Abstract: A wavelength dispersion compensating apparatus, including: a signal light generating unit which generates, from predetermined signal light, signal light having a phase correlation centered on a degenerate frequency of a phase sensitive amplifier; a dispersion compensation transmission path which compensates for a wavelength dispersion of the predetermined signal light included in the signal light; a filter which compensates for a residual wavelength dispersion after compensation by the dispersion compensation transmission path of the predetermined signal light included in the signal light; a phase sensitive amplifier which amplifies the signal light input via the dispersion compensation transmission path and the filter; a residual wavelength dispersion calculating unit which calculates a residual wavelength dispersion amount based on a measurement result of output light amplified by the phase sensitive amplifier; and a filter control unit which controls the filter so as to add a wavelength dispersion that can

Abstract: An optical circuit is provided in which electric circuit parts and optical circuit parts are integrated in a stack on a printed substrate. The optical circuit is provided with a lid having a temperature regulation function that uses a temperature control element and an optical fiber block capable of optical input and output. Temperature control of optical circuit elements can be efficiently performed by mounting electric circuit parts and optical circuit parts on a printed substrate in advance by a reflow step using OBO technology and subsequently attaching a lid that includes a temperature control element.

Abstract: A highly-efficient ridge waveguide includes a base substrate of a single-crystal and a core substrate made of a nonlinear optical medium, the base substrate and the core substrate being directly bonded, and includes a thin film layer formed on a surface of the core substrate on the upper side of a periodically polarization-reversed structure, and becomes a wavelength conversion element. A direct bonding method through thermal diffusion is applied to bonding. The core substrate has a ridge structure formed in a light propagating direction and a reversed structure formed by processing this. A surface of the core substrate is ground and a thin film layer is formed on the ground surface. A core formed by digging a core layer of the core substrate in an unbonded state is provided on an upper surface of an undercladding layer of the base substrate in a bonded state. Two side surfaces of the core are in contact with an air layer.

Abstract: A balanced homodyne detection optical circuit according to the present disclosure is a planar optical waveguide circuit in which a circuit made of an optical waveguide including a dielectric or a semiconductor is formed on a substrate, the balanced homodyne detection optical circuit including an input port of local oscillator light and an input port of measurement light (squeezed light (including excitation light)), wherein a wavelength demultiplexing circuit which demultiplexes only the measurement light is arranged immediately after the input port of measurement light, a 50% multiplexing/demultiplexing circuit is arranged which causes squeezed light having been demultiplexed by the wavelength demultiplexing circuit and the local oscillator light to respectively branch at a branching ratio of 50% and to interfere with each other, and two output ports are arranged to which two outputs from the 50% multiplexing/demultiplexing circuit are guided.

Abstract: An optical module includes: a substrate; one or more light sources that produce light that is an optical signal; one or more light reflection units that change the direction of travel of the light to a direction substantially perpendicular to the substrate; one or more optical waveguides that optically connect the one or more light sources and the one or more light reflection units to each other; and a lid that is attached to the substrate to cover the one or more light sources, the one or more light reflection units and the one or more optical waveguides. The lid has one or more lenses that collimate light directed by the one or more light reflection units and transmit the light to the outside of the lid.

Abstract: There is provided an optical element mounted on a substrate and an optical coupling element mounted on the substrate. The optical coupling element includes a guide unit extending in a direction parallel to a plane of the substrate so as to fix an optical fiber. There is provided a mold resin layer formed on the substrate so as to cover the optical element and expose a side surface of the optical coupling element at one end of the guide unit. The optical element includes a light incidence/emission unit on a side surface perpendicular to the plane of the substrate, and the other end of the guide unit and the light incidence/emission unit are disposed to face each other.

