Abstract: An n-GaN low-temperature buffer layer, an n-GaN buffer layer, an n-In0.05Ga0.95N buffer layer, an n-Al0.15Ga0.85N clad layer, an n-GaN optical guide layer, an undoped active layer, a p-GaN optical guide layer, a p-Al0.15Ga0.85N clad layer, and a p-GaN cap layer, are grown on a sapphire substrate. Then, an epitaxial layer other than a light-emitting region is etched until the n-GaN buffer layer is exposed. Next, in a similar process, etching is performed up to anywhere within the p-Al0.15Ga0.85N clad layer so that a 4-&mgr;m-wide stripe region in the form of a ridge remains. The length from the light-emitting facet to the opposite facet is between 30 and 250 &mgr;m.

Abstract: In a semiconductor laser device, an optical guide region includes an active layer and first and second optical waveguide layers respectively formed above and under the active layer, and first and second cladding layers are respectively formed above and under the optical guide region. Each of the first and second cladding layers includes at least one AlGaN layer.

Abstract: A GaN substrate formed with a substrate, a first GaN layer, a first preventing film, a second GaN layer, and a second preventing film. The first GaN layer is formed on the substrate, and includes a plurality of stripe portions which form at least one first groove between adjacent ones of the plurality of stripe portions. The second GaN layer is formed over the substrate and the first GaN layer. The first preventing film is arranged on upper surfaces of the plurality of stripe portions, and prevents crystal growth of a GaN layer in a vertical up direction from the upper surfaces of the plurality of stripe portions. The second preventing film is arranged on at least one bottom surface of the at least one first groove, and prevents crystal growth of a GaN layer in a vertical up direction from the at least one bottom surface.

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: A semiconductor laser module includes: a semiconductor laser element which emits laser light; a waveguide-type optical wavelength selection element which includes an optical waveguide, and selects a first portion of the laser light having a predetermined wavelength; and an optical wavelength conversion element which converts a second portion of the laser light having the predetermined wavelength to wavelength-converted laser light having a converted wavelength. The semiconductor laser element, the waveguide-type optical wavelength selection element, and the optical wavelength conversion element are coupled. The semiconductor laser element contains a multiple-quantum-well active layer including a plurality of quantum-well sublayers, where one of the plurality of quantum-well sublayers is different from another of the plurality of quantum-well sublayers in thickness and/or composition.

Abstract: In a semiconductor laser device, an active region, including a quantum well layer sandwiched between upper and lower optical waveguide layers, is formed on a substrate. A near-edge portion of the active region is etched down to a mid-thickness of the lower optical waveguide layer. A non-absorbing layer, made of a semiconductor material having a bandgap greater than photon energy of laser light generated in the active region, is formed over the active region. An etching stop layer is formed at the mid-thickness location in the lower optical waveguide layer so as to selectively stop the etching of the near-edge portion of the active region. An electron barrier layer, made of a semiconductor material having a bandgap greater than the bandgap of the upper optical waveguide layer, is formed at a mid-thickness location in the upper optical waveguide layer.

Abstract: In a semiconductor laser device including having an index-guided structure and oscillating in a fundamental transverse mode, a lower cladding layer, a lower optical waveguide layer, a quantum well layer, an upper optical waveguide layer, and a current confinement structure are formed in this order. The thickness of the upper optical waveguide layer is smaller than the thickness of the lower optical waveguide layer. In addition, the sum of the thicknesses of the upper and lower optical waveguide layers may be 0.5 micrometers or greater. Further, the distance between the bottom of the current confinement structure and the upper surface of the quantum well layer may be smaller than 0.25 micrometers.

Abstract: A high-output semiconductor laser element includes a plurality of laser structures which are superposed on a substrate one on another with a P+N+-tunnel junction intervening between each pair of the laser structures. Each of the laser structures includes at least one active layer interposed between a P-type clad layer and a N-type clad layer. The active region of each of the laser structures is not smaller than 10 &mgr;m and not larger than 80 &mgr;m in width. The distance h between the active layers which are most distant from each other in the active layers of the laser structures is not larger than the width W of the active region which is the widest in the laser structures. The width of said semiconductor laser element is not smaller than W+2h.

