Abstract: Provided is an optical waveguide device capable of reducing stress that occurs inside an optical waveguide substrate due to a difference in a coefficient of thermal expansion. The optical waveguide device (10) includes an optical waveguide substrate (11) having a thickness of 30 ?m or less, and a liquid crystal polymer substrate (12) which holds the optical waveguide substrate (11) and has permittivity lower than that of the optical waveguide substrate (11). The optical waveguide substrate (11) and the liquid crystal polymer substrate (12) are bonded to each other by an adhesive layer (14).

Abstract: It is possible to suppress carrier light with a simple configuration when modulating the carrier light to generate optical sideband components. An optical carrier-suppressed signal generator includes first splitting means used to split input carrier light into two light beams, an optical modulator which modulates one split carrier light beam and outputs light including optical sideband components, a phase modulator which phase-modulates another split carrier light beam, and second or third splitting means used to split the output light of the optical modulator into two light beams. The output light split by the second or third splitting means and the output light of the phase modulator are multiplexed to obtain the amplitude of the signal waveform of optical power, and the optical modulator is controlled such that the obtained value is minimized.

Abstract: An optical control element which has a thin plate having an electro-optical effect and a thickness of 10 ?m or less, optical waveguides formed in the thin plate, and a plurality of optical control portions for controlling light propagating through the optical waveguide, wherein, a portion between a plurality of optical control portions is connected by a control signal wiring line that includes any one of a coplanar waveguide type disposed only on a surface of the thin plate, a coplanar waveguide type disposed on the surface of the thin plate and a ground electrode disposed on a back surface thereof, or a micro strip line, for arrival times of light and electric signal set to be substantially the same.

Abstract: A method for evaluating a characteristic of, especially, each of Mach-Zehnder interferometers (MZIs) of an optical modulator. The method includes a step of measuring the intensity of the output of the optical modulator containing MZIs and a step of evaluating a characteristic of each MZI by using the sideband. The output intensity measuring step is the one of measuring the intensity Sn,k of the sideband signal contained in the output light from the optical modulator. The characteristic evaluating step is the one of evaluating a characteristic of the MZIk by using the Sn,k.

Abstract: An optical modulator includes: a substrate made of a material having an electro-optical effect; an optical waveguide formed on the substrate; and a modulation electrode for modulating an optical wave propagating through the optical waveguide, wherein emitted light emitted from the optical waveguide is guided by optical fiber, and polarization of the substrate is reversed in a predetermined pattern along the optical waveguide so as to provide waveform distortion having a characteristic opposite to a wavelength dispersion characteristic of the optical fiber.

Abstract: An optical control element having a substrate 1 having an electro-optic effect, an optical waveguide 2 formed on the substrate, and a control electrode 3 that is provided on the substrate and controls the phase of light that propagates through the optical waveguide, in which the control electrode 3 has a plurality of resonant-type electrodes 31 and 32 that are disposed along the optical waveguide 2 and have different resonance frequencies (f1 and f2), an feeder electrode 30 through which control signals are input and branched signal electrodes that are branched from the feeder electrode are connected to the respective resonant-type electrodes, and the branched signal electrode is configured to match a timing at which the electric control signal is applied to each of the resonant-type electrodes and a timing at which the light that propagates through the optical waveguide passes at the section of each of the resonant-type electrodes.

Abstract: An optical modulator that includes a substrate 1 composed of a material having an electro-optical effect, an optical waveguide 2 formed in the substrate, and a modulation electrode 3 for modulating light waves propagating through the optical waveguide, in which output light L2 that is output from the optical waveguide is guided with an optical fiber, wavelength dispersion characteristics of the optical fiber transition line are compensated for by performing polarization reversal 10 of the substrate along the optical waveguide with a predetermined pattern so that the substrate along the optical waveguide has waveform distortion with characteristics that are inverse to the wavelength dispersion characteristics of the optical fiber transition line, and the compensation for the wavelength dispersion characteristics is adjusted to a predetermined level by disposing an adjustment member made of a dielectric material or a metal material in the vicinity of the modulation electrode.

