Refractive Index Control of Polyimide by Synchrotron Radiation, and the Application to Fabrication of a Waveguide Grating

✍ Scribed by Junya Kobayashi; Tetsuyoshi Ishii; Yasuko Maruo; Toshiaki Tamamura

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 639 KB
• Volume: 85
• Category: Article
• ISSN: 8756-663X
• DOI: 10.1002/ecjb.1087

✦ Synopsis

Abstract

Synchrotron radiation alters the refractive index of fluorinated polyimide, and it is possible to adjust the refractive index to within 10^–2^ by varying the irradiation dose. The chemical condition of the polyimide after irradiation was investigated by XPS, and it was shown that the refractive index change was caused by decreasing molecular volume following separation of fluorine atoms. Using this refractive index controllability and the linearity of the synchrotron radiation, a method of fabrication of a waveguide diffraction grating using only synchrotron irradiation of a fluorinated polyimide optical waveguide through an X‐ray mask having a diffraction grating pattern was proposed. The waveguide diffraction grating fabricated by this method exhibited a reflectivity of 60% and a half‐value width of 0.25 nm. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 85(1): 59–66, 2002