LAUSR

Abstract We propose a refractive index sensing structure based on Mach–Zehnder interferometer (MZI) with a hybrid silica/polymer waveguide. Due to the thermo-optic (TO) effects of polymer and silica, the refractive index of sample can be measure by an integrated circuit. We discuss the design principle of the refractive index sensing waveguide and give its equivalent circuit to explain the sensing process. The sensitivity of MZI waveguide achieves 5556 °C/RIU which has a compact size of 10 μm × 6 mm. The sensing structure can be applied in a highly compact biosensing system and possess a great potential in point-of-care diagnostics and healthcare applications.