Method of manufacturing optical waveguide
An optical waveguide is cut by moving a heated knife blade across the optical waveguide with the knife blade maintained at a predetermined angle. At that time, by maintaining the temperature of the knife blade at a temperature not lower than the glass transition point of the optical waveguide, a portion, in contact with a bevel plane of the knife blade, of the optical waveguide softens to be planarized along the bevel plane. In this way, an optical path conversion mirror constituted of a planarized cut plane is formed in a region through which the bevel plane has passed.
1. A method of manufacturing an optical waveguide having an optical path conversion mirror, comprising:
preparing a sheet-shaped optical waveguide made of a polymer material; and
forming an optical path conversion mirror constituted of an inclined cut plane by cutting the optical waveguide with a knife blade having a leading edge of the knife blade inclined along the direction of travel during the cutting step, the knife blade having a bevel plane a side of which is the leading edge and a height of which is higher than a thickness of the optical waveguide when the knife blade is stuck into the optical waveguide through the entire thickness thereof while the knife blade is held perpendicularly to a surface of the optical waveguide, and being maintained at a temperature not lower than a glass transition point of material constituting the optical waveguide.
2. A method of manufacturing an optical waveguide, according to claim 1 , wherein the optical path conversion mirror is formed by cutting the optical waveguide while moving the knife blade in a direction perpendicular to a longitudinal direction of the optical waveguide.
3. A method of manufacturing an optical waveguide, according to claim 2 , wherein the optical waveguide is cut with the knife blade by sticking the knife blade into the optical waveguide through the entire thickness thereof without contacting the core and then moving the knife blade in a direction perpendicular to a longitudinal direction of the core.
4. A method of manufacturing an optical waveguide, according to claim 1 , wherein the optical path conversion mirror is formed at such an angle that an optical path of light traveling in a core of the optical waveguide is changed by 90°.
5. A method of manufacturing an optical waveguide, according to claim 1 , wherein the optical waveguide is made of a high polymer material selected from the group consisting of epoxy resin, polyimide resin, polycarbonate resin, fluorinated polyimide resin, and polyethylene resin.