Optical waveguide and method of manufacturing the same

1. A method of manufacturing an optical waveguide having a core and a clad, comprising

forming a first clad by applying a resin on a substrate and curing the resin;

applying a core material between a recessed mold which has a recess having a shape identical to a shape of the core and the first clad which is provided on the substrate;

curing the core material applied, thereby forming a core pattern having a shape identical to that of the recess;

peeling the recessed mold from the core pattern and the first clad; and

removing a thin core layer from the surface of the first clad after completion of the peeling the recessed mold.

2. The method of manufacturing an optical waveguide, according to claim 1 , wherein removing a thin core layer is performed by using an oxygen-plasma process.

3. A method of manufacturing an optical waveguide having a core and a clad, comprising:

forming a first clad by applying a resin on a substrate and curing the resin;

applying a core material between a recessed mold which has a recess having a shape identical to a shape of the core and the first clad which is provided on the substrate;

curing the core material applied, thereby forming a core pattern having a shape identical to that of the recess; and

peeling the recessed mold from the core pattern and the first clad, wherein:

the recessed mold has, at the ends of the recess, surfaced inclined at about 45° which are equivalent to inclined mirrors; and

the core pattern has ends to which the surfaces equivalent to inclined mirrors have been transferred.

4. The method of manufacturing an optical waveguide, according to claim 3 , further comprising forming reflecting films on the mirror-equivalent surfaces of the recessed mold before applying a core material,

wherein peeling the recessed mold includes transferring the reflecting films to the ends of the core pattern.

5. A method of manufacturing an optical waveguide, having a core and a clad, comprising:

forming a first clad by applying a resin on a substrate and curing the resin;

applying a core material between a recessed mold which has a recess having a shape identical to a shape of the core and the first clad which is provided on the substrate;

curing the core material applied, thereby forming a core pattern having a shape identical to that of the recess; and

peeling the recessed mold from the core pattern and the first clad,

wherein the recess of the recessed mold is shaped like a spacer and is deeper than the depth of core pattern.

6. A method of manufacturing an optical waveguide having a clad and a core, comprising:

forming a first clad by applying a resin on a substrate and curing the resin;

applying a core material between a recessed mold which has a recess having a shape identical to a shape of the core and the first clad which is provided on the substrate;

curing the core material applied, thereby forming a core pattern having a shape identical to that of the recess;

peeling the recessed mold from the core pattern and the first clad; and performing a surface treatment on the recessed mold before applying a core material, thereby to make the recessed mold have more affinity for the core material.

7. The method of manufacturing an optical waveguide, according to claim 6 , wherein the surface treatment is an oxygen-plasma process.

8. The method of manufacturing an optical waveguide, according to claim 6 , wherein the contact angle of the core material to the recessed mold is 45° or less.

9. A method of manufacturing an optical waveguide having a clad and a core, comprising:

forming a first clad by applying a resin on a substrate and curing the resin;

applying a core material between a recessed mold which has a recess having a shape identical to a shape of the core and the first clad which is provided on the substrate;

curing the core material applied, thereby forming a core pattern having a shape identical to that of the recess;

peeling the recessed mold from the core pattern and the first clad forming a projecting mold by providing a projection shaped like a core pattern, on a substrate; and

applying a resin to the projecting mold curing the resin and peeling the projected mold from the resin, thereby providing a recessed mold.

10. The method of manufacturing an optical waveguide, according to claim 9 , wherein the projection of the projecting mold comprises two straight parts connected together, inclined at right angles to each other, and surfaces equivalent to in-plane mirrors and designed to connect the straight parts optically.

11. The method of manufacturing an optical waveguide, according to claim 10 , wherein the surfaces of the projection, which are equivalent to in-plane mirrors, are formed by a laser process.

12. The method of manufacturing an optical waveguide, according to claim 10 , wherein the projection has surfaces at ends, which are equivalent to inclined mirrors.

13. The method of manufacturing an optical waveguide, according to claim 12 , wherein the surfaces of the projection, which are equivalent to inclined mirrors, are inclined convex surfaces.

14. The method of manufacturing an optical waveguide, according to claim 12 , wherein the surfaces of the projection, which are equivalent to inclined mirrors, are formed by a laser process.

15. The method of manufacturing an optical waveguide, according to claim 13 , wherein forming a projecting mold further comprises:

forming a projection made of a resist pattern and shaped like a core pattern, on the substrate by means of photolithography;

forming the inclined convex surface by obliquely applying a laser beam to the ends of the projection and thereby evaporating the ends of the projections in part, said laser beam defining a substantially circular shadow.

16. The method of manufacturing an optical waveguide, according to claim 13 , wherein forming a projecting mold further comprises:

forming a projection made of a resist pattern and shaped like a core pattern, on the substrate by means of photolithography; and

forming the inclined convex surfaces by obliquely applying a laser beam to the ends of the projection a number of times, each time in a different direction, and thereby evaporating the ends of the projections in part.

17. The method of manufacturing an optical waveguide, according to claim 13 , wherein forming a projecting mold further comprises:

forming a projection made of a resist pattern and shaped like a core pattern, on the substrate by means of photolithography;

forming inclined surface on the ends of the projection by obliquely applying a laser beam to the ends of the projection and thereby evaporating the ends of the projections in part; and

forming the inclined convex surfaces by raising a temperature after applying the laser beam, thereby causing the resist to flow.