Abstract: An optical modulator having an optical modulation part and a connection part for an optical fiber propagating light. The optical modulation part has a modulation substrate of an electro-optic material, a modulation optical waveguide formed on the modulation substrate, a high frequency interaction part for applying a voltage to the modulation optical waveguide to modulate the propagation of light, a first supporting substrate and a first adhesion layer for adhering the modulation substrate to the first supporting substrate. The connection part has a connection substrate of an electro-optic material, a connection optical waveguide formed on the connection substrate, a second supporting substrate, and a second adhesion layer for adhering the connection substrate to the second supporting substrate. The modulation substrate is adhered to the connection substrate. The first supporting substrate is adhered to the second supporting substrate.

Abstract: An object of the present invention is, in an optical modulator, to increase the production yield by enhancing the patterning accuracy of the electrodes, as well as to reduce the electrode loss by increasing the thickness of the electrodes. An optical modulator has a substrate 5 made of an electro-optical material; a modulation electrode 2A, 3A, 2B provided on the substrate 5; and an optical waveguide 1c provided on the substrate 5. Light propagating through the optical waveguide 1c is modulated by applying a modulation voltage to the modulation electrode. At least a part of the modulation electrode includes a base 2a, 3a formed on the substrate 5 and a projection part 2b, 3b having a width narrower than that of the base.

Abstract: An object of the present invention is to widen the band of the velocity matching frequency as well as to reduce the electrode loss in the modulation electrode. An optical modulator has a substrate made of an electro-optical material, a signal electrode 3A, 3B and a ground electrode 2A, 2B provided on the substrate, an optical waveguide provided on the substrate. The signal electrode and the ground electrode each has an interaction section 2a, 2c, 3a, 3c and a feed-through section 2b, 2d, 3b, 3d. Light propagating through the optical waveguide is modulated by applying a modulation voltage on the interaction section. The thickness of the feed-through section is greater than that of the interaction section.

Abstract: An optical modulator 20 has an optical waveguide substrate 1 having a pair of principal surfaces 1a, 1c, a pair of side surfaces 1b and an incident face 1d and exit face 1e of light, the substrate being composed of a ferroelectric material; a channel optical waveguide 4 having at least a pair of branch sections 4b, a multiplexing section 6 of the branch sections and an exit section 4c provided on the downstream of the multiplexing section, the waveguide being formed on the principal surface 1a; a modulation electrode 2, 3 for applying a signal voltage for modulating light propagating in the branch sections; and a reflective groove 7 for reflecting leaked light of off-mode emitted from the multiplexing section 6 and emitting the light from the one principal surface 1a. An operating point of the optical modulator is controlled by changing a DC bias applied on the modulation electrode based on optical output of the leaked light of off-mode.

Abstract: An optical functional device has a slab type two-dimensional photonic crystal layer. The photonic crystal layer has a dielectric layer and a plurality of lattice columns each comprising dielectric pillars. A waveguide portion is provided in the photonic crystal layer. A ground electrode and a signal electrode are formed on the dielectric layer for applying a modulating voltage on light propagating in the waveguide portion. A layer of a high dielectric constant is laminated on the dielectric layer. A low dielectric portion is formed direct under the waveguide portion and the lattice columns 7A, 7B and 7C of at least first, second and third orders in distance with respect to said waveguide portion.

Abstract: The present invention provides an optical waveguide device having a configuration such that the optical waveguide is folded back on an end area of the optical waveguide substrate to widen the modulation band. The optical waveguide device 1A includes a substrate body 2 made of an electro-optical material, optical waveguide 6, and modulation electrodes 3, 4 and 5 for applying a voltage on the optical waveguide 6. The optical waveguide 6 includes first primary areas 6e and 6f, a first curved area 7A, first folding-back areas 6g and 6h provided between the first curved area 7A and a folding-back point 8, second primary areas 6m and 6n, a second curved area 7B, and second folding-back areas 6j and 6k provided between the second curved area 7B and the folding-back point 8. At least a part of the signal electrode is provided in a folding-back region extending from the first curved area 7A and the second curved area 7B to the folding-back point 8.

