Optical coupling element and manufacturing method

1. An optical coupling element constituted by a multi-core optical fiber having a plurality of cores each of which allows light to propagate therein and is integrally surrounded by a common cladding, the optical coupling element comprising:

a first end in which one end faces of the cores are arranged;

a second end opposed to the first end, in which the other end faces of the cores are arranged, the second end being different from the first end in a core interval of the cores integrally surrounded by the common cladding; and

a fixed bent shape of at least a part of the optical coupling element itself comprising the cores integrally surrounded by the common cladding being hardened in the fixed bent shape, so that a light input/output direction at the first end is different from a light input/output direction at the second end,

wherein the fixed bent shape is undeformable.

2. The optical coupling element according to claim 1 , wherein a core array in the first end is similar to a core array in the second end, and wherein the core interval in the first end is different from the core interval in the second end.

3. The optical coupling element according to claim 1 , wherein the interval of the cores changes stepwise from the first end to the second end.

4. The optical coupling element according to claim 1 , wherein the interval of the cores changes continuously from the first end to the second end.

5. The optical coupling element according to claim 1 , wherein each core array in the first end and the second end is comprised of a one-dimensional pattern.

6. The optical coupling element according to claim 1 , wherein each core array in the first end and the second end is comprised of a two-dimensional pattern.

7. The optical coupling element according to claim 1 , wherein the first end and the second end are different from each other with respect to one of a diameter and a refractive index of the cores.

8. An optical coupling element manufacturing method for manufacturing the optical coupling element defined in claim 1 , comprising softening a starting material with a plurality of cores in a common cladding, and extending the softened starting material.

9. An optical component comprising:

a multi-core optical fiber having a plurality of cores each surrounded by a common cladding, and one end in which end faces of the cores are arranged;

the optical coupling element according to claim 1 ; and

a planar optical waveguide having a main surface in which a plurality of light input/output portions are arranged,

wherein the multi-core optical fiber is optically connected with the optical coupling element while the cores in the one end of the multi-core optical fiber are respectively coincident with the cores in the first end of the optical coupling element, and the planar optical waveguide is optically connected with the optical coupling element while the light input/output portions in the main surface of the planar optical waveguide are respectively coincident with the cores in the second end of the optical coupling element.

10. An optical coupling element comprising a plurality of cores each of which allows light to propagate therein, and comprising:

a first end in which one end faces of the cores are arranged;

a second end opposed to the first end, in which the other end faces of the cores are arranged, the second end differing in at least either of a core array and a core interval from the first end; and

a bent shape of at least a part of the optical coupling element itself comprising the cores, so that a light input/output direction at the first end is different from a light input/output direction at the second end,

wherein the first end and the second end are different from each other with respect to at least either of a diameter and a refractive index of the cores,

wherein in at least one of the first end and the second end, at least either of the diameter and the refractive index of the cores is changed by thermal diffusion of a dopant in the cores.

11. The optical coupling element according to claim 10 , which is comprised of a plurality of optical fibers each of which has a single core corresponding to any one of the cores,

wherein at one ends of the respective optical fibers, the refractive index of the single cores is changed by relaxation of residual stress in the single cores.

12. An optical coupling element constituted by a multi-core optical fiber having a plurality of cores each of which allows light to propagate therein and is integrally surrounded by a common cladding, the optical coupling element comprising:

a first end in which one end faces of the cores are arranged;

a second end opposed to the first end, in which the other end faces of the cores are arranged, the second end being different from the first end in a core interval of the cores integrally surrounded by the common cladding, and

a fixed bent shape of at least a part of the optical coupling element itself comprising the cores integrally surrounded by the common cladding being hardened in the fixed bent shape, so that a light input/output direction at the first end is different from a light input/output direction at the second end,

wherein the core interval of the cores integrally surrounded by the common cladding changes stepwise from the first end to the second end, and

wherein the fixed bent shape is undeformable.