaN. The refractive index of the second insulating film is 2 to 2.3 thick. The first insulating film is 10 nm or less. The first insulating film is an oxide film having a stoichiometric composition.