Abstract: An 830 nm broad area semiconductor laser having a distributed Bragg reflector (DBR) structure. The semiconductor laser supports multiple horizontal transverse modes of oscillation extending within a plane perpendicular to a crystal growth direction of the laser, in a direction perpendicular to the length of the resonator of the laser. The resonator includes a diffraction grating in the vicinity of the emitting facet of the laser. The width of the diffraction grating in a plane perpendicular to the growth direction and perpendicular to the length of the resonator is different at first and second locations along the length of the resonator. The width of the diffraction grating along a direction which is perpendicular to the length of the resonator increases with increasing distance from the front facet of the semiconductor laser.

Abstract: A semiconductor laser device can suppress electrode-to-electrode resonance of laser light emitted from an active layer, increasing electrical conversion efficiency. The semiconductor laser device has a substrate and an active layer. The energy of the laser light emitted from the active layer is smaller than the band gap energy of the substrate, and the carrier concentration of the substrate is at least 2.2×1018 cm?3.

Abstract: A semiconductor laser includes: a DBR (Distributed Bragg Reflector) region having a diffraction grating; a FP (Fabry-Perot) region having no diffraction grating; and an optical waveguide section placed between the DBR region and an outputting end surface. A length of the optical waveguide section is longer than a length of the DBR region in a resonator length direction.

Abstract: A semiconductor laser device includes: an n-type cladding layer, a p-type cladding layer, an active layer located between the n-type cladding layer and the p-type cladding layer, an n-side guiding layer located on the same side of the active layer as the n-type cladding layer, and a p-side guiding layer located on the same side of the active layer as the p-type cladding layer. The n-side guiding layer, the active layer, and the p-side guiding layer are undoped or substantially undoped. The sum of the thicknesses of the n-side guiding layer, the active layer, and the p-side guiding layer is not less than 0.5 times the lasing wavelength of the semiconductor laser device and is not more than 2 ?m. The p-side guiding layer is thinner and has a lower refractive index than the n-side guiding layer.

Abstract: A semiconductor laser device can suppress electrode-to-electrode resonance of laser light emitted from an active layer, increasing electrical conversion efficiency. The semiconductor laser device has a substrate and an active layer. The energy of the laser light emitted from the active layer is smaller than the band gap energy of the substrate, and the carrier concentration of the substrate is at least 2.2×1018 cm?3.

Abstract: A semiconductor laser device includes: an n-type cladding layer; a p-type cladding layer; and an optical waveguide portion disposed between the n-type and p-type cladding layers and including spaced-apart active layers. The optical waveguide portion permits lasing in a crystal growth direction of the active layers in at least three modes, including the fundamental mode and two higher order modes. The number of active layers is equal to or greater than the number of extreme points of the electric field of a particular one of the higher order modes. At least one of the active layers is disposed near each extreme point of the electric field of the particular higher order mode, within the optical waveguide portion.

Abstract: A coating film is provided on an end surface of a semiconductor photonic element including an active layer through which light propagates. The coating film has a two-layer structure including a first layer film and a second layer film arranged in a stacked relation. The thicknesses of the first and second layer films are determined so that the value of the amplitude reflectivity of the coating film is equal to an imaginary number.

Abstract: A semiconductor laser device includes: a p-type cladding layer; a p-type cladding layer guide layer; an active layer; an n-type cladding layer guide layer; and an n-type cladding layer, in which each of the p-type and n-type cladding layer guide layers is undoped or close to undoped, the sum of the thickness of the p-type cladding layer guide layer and the thickness of the n-type cladding layer guide layer is at least 200 nm, and both of (i) the difference between the band gap energy of the p-type cladding layer guide layer and the band gap energy of the active layer, and (ii) the difference between the band gap energy of the n-type cladding layer guide layer and the band gap energy of the active layer do not exceed 0.3 eV.

Abstract: A semiconductor laser apparatus can improve electric conversion efficiency to a satisfactory extent. The apparatus includes an n-type cladding layer, an n-type cladding layer side guide layer, an active layer, a p-type cladding layer side guide layer, and a p-type cladding layer, wherein electrons and holes are injected into the active layer, transverse to the active layer, through the n-type cladding layer side guide layer and the p-type cladding layer side guide layer. The p-type cladding layer side guide layer is thinner than the n-type cladding layer side guide layer to position the active layer closer to the p-type cladding layer, and, at the same time, the refractive index of the p-type cladding layer side guide layer is higher than the refractive index of the n-type cladding layer side guide layer.

Abstract: A semiconductor laser device includes an active layer, a pair of guiding layers sandwiching the active layer, and a pair of cladding layers sandwiching the active layer and the pair of guiding layers. The pair of guiding layers are InGaAsP lattice-matched to GaAs. The pair of cladding layers are AlGaAs. The Al composition ratios of the pair of AlGaAs cladding layers are 0.4 or less. The Al composition ratios are set such that the refractive indices of the pair of AlGaAs cladding layers do not exceed those of the pair of InGaAsP guiding layers.

