Abstract: A chip on submount includes: a submount including a first surface directed in a first direction; a covering layer mounted on the first surface, extending to intersect the first direction, and including a second surface directed in the first direction; a laser element mounted on the second surface and including: a third surface directed in the first direction; and a light emission unit positioned at an intermediate portion of the laser element along a second direction intersecting the first direction, extending in a third direction intersecting the first direction and second direction, and configured to output laser light in the third direction; and a bonding wire attached onto the third surface and configured to exert a pressing force on the laser element, the pressing force including a component force directed in a direction opposite to the first direction.

Abstract: A reflection filter device includes: a ring resonator filter including a ring-shaped waveguide and two arms, each of the two arms being optically coupled to the ring-shaped waveguide; and a dual-branch portion including a light input/output port and two branch ports, the light input/output port being configured to allow input and output of light, the two branch ports being configured to allow output of the light input from the light input/output port, the light being split into two, the two arms being connected to the two branch ports, respectively, at least one of the two arms being equipped with a phase adjuster.

Abstract: A semiconductor laser device includes: a layered structure in which a first conductivity type cladding layer, an active layer, a second conductivity type cladding layer, and a contact layer are layered in a first direction, the layered structure including a facet in a second direction intersecting the first direction, the facet outputting laser light, a non-window region, and a window region, the window region having a bandgap larger than a bandgap of the non-window region; a first electrode electrically connected to the first conductivity type cladding layer; a second electrode that is formed on the contact layer and constitutes a current path through the layered structure with the first electrode; a passivation layer formed on the facet and having a bandgap larger than the bandgap of the window region; and a dielectric reflecting coating configured to cover an opposite side of the passivation layer from the facet.

Abstract: An optical waveguide structure includes a lower cladding layer positioned on a substrate; an optical guide layer positioned on the lower cladding layer; an upper cladding layer positioned on the optical guide layer; and a heater positioned on the upper cladding layer. The lower cladding layer, the optical guide layer, and the upper cladding layer constitute a mesa structure. The optical guide layer has a lower thermal conductivity than the upper cladding layer. An equation “Wwg?Wmesa?3×Wwg” is satisfied, wherein Wmesa represents a mesa width of the mesa structure, and Wwg represents a width of the optical guide layer. The optical guide layer occupies one-third or more of the mesa width in a width direction of the mesa structure.

Abstract: An optical functional device includes: first and second optical couplers each including a multi-mode interferometer waveguide portion having a first end portion and a second end portion, two units of first input/output ports and two units of second input/output ports; and first and second arc-shaped waveguides each optically connecting one of the first and second input/output ports of the first and second optical coupler and one of the first and second input/output ports of the second optical coupler, respectively. Further, the first optical coupler, the second optical coupler, the first arc-shaped waveguide, and the second arc-shaped waveguide constitute a ring resonator, and each of the multi-mode waveguide portions of the first optical coupler and the second optical coupler have a narrow portion, an average width of the narrow portion in a longitudinal direction being narrower than widths at the first end portion and the second end portion.

Abstract: A laser device includes a wavelength-tunable laser including plural wavelength selectors in an optical resonator; a semiconductor optical amplifier that amplifies the laser light input thereto; a light intensity variation detector that detects variation in intensity of the laser light output from the wavelength-tunable laser before the laser light is input to the semiconductor optical amplifier; a wavelength dithering generation unit that generates a resonator mode wavelength dithering to modulate a resonator mode of the resonator; a wavelength dithering feedback controller that performs, on the resonator mode wavelength dithering, feedback control based on the variation in intensity detected by the light intensity variation detector; a light intensity detector that detects an intensity of the laser light output from the semiconductor optical amplifier; and a semiconductor optical amplifier feedback controller that performs feedback control on the semiconductor optical amplifier based on the intensity detecte

Abstract: A semiconductor laser device is a vernier-type wavelength-tunable semiconductor laser device including an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods. At least one of the first and second reflective elements has a sampled grating structure having a reflection comb spectrum in which reflection phases at the respective reflection peaks are aligned and the intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than the intensity of a reflection peak within the laser emission wavelength bandwidth.

Abstract: A reflection filter device includes: a ring resonator filter including a ring-shaped waveguide and two arms, each of the two arms being optically coupled to the ring-shaped waveguide; and a dual-branch portion including a light input/output port and two branch ports, the light input/output port being configured to allow input and output of light, the two branch ports being configured to allow output of the light input from the light input/output port, the light being split into two, the two arms being connected to the two branch ports, respectively, at least one of the two arms being equipped with a phase adjuster.

