Optical waveguide production method

An optical waveguide production method, comprising:

• forming a core in a predetermined pattern on a surface of an under-cladding layer;
• and
• forming an over-cladding layer to cover the core using a mold, said mold including a cavity having a mold surface conformable to a shape of the over-cladding layer;
• wherein the mold is a light-transmissive resin mold produced by placing a mold component having the same shape as the over-cladding layer in a mold production container, filling the container with a light-transmissive resin, curing the light-transmissive resin, taking out the cured resin from the container and removing the mold component from the cured resin, and the cavity for the formation of the over-cladding layer is defined by a recess formed in the mold by the removal of the mold component;
• and
• wherein the over-cladding layer forming step includes placing the mold with the cavity of the mold positioned upwards, filling the cavity of the mold with a photosensitive resin as an over-cladding layer material, and, after the filling, immersing the core in the photosensitive resin and exposing the photosensitive resin through the mold.