Simple process for fabricating a monolithic polymer optical waveguide

A simple and economical fabrication process for a monolithic polymer optical waveguide in which different materials are serially grafted is proposed and demonstrated. A cladding layer with a waveguide core groove is fabricated by microtransfer molding. An epoxy resin solution is spin coated onto the cladding before selective photoexposure to form a transparent waveguide core. An optical functional polymer solution is then spin coated to form a serially grafted waveguide structure. Thus two types of polymer fill the groove to realize a monolithically integrated waveguide. Controlling the groove shape results in a flat surface. A low connection loss between the two polymers, less than 0.01 dB/point, is obtained.