Abstract: Provided is a tobacco sheet having high swelling property for a non-combustion heating type flavor inhaler. The tobacco sheet for a non-combustion heating type flavor inhaler includes tobacco powder having a cumulative 90% particle size (D90) of 200 ?m or more in a volume-based particle size distribution measured by a dry laser diffraction method.

Abstract: An optical element includes a distributed Bragg reflector, wherein the distributed Bragg reflector includes a first-order diffraction grating of a first-order period disposed in a central region, and second-order diffraction gratings of a second-order period having a coupling coefficient smaller than a coupling coefficient of the first-order diffraction grating and disposed in both end regions between which the central region is located.

Abstract: An optical element includes a first optical waveguide that extends from a first end portion toward a second end portion, and has a first active layer, a second optical waveguide that has a second active layer, and is disposed side by side with the first optical waveguide and extends from the first end portion toward the second end portion, a reflective film disposed on an end face of the first optical waveguide at a side of the first end portion, and an anti-reflection film disposed on an end face of the second optical waveguide at the side of the first end portion, wherein the anti-reflection film extends from a side of the second optical waveguide to the first optical waveguide at the first end portion, and the reflective film includes the anti-reflection film as one of constituent elements.

Abstract: A semiconductor laser in a ridge waveguide structure includes: a semiconductor substrate; a lower cladding layer which is formed on the semiconductor substrate; an active layer and a semiconductor layer which are in parallel on the lower cladding layer and are connected with each other; a first upper cladding layer locally aligned above the active layer; a second upper cladding layer locally aligned above the semiconductor layer; and a third upper cladding layer locally aligned above the active layer to confine light which is guided in the active layer, wherein the semiconductor layer has a band gap which is larger than that of the active layer. According to this constitution, an optical semiconductor device with high reliability in which the ridge waveguide structure whose manufacturing is relatively easy is applied, and current diffusion and electrical crosstalk between lasers in the ridge waveguide structure are suppressed is enabled.

Abstract: An optical element includes a distributed Bragg reflector, wherein the distributed Bragg reflector includes a first-order diffraction grating of a first-order period disposed in a central region, and second-order diffraction gratings of a second-order period having a coupling coefficient smaller than a coupling coefficient of the first-order diffraction grating and disposed in both end regions between which the central region is located.

Abstract: An optical semiconductor device includes: an active region which includes an active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a prescribed grating period, and a phase shift portion formed within the first diffraction grating layer, wherein the phase shift portion provides a phase shift not smaller than 1.5? but not larger than 1.83?; and a distributed reflection mirror region which is optically coupled to a first end of the active region as viewed along a direction of an optical axis, and which includes a second diffraction grating which reflects the light produced by the active region back into the active region.

Abstract: A tunable laser includes: a wavelength filter that includes a first ring resonator and a second ring resonator each of which is formed by a waveguide including a silicon waveguide core, and each of which is capable of shifting each of resonance wavelengths that exit periodically and whose intervals are different from each other; and an integrated device that is optically coupled to the wavelength filter, and in which a first semiconductor optical amplifier and a reflector are provided in sequence from a side of the wavelength filter, wherein the resonance wavelengths of the first ring resonator and the second ring resonator are overlapped with each other at one wavelength, and the resonance wavelengths are overlapped with each other also at a plurality of wavelengths other than the one wavelength.

Abstract: An optical device includes an active layer disposed over a semiconductor substrate, a diffraction grating disposed over the active layer, a clad layer partly disposed over the diffraction grating, at least one first burying material layer disposed beside side surfaces of end portions of the clad layer over the diffraction grating, and at least one second burying material layer disposed beside side surfaces of a center portion of the clad layer over the diffraction grating. A refractive index of the at least one first burying material layer is different from a refractive index of the at least are second burying material layer.

Abstract: An optical device includes an active layer disposed over a semiconductor substrate, a diffraction grating disposed over the active layer, a clad layer partly disposed over the diffraction grating, at least one first burying material layer disposed beside side surfaces of end portions of the clad layer over the diffraction grating, and at least one second burying material layer disposed beside side surfaces of a center portion of the clad layer over the diffraction grating. A refractive index of the at least one first burying material layer is different from a refractive index of the at least are second burying material layer.

Abstract: A semiconductor laser in a ridge waveguide structure includes: a semiconductor substrate; a lower cladding layer which is formed on the semiconductor substrate; an active layer and a semiconductor layer which are in parallel on the lower cladding layer and are connected with each other; a first upper cladding layer locally aligned above the active layer; a second upper cladding layer locally aligned above the semiconductor layer; and a third upper cladding layer locally aligned above the active layer to confine light which is guided in the active layer, wherein the semiconductor layer has a band gap which is larger than that of the active layer. According to this constitution, an optical semiconductor device with high reliability in which the ridge waveguide structure whose manufacturing is relatively easy is applied, and current diffusion and electrical crosstalk between lasers in the ridge waveguide structure are suppressed is enabled.