Abstract: A method for forming a ferroelectric spontaneous polarization reversal in a desired region of a ferroelectric substrate includes the steps of forming, for the desired region of the surface of the ferroelectric substrate, an electrode pattern or a mask pattern composed of aggregates of micropatterns, and then applying a given voltage into the desired region. The configuration of the micropatterns can be a stripe-shaped pattern, an ellipse-shaped pattern, a hexagon-shaped pattern, a network pattern, or a double cross shaped pattern. The method can further include the steps of generating many nucleuses by using the electrode pattern or the mask pattern composed of the aggregates of micropatterns, forming another electrode pattern or another mask pattern corresponding to the desired region, and then applying a given voltage into the desired region to generate a ferroelectric spontaneous polarization reversal around the nucleuses.

Abstract: Provided is an optical waveguide device capable of reducing stress that occurs inside an optical waveguide substrate due to a difference in a coefficient of thermal expansion. The optical waveguide device (10) includes an optical waveguide substrate (11) having a thickness of 30 ?m or less, and a liquid crystal polymer substrate (12) which holds the optical waveguide substrate (11) and has permittivity lower than that of the optical waveguide substrate (11). The optical waveguide substrate (11) and the liquid crystal polymer substrate (12) are bonded to each other by an adhesive layer (14).

Abstract: It is an object to provide an optical control device capable of realizing speed matching between a microwave and a light wave or impedance matching of microwaves and of reducing a driving voltage. An optical control device including a thin plate 1 (11) which has an electro-optical effect and has a thickness of 10 ?m or less, an optical waveguide 2 formed in the thin plate, and control electrodes for controlling light passing through the optical waveguide is characterized in that the control electrodes are configured to include a first electrode and a second electrode disposed to interpose the thin plate therebetween, the first electrode has a coplanar type electrode including at least a signal electrode 4 and a ground electrode 5, and the second electrode has at least a ground electrode 54 (55, 56) and is configured to apply an electric field to the optical waveguide in cooperation with the signal electrode of the first electrode.

Abstract: In a light control element comprising a thin plate having a thickness of 10 [mu]m or less and exhibiting electro optic effect, an optical waveguide formed on the thin plate, and a control electrode for controlling light passing through the optical waveguide, the control electrode includes a first electrode and a second electrode so arranged as to sandwich the thin plate, and the first electrode has a coplanar electrode consisting of a first signal electrode and a ground electrode, while the second electrode has a second signal electrode. Modulation signals having mutually inverted amplitudes are inputted to the first signal electrode of the first electrode and the second signal electrode of the second electrode such that the modulation signals cooperate to apply an electric field to the optical waveguide.

Abstract: A light control device with a reduced electric loss is provided which can suppress a phenomenon of electrically reflecting a high-frequency signal even when it employs a dielectric anisotropic substrate. A light control device includes a signal electrode formed on a dielectric anisotropic substrate and ground electrodes disposed with the signal electrode interposed therebetween. Here, the signal electrode includes at least two signal electrode portions disposed in directions in which the dielectric constant of the substrate is different from each other and a curved connecting portion connecting the at least two signal electrode portions. The connecting portion is configured so that the characteristic impedance in parts connected to the at least two signal electrode portions is equal to that of the corresponding signal electrode portion, and the characteristic impedance in the connecting portion between the at least two signal electrode portions continuously varies.

Abstract: A method for forming a ferroelectric spontaneous polarization reversal, including the steps of forming a concave portion on a top face of a ferroelectric substrate or a bottom face of a ferroelectric substrate, and applying an electric field into the substrate, wherein a ferroelectric spontaneous polarization reversal is formed at least in one portion of a region of the substrate with the concave portion, and wherein the shape of the concave portion is configured such that the width of the concave portion gets narrower gradually toward the inside of the substrate. The method may further include the steps of, after the reversal, making into almost a flat-plane the top or bottom face having the concave portion, and then, forming a new concave portion in another region and applying an electric field to form another reversal in one portion of the region of the substrate having the new concave portion.

