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: 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: 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: 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: A wavelength-variable 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; a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer; and 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.

Abstract: A wavelength-variable 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; a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer; and 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.

Abstract: A surface-emitting laser apparatus includes: a surface-emitting laser element; and a driving apparatus supplying a modulation-driving current to the surface-emitting laser element. The modulation-driving current is intensity-modulated to vary across a value of a bias current. The number of lateral modes of laser oscillation of the surface-emitting laser element changes from one to three at maximum in accordance with a value of the modulation-driving current. Among changing currents at which number of the lateral modes of the laser oscillation of the surface-emitting laser element changes, if a first changing current is defined at which the number of the lateral mode of the laser oscillation changes from one to two, the driving apparatus supplies the modulation-driving current to the surface-emitting laser element. The modulation-driving current is set so that a value of the first changing current is not between the bias current and a maximum value of the modulation-driving current.

Abstract: An optical amplifier device comprising an input/output section that inputs incident light and outputs emission light; a polarized light splitting section that causes a polarized light component of the incident light input from the input/output section to branch, and outputs first polarization mode light having a first polarization and second polarization mode light having a second polarization different from the first polarization; a polarization converting section that receives the first polarization mode light, converts the first polarization to the second polarization, and outputs first polarization converted light; and an optical amplifying section that amplifies the first polarization converted light input to one end of a waveguide, outputs the resulting amplified first polarization converted light from another end of the waveguide, amplifies the second polarization mode light input to the other end of the waveguide, and outputs the resulting amplified second polarization mode light from the one end of t

Abstract: A semiconductor laser module includes: a semiconductor laser outputting a laser light from an output-facet side of a waveguide which has a first narrow portion identical in width, a wide portion wider than the first narrow portion, a second narrow portion narrower than the wide portion, a first tapered portion between the first narrow portion and the wide portion and increasing in width toward the wide portion, and a second tapered portion between the wide portion and the second narrow portion and decreasing in width toward the second narrow portion; and an optical fiber to which the laser light is input has an optical-feedback unit reflecting a predetermined wavelength of light. The semiconductor laser is enclosed in a package with one end of the optical fiber. The optical-feedback unit has a first optical-feedback unit set at a predetermined reflection center wavelength determining an oscillation wavelength and a second optical-feedback unit.

Abstract: A surface-emitting laser apparatus includes: a surface-emitting laser element; and a driving apparatus supplying a modulation-driving current to the surface-emitting laser element. The modulation-driving current is intensity-modulated to vary across a value of a bias current. The number of lateral modes of laser oscillation of the surface-emitting laser element changes from one to three at maximum in accordance with a value of the modulation-driving current. Among changing currents at which number of the lateral modes of the laser oscillation of the surface-emitting laser element changes, if a first changing current is defined at which the number of the lateral mode of the laser oscillation changes from one to two, the driving apparatus supplies the modulation-driving current to the surface-emitting laser element. The modulation-driving current is set so that a value of the first changing current is not between the bias current and a maximum value of the modulation-driving current.

Abstract: A semiconductor laser outputs a laser light from an output facet of a waveguide having an index waveguide structure, via a lens system. The waveguide includes, in order from a rear facet opposite to the output facet, a first narrow portion, a wide portion that is wider than the first narrow portion, a second narrow portion narrower than the wide portion, a first tapered portion formed between the first narrow portion and the wide portion, which expands toward the wide portion, and a second tapered portion formed between the wide portion and the second narrow portion, which narrows toward the second narrow portion. Each of the first narrow portion, the wide portion, and the second narrow portion has a uniform width.

Abstract: The invention of the present application provides an SOA-PLC hybrid integrated polarization diversity circuit including a PLC-PBS chip and an SOA-COS whose respective waveguides are coupled to each other. The PLC-PBS chip includes: first and second optical waveguides; a Mach-Zehnder interferometer circuit; and a half-wave plate placed in the first optical waveguide which TM mode light is split into. The SOA-COS includes: a third optical waveguide connected to the first optical waveguide; a fourth optical waveguide connected to the second optical waveguide; and an SOA formed in at least one of the third and fourth optical waveguides. One end of the third optical waveguide and one end of the fourth optical waveguide are connected to a U-turn optical waveguide, the one ends being not connected to the first optical waveguide and the second optical waveguide, respectively.

Abstract: A semiconductor laser outputs a laser light from an output facet of a waveguide having an index waveguide structure, via a lens system. The waveguide includes, in order from a rear facet opposite to the output facet, a first narrow portion, a wide portion that is wider than the first narrow portion, a second narrow portion narrower than the wide portion, a first tapered portion formed between the first narrow portion and the wide portion, which expands toward the wide portion, and a second tapered portion formed between the wide portion and the second narrow portion, which narrows toward the second narrow portion. Each of the first narrow portion, the wide portion, and the second narrow potion has a uniform width.