Abstract: A GaN substrate formed with a substrate, a first GaN layer, a first preventing film, a second GaN layer, and a second preventing film. The first GaN layer is formed on the substrate, and includes a plurality of stripe portions which form at least one first groove between adjacent ones of the plurality of stripe portions. The second GaN layer is formed over the substrate and the first GaN layer. The first preventing film is arranged on upper surfaces of the plurality of stripe portions, and prevents crystal growth of a GaN layer in a vertical up direction from the upper surfaces of the plurality of stripe portions. The second preventing film is arranged on at least one bottom surface of the at least one first groove, and prevents crystal growth of a GaN layer in a vertical up direction from the at least one bottom surface.

Abstract: A laser apparatus includes a semiconductor laser element, a surface-emitting semiconductor element including a first mirror, a second mirror, and a modulation unit. The semiconductor laser element emits first laser light having a first wavelength. The surface-emitting semiconductor element is excited with the first laser light, emits second laser light having a second wavelength which is longer than the first wavelength. The first mirror in the surface-emitting semiconductor element is arranged on one side of the first active layer. The second mirror is arranged outside the surface-emitting semiconductor element so that the first and second mirrors form a resonator in which the second laser light resonates. The modulation unit modulates the surface-emitting semiconductor element.

Abstract: An end face emitting type semiconductor laser has a first semiconductor layer including a first clad layer, an active layer and a second semiconductor layer including a second clad layer superposed one on another in this order on a substrate. A first electrode is formed on the substrate or the first semiconductor layer and a second electrode is formed on the upper surface of the second semiconductor layer. The second semiconductor layer is transparent to light of a wavelength at which the semiconductor laser oscillates, and a pattern of concavity and convexity is formed on the upper surface of the second semiconductor layer in a region corresponding to an oscillating part of the semiconductor laser.

Abstract: An image exposing device which, on the basis of image data, modulates light beams outputted from three light sources having respectively different wavelengths, and which scans/exposes the light beams onto a photosensitive material. The three light sources includes a first light source having a light-emitting peak wavelength in a vicinity of 635 nm, a second light source having a light-emitting peak wavelength in a range of 670 to 710 nm, and a third light source having a light-emitting peak wavelength in a vicinity of 780 nm. The photosensitive material includes a first photosensitive layer having a peak spectral sensitivity corresponding to the first light source, a second photosensitive layer having a peak spectral sensitivity corresponding to the second light source, and a third photosensitive layer having a peak spectral sensitivity corresponding to the third light source.

Abstract: A laser-diode-pumped solid-state laser in which a solid-state laser crystal is pumped by a laser beam emitted from a laser diode. An index-guided type multi-transverse mode broad area laser having a single optical waveguide is used as the laser diode. This leads to reduced output variations and noise of the laser. Preferably, the front reflectivity of the laser with respect to the oscillation wavelength of the laser should be more than 20%.

Abstract: A semiconductor light emitting device includes a semiconductor light amplifier, a mirror which reflects light emanating from the rear end face of the semiconductor light amplifier to return the light to the rear end face of the semiconductor light amplifier, and a band pass filter which is inserted into the optical path of the light emanating from the rear end face of the semiconductor light amplifier and has a narrow transmission wavelength band.

Abstract: A semiconductor light emitting device includes a semiconductor light amplifier, a mirror which reflects light emanating from the rear end face of the semiconductor light amplifier to return the light to the rear end face of the semiconductor light amplifier, and a band pass filter which is inserted into the optical path of the light emanating from the rear end face of the semiconductor light amplifier and has a narrow transmission wavelength band.

Abstract: A high-power laser diode that has a wide emitting aperture and good stability to external perturbations. Structurally, the laser diode includes an array of independently-operating narrow stripe single-mode lasers coupled at each end to a single wide stripe region having a width of 30 .mu.m or more in an arrangement which minimizes phase locking.

Abstract: A high efficiency laser diode that has a narrow beam divergence in a direction perpendicular with respect to the substrate, and a low threshold current.

Abstract: A strained quantum well laser diode in which higher reliability is achieved by reducing the degrading effects of stress. By using an active layer orientation that is equal or close to (111), it is possible to suppress degradation caused by stress, which acts in a direction parallel to the quantum well layer.

Abstract: A high efficiency laser diode that has a narrow beam divergence in a direction perpendicular with respect to the substrate, and a low threshold current.

Abstract: A semiconductor laser array includes a plurality of stripe-shaped stimulated regions of the index guide type. A plurality of buried layers are disposed between each of the plurality of stripe-shaped stimulated regions. A light absorption layer is formed in each of the plurality of stripe-shaped stimulated regions so that the stimulated region has the optical loss greater than an buried layer, whereby optical coupling is performed with no phase difference.