CO2 phase study using an optical fiber refractometer

A refractive index sensor based on the Fresnel reflection at the tip of a single mode optical fiber is used to study phase changes of CO2 when cooled down from room to -50° C. The sensor system is compact and can be readily integrated into other optical and electronic systems. The refractive index measurements present good agreement with the literature. The use of the refractometer as a tool to determine the CO2 phase in oil fields is envisaged.