Abstract: An optical amplifier device comprising an input/output section that inputs incident light and outputs emission light; a polarized light splitting section that causes a polarized light component of the incident light input from the input/output section to branch, and outputs first polarization mode light having a first polarization and second polarization mode light having a second polarization different from the first polarization; a polarization converting section that receives the first polarization mode light, converts the first polarization to the second polarization, and outputs first polarization converted light; and an optical amplifying section that amplifies the first polarization converted light input to one end of a waveguide, outputs the resulting amplified first polarization converted light from another end of the waveguide, amplifies the second polarization mode light input to the other end of the waveguide, and outputs the resulting amplified second polarization mode light from the one end of t

Abstract: It is desirable to provide a semiconductor optical amplifier from which it becomes able to obtain a higher output power. A semiconductor optical amplifier in comprises an active wave guiding layer which comprises a passive core region that is formed of a semiconductor, and active cladding regions that are located at both sides of the passive core region and each of that is comprised of an active layer which is formed of a semiconductor and which has an index of refraction to be lower than that of the passive core region, wherein a light is wave guided with being amplified in the active wave guiding layer. Moreover, it is desirable for the active wave guiding layer to be formed of a compound semiconductor, and to be formed by integrating the passive core region and the active cladding regions to be monolithic on to a substrate that is formed of a compound semiconductor by making use of a process of a butt joint growth.

Abstract: There is provided an optical interconnection system including a plurality of semiconductor integrated devices each including a surface emitting laser array device including a plurality of surface emitting laser devices each emitting an output laser signal light of a different wavelength modulated based on an input modulated signal, a silicon optical waveguide that guides output laser signal lights emitted from the surface emitting laser devices of each of the semiconductor integrated devices to another semiconductor integrated device, a plurality of optical couplers respectively corresponding to the semiconductor integrated devices and guiding the output laser signal lights to the silicon optical waveguide, and a plurality of optical splitters respectively corresponding to the semiconductor integrated devices, receiving the output laser signal lights guided by the silicon optical waveguide, and inputting an input laser signal light to a corresponding one of the semiconductor integrated devices.

Abstract: Included are a semiconductor device unit in which a semiconductor optical amplifier and a first semiconductor photo detector being configured to monitor a part of an input light input to the semiconductor optical amplifier or a part of an output light output from the semiconductor optical amplifier are integrated on a mutually same substrate, and a passive waveguide unit connected to the semiconductor device unit and in which a first passive waveguide being configured to cause the input light to be input to the semiconductor optical amplifier or to cause the output light to be output from the semiconductor optical amplifier and a second passive waveguide branching from the first passive waveguide and being configured to cause a part of the input light or a part of the output light to be input to the first semiconductor photo detector are provided on a mutually same substrate.

Abstract: A semiconductor laser element 10 according to the present invention comprises a waveguide 12 of a high mesa type. And then such the waveguide 12 comprises an oblique end face 17 as an emitting facet that is different from a cleaved end face 16. And hence it becomes possible to reduce a reflection factor at the end face by making of such the oblique end face 17, and it becomes possible to design a direction of an emitting beam 21, that is to be emitting from the oblique end face 17, to be independent of that for the cleaved end face 16 as well. Moreover, the emitting beam 21 is designed to be emitting as vertical to the cleaved end face 16. And then therefore in a case where an emitting beam from a semiconductor optical device is designed to be coupled with such as an optical fiber or another waveguide or the like, it is not necessary to device such as that the semiconductor laser element 10 is required to be arranged at a sub mount by being inclined to be oblique or the like.

Abstract: Included are a semiconductor device unit in which a semiconductor optical amplifier and a first semiconductor photo detector being configured to monitor a part of an input light input to the semiconductor optical amplifier or a part of an output light output from the semiconductor optical amplifier are integrated on a mutually same substrate, and a passive waveguide unit connected to the semiconductor device unit and in which a first passive waveguide being configured to cause the input light to be input to the semiconductor optical amplifier or to cause the output light to be output from the semiconductor optical amplifier and a second passive waveguide branching from the first passive waveguide and being configured to cause a part of the input light or a part of the output light to be input to the first semiconductor photo detector are provided on a mutually same substrate.

Abstract: A semiconductor laser outputs a laser light from an output facet of a waveguide having an index waveguide structure, via a lens system. The waveguide includes, in order from a rear facet opposite to the output facet, a first narrow portion, a wide portion that is wider than the first narrow portion, a second narrow portion narrower than the wide portion, a first tapered portion formed between the first narrow portion and the wide portion, which expands toward the wide portion, and a second tapered portion formed between the wide portion and the second narrow portion, which narrows toward the second narrow portion. Each of the first narrow portion, the wide portion, and the second narrow potion has a uniform width.