An all-fiber Fabry-Perot sensor for emulsion concentration measurements

This paper describes a Fabry–Pérot sensor-based measuring system for measuring fluid composition in demanding industrial applications. The design of the sensor is based on a two-parametric sensor, which enables the simultaