Abstract: An optical waveguide structure has a single port on one input/output side, a plurality of ports on another input/output side and an S-curve optical waveguide portion arranged on the outermost side of the waveguide structure and including a first circular arc optical waveguide portion and a second circular arc optical waveguide portion connected thereto. The waveguide portion also has a third circular arc optical waveguide portion extending from a first splitting/coupling point side in the first circular arc waveguide portion toward the plural/ports side and having a curvature inverted relative to the first circular arc optical waveguide portion. At the first splitting/coupling point, a tangential line of the first circular arc optical waveguide portion and a tangential line of the third circular arc optical waveguide portion are parallel to and spaced from each other.

Abstract: The invention is directed to an optical waveguide that reduces an excess loss caused in a curved waveguide region by a deviation of the center axis of a beam propagating mode from the center axis of the optical waveguide. The optical waveguide has its part curved, and assuming that the shortest distance from a certain point of a convex edge of the curved portion to a concave edge is a waveguide width at that point, the optical waveguide has its width progressively reduced from the maximum waveguide width in the midst of the curved portion toward the opposite ends of the curved portion.

Abstract: The present invention relates to a curved optical waveguide which is free of any axis-deviation structure in the middle of the waveguide and which has a sigmoidal core shape, wherein the curvature thereof at one end is zero and the curvature thereof at the other end is finite (>0) and the use of such a curved optical waveguide permits the reduction of optical loss at the connected portions to the lowest possible level even when it is applied to, for instance, an optical splitter or a directional coupler and the curved optical waveguide of the present invention can provide an optical waveguide which never requires the use of any offset.

Abstract: An optical device is provided to prevent a dicing blade form being clogged when a wafer is cut by means thereof. Further, an optical device is provided to the present invention can prevent unnecessary expansion of a resin used in the optical device. The present invention relates an optical device having a substrate and an optical waveguide layer laminated thereon. The optical waveguide layer has a first lateral surface connected to an optical fiber or an optical fiber array and a second lateral surface not connected to the same. The substrate has a lateral surface disposed on the same side as that of the second lateral surface of the optical waveguide layer. At least a portion of the second lateral surface of the optical waveguide layer is disposed in a plane different from the lateral surface of the substrate so that an exposed area of the substrate is formed between the second lateral surface of the optical waveguide layer and the lateral surface of the substrate.

Abstract: An optical module (1) according to the present invention has an optical filter (6) having an input surface (2) and an output surface (4), an input core (8) connected to the input surface (2), and an output core (10) connected to the output surface (4). Assuming that light having a predetermined wavelength is input at an input position (14) and transmitted according to Snell's law, a position at which the light is output from the output surface (4) is referred to as a Snell output position (20). In an equivalent optical filter (6?), the output position (16) is located away from the Snell output position (20) in a direction away from the input position (14) by a distance (D) relating to a group delay.

Abstract: An optical reflector, an optical multiplexer/demultiplexer device and an optical system which can allow more flexible arrangement of an optical filter thereof, and enhance performance of wavelength division multiplexing communication thereof are provided. An optical reflector according to the present invention comprises a first and second optical fiber 14, 16, each being connected to one side of an optical propagating region such as a rod lens 12 causing optical strength distributions depending on respective wavelengths of lights to be propagated in the optical propagating region; a mirror 18 disposed on the other side of the optical propagating region; and an optical filter 20 disposed between the first and second optical fibers 14, 16 and the mirror 18.

Abstract: An optical waveguide structure (6) comprises a substrate (12) having a first groove array (8) and a second groove array (10) which are longitudinally spaced from each other, and an optical waveguide (14) layered on the substrate (12) between the first and second groove arrays (8, 10). Each groove array (8, 10) includes a plurality of grooves (8a-8g, 10a-10h) extending longitudinally and arranged laterally relative to each other. The optical waveguide (14) has a cladding layered on the substrate (14), and a core (14b) formed on the cladding so that, when optical fibers (2, 4) are supported and positioned on the grooves (8a-8g, 10a-10h) of the first and second groove arrays (8, 10), the core (14b) of the optical waveguide (14) is aligned with cores (2a, 4a) of the optical fibers (2, 4) at the same level in an vertical direction.

Abstract: A curved optical waveguide comprising a core and a clad, characterized in that: the core shape of the curved optical waveguide has no reversal of a curvature on a halfway; and curvatures at both ends of the curved optical waveguide gradually approach zero. A curved optical waveguide comprising a core and a clad, characterized in that: the core shape of the curved optical waveguide has no reversal of a curvature on a halfway; a curvature at one end of the curved optical waveguide gradually approaches zero; and a radius of curvature at other end is finite. An optical waveguide comprising such a curved optical waveguide and an optical waveguide having a different core shape optically connected with the former, and an optical device using such a curved optical waveguide.

