Abstract: An optical waveguide device in which an optical loss is reduced by removing an air bubble inside an adhesive layer for joining a reinforcing member from near an optical waveguide or the like even in a case where a protruding part such as a rib type optical waveguide or a spot size converter is formed on an optical waveguide substrate is provided. An optical waveguide device includes an optical waveguide substrate (1, 2) provided with an optical waveguide (10, 12), and a reinforcing member (3) disposed on an upper side of the optical waveguide (10, 12) near an end portion of the optical waveguide (10, 12), the optical waveguide substrate (1, 2) and the reinforcing member (3) being joined through an adhesive layer (4), in which a protective layer (13) that covers the optical waveguide (10, 12) is provided on the optical waveguide (10, 12) positioned on a lower side of the reinforcing member (3), and the adhesive layer (4) is disposed outside the protective layer (13).

Abstract: Provided is an optical waveguide element including spot size conversion means with suppressed optical insertion loss without complicating a manufacturing process.

Abstract: An optical waveguide device including an optical waveguide substrate that has an electro-optic effect, is a crystal having anisotropy in thermal expansion rate, has a thickness set to 10 ?m or lower, and includes an optical waveguide and a holding substrate that holds the optical waveguide substrate, the optical waveguide substrate and the holding substrate being joined to each other, in which the holding substrate is formed of a crystal having a lower dielectric constant than the optical waveguide substrate and having anisotropy in thermal expansion rate, and the optical waveguide substrate and the holding substrate are joined to each other such that differences in thermal expansion rate between the optical waveguide substrate and the holding substrate become small in different axial directions on a joint surface.

Abstract: To provide an optical waveguide device in which damage to a thin plate, particularly damage to an optical waveguide, is prevented. An optical waveguide device includes: a thin plate 1 that has an electro-optic effect and that has a thickness of equal to or thinner than 10 ?m, an optical waveguide 2 being formed on the thin plate; and a reinforcing substrate that supports the thin plate, in which the thin plate 1 has a rectangular shape in a plan view, a dissimilar element layer 3, in which an element different from an element constituting the thin plate is disposed in the thin plate, is formed on at least a portion between an outer periphery of the thin plate and the optical waveguide 2, and a total length over which a cleavage plane of the thin plate traverses a region where the dissimilar element layer is formed, is equal to or longer than 5% of a width of the thin plate in a short side direction.

Abstract: In an optical waveguide element, performance deterioration due to recoupling of unnecessary light leaking from an optical waveguide with the optical waveguide is prevented. An optical waveguide element includes an optical substrate on which an optical waveguide is formed, and a support substrate that is bonded to the optical substrate, on a bonded surface of the support substrate bonded to the optical substrate, a recess portion along the optical waveguide on the optical substrate is formed directly under the optical waveguide, a portion of the support substrate from an upper surface of the support substrate to at least a depth of a bottom surface of the recess portion has a refractive index higher than a substrate refractive index of the optical substrate, and the recess portion is filled with a substance having a refractive index lower than the substrate refractive index.

Abstract: An optical waveguide device including an optical waveguide substrate that has an electro-optic effect, is a crystal having anisotropy in thermal expansion rate, has a thickness set to 10 ?m or lower, and includes an optical waveguide and a holding substrate that holds the optical waveguide substrate, the optical waveguide substrate and the holding substrate being joined to each other, in which the holding substrate is formed of a crystal having a lower dielectric constant than the optical waveguide substrate and having anisotropy in thermal expansion rate, and the optical waveguide substrate and the holding substrate are joined to each other such that differences in thermal expansion rate between the optical waveguide substrate and the holding substrate become small in different axial directions on a joint surface.

Abstract: Provided is an optical modulator that includes an adhesive layer whose thickness can be reduced and that ensures high reliability, while band-widening and low voltage drive are realized. An optical modulator includes features as follows: a substrate (optical waveguide substrate) having an electro-optic effect; an optical waveguide formed on the substrate; and a traveling-wave electrode (signal electrode and ground electrode) formed on the substrate in order to modulate a light wave propagating through the optical waveguide, in which the substrate has a thickness of 30 ?m or lower, a reinforcing substrate that holds the substrate through an adhesive layer interposed between the reinforcing substrate and the substrate is provided, and the adhesive layer includes an air gap section where no adhesive agent is present.

Abstract: An optical device including a core layer that includes an EO polymer, and clad layers that are disposed on and beneath the core layer, in which a polymer polymerized in a composition containing a reactive ionic liquid is used in the clad layers.

Abstract: An optical device including a core layer that includes an EO polymer, and clad layers that are disposed on and beneath the core layer, in which a polymer polymerized in a composition containing a reactive ionic liquid is used in the clad layers.