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: 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: 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: 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 member-bonding structure includes a first optical component, a second optical component, and an integral substrate having a mounting face on which the first and second optical components are mounted, at least the first optical member being bonded to the integral substrate, wherein a bonding face of the first optical member is bonded to the mounting face of the integral substrate with a cured and shrunk optical adhesive in such a state that an optical axis of the first optical member is aligned with that of the second optical member at a precision of not more than 1 &mgr;m, a groove is formed in a such bonding region of that mounting face of the integral substrate as being bonded with the first optical member, and at least part of the optical adhesive is filled into the groove.

Abstract: A bonding structure of optical members has a first optical member, a second optical member, a first support member supporting the first optical member, and a second support member supporting the second optical member. The first support member is bonded to the second support member. The first support member and the second support member are bonded with each other via a hardened acrylic resin adhesive under a condition such that an optical axis of the first optical member and an optical axis of the second optical member are optically aligned with each other with an accuracy of within 1 &mgr;m. A viscosity of the acrylic resin adhesive before hardening is larger than 500 cP and lower than 5000 cP.

Abstract: An optical member-bonding structure includes a first optical component, a second optical component, and an integral substrate having a mounting face on which the first and second optical components are mounted, at least the first optical member being bonded to the integral substrate, wherein a bonding face of the first optical member is bonded to the mounting face of the integral substrate with a cured and shrunk optical adhesive in such a state that an optical axis of the first optical member is aligned with that of the second optical member at a precision of not more than 1&mgr;m, a groove is formed in a such bonding region of that mounting face of the integral substrate as being bonded with the first optical member, and at least part of the optical adhesive is filled into the groove.

Abstract: A bonding structure of optical members has a first optical member, a second optical member, a first support member supporting the first optical member, and a second support member supporting the second optical member. The first support member is bonded to the second support member. The first support member and the second support member are bonded with each other via a hardened acrylic resin adhesive under a condition such that an optical axis of the first optical member and an optical axis of the second optical member are optically aligned with each other with an accuracy of within 1 &mgr;m. A viscosity of the acrylic resin adhesive before hardening is larger than 500 cP and lower than 5000 cP.

Abstract: In order not to vary a light dividing ratio, a light insertion loss and a light extinction ratio, even if an environmental temperature is varied, in a first aspect, an optical waveguide device has at least one optical waveguide substrate made of ferroelectric crystals, an optical waveguide formed in the optical waveguide substrate, a first crystal plane formed in the optical waveguide substrate in which charges of one polarity are generated due to pyroelectrical effects, a second crystal plane made of ferroelectrical crystals in which charges of the other polarity are generated, a first conductive layer formed on the first crystal plane, and a second conductive layer formed on the second crystal plane, wherein the first conductive layer is connected electrically to the first conductive layer.