Pressure, temperature and refractive index determination of fluids using a single fibre optic point sensor

The accurate determination of physico-chemical fluid parameters is of major importance in many process engineering applications. Not only the monitoring of the phase distribution in piping systems but also the detection of chemical concentrations in liquids is of interest for an efficient, safe and reliable operation of laboratory as well as industry scale applications. In this paper, we present a miniature all-silica fibre optic sensor capable of measuring pressure, temperature and refractive index of a fluid at a single point simultaneously. In future, such a sensor can be utilized in applications, where these quantities and, hence, phase composition or chemical concentration have to be monitored possibly under harsh environments such as geothermal or oil drilling wells.