Refractive-index measurements using an integrated Mach-Zehnder interferometer

Abstract In this paper a refractometer system with an integrated optical sensor is presented. The sensitive element is a single or multichannel Mach-Zehnder interferometer (MZI) fabricated on silicon using waveguides made from SiO2 and SiON. The refractometer allows for real-time monitoring of refractive indices of gases and liquids in an index range between 1 and 1.49 using the silicon MZI as a low-cost disposable part.