WAVEGUIDE HAVING EXPANDED CORE FOR HIGH COUPLING EFFICIENCY AND FABRICATING METHOD THEREOF

摘要

PURPOSE: A waveguide having an expanded core for high coupling efficiency and a fabricating method thereof are provided to expand simultaneously cores of plural optical fibers by improving a method for expanding thermally a core. CONSTITUTION: A photoresist material is coated around a core including an end portion(16) of a waveguide. An input end(18) of the waveguide is connected to the end portion(16) of the waveguide. The beam is irradiated from the input end(18) of the waveguide to a core expansion region of the end portion(16) of the waveguide. A peripheral part of the core is exposed by etching the exposed part of the photoresist material. A hydrogen process or a deuterium process for the exposed part of the core is performed. The external beam is irradiated to increase a refractive index of the hydrogen-processed region.