[OPTICAL REVIEW Vol. 7, No. 6 (2000) 505-510]

Properties of a Thin-Film Optical Waveguide Using Fluorinated Silicon Oxide and Organic Spin-on-Glass Films

Tetsuya HOMMA,1,2,* Hiroyasu KONDO,1 Masaya SAKAMOTO,1 Masahiro NOMOTO,1 Kazuaki INOHARA,1 Yuji ARIYAMA,3 Masahiro ITOH4 and Hideo TAKAHASHI1

1Department of Electronic Engineering, Faculty of Engineering, 2Center for Informative and Environmental Materials, Research Organization for Advanced Engineering, Shibaura Institute of Technology, 3-9-14, Shibaura, Minato-ku, Tokyo, 108-8548 Japan

(Received June 17, 2000; Accepted July 15, 2000)

A thin-film optical waveguide using a fluorinated silicon oxide (SiOF) as a core layer was investigated. An organic spin-on-glass (SOG) film was used for a cladding layer. The SiOF films were formed at 23°C by a liquid-phase deposition (LPD) technique using a supersaturated hydrofluosilicic acid (H2SiF6) aqueous solution. A thin-film optical waveguide structure for single mode was designed and fabricated, based on the dispersion properties of refractive indices for the LPD-SiOF and organic SOG films. The refractive indices at a wavelength of 632.8 nm were 1.430 and around 1.400 for the LPD-SiOF and organic SOG films, respectively. The thickness of LPD-SiOF films deposited was 1.18 μm. Thicknesses of cladding organic SOG films cured at 300 and 400°C were 1.28 and 1.31 μm, respectively. The effective refractive indices for single mode were 1.4169 and 1.4158 at a wavelength of 632.8 nm for the cladding organic SOG films cured at 300 and 400°C, respectively, and differences between the measured and calculated incident angles were 0.84° and 1.29° for the cladding organic SOG films cured at these respective temperatures. A streak of guided-light was observed for the LPD-SiOF/SOG structure optical waveguide. The transmission loss was 7.6-7.9 dB/cm.

Key words : thin-film optical waveguide, liquid-phase deposition, fluorinated silicon oxide, spin-on-glass, refractive index, prism coupling