Abstract: An optical device includes: a multi-mode interference waveguide that includes a first end portion in a first direction and a second end portion in opposite direction to the first direction; a first port that is arranged in the first end portion; a second port that is arranged in the first end portion; a third port that is arranged in the second end portion and that is positioned at a center of the second end portion in the second direction; and two fourth ports that are arranged in the second end portion and that are positioned on both sides of the third port in the second direction.

Abstract: A semiconductor optical device includes: a base configured to intersect with a first direction; a first protrusion configured to protrude from the base in the first direction, the first protrusion including a planar lightwave circuit including: a core layer; and a cladding layer surrounding the core layer; a second protrusion configured to protrude from the base in the first direction and arranged along the first protrusion in a second direction intersecting with the first direction, a height of the second protrusion from the base in the first direction being lower than a height of the first protrusion; an optical semiconductor element placed on a facet of the second protrusion in the first direction and optically connected to the core layer; and a marker provided on the second protrusion in a manner exposed on the facet, the marker being made of a same material as the core layer.

Abstract: An optical integrated device includes a substrate a passive waveguide region and an active region. The active region and the passive waveguide region include a first mesa structure having an upper cladding portion formed of a same material as the upper cladding layer. The passive waveguide region includes a second spot size converter having the first mesa structure, a second mesa structure having a first core portion, a lower cladding portion, and a second core portion that are formed of same materials as the first core layer, the lower cladding layer, and the second core layer, respectively. The second mesa structure has a width wider than a width of the first mesa structure, and the width of the first mesa structure continuously changes along a longitudinal direction in which light is guided through the second core portion, the width being along a direction perpendicular to the longitudinal direction.

Abstract: A semiconductor laser apparatus includes a semiconductor optical integrated device including a semiconductor laser array including a plurality of semiconductor laser elements, a semiconductor arrayed waveguide grating, made of a semiconductor, including an inputting slab waveguide connected to the plurality of the semiconductor laser elements, an array waveguide connected to the inputting slab waveguide and including a plurality of waveguides having different lengths from each other and arranged in a parallel manner, and an outputting slab waveguide connected to the array waveguide; a substrate on which the semiconductor laser array and the semiconductor arrayed waveguide grating are monolithically integrated; and an output facet outputting a laser light emitted from the semiconductor laser elements and including an output end of the outputting slab waveguide.

Abstract: An optical integrated device includes a substrate a passive waveguide region and an active region. The active region and the passive waveguide region include a first mesa structure having an upper cladding portion formed of a same material as the upper cladding layer. The passive waveguide region includes a second spot size converter having the first mesa structure, a second mesa structure having a first core portion, a lower cladding portion, and a second core portion that are formed of same materials as the first core layer, the lower cladding layer, and the second core layer, respectively. The second mesa structure has a width wider than a width of the first mesa structure, and the width of the first mesa structure continuously changes along a longitudinal direction in which light is guided through the second core portion, the width being along a direction perpendicular to the longitudinal direction.

Abstract: An optical semiconductor apparatus includes: semiconductor laser devices having different emission wavelengths and grouped into at least a first group and a second group; and an arrayed waveguide grating connected to the semiconductor laser devices of the first and second groups and configured to combine laser light beams radiating from the semiconductor laser devices into a same point. The arrayed waveguide grating is configured to combine laser light beams from the semiconductor laser devices belonging to the first group into the same point by diffraction in a first diffraction order in the arrayed waveguide grating, and combine laser light beams from the semiconductor laser devices belonging to the second group into the same point by diffraction in a second diffraction order different from the first diffraction order, in the arrayed waveguide grating.

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 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 apparatus includes a semiconductor optical integrated device including a semiconductor laser array including a plurality of semiconductor laser elements, a semiconductor arrayed waveguide grating, made of a semiconductor, including an inputting slab waveguide connected to the plurality of the semiconductor laser elements, an array waveguide connected to the inputting slab waveguide and including a plurality of waveguides having different lengths from each other and arranged in a parallel manner, and an outputting slab waveguide connected to the array waveguide; a substrate on which the semiconductor laser array and the semiconductor arrayed waveguide grating are monolithically integrated; and an output facet outputting a laser light emitted from the semiconductor laserelements and including an output end of the outputting slab waveguide.

Abstract: An optical semiconductor apparatus includes: semiconductor laser devices having different emission wavelengths and grouped into at least a first group and a second group; and an arrayed waveguide grating connected to the semiconductor laser devices of the first and second groups and configured to combine laser light beams radiating from the semiconductor laser devices into a same point. The arrayed waveguide grating is configured to combine laser light beams from the semiconductor laser devices belonging to the first group into the same point by diffraction in a first diffraction order in the arrayed waveguide grating, and combine laser light beams from the semiconductor laser devices belonging to the second group into the same point by diffraction in a second diffraction order different from the first diffraction order, in the arrayed waveguide grating.

Abstract: A semiconductor laser includes a semiconductor substrate, an active region provided over the semiconductor substrate and having an active layer and a first diffraction grating, and a guiding region provided over the semiconductor substrate and having a guiding layer continuously extending from the active layer in an optical axis direction and a second diffraction grating continuously extending from the first diffraction grating in the optical axis direction. A grating period of the second diffraction grating is uniform, the first diffraction grating has a first part in which a grating period becomes uneven, and a grating formation density of the first diffraction grating is smaller than the grating formation density of the second diffraction grating.

Abstract: A semiconductor laser includes a semiconductor substrate, an active region provided over the semiconductor substrate and having an active layer and a first diffraction grating, and a guiding region provided over the semiconductor substrate and having a guiding layer continuously extending from the active layer in an optical axis direction and a second diffraction grating continuously extending from the first diffraction grating in the optical axis direction. A grating period of the second diffraction grating is uniform, the first diffraction grating has a first part in which a grating period becomes uneven, and a grating formation density of the first diffraction grating is smaller than the grating formation density of the second diffraction grating.

Abstract: A semiconductor laser module includes: a semiconductor laser element having at least one semiconductor laser; a first support member on which the semiconductor laser element is mounted; a first temperature-adjusting element adjusting a temperature of the first support member; a semiconductor optical element having a semiconductor optical amplifier amplifying a laser light outputted from the semiconductor laser element; and a second support member on which the semiconductor optical element is mounted.

Abstract: A semiconductor laser module includes: a semiconductor laser element having at least one semiconductor laser; a first support member on which the semiconductor laser element is mounted; a first temperature-adjusting element adjusting a temperature of the first support member; a semiconductor optical element having a semiconductor optical amplifier amplifying a laser light outputted from the semiconductor laser element; and a second support member on which the semiconductor optical element is mounted.

Abstract: An optical-waveguide device mounted on a fixing member having a pair of opposing upright walls and a sub-mount unit including a metallic sub-mount of a rectangular solid shape inserted between the opposing upright walls and a nonmetallic sub-mount of a rectangular solid shape mounted on the metallic sub-mount, and fixed onto a base table. The fixing member and the sub-mount unit as well as the fixing member and the base table are spot-welded together using YAG welding.

Abstract: An optical-waveguide device mounted on a fixing member having a pair of opposing upright walls and a sub-mount unit including a metallic sub-mount of a rectangular solid shape inserted between the opposing upright walls and a nonmetallic sub-mount of a rectangular solid shape mounted on the metallic sub-mount, and fixed onto a base table. The fixing member and the sub-mount unit as well as the fixing member and the base table are spot-welded together using YAG welding.