A Simple Method for Fabricating a Mach-Zehnder Type Waveguide Using Sol-Gel Derived Photopatternable Hybrid Materials for Optical Biosensors

In this work, we report on a simple method to fabricate a Mach-Zehnder type waveguide pattern using photopatternable sol-gel organic-inorganic hybrid materials. The refractive indices and propagation losses of the gel films were measured using the prism coupling method. The refractive indices of the resulting films were significantly influenced by the 3-trimethoxysilylpropylmethacrylate (TMSPM) concentration, and the average propagation loss was 0.32-0.52 dB/cm at the wavelength of 632.8 nm. The waveguides were fabricated using spin-coating and a photolithography technique. The Y-branch and straight pattern of the Mach-Zehnder waveguide were well-defined and had high transparency (>97%) in the visible region. The average thickness of the gel films was 10 mu m, and the average width of the Mach-Zehnder pattern was 10 mu m. The structural and optical properties of the fabricated patterns were analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM), near-infrared (IR) spectroscopy, and ultraviolet (UV)-visible spectroscopy