Abstract: With a wavelength conversion device based on a nonlinear optical effect, when arrayed waveguides including an intended nonlinear waveguide are fabricated, unwanted slab waveguides are inevitably formed. The slab waveguides can cause an erroneous measurement in the selection of a waveguide having desired characteristics from the arrayed waveguides. The erroneous measurement can lead to redoing steps for fabricating the wavelength conversion device and a decrease in the yield and inhibit the evaluation of the characteristics in selection of the waveguide and the subsequent fabrication of the wavelength conversion device from being efficiently performed. A wavelength conversion device according to the present invention includes a plurality of waveguides formed on a substrate, and a plurality of slab waveguides that are arranged substantially in parallel with and spaced apart from the plurality of waveguides, and a guided light attenuator is formed in each of the slab waveguides.

Abstract: To provide an optical module, an optical wiring board, and a method for manufacturing an optical module that provide the two-dimensional freedom degree of the joint portion between the optical module and the optical fiber even through the OBO method is applied to an optical module mounted via WLP.

Abstract: A wavelength conversion device that restrains output power of light that has a wavelength converted from reducing due to a pyroelectric effect when a temperature of a wavelength conversion element including a ferroelectric substrate is changed is a wavelength conversion device that includes, in a casing, the wavelength conversion element, a temperature control element that controls a temperature of the wavelength conversion element, a static elimination mechanism and a surface potential measurement mechanism, and eliminates static electricity by driving the static elimination mechanism when the surface potential measurement mechanism detects a change in surface potential of the wavelength conversion element.

Abstract: A wavelength conversion optical element using a nonlinear optical effect of a device structure in which wavelength conversion efficiency rises as targeted when the length of a waveguide is increased is provided. The element adopts a waveguide structure using lithium niobate of a second-order nonlinear optical material. Wavelength conversion regions are formed to correspond to two linear waveguides extending in parallel to each other on a plane of the planar structure and correspond to the lengths of the two linear waveguides. One end side of the linear waveguide is an incident side of excitation light and one end side of the linear waveguide is an emission side of wavelength converted light. The linear waveguides excluding the incident side and the emission side are joined by a bent waveguide.

Abstract: An optical signal processing device includes: a light source which generates a fundamental wave light; an optical modulator which modulates the fundamental wave light, and generates a fundamental wave light having a plurality of carriers synchronized in phase; an optical filter which passes through required components among the plurality of carriers; a first second-order nonlinear optical element on which a light which passes through the optical filter is incident, and which generates a second harmonic of the fundamental wave light; and a second second-order nonlinear optical element on which a signal light and the second harmonic are incident, the second second-order nonlinear optical element performing nondegenerate parametric amplification, wherein the second second-order nonlinear optical element has an output unit for picking up a wavelength converted light corresponding to difference in frequency between the signal light and the second harmonic or an amplified light of the signal light.

Abstract: Provided is a wavelength conversion element capable of achieving highly efficient wavelength conversion, without relying on a method of applying electric fields. A wavelength conversion element is formed of a second-order nonlinear optical crystal and has a z-axis, running along a direction of spontaneous polarization, within a substrate plane. The wavelength conversion element includes a waveguide in which, when a plurality of circles having their centers on a straight line parallel to the z-axis and having the same radius are depicted so that circumferences of the plurality of circles contact each other, semicircular waveguides corresponding to one semicircles of the circumferences with the straight line as a boundary, are alternately connected.

Abstract: A wavelength conversion apparatus using a nonlinear optical medium having a periodically poled structure is operated at an optimal temperature in a stable manner. The wavelength conversion apparatus includes a wavelength converter using a nonlinear optical medium and a controller for controlling temperature of the wavelength converter. The wavelength conversion apparatus further includes a first optical branch coupler for branching part of output light from the wavelength converter, and first and second wavelength separation filters for separating and outputting, from part of the output light, each of two light components generated by parametric fluorescence in the wavelength converter. The controller controls the temperature of the wavelength converter on the basis of difference in light intensity of the two light components.