Abstract: A laser device includes a wavelength-tunable laser including plural wavelength selectors in an optical resonator; a semiconductor optical amplifier that amplifies the laser light input thereto; a light intensity variation detector that detects variation in intensity of the laser light output from the wavelength-tunable laser before the laser light is input to the semiconductor optical amplifier; a wavelength dithering generation unit that generates a resonator mode wavelength dithering to modulate a resonator mode of the resonator; a wavelength dithering feedback controller that performs, on the resonator mode wavelength dithering, feedback control based on the variation in intensity detected by the light intensity variation detector; a light intensity detector that detects an intensity of the laser light output from the semiconductor optical amplifier; and a semiconductor optical amplifier feedback controller that performs feedback control on the semiconductor optical amplifier based on the intensity detecte

Abstract: An optical waveguide structure includes a lower cladding layer positioned on a substrate; an optical guide layer positioned on the lower cladding layer; an upper cladding layer positioned on the optical guide layer; and a heater positioned on the upper cladding layer. The lower cladding layer, the optical guide layer, and the upper cladding layer constitute a mesa structure. The optical guide layer has a lower thermal conductivity than the upper cladding layer. An equation “Wwg?Wmesa?3×Wwg” is satisfied, wherein Wmesa represents a mesa width of the mesa structure, and Wwg represents a width of the optical guide layer. The optical guide layer occupies one-third or more of the mesa width in a width direction of the mesa structure.

Abstract: A wavelength tunable laser device includes: a laser cavity formed of a grating and a reflecting mirror including a ring resonator filter; a gain portion; and a phase adjusting portion. The grating creates a first comb-shaped reflection spectrum. The ring resonator filter includes a ring-shaped waveguide and two arms and creates a second comb-shaped reflection spectrum having peaks of a narrower full width than peaks in the first comb-shaped reflection spectrum at a wavelength interval different from that of the first comb-shaped reflection spectrum. One of the peaks in the first comb-shaped reflection spectrum and one of the peaks in the second comb-shaped reflection spectrum are overlapped on a wavelength axis, and a spacing between cavity modes is narrower than the full width at half maximum of the peaks in the first comb-shaped reflection spectrum.

Abstract: A semiconductor laser device is a vernier-type wavelength-tunable semiconductor laser device including an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods. At least one of the first and second reflective elements has a sampled grating structure having a reflection comb spectrum in which reflection phases at the respective reflection peaks are aligned and the intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than the intensity of a reflection peak within the laser emission wavelength bandwidth.

Abstract: A semiconductor device includes a semiconductor layer formed of a III-V group semiconductor crystal containing As as a primary component of a V group. A V group element other than As has been introduced at a concentration of 0.02 to 5% into a V group site of the III-V group semiconductor crystal in the semiconductor layer.

Abstract: A semiconductor optical device includes an active layer, the active layer including a plurality of quantum well layers having gain peak wavelengths different from one another in a layering direction thereof, and a plurality of barrier layers, wherein the quantum well layers and the barrier layers are alternately layered over each other, and an n-type dopant has been added in the plurality of quantum well layers having gain peak wavelengths different from one another and in the plurality of barrier layers.

Abstract: A wavelength tunable laser device includes: a laser cavity formed of a grating and a reflecting mirror including a ring resonator filter; a gain portion; and a phase adjusting portion. The grating creates a first comb-shaped reflection spectrum. The ring resonator filter includes a ring-shaped waveguide and two arms and creates a second comb-shaped reflection spectrum having peaks of a narrower full width than peaks in the first comb-shaped reflection spectrum at a wavelength interval different from that of the first comb-shaped reflection spectrum. One of the peaks in the first comb-shaped reflection spectrum and one of the peaks in the second comb-shaped reflection spectrum are overlapped on a wavelength axis, and a spacing between cavity modes is narrower than the full width at half maximum of the peaks in the first comb-shaped reflection spectrum.

Abstract: A semiconductor optical device includes an active layer, the active layer including a plurality of quantum well layers having gain peak wavelengths different from one another in a layering direction thereof, and a plurality of barrier layers, wherein the quantum well layers and the barrier layers are alternately layered over each other, and an n-type dopant has been added in the plurality of quantum well layers having gain peak wavelengths different from one another and in the plurality of barrier layers.

Abstract: A semiconductor laser device includes an active layer including a well layer and a barrier layer formed of a III-V group semiconductor crystal containing As as a primary component of a V group. A V group element other than As has been introduced at a concentration of 0.02 to 5% into a V group site of the III-V group semiconductor crystal in at least one of the well layer and the barrier layer, and a III group site of the III-V group semiconductor crystal in at least one of the well layer and the barrier layer contains Al.

Abstract: A semiconductor device includes a semiconductor layer formed of a III-V group semiconductor crystal containing As as a primary component of a V group. A V group element other than As has been introduced at a concentration of 0.02 to 5% into a V group site of the III-V group semiconductor crystal in the semiconductor layer.

Abstract: Provided is a laser device comprising a substrate, an active layer, and a current confinement layer. The current confinement layer includes an oxide layer that is formed extending from a edge of the current confinement layer in a parallel plane parallel to a surface of the substrate, toward a center of the current confinement layer along the parallel plane, and that does not have an inflection point between the edge and a tip portion formed closer to the center or has a plurality of inflection points formed between the edge and the tip portion.

Abstract: Provided is a vertical light emitting device comprising an upper multilayer reflective film and a lower multilayer reflective film that are formed facing each other and oscillate light; an intermediate layer that is formed below the upper multilayer reflective film and includes a layer having a different composition than the upper multilayer reflective film; and an electrode portion that is formed to sandwich the intermediate layer in a cross-sectional plane parallel to an oscillation direction of the light and to have a top end that is higher than a top surface of the intermediate layer. After the electrode portion is formed to sandwich the intermediate layer, the upper multilayer reflective film is layered on the intermediate layer.