Abstract: An optical directional coupler (1) comprises first and second straight optical waveguides (2, 3) having respective cores (2a, 3a) extending longitudinally close to each other to form an optical coupler portion, and a tapered optical waveguide (4) having a core (4a) connected to the core (2a) of the first straight waveguide (2). The core (2a) of the first straight waveguide (2) has a centerline (2d). A width of the core (4a) of the tapered waveguide (4) becomes narrow toward the first straight waveguide (2) and a profile of the tapered waveguide (4) is asymmetric relative to the centerline (2d) of the core (2a) of the first straight waveguides (2).

Abstract: The present invention provides an optical system with waveguides, which comprises first, second and third optical input/output means (12, 14, 16), fourth and fifth multi-mode optical waveguides (20, 22) each capable of propagating light with plural propagation modes, and optical-filter mounting means (26) for mounting an optical filter (24) between the fourth and fifth multi-mode optical waveguides (20, 22) across a traveling direction of light in the fourth and fifth multi-mode optical waveguides (20, 22). The first optical input/output means (12) is connected to an end face of the fourth multi-mode optical waveguide (20) on a side thereof opposite to the optical-filter mounting means (26). Each of the second and third optical input/output means (14, 16) is connected to an end face of the fifth multi-mode optical waveguide (22) on a side opposite to the optical-filter mounting means (26).

Abstract: The invention is directed to an optical waveguide that reduces an excess loss caused in a curved waveguide region by a deviation of the center axis of a beam propagating mode from the center axis of the optical waveguide. The optical waveguide has its part curved, and assuming that the shortest distance from a certain point of a convex edge of the curved portion to a concave edge is a waveguide width at that point, the optical waveguide has its width progressively reduced from the maximum waveguide width in the midst of the curved portion toward the opposite ends of the curved portion.

Abstract: The present invention relates to a curved optical waveguide which is free of any axis-deviation structure in the middle of the waveguide and which has a sigmoidal core shape, wherein the curvature thereof at one end is zero and the curvature thereof at the other end is finite (>0) and the use of such a curved optical waveguide permits the reduction of optical loss at the connected portions to the lowest possible level even when it is applied to, for instance, an optical splitter or a directional coupler and the curved optical waveguide of the present invention can provide an optical waveguide which never requires the use of any offset.

Abstract: Provided is a light branching optical waveguide including: at least one incident light waveguide (A) optically connected to one end of a multi-mode optical waveguide; and output light waveguides (B) larger in number than the incident light waveguide (A) optically connected to the other end thereof, the light branching optical waveguide being characterized in that: an intensity distribution of light incident from at least one optical waveguide (a) out of the incident light waveguide (A) on the multi-mode optical waveguide at a connecting surface of the incident light waveguide (A) and the multi-mode optical waveguide is asymmetric with respect to a geometrical central axis of the optical waveguide (a); and an extended line of the geometrical center axis of the optical waveguide (a) does not coincide with a geometrical central axis of the multi-mode optical waveguide.

Abstract: An optical waveguide structure has a single port 10 on one input/output side, a plurality of ports 12 on another input/output side and an S-bent optical waveguide portion 20 arranged on the outermost side of the waveguide structure. Tangential lines at opposed ends of the S-bent waveguide portion are parallel to each other. The S-bent optical waveguide portion includes a first circular arc optical waveguide portion 24 and a second circular arc optical waveguide portion 26 connected thereto at a first inflection point 22 where a curvature of the S-bent optical waveguide portion 20 is inverted. The first circular arc optical waveguide portion 24 has a first splitting/coupling point located on a single-port side relative to the first inflection point 22. The waveguide portion also has a third circular arc optical waveguide portion 32 extending from the first splitting/coupling point 30 toward the plural-ports 12 side and having a curvature inverted relative to the first circular arc optical waveguide portion 24.

Abstract: The present invention herein provides an optical waveguide which comprises a cladding and a core formed on a substrate, wherein a refractive index of a material constituting the cladding on the upper side of the core is smaller than a refractive index of a material constituting the cladding on the lateral side of the core and a refractive index of a material constituting the cladding on the lower side of the core; an optical waveguide (an optical waveguide for coupling) which is used for coupling with an optical waveguide (an optical waveguide to be coupled) having a refractive index distribution within a core in the vertical direction, wherein a cladding has a refractive index distribution in the vertical direction; and a method for the preparation thereof. The optical waveguide of the present invention permits the reduction of the coupling loss observed when it is coupled with an optical waveguide whose core is formed by the diffusion technique such as a lithium niobate optical waveguide.

Abstract: The present invention disclosed is an optical waveguide structure that has a first waveguide provided with the opposite ends A and B, a second waveguide with the opposite ends C and D, a third waveguide with the opposite ends E and F, and a coupling waveguide having its first beam incoming/outgoing end connected to the end B of the first waveguide and its second beam incoming/outgoing end connected to the end C of the second waveguide and the end E of the third waveguide. The optical waveguide is characterized in that the first waveguide and the coupling waveguide are longitudinally dimensioned so that light beam at its peak of light intensity can transit the point of axial mal-alignment at the end A of the first waveguide and further transit the axial zone at the second beam incoming/outgoing end of the coupling waveguide.