Method for producing tapered waveguide

摘要

A method for producing a tapered waveguide is produced using an undercut-type shadow mask having an overhanging part. The shadow mask includes a photoresist layer having the overhanging part and a metal layer for supporting the photoresist layer on a substrate. After the shadow mask is provided on the substrate, film-forming particles are caused to jump from above the shadow mask toward the substrate, thereby forming a dielectric film having a tapered part on the substrate. Then, the shadow mask is removed together with the film-forming particles thereon by lift-off. Then, an optical waveguide is formed on the substrate so as to cover the dielectric film having the tapered part. The thickness of the metal layer is preferably in the range of about 0.1 to 10 mu m and more preferably about 1 mu m.