Properties of a thin-film optical waveguide using fluorinated silicon oxide and organic spin-on-glass films

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 degreesC by a liquid -phase deposition (LPD) technique using a supersaturated hydrofluosilicic a cid (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 refracti ve 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 fil ms deposited was 1.18 mum. Thicknesses of cladding organic SOG films cured at 300 and 400 degreesC were 1.28 and 1.31 mum, 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 degrees C, respectively, and differences between the measured and calculated incide nt angles were 0.84 degrees and 1.29 degrees for the cladding organic SOG f ilms cured at these respective temperatures. A streak of guided-light was o bserved for the LPD-SIOF/SOG structure optical waveguide. The transmission loss was 7.6-7.9 dB/cm.