Abstract: Provided is a light control element wherein stable operation at low driving voltage is possible.

Abstract: An optical waveguide device having multiple functions or high performance, to improve the productivity of products, and to provide an optical waveguide device capable of suppressing deterioration of an operating characteristic of the optical waveguide device, including a thin plate 1 having a thickness of 20 ?m or less and at least an optical waveguide 2 formed in the thin plate. The thin plate is bonded and fixed to a supporting substrate 5 with an adhesive 4 interposed therebetween, and a film having a higher refractive index than the thin plate and the adhesive is provided on a surface of the thin plate bonded and fixed to the supporting substrate so as to be in contact with at least a part of the optical waveguide. Preferably, the thin plate is formed of a material having a nonlinear optical effect or an electro-optical effect.

Abstract: An optical waveguide device having multiple functions or high performance, to improve the productivity of products, and to provide an optical waveguide device capable of suppressing deterioration of an operating characteristic of the optical waveguide device, including a thin plate 1 having a thickness of 20 ?m or less, and at least an optical waveguide 2 formed in the thin plate. The thin plate is bonded and fixed to a supporting substrate 5 with an adhesive 4 interposed therebetween, and a film having a higher refractive index than the thin plate is provided on a surface of the thin plate bonded and fixed to the supporting substrate so as to be in contact with a part of the optical waveguide.

Abstract: The present invention relates to an optical control device capable of achieving an accurate match of modulation timing and modulation intensity between optical waves propagating through optical waveguides disposed between a plurality of signal electrodes in an optical control device using an anisotropic dielectric substrate.

Abstract: Disclosed is an optical element which includes a support substrate and a thin plate of single crystal stacked on the support substrate through a thermoplastic adhesive, having the advantages of easily regulating the phase of light waves and restoring the regulated state to the original state. The optical element includes a support substrate 4 and a thin plate 1 of single crystal stacked on the support substrate 4 through a thermoplastic adhesive 3. The optical characteristics of the optical element are regulated by applying stress within an elastic limit to at least a part of the thin plate in a state where the thermoplastic adhesive is softened by heating the optical element, forming a concavo-convex part 10 in the thin plate, and then cooling the optical element to fix the concavo-convex part.

Abstract: A method for forming a ferroelectric spontaneous polarization reversal includes the steps of forming a convexo-concave structure on a top face of a ferroelectric substrate firstly, and then forming a ferroelectric spontaneous polarization region on the substrate including one portion of a convex portion, with a concave portion being formed on the bottom face of the substrate within a region where a ferroelectric spontaneous polarization reversal is to be formed and the convex portion is formed, and then applying an electric field into the substrate. The depth of the concave portion on the bottom face of the substrate may be greater than the height of the convex portion on the top face of the substrate. The width of the concave portion on the bottom face of the substrate may be wider than width of said convex portion on the top face of the substrate.

Abstract: An optical control element having a substrate 1 having an electro-optic effect, an optical waveguide 2 formed on the substrate, and a control electrode 3 that is provided on the substrate and controls the phase of light that propagates through the optical waveguide, in which the control electrode 3 has a plurality of resonant-type electrodes 31 and 32 that are disposed along the optical waveguide 2 and have different resonance frequencies (f1 and f2), an feeder electrode 30 through which control signals are input and branched signal electrodes that are branched from the feeder electrode are connected to the respective resonant-type electrodes, and the branched signal electrode is configured to match a timing at which the electric control signal is applied to each of the resonant-type electrodes and a timing at which the light that propagates through the optical waveguide passes at the section of each of the resonant-type electrodes.