Abstract: A device 4 has a substrate 5, an optical waveguide 2 and modulation electrodes 1A, 1B, 1C. The substrate 5 is made of an electro-optic material and has a thickness of ?30 ?m at least in a region where the modulation electrode applies an electric field. The device has a ridge generated when the optical waveguide is formed, and the ridge has a height H (angstrom) and a width “W” (?m) whose product (H×W) is 7150 angstrom·?m or smaller to realize single mode propagation of light in the optical waveguide. The wave guide has branched parts in the region where the modulation electrode applied an electric field. The deviation of positions of peaks and bottoms in the extinction ratio curve can be reduced, by increasing the distance of the branched parts of the optical waveguide to ?46 ?m.

Abstract: The present invention provides a radio signal radiation system that alleviates the necessity of a highly specified pass band reception filter and a high performance/reliability amplifier. The radio signal radiation system includes an optical modulator; a light source for inputting an optical carrier wave into the optical modulator; a power source for applying a modulating signal having a frequency Fm on the optical modulator to superimpose a sideband wave onto the carrier wave, the modulating signal having an amplitude of N-times the drive voltage of the optical modulator; a light receiver to receive and convert the outgoing light into an electrical signal; and a radiating means for radiating a radio signal based on the electrical signal, wherein the sideband wave is superimposed at a position shifted by n×fm.

Abstract: The present invention provides an optical waveguide device having a configuration such that the optical waveguide is folded back on an end area of the optical waveguide substrate to widen the modulation band. The optical waveguide device includes a substrate body made of an electro-optical material, optical waveguide, and modulation electrodes for applying a voltage on the optical waveguide. The optical waveguide includes first primary areas, a first curved area, first folding-back areas provided between the first curved area and a folding-back point, second primary areas, a second curved area, and second folding-back areas provided between the second curved area and the folding-back point. At least a part of the signal electrode is provided in a folding-back region extending from the first curved area and the second curved area to the folding-back point.

Abstract: An optical functional device comprises a dielectric substrate 5, a ferroelectric thin layer 10 provided on the dielectric substrate 5 and comprising a material having electro-optical effect and an electrode 3A, 3B provided on the ferroelectric thin layer 10. A part of the ferroelectric thin layer 10 functions as a core 9 of the optical wave guide and the dielectric substrate functions as a clad for the optical waveguide. The optical waveguide 9 constitutes a multi-mode waveguide in the direction “D” of depth of the ferroelectric thin layer.

Abstract: It is provided an optical waveguide device in which the radius of curvature of a curved part of an optical waveguide can be lowered and the radiation loss of light in the curved part can be reduced. An optical waveguide device 2 has a ferroelectric optical waveguide substrate and an optical waveguide 5 formed in or on the substrate and modulating electrodes 4A, 4B and 4C. The thickness of the optical waveguide substrate is 30 ?m or smaller at least in a region where the optical waveguide is formed. The optical waveguide has curved part having a radius of curvature of 30 mm or smaller.

Abstract: An optical functional device 1 has a slab type two-dimensional photonic crystal layer 29. The layer 29 has a dielectric layer 4 and a plurality of lattice columns 5 each comprising dielectric pillars. A waveguide portion 6 is provided in the photonic crystal layer 29. A ground electrode 8 and a signal electrode 9 are formed on the dielectric layer 4 for applying a modulating voltage on light propagating in the waveguide portion 6. A layer 2 of a high dielectric constant is laminated on the dielectric layer 4. A low dielectric portion is formed direct under the waveguide portion 6 and the lattice columns 7a, 7B and 7C of at least first, second and third orders in distance with respect to said waveguide portion.

Abstract: A first main face 1a of a substrate 1 of a dielectric single crystal is etched to form recesses 4 in the substrate 1. A second main face 1b of the substrate 1 is mechanically processed to form a slab 10, so that the recesses 4 pass through the substrate 1 to form through holes 11.

