Abstract: An optical waveguide has: a core layer which includes at least one core portion for transmitting a light signal and at least two side cladding portions respectively provided at lateral sides of the core portion so as to be opposed to each other; and two cladding layers respectively provided at vertical sides of the core layer. The core layer is configured to have a horizontal refractive index distribution curve W in a width direction of a cross-sectional plane of the core layer. The horizontal refractive index distribution curve W has a region including at least two local minimum values, at least one first local maximum value and at least two second local maximum values smaller than the first local maximum value. A refractive index in whole of the horizontal refractive index distribution curve W continuously varies.

Abstract: An optical waveguide has: a core layer which includes at least one core portion for transmitting a light signal and at least two side cladding portions respectively provided at lateral sides of the core portion so as to be opposed to each other; and two cladding layers respectively provided at vertical sides of the core layer. The core layer is configured to have a horizontal refractive index distribution curve W in a width direction of a cross-sectional plane of the core layer. The horizontal refractive index distribution curve W has a region including at least two local minimum values, at least one first local maximum value and at least two second local maximum values smaller than the first local maximum value. A refractive index in whole of the horizontal refractive index distribution curve W continuously varies.

Abstract: A substrate on which an optical element is mounted is provided, including: an optical element; an optical circuit substrate which is formed by an optical waveguide layer having a core portion and cladding portions; and an electrical circuit substrate on which is provided a mounting portion that is used for mounting the optical element, wherein the optical element is mounted on the electrical circuit substrate via the optical circuit substrate and wherein the optical circuit substrate has an optical element mounted thereon and is provided with a receptor structure having a conductive portion that conducts electricity between an electrode of the optical element and an electrode of the electrical circuit substrate.

Abstract: An optical waveguide structure has excellent heat resistance and a low water absorbing property and can be manufactured with a low material cost. Such an optical waveguide structure includes: an optical waveguide having two surfaces, a core layer including core portions and cladding portions each having a refractive index lower than that of each of the core portions, the core layer having two surfaces, and cladding layers provided so as to make contact with the two surfaces of the core layer and having a refractive index lower than that of each of the core portions; and conductor layers provided on the two surfaces of the optical waveguide. In the optical waveguide structure, each of the cladding layers is formed of a norbornene-based polymer as a major component thereof.

Abstract: A substrate on which an optical element is mounted is provided, including: an optical element; an optical circuit substrate which is formed by an optical waveguide layer having a core portion and cladding portions; and an electrical circuit substrate on which is provided a mounting portion that is used for mounting the optical element, wherein the optical element is mounted on the electrical circuit substrate via the optical circuit substrate and wherein the optical circuit substrate has an optical element mounted thereon and is provided with a receptor structure having a conductive portion that conducts electricity between an electrode of the optical element and an electrode of the electrical circuit substrate.

Abstract: A substrate on which an optical element is mounted is provided, including: an optical element; an optical circuit substrate which is formed by an optical waveguide layer having a core portion and cladding portions; and an electrical circuit substrate on which is provided a mounting portion that is used for mounting the optical element, wherein the optical element is mounted on the electrical circuit substrate via the optical circuit substrate and wherein the optical circuit substrate has an optical element mounted thereon and is provided with a receptor structure having a conductive portion that conducts electricity between an electrode of the optical element and an electrode of the electrical circuit substrate.

Abstract: An optical waveguide structure has excellent heat resistance and a low water absorbing property and can be manufactured with a low material cost. Such an optical waveguide structure includes: an optical waveguide having two surfaces, a core layer including core portions and cladding portions each having a refractive index lower than that of each of the core portions, the core layer having two surfaces, and cladding layers provided so as to make contact with the two surfaces of the core layer and having a refractive index lower than that of each of the core portions; and conductor layers provided on the two surfaces of the optical waveguide. In the optical waveguide structure, each of the cladding layers is formed of a norbornene-based polymer as a major component thereof.

Abstract: A substrate on which an optical element is mounted is provided, including: an optical element; an optical circuit substrate which is formed by an optical waveguide layer having a core portion and cladding portions; and an electrical circuit substrate on which is provided a mounting portion that is used for mounting the optical element, wherein the optical element is mounted on the electrical circuit substrate via the optical circuit substrate and wherein the optical circuit substrate has an optical element mounted thereon and is provided with a receptor structure having a conductive portion that conducts electricity between an electrode of the optical element and an electrode of the electrical circuit substrate.