Abstract: A semiconductor laser device includes: an n-type cladding layer; a p-type cladding layer; and an optical waveguide portion disposed between the n-type and p-type cladding layers and including spaced-apart active layers. The optical waveguide portion permits lasing in a crystal growth direction of the active layers in at least three modes, including the fundamental mode and two higher order modes. The number of active layers is equal to or greater than the number of extreme points of the electric field of a particular one of the higher order modes. At least one of the active layers is disposed near extreme point of the electric field of the particular higher order mode, within the optical waveguide portion.

Abstract: A semiconductor laser device includes: an n-type cladding layer, a p-type cladding layer, an active layer located between the n-type cladding layer and the p-type cladding layer, an n-side guiding layer located on the same side of the active layer as the n-type cladding layer, and a p-side guiding layer located on the same side of the active layer as the p-type cladding layer. The n-side guiding layer, the active layer, and the p-side guiding layer are undoped or substantially undoped. The sum of the thicknesses of the n-side guiding layer, the active layer, and the p-side guiding layer is not less than 0.5 times the lasing wavelength of the semiconductor laser device and is not more than 2 ?m. The p-side guiding layer is thinner and has a lower refractive index than the n-side guiding layer.

Abstract: Method for manufacturing a semiconductor optical device includes forming an epitaxial structure containing at least an active layer which can emit light, of a III-V group semiconductor material; forming an insulating layer over the epitaxial structure, which prevents the V group element from escaping from the epitaxial structure during heat treatment; heat treating the epitaxial structure at at least 800 degrees C.; and removing the insulating layer, thereby enhancing the reliability of the device.

Abstract: A semiconductor laser device producing light having a TE-polarized component suitable for practical use (i.e., light having TE-polarized light intensity sufficiently high for practical use). A semiconductor laser device includes a GaAsP active layer, InGaP guide layers, and AlGaInP cladding layers. The GaAsP active layer emits light. The GaAsP active layer is interposed between the InGaP guide layers. The InGaP guide layers and GaAsP active layer are interposed between the AlGaInP cladding layers. Polarization ratio, which is a ratio of light intensity of TM-polarized light to light intensity of TE-polarized light, of the light produced by the semiconductor laser device is less than 2.3.

Abstract: A coating film is provided on an end surface of a semiconductor photonic element including an active layer through which light propagates. The coating film has a two-layer structure including a first layer film and a second layer film arranged in a stacked relation. The thicknesses of the first and second layer films are determined so that the value of the amplitude reflectivity of the coating film is equal to an imaginary number.

Abstract: A semiconductor laser apparatus can improve electric conversion efficiency to a satisfactory extent. The apparatus includes an n-type cladding layer, an n-type cladding layer side guide layer, an active layer, a p-type cladding layer side guide layer, and a p-type cladding layer, wherein electrons and holes are injected into the active layer, transverse to the active layer, through the n-type cladding layer side guide layer and the p-type cladding layer side guide layer. The p-type cladding layer side guide layer is thinner than the n-type cladding layer side guide layer to position the active layer closer to the p-type cladding layer, and, at the same time, the refractive index of the p-type cladding layer side guide layer is higher than the refractive index of the n-type cladding layer side guide layer.

Abstract: A semiconductor laser device includes an active layer, a pair of guiding layers sandwiching the active layer, and a pair of cladding layers sandwiching the active layer and the pair of guiding layers. The pair of guiding layers are InGaAsP lattice-matched to GaAs. The pair of cladding layers are AlGaAs. The Al composition ratios of the pair of AlGaAs cladding layers are 0.4 or less. The Al composition ratios are set such that the refractive indices of the pair of AlGaAs cladding layers do not exceed those of the pair of InGaAsP guiding layers.

Abstract: A semiconductor laser device includes an active layer, a pair of guiding layers sandwiching the active layer, and a pair of cladding layers sandwiching the active layer and the pair of guiding layers. The pair of guiding layers are InGaAsP lattice-matched to GaAs. The pair of cladding layers are AlGaAs. The Al composition ratios of the pair of AlGaAs cladding layers are 0.4 or less. The Al composition ratios are set such that the refractive indices of the pair of AlGas cladding layers do not exceed those of the pair of InGaAsP guiding layers.

Abstract: A semiconductor laser device includes first and second conductivity type cladding layer side guide layers disposed in direct contact with respective surfaces of an active layer, sandwiching the active layer; and first and second conductivity type cladding layers disposed in direct contact with the first and second conductivity type cladding layer side guide layer, respectively. The first and second conductivity type cladding layer side guide layers are InGaAsP which is lattice-matched to GaAs and have an As composition ratio more than 0 and not exceeding 0.3. The first and second conductivity type cladding layers are AlGaAs, having an Al composition ratio less than 1.0 and at least equal to an Al composition ratio at which refractive index of the AlGaAs is less than the refractive index of the InGaAsP.

Abstract: A semiconductor laser device includes an active layer, a pair of guiding layers sandwiching the active layer, and a pair of cladding layers sandwiching the active layer and the pair of guiding layers. The pair of guiding layers are InGaAsP lattice-matched to GaAs. The pair of cladding layers are AlGaAs. The Al composition ratios of the pair of AlGaAs cladding layers are 0.4 or less. The Al composition ratios are set such that the refractive indices of the pair of AlGas cladding layers do not exceed those of the pair of InGaAsP guiding layers.