Abstract: An optical modulator is provided for modulating light propagating in a three-dimensional optical waveguide 5 by applying a voltage thereto. The optical modulator has the three-dimensional optical waveguide 5 including at least one pair of branch optical waveguides 5c and 5d, a multiplexing part 5e of the branch optical waveguides and an emission part 5f provided in the downstream of the multiplexing part, modulation electrodes 3A, 3B and 4 for applying a signal voltage for modulating light propagating in the three-dimensional optical waveguide 5, and guiding waveguides 6A and 6B for guiding primary mode light from the multiplexing part. Thickness of the substrate is 20 ?m or less at least under the modulation electrodes, and an operation point of the optical modulator is controlled by changing, based on light output from the guiding waveguides, DC bias applied onto the modulation electrodes.

Abstract: A voltage is applied on a first branch 3a by a first ground electrode 10 and a signal electrode 11, and a voltage is applied on a second branch 3b by a second ground electrode 12A and the signal electrode 11. A first gap 13 is formed between the first ground electrode 10 and the signal electrode 11, and a second gap 14 is formed between the second ground electrode 12A and the signal electrode 11. The first gap 13 and the second gap 14 are divided into voltage applying portions 13a, 14a, feed-through portions and connection portions 13b, 14b therebetween, respectively, and satisfy the formula: G12/G11?G22/G21<G32/G31.

Abstract: An optical waveguide structure has a slab type photonic crystal and an optical waveguide provided in the photonic crystal. The photonic crystal has a slab of a dielectric film and a plurality of lattice columns each having dielectric pillars. The dielectric pillars included in the lattice columns at least in n'th order (n represents 1, 2, 3, 4 and 5) in distance with respect to said optical waveguide, respectively, has a planar shape of an equilateral polygon or exact circle. At least one of the dielectric pillars included in the lattice columns at least in n'th order (n represents 2, 3, 4 and 5) with respect to the optical waveguide has a size rn different from a fundamental size ro.

Abstract: It is provided a practical radio oscillating system for a radar system to alleviate the necessity of a reception filter of severe specification of pass band and an oscillating system and an amplifier of high performance and high reliability. The radio oscillating system has an optical modulator 2 for oscillation; a modulating means 6 for modulating a carrier wave “P” passing through the optical modulator 2 so as to superimpose sideband waves “Q” and “R” onto the carrier wave; an optical receiver 7 for oscillation to receive outgoing light “B” from the optical modulator 2 and to convert the outgoing light into an electrical signal; and a radiating means 8 for radiating radio signal “C” based on the electrical signal.

Abstract: A device 4 has a substrate 5, an optical waveguide 2 and modulation electrodes 1A, 1B, 1C. The substrate 5 is made of an electro-optic material and has a thickness of ?30 ?m at least in a region where the modulation electrode applies an electric field. The device has a ridge generated when the optical waveguide is formed, and the ridge has a height H (angstrom) and a width “W” (?m) whose product (H×W) is 7150 angstrom·?m or smaller to realize single mode propagation of light in the optical waveguide. The waveguide has branched parts in the region where the modulation electrode applied an electric field. The deviation of positions of peaks and bottoms in the extinction ratio curve can be reduced, by increasing the distance of the branched parts of the optical waveguide to ?46 ?m.

Abstract: An optical functional device comprises a dielectric substrate 5, a ferroelectric thin layer 10 provided on the dielectric substrate 5 and comprising a material having electro-optical effect and an electrode 3A, 3B provided on the ferroelectric thin layer 10. A part of the ferroelectric thin layer 10 functions as a core 9 of the optical wave guide and the dielectric substrate functions as a clad for the optical waveguide. The optical waveguide 9 constitutes a multi-mode waveguide in the direction “D” of depth of the ferroelectric thin layer.

Abstract: An object of the invention is to provide an electrode system for optical modulation of an optical modulator to reduce a thickness “E” of an electrode required for velocity matching and for reducing a propagation loss in the electrode. A substrate 2 is made of an electrooptic material and has one and the other main faces 2a, 2b opposing each other. An electrode system 20A is provided on the substrate 2 for applying a voltage for modulating light propagating in optical waveguides 6A and 6B. The electrode system 20A includes ground electrodes 3A, 3B and a signal electrode 4. A ratio “W/G” of a width “W” of the signal electrode 4 to a gap “G” between the ground and signal electrodes is 0.8 or higher. Preferably, the substrate 2 has a thickness “T” of 20 ?m or larger, in a region where the optical waveguides 6A and 6B are provided.