Abstract: A semiconductor device includes a first pair of nitride semiconductor regions, and a current confinement region which includes a first portion, a second portion disposed on a side of the first portion, and a third portion disposed on another side of the first portion. A width of the second portion is larger than a width of the first portion, the width of the second portion is larger than a width between the first pair of nitride semiconductor regions, and both ends of the second portion are covered by the first pair of nitride semiconductor regions, respectively.

Abstract: A semiconductor device includes a first pair of nitride semiconductor regions, and a current confinement region which includes a first portion, a second portion disposed on a side of the first portion, and a third portion disposed on another side of the first portion. A width of the second portion is larger than a width of the first portion, the width of the second portion is larger than a width between the first pair of nitride semiconductor regions, and both ends of the second portion are covered by the first pair of nitride semiconductor regions, respectively.

Abstract: A semiconductor laser including current block layers disposed between a p-type clad layer and a p-type light guide layer and a current confinement region which is a region between the current block layers is configured as follows. A width of an opening portion of an insulating layer is made narrow above a wide portion of the current confinement region in which the wide portion, a tapered portion, a narrow portion, a tapered portion and the wide portion are disposed in this order between an incidence side (HR side) and an emission side (AR side), and both ends of the wide portion are covered by an insulating layer. According to such a configuration, it is possible to suppress generation of super luminescence in the wide portion, and it is thus possible to achieve improvement in beam quality and higher output of the beam.

Abstract: A semiconductor laser including current block layers disposed between a p-type clad layer and a p-type light guide layer and a current confinement region which is a region between the current block layers is configured as follows. A width of an opening portion of an insulating layer is made narrow above a wide portion of the current confinement region in which the wide portion, a tapered portion, a narrow portion, a tapered portion and the wide portion are disposed in this order between an incidence side (HR side) and an emission side (AR side), and both ends of the wide portion are covered by an insulating layer. According to such a configuration, it is possible to suppress generation of super luminescence in the wide portion, and it is thus possible to achieve improvement in beam quality and higher output of the beam.

Abstract: Provided is a semiconductor laser, wherein (?a??w)>15 (nm) and Lt<25 (?m), where ?w is the wavelength of light corresponding to the band gap of the active layer disposed at a position within a distance of 2 ?m from one end surface in a resonator direction, ?a is the wavelength of light corresponding to the band gap of the active layer disposed at a position that is spaced a distance of equal to or more than ( 3/10)L and ?( 7/10)L from the one end surface in a resonator direction, “L” is the resonator length, and “Lt” is the length of a transition region provided between the position of the active layer with a band gap corresponding to a light wavelength of ?w+2 (nm) and the position of the active layer with a band gap corresponding to a light wavelength of ?a?2 (nm) in the resonator direction.

Abstract: Provided is a semiconductor laser, wherein (?a??w) >15 (nm) and Lt<25 (?m), where ?w is the wavelength of light corresponding to the band gap of the active layer disposed at a position within a distance of 2 ?m from one end surface in a resonator direction, ?a is the wavelength of light corresponding to the band gap of the active layer disposed at a position that is spaced a distance of equal to or more than ( 3/10)L and ?( 7/10)L from the one end surface in a resonator direction, “L” is the resonator length, and “Lt” is the length of a transition region provided between the position of the active layer with a band gap corresponding to a light wavelength of ?w+2 (nm) and the position of the active layer with a band gap corresponding to a light wavelength of ?a?2 (nm) in the resonator direction.

Abstract: Provided is a semiconductor laser, wherein (?a??w)>15 (nm) and Lt<25 (?m), where ?w is the wavelength of light corresponding to the band gap of the active layer disposed at a position within a distance of 2 ?m from one end surface in a resonator direction, ?a is the wavelength of light corresponding to the band gap of the active layer disposed at a position that is spaced a distance of equal to or more than ( 3/10)L and <( 7/10)L from the one end surface in a resonator direction, “L” is the resonator length, and “Lt” is the length of a transition region provided between the position of the active layer with a band gap corresponding to a light wavelength of ?w+2 (nm) and the position of the active layer with a band gap corresponding to a light wavelength of ?a?2 (nm) in the resonator direction.

