Summary: A strategy for the synthesis of sol‐gel hybrid materials that contain perfluorocyclobutyl groups is reported. Sol‐gel films have been prepared from three types of siloxane monomers using a typical sol‐gel method in an acidic atmosphere, followed by UV irradiation and dimerization. The materials show high thermal stability that exceeds 400 °C. At a wavelength of 1 550 nm, the refractive index, the birefringence, and the optical loss of the sol‐gel materials are found to be in the ranges of 1.4568–1.4876, ?0.0003–0.0029, and 0.34–0.45 dB · cm?1, respectively.
Zero mode birefringence (TE: solid, TM: dash dot) of sol‐gel materials (PFSI/TFVOSI/MSI = 6:1:3) (TE and TM represent polarization perpendicular and parallel to the plane of incidence, respectively).
