Manufacturing method of optical waveguide

A method of manufacturing an optical waveguide comprising the steps of:

• forming a core in a pattern on a surface of an under cladding layer;
• and
• forming an over cladding layer on a surface of the core by coating,
• said step of forming said over cladding layer including the steps of
• preparing a molding die formed with a recessed portion having a die surface conformable in shape to a surface of the over cladding layer and a through hole in communication with said recessed portion;
• bringing an open surface of said recessed portion of the molding die into close contact with said surface of the under cladding layer;
• while keeping this state, pouring a liquid resin which is a material for the formation of said over cladding layer through said through hole into a mold space surrounded by said die surface of the recessed portion and the surface of the under cladding layer;
• and
• hardening the liquid resin.