Abstract: A waveguide based wavelength-tunable laser formed on a semiconductor substrate includes a first reflector from which laser light is output, a second reflector configuring a laser resonator together with the first reflector, a gain portion that is provided between the first reflector and the second reflector, at least two wavelength filters that can adjust wavelength characteristics and adjust a wavelength of the laser light, and a phase adjuster that adjusts an optical path length in the laser resonator, and a waveguide is formed to fold back an optical path by an angle of substantially 180 degrees between the first reflector and the second reflector.

Abstract: A laser device includes: a first reflecting unit; a second reflecting unit; a gain unit provided between the first reflecting unit and the second reflecting unit; a divider provided after the first reflecting unit and configured to divide laser light from the first reflecting unit into first light and second light; a first end portion positioned separately from the divider in a first direction, and positioned after the divider, the first end portion being configured to output, as output light, the first light or the first light that has been amplified; and a second end portion positioned separately from the divider in a second direction different from the first direction, the second end portion being configured to output the second light.

Abstract: A laser apparatus includes: a laser unit including: a laser element unit including a phase adjusting portion configured to adjust an optical length of a laser resonator and enable frequency of laser light to be tuned; and a monitor unit configured to obtain a monitored value corresponding to the frequency of the laser light; a temperature controller configured to control temperature of the laser unit; and a control unit configured to execute: controlling the phase adjusting portion such that the monitored value is adjusted to a target monitored value corresponding to a target frequency set as the frequency of the laser light, while maintaining temperature set for the temperature controller constant; and controlling the temperature controller such that the frequency of the laser light is adjusted to the target frequency in a case where continuous fine adjustment control of the frequency of the laser light has been instructed.

Abstract: A semiconductor optical amplifier array device includes: a substrate; and a plurality of semiconductor optical amplifiers formed on the substrate, each of the semiconductor optical amplifiers including an active region, and two input-output ports optically connected to the active region and disposed on same facet of the semiconductor optical amplifier array device. The plurality of semiconductor optical amplifiers include a first semiconductor optical amplifier in which length of the active region is equal to a first length, and a second semiconductor optical amplifier in which length of the active region is equal to a second length that is different from the first length.

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: An optical integrated element includes: a substrate; a first waveguide region in which a lower cladding layer, a first core layer, and an upper cladding layer are sequentially laminated in this order on the substrate; and an active region in which the lower cladding layer, a second core layer, a quantum well layer that amplifies light when a current is injected, and the upper cladding layer are sequentially laminated on the substrate. Further, the second core layer and the quantum well layer are close to each other within a range of a mode field of light guided in the second core layer, and the first core layer is butt-jointed to the second core layer and the quantum well layer.

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 waveguide based wavelength-tunable laser formed on a semiconductor substrate includes a first reflector from which laser light is output, a second reflector configuring a laser resonator together with the first reflector, a gain portion that is provided between the first reflector and the second reflector, at least two wavelength filters that can adjust wavelength characteristics and adjust a wavelength of the laser light, and a phase adjuster that adjusts an optical path length in the laser resonator, and a waveguide is formed to fold back an optical path by an angle of substantially 180 degrees between the first reflector and the second reflector.

Abstract: An optical integrated element includes: a substrate; a first waveguide region in which a lower cladding layer, a first core layer, and an upper cladding layer are sequentially laminated in this order on the substrate; and an active region in which the lower cladding layer, a second core layer, a quantum well layer that amplifies light when a current is injected, and the upper cladding layer are sequentially laminated on the substrate. Further, the second core layer and the quantum well layer are close to each other within a range of a mode field of light guided in the second core layer, and the first core layer is butt-jointed to the second core layer and the quantum well layer.

Abstract: A laser module that can suppress influence due to a reflected light between chips is provided. A laser module 100 according to one embodiment of the present invention includes: a laser element 110 provided on a first substrate and having a laser oscillation unit that generates a laser light and a first optical waveguide that guides the laser light; and an optical amplifier 120 provided on a second substrate and having a second waveguide that guides the laser light. The first optical waveguide is nonparallel relative to an end face of the first substrate and connected thereto, the second optical waveguide is nonparallel relative to an end face of the second substrate and connected thereto, and the first substrate and the second substrate are arranged such that the laser light output from the first optical waveguide is optically coupled to the second optical waveguide.

Abstract: A disclosed semiconductor laser device includes a distributed feedback portion serving as a light-emittable active region the distributed feedback portion having a diffraction grating; and a distributed reflective portion serving as a passive reflective mirror, the distributed reflective portion having a diffraction grating, wherein the distributed feedback portion includes a first region adjacent to the distributed reflective portion and having a diffraction grating having a predetermined standard period, a phase shift region adjacent to the first region, the phase shift region being longer by twice or more than the standard period, and a second region adjacent to an opposite side to the first region of the phase shift region and having a diffraction grating with the standard period, and the phase shift region optically changes a phase of laser beam between the first region and the second region.

Abstract: An optical module includes a first optical function device that has an emission end and emits a light from the emission end; a second optical function device that has an entry end and an emission end, amplifies the light entering the entry end, and emits the amplified light from the emission end, wherein the light is emitted from the emission end of the first optical function device and enters the entry end; a first optical non-reciprocal device that is arranged between the emission end of the first optical function device and the entry end of the second optical function device, transmits a light in a first direction from the emission end of the first optical function device toward the entry end of the second optical function device, and blocks or attenuates a light in a second direction opposite to the first direction; and a second optical non-reciprocal device that is arranged on the emission end side of the second optical function device, transmits a light in a third direction outward from the emission end

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: A semiconductor optical integrated device includes: a substrate; at least a lower cladding layer, a waveguide core layer, and an upper cladding layer sequentially layered on the substrate, a buried hetero structure waveguide portion having a waveguide structure in which a semiconductor cladding material is embedded near each of both sides of the waveguide core layer; and a ridge waveguide portion having a waveguide structure in which a semiconductor layer including at least the upper cladding layer protrudes in a mesa shape. Further, a thickness of the upper cladding layer in the buried hetero structure waveguide portion is greater than a thickness of the upper cladding layer in the ridge waveguide 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 optical integrated device includes: a substrate; at least a lower cladding layer, a waveguide core layer, and an upper cladding layer sequentially layered on the substrate, a buried hetero structure waveguide portion having a waveguide structure in which a semiconductor cladding material is embedded near each of both sides of the waveguide core layer; and a ridge waveguide portion having a waveguide structure in which a semiconductor layer including at least the upper cladding layer protrudes in a mesa shape. Further, a thickness of the upper cladding layer in the buried hetero structure waveguide portion is greater than a thickness of the upper cladding layer in the ridge waveguide portion.

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 disclosed semiconductor laser device includes a distributed feedback portion serving as a light-emittable active region the distributed feedback portion having a diffraction grating; and a distributed reflective portion serving as a passive reflective mirror, the distributed reflective portion having a diffraction grating, wherein the distributed feedback portion includes a first region adjacent to the distributed reflective portion and having a diffraction grating having a predetermined standard period, a phase shift region adjacent to the first region, the phase shift region being longer by twice or more than the standard period, and a second region adjacent to an opposite side to the first region of the phase shift region and having a diffraction grating with the standard period, and the phase shift region optically changes a phase of laser beam between the first region and the second region.