Abstract: Provided is a semiconductor laser, wherein (?a??w)>15 (nm) and Lt<25 (?m), where ?w is the wavelength of light corresponding to the band gap of the active layer disposed at a position within a distance of 2 ?m from one end surface in a resonator direction, ?a is the wavelength of light corresponding to the band gap of the active layer disposed at a position that is spaced a distance of equal to or more than ( 3/10)L and <( 7/10)L from the one end surface in a resonator direction, “L” is the resonator length, and “Lt” is the length of a transition region provided between the position of the active layer with a band gap corresponding to a light wavelength of ?w+2 (nm) and the position of the active layer with a band gap corresponding to a light wavelength of ?a?2 (nm) in the resonator direction.

Abstract: The present invention provides a ridge waveguide structure of a cladding layer in a semiconductor light emitting device. The ridge waveguide structure comprises: at least a current injection region; and current non-injection regions adjacent to facets and separating the current injection region from the facets, wherein the current non-injection regions are smaller in height than the at least current injection region, and wherein the at least current injection region and the current non-injection regions have a uniform width at least at a lower level than an intermediate level of the ridge waveguide structure.

Abstract: A window type semiconductor layer light emitting device has a compound semiconductor structure including a first clad layer formed on a crystal plane closer to (100) plane, an active layer formed on the first clad layer and a second clad layer formed on the active layer and window layers grown on both sides of the compound semiconductor structure, and the buried window layers are epitaxially grown on the side surfaces of the compound semiconductor structure by restricting the epitaxial growth in a vertical direction to the crystal lane so that the upper surfaces of the buried window layers are substantially coplanar with the upper surface of the second clad layer, thereby decreasing the coupling loss.

Abstract: The present invention provides a ridge waveguide structure of a cladding layer in a semiconductor light emitting device. The ridge waveguide structure comprises: at least a current injection region; and current non-injection regions adjacent to facets and separating the current injection region from the facets, wherein the current non-injection regions are smaller in height than the at least current injection region, and wherein the at least current injection region and the current non-injection regions have a uniform width at least at a lower level than an intermediate level of the ridge waveguide structure.

Abstract: A fabrication method of a semiconductor QW laser by MOVPE with a high fabrication yield, providing a laser device sufficiently reliable in operation over long period of time and applicable for optical communications. An InGaAs QW active layer is grown on a first semiconductor layer formed on or over a semiconductor substrate at a growth temperature ranging from 580.degree. to 640.degree. C. Then, a second semiconductor layer is grown on the active layer at the same growth temperature as that of the active layer. Preferably, the active layer is grown under a condition that the total pressure in a growth chamber is substantially equal to an atmospheric pressure and a partial pressure of arsine (AsH.sub.3) for As component ranges from 1.6.times.10.sup.-7 to 3.times.10.sup.-1 Torr.

Abstract: A semiconductor double heterostructure formed on a GaAs substrate having an off (100) plane slightly tilted toward a predetermined direction, the double heterostructure including an InGaAs quantum well active strained layer sandwiched between potential barrier layers and including an interface between the InGaAs quantum well active strained layer and an upper potential barrier layer grown on the active strained layer, wherein the interface has a periodical ridge-like bunching structure comprising quadrilateral waveform parts and triangular waveform parts, each of the quadrilateral waveform parts comprises a series of a bottom terrace of the just (100) plane, a reverse direction multiple step plane largely tilted from (100) direction toward the opposite direction to the predetermined direction, a top terrace of the just (100) plane and a forward direction multiple step plane largely tilted from (100) direction toward the predetermined direction, each of the triangular waveform parts comprises the just (100) pl