| 摘要 |
PROBLEM TO BE SOLVED: To suppress the variation in film thickness and refractive index as small as possible so as to make waveguides adaptable to mass production without increasing surface roughness by forming a dielectric film having tapered shape part by using a shadow mask of an undercut type. SOLUTION: This tapered waveguide comprises a photoresist layer 13 partly constituting its eaves parts 13a and a metallic film 12 for supporting the photoresist layer 13 on a substrate 11. Film forming particles fly by having a spread at the time of using a film forming method, such as RR sputtering and, therefore, the particles infiltrate to the underside of the eaves parts 13a of the photoresist layer 13 and eventually the dielectric layers 14a having the tapered shape parts are formed. The photoresist layer 13 and the unnecessarily grown films 14, etc., are removed and an optical waveguide layer 15 is so laminated on the substrate 11 as to cover the Al layer 13. As a result, the tapered waveguides 101 which are the desired structure are obtd. |
