Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

Abstract: A Raman amplifier includes: a Raman amplification optical fiber configured to Raman amplify incoherent light in which relative intensity noise (RIN) is suppressed while transmitting the incoherent light; and a pumping light source configured to supply pumping light to the Raman amplification optical fiber. A corner frequency fc [Hz] at which the suppression of the RIN starts in the Raman-amplified incoherent light is estimated by using the following Equation (1): fc = 1 / ( D · ?? · L ) ( 1 ) in which a full width at half maximum of a wavelength spectrum of the incoherent light is ?? [nm], a length of the Raman amplification optical fiber is L [km], and a chromatic dispersion of the Raman amplification optical fiber at a center wavelength of the incoherent light is D [ps/nm/km].

Abstract: A light source includes: a seed light source configured to output incoherent seed light having a predetermined bandwidth; and a booster amplifier that is a semiconductor optical amplifier configured to optically amplify the seed light entered through a first end facet and output the amplified light through a second end facet. The booster amplifier has nL being set, which is a product of a refractive index n and a chip length L, so as to simultaneously suppress relative intensity noise (RIN) and ripple in the amplified light.

Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

Abstract: A light source includes: a seed light source configured to output incoherent seed light with a predetermined bandwidth; and a booster amplifier that is a semiconductor optical amplifier configured to optically amplify the seed light input from a first facet, and output the amplified seed light as amplified light from a second facet, wherein the first facet and the second facet of the booster amplifier are subjected to a reflection reduction treatment, the booster amplifier is configured to operate in a gain saturated state, and relative intensity noise (RIN) and ripple are simultaneously suppressed in the amplified light.

Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The quantum well active layer is doped with 0.3 to 1×1018/cm3 of n-type impurity.

Abstract: An air cleaner may include a filter element and a housing defining an inner space. The inner space may be divided by the filter element into a dust-side air chamber on an upstream side and a clean-side air chamber on a downstream side. Air introduced into the housing may be dischargable via an outlet pipe, to which an air flow sensor is attachable, connected to the clean-side air chamber. The outlet pipe may extend in a direction different from a normal to the filter element. A plurality of ribs may be disposed on an inner surface of a clean-side portion of the housing that defines the clean-side air chamber. The plurality of ribs may extend from a corner portion of the housing toward the filter element and the outlet pipe. A distance between adjacent ribs of the plurality of ribs may decrease in a direction toward the outlet pipe.

Abstract: A semiconductor laser array includes: a plurality of semiconductor lasers configured to oscillate in a single mode at oscillation wavelengths different from one another, each semiconductor laser including an active layer including a multi-quantum well structure including a plurality of will layers and a plurality of barrier layers laminated alternately, and an n-side separate confinement heterostructure layer and p-side separate confinement heterostructure layer configured to sandwich the active layer therebetween in a thickness direction, band gap energies of the n-side separate confinement heterostructure layer and the p-side separate confinement heterostructure layer being greater than band gap energies of the barrier layers of the active layer. The active layer is doped with an n-type impurity.

Abstract: A constant velocity joint includes spherical rollers. At least parts of first inner bottom wall portions provided on an inner bottom wall surface of a cylindrical portion of the constant velocity joint are located in closer proximity to the side of an opening of the cylindrical portion than second inner bottom wall portions. When the spherical rollers are disposed at an innermost location inside the cylindrical portion and the axial directions of the spherical rollers are perpendicular to the axial direction of the cylindrical portion, at least parts of the first inner bottom wall portions abut against inner side outer circumferential surface portions of the spherical rollers, and the second inner bottom wall portions are separated away from outer side outer circumferential surface portions of the spherical rollers.

Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

Abstract: An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The quantum well active layer is doped with 0.3 to 1×1018/cm3 of n-type impurity.

Abstract: An air cleaner capable of, even when a flow rate of air flow flowing in the air cleaner is high, performing flow rate measurement with high measurement accuracy via an air flow sensor attached to an outlet pipe is provided. The above problem can be solved by an air cleaner 1 including a plurality of ribs 41, 42, 43 disposed at an inner surface of a housing 2 defining a clean-side air chamber 23, the plurality of ribs 41, 42, 43 extending from a corner portion 24 of the housing, the corner portion 24 being distant from a filter element 4 and an outlet pipe 21, toward the filter element 4 and the outlet pipe 21 and terminating short of a surface 25 of the housing with the outlet pipe 21 provided, the plurality of ribs 41, 42, 43 being configured such that a distance d between adjacent ribs narrows toward the outlet pipe 21.

Abstract: A circuit conductor is provided on a base. A semiconductor laser is connected to the circuit conductor. Cutout parts on which the circuit conductor is not formed are provided at, for example, the vicinity of the four corners of the base, and a hole is provided at each of the said portions. The holes penetrate the base. Fixing members are inserted through the holes. The fixing members are, for example, male threads. Since the head part of the fixing members is located in the cutout part, the fixing members and the circuit conductor are not in contact with each other. A platform has holes formed at portions corresponding to the holes in the optical unit and female threads formed on the inner surface. The fixing members and the platform are therefore joined. As a result, the optical unit is fixed to the platform.

Abstract: A distributed feedback (DFB) laser outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The DFB laser includes a separate confinement heterostructure layer positioned between the quantum well active layer and then-type cladding layer. The DFB laser includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and then-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The DFB laser has a function to select a specific wavelength by returning a specific wavelength in the wavelength-variable laser.

Abstract: In a method of manufacturing a Ni plated coating that includes at least one Ni plated layer, an agitation intensity of a plating bath is changed while the Ni plated layer is being electrodeposited to change potential of the deposited Ni plated layer in a deposition depth direction. A Ni plated coating including a D-Ni plated layer and a B-Ni plated layer adjoining the D-Ni plated layer has, other than an interface voltage changing region at an interface between the D-Ni plated layer and the B-Ni plated layer, an in-layer voltage changing region in which, in the D-Ni plated layer or in the B-Ni plated layer, potential is changed in a deposition depth direction at an average rate of 1 mV/0.1 ?m or greater.

Abstract: A constant velocity joint includes spherical rollers. At least parts of first inner bottom wall portions provided on an inner bottom wall surface of a cylindrical portion of the constant velocity joint are located in closer proximity to the side of an opening of the cylindrical portion than second inner bottom wall portions. When the spherical rollers are disposed at an innermost location inside the cylindrical portion and the axial directions of the spherical rollers are perpendicular to the axial direction of the cylindrical portion, at least parts of the first inner bottom wall portions abut against inner side outer circumferential surface portions of the spherical rollers, and the second inner bottom wall portions are separated away from outer side outer circumferential surface portions of the spherical rollers.