Abstract: The present invention provides a configuration of a novel optical transmitter which outputs stable PDM signals. The novel optical transmitter generates phase conjugate light using a single second-order non-linear optical element included in a phase conjugate light generator with a looped configuration. A relative phase of main signal light with respect to excitation light and phase conjugate light of the main signal light stabilizes between two polarized components, and a PDM signal including a pair of a polarization-multiplexed signal and phase conjugate light in a stable phase state can be generated and transmitted. The present invention can provide an optical transmitter that generates a PDM signal in which a variation in a phase between quadrature polarized waves is suppressed. By stabilizing quality of a PDM transmission signal on a side of the optical transmitter, a phase sensitive amplifier in a polarization diversity configuration can be operated in a stable manner.

Abstract: A configuration of an excitation light generation device for providing an excitation light having a good SN ratio to a PSA is disclosed. Further, a configuration of a relay amplifier of the PSA including the excitation light generation device is also shown. The following disclosure includes the excitation light generation device, an optical amplification device including the excitation light generation device, and an optical transmission system. More specifically, the excitation light generation device for maintaining the SN ratio of the excitation light in a high state by utilizing an optical sensitive amplification function with respect to the excitation light generated by an optical phase lock loop is disclosed. The excitation light generation device of the present disclosure generates a local oscillation excitation light using the OPLL and having a sufficiently high SN ratio, which makes an inherent low noise operation of the PSA possible even to a signal light having a high SN ratio.

Abstract: With a wavelength conversion device based on a nonlinear optical effect, when arrayed waveguides including an intended nonlinear waveguide are fabricated, unwanted slab waveguides are inevitably formed. The slab waveguides can cause an erroneous measurement in the selection of a waveguide having desired characteristics from the arrayed waveguides. The erroneous measurement can lead to redoing steps for fabricating the wavelength conversion device and a decrease in the yield and inhibit the evaluation of the characteristics in selection of the waveguide and the subsequent fabrication of the wavelength conversion device from being efficiently performed. A wavelength conversion device according to the present invention includes a plurality of waveguides formed on a substrate, and a plurality of slab waveguides that are arranged substantially in parallel with and spaced apart from the plurality of waveguides, and each of the slab waveguides has a grating structure that reflects light of a particular wavelength.

Abstract: A wavelength conversion element manufacturing method capable of realizing, in a wavelength conversion element having a structure in which a thin film substrate having a periodic polarization inversion structure and a support substrate are laminated, highly efficient wavelength conversion by confining light in a cross-sectional area smaller than in the known art.

Abstract: Reduction of output power of light with a wavelength converted is suppressed, which is caused by a pyroelectric effect that occurs when a temperature of a wavelength conversion element including a ferroelectric substrate is changed. Provided is a wavelength conversion device that generates light different from a wavelength of a signal light when the signal light is inputted, and includes a wavelength conversion element that converts a wavelength of the signal light, and a temperature control element for controlling a temperature of the wavelength conversion element, wherein the wavelength conversion element and the temperature control element are sealed in an inside of a metal casing, the wavelength conversion element includes an optical waveguide core and a substrate having a lower refractive index to the signal light than the optical waveguide core, and the substrate is a ferroelectric substance in which directions of spontaneous polarization are random.

Abstract: A wavelength conversion apparatus using a nonlinear optical medium having a periodically poled structure is operated at an optimal temperature in a stable manner. The wavelength conversion apparatus includes a wavelength converter using a nonlinear optical medium and a controller for controlling temperature of the wavelength converter. The wavelength conversion apparatus further includes a first optical branch coupler for branching part of output light from the wavelength converter, and first and second wavelength separation filters for separating and outputting, from part of the output light, each of two light components generated by parametric fluorescence in the wavelength converter. The controller controls the temperature of the wavelength converter on the basis of difference in light intensity of the two light components.

Abstract: To provide an optical module, an optical wiring board, and a method for manufacturing an optical module that provide the two-dimensional freedom degree of the joint portion between the optical module and the optical fiber even through the OBO method is applied to an optical module mounted via WLP.