Laminated polymer optical waveguide and process for producing the same
A laminated polymer optical waveguide including two or more optical waveguide films each of which includes an optical waveguide core on a light-transmissive clad film, the two or more optical waveguide films being laminated on each other by using a clad-forming curable resin having a refractive index close to that of the light-transmissive clad film. The laminated polymer optical waveguide includes, at an end thereof, plural strip-shaped structures which each include at least one optical waveguide core and which can be each independently bent in the direction along which the optical waveguide films are laminated.
1. A laminated polymer optical waveguide comprising two or more optical waveguide films each of which comprises an optical waveguide core on a light-transmissive clad film, the two or more optical waveguide films being laminated on each other by using a clad-forming curable resin having a refractive index close to that of the light-transmissive clad film,
wherein the laminated polymer optical waveguide comprises, at an end thereof, a plurality of strip-shaped structures which each comprise at least one optical waveguide core and which can be each independently bent in the direction along which the optical waveguide films are laminated.
2. The laminated polymer optical waveguide of claim 1 , wherein, in the vicinity of an end of each of the optical waveguide films, an area where the optical waveguide core is not present is removed.
3. The laminated polymer optical waveguide of claim 1 , wherein at least one of the strip-shaped structures is bent to arrange end faces of the optical waveguide cores in the different strip-shaped structures at given intervals.
4. The laminated polymer optical waveguide of claim 3 , wherein ends of the strip-shaped structures are fixed to a fixed face.
5. The laminated polymer optical waveguide of claim 4 , wherein the ends of the strip-shaped structures are fixed to an optical connector.
6. The laminated polymer optical waveguide of claim 1 , wherein at least one of the strip-shaped structures is bent to be aligned with a strip-shaped structure adjacent thereto with respect to a direction along which the optical waveguide films are laminated, thereby arranging end faces of the optical waveguide cores in the different strip-shaped structures along a straight line.
7. The laminated polymer optical waveguide of claim 1 , wherein a refractive index of the light-transmissive clad film is less than 1.55.
8. The laminated polymer optical waveguide of claim 1 , wherein the clad-forming curable resin comprises at least one selected from the group consisting of epoxy ultraviolet ray-curable resins, polyimide ultraviolet ray-curable resins and acrylic ultraviolet ray-curable resins.
9. The laminated polymer optical waveguide of claim 1 , wherein a refractive index of the optical waveguide core is from 1.20 to 1.60.
10. A process for producing the laminated polymer optical waveguide of claim 1 , comprising:
performing the following processes (a) to (e) two or more times to form two or more optical waveguide films:
(a) preparing a mold which is made of a mold-forming-curable resin and has a concave portion corresponding to a convex portion of an optical waveguide core,
(b) bringing a light-transmissive clad film into close contact with the mold,
(c) filling a core-forming curable resin into the concave portion of the mold with which the light-transmissive clad film is in close contact,
(d) curing the filled core-forming curable resin, and
(e) removing the mold from the light-transmissive clad film;
laminating the two or more optical waveguide films by using a clad-forming curable resin; and
forming a plurality of strip-shaped structures in a laminated product made of the laminated optical waveguide films.
11. The process of claim 10 , wherein the mold has a plurality of concave portions to form alignment marks on the optical waveguide films, and the two or more optical waveguide films are laminated by using the alignment marks.
12. The process of claim 10 , further comprising cutting ends of the strip-shaped structures simultaneously in a state in which at least one of the strip-shaped structures is bent and in which end faces of the optical waveguide cores in the different strip-shaped structures are arranged and fixed at given intervals.
13. The process of claim 11 , further comprising cutting ends of the strip-shaped structures simultaneously in a state in which at least one of the strip-shaped structures is bent and in which end faces of the optical waveguide cores in the different strip-shaped structures are arranged and fixed at given intervals.