Abstract: A tunable laser includes: a wavelength filter that includes a first ring resonator and a second ring resonator each of which is formed by a waveguide including a silicon waveguide core, and each of which is capable of shifting each of resonance wavelengths that exit periodically and whose intervals are different from each other; and an integrated device that is optically coupled to the wavelength filter, and in which a first semiconductor optical amplifier and a reflector are provided in sequence from a side of the wavelength filter, wherein the resonance wavelengths of the first ring resonator and the second ring resonator are overlapped with each other at one wavelength, and the resonance wavelengths are overlapped with each other also at a plurality of wavelengths other than the one wavelength.

Abstract: An optical semiconductor device includes: an active region which includes an active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a prescribed grating period, and a phase shift portion formed within the first diffraction grating layer, wherein the phase shift portion provides a phase shift not smaller than 1.5? but not larger than 1.83?; and a distributed reflection mirror region which is optically coupled to a first end of the active region as viewed along a direction of an optical axis, and which includes a second diffraction grating which reflects the light produced by the active region back into the active region.

Abstract: A method for manufacturing a semiconductor light emitting device includes forming a lower cladding layer over a GaAs substrate; forming a quantum dot active layer over the lower cladding layer; forming a first semiconductor layer over the quantum dot active layer; forming a diffraction grating by etching the first semiconductor layer; forming a second semiconductor layer burying the diffraction grating; and forming an upper cladding layer having a conductive type different from that of the lower cladding layer over the second semiconductor layer, wherein the processes after forming the quantum dot active layer are performed at a temperature not thermally deteriorating or degrading quantum dots included in the quantum dot active layer.

Abstract: An optical device includes an active layer disposed over a semiconductor substrate, a diffraction grating disposed over the active layer, a clad layer partly disposed over the diffraction grating, at least one first burying material layer disposed beside side surfaces of end portions of the clad layer over the diffraction grating, and at least one second burying material layer disposed beside side surfaces of a center portion of the clad layer over the diffraction grating. A refractive index of the at least one first burying material layer is different from a refractive index of the at least are second burying material layer.

Abstract: A semiconductor laser includes an active region including an active layer, and a diffraction grating and a phase shift which determine an oscillation wavelength, and a distributed reflector region including a light guide layer and a refection diffraction grating. The distributed reflector region has an effective diffraction grating period which varies along a direction of a cavity.

Abstract: A method for manufacturing a semiconductor light emitting device includes forming a lower cladding layer over a GaAs substrate; forming a quantum dot active layer over the lower cladding layer; forming a first semiconductor layer over the quantum dot active layer; forming a diffraction grating by etching the first semiconductor layer; forming a second semiconductor layer burying the diffraction grating; and forming an upper cladding layer having a conductive type different from that of the lower cladding layer over the second semiconductor layer, wherein the processes after forming the quantum dot active layer are performed at a temperature not thermally deteriorating or degrading quantum dots included in the quantum dot active layer.

Abstract: An optical device includes: an optical waveguide; and a plurality of diffraction grating layers, provided along the optical waveguide, each including a diffraction grating defined by a discontinuous first semiconductor layer and a second semiconductor layer having a refractive index different from a refractive index of the first semiconductor layer and burying the first semiconductor layer, one diffraction grating layer of the plurality of diffraction grating layers including a third semiconductor layer being continuous with the diffraction grating and made from a material different from materials of the first and the second semiconductor layers.

Abstract: An optical semiconductor device is disclosed including an active region including an active layer and a diffraction grating having a ?/4 phase shift; passive waveguide regions each including a passive waveguide and a diffraction grating, disposed on the side of an emission facet and on the side of a rear facet sandwiching the active region between the passive waveguide regions, respectively; and an anti-reflection coating applied on the emission facet, wherein the passive waveguide region on the side of the emission facet has a length shorter than a length of the passive waveguide region on the side of the rear facet side.

Abstract: A liquid ejection head includes an energy-generating element arranged on a semiconductor substrate, a barrier layer deposited on the semiconductor substrate for forming a liquid chamber in the periphery of the energy-generating element, and a nozzle sheet bonded on the barrier layer and having a nozzle formed at a position opposing the energy-generating element, in which the liquid ejection head ejects liquid contained in the liquid chamber from the nozzle as liquid droplets by the energy-generating element, and the barrier layer is provided with a plurality of depressions, each having an independent contour, arranged within a range, which is separated from the border of the barrier layer, on an adhesive region adhering to the nozzle sheet.

Abstract: A liquid ejection head includes an energy-generating element arranged on a semiconductor substrate, a barrier layer deposited on the semiconductor substrate for forming a liquid chamber in the periphery of the energy-generating element, and a nozzle sheet bonded on the barrier layer and having a nozzle formed at a position opposing the energy-generating element, in which the liquid ejection head ejects liquid contained in the liquid chamber from the nozzle as liquid droplets by the energy-generating element, and the barrier layer is provided with a plurality of depressions, each having an independent contour, arranged within a range, which is separated from the border of the barrier layer, on an adhesive region adhering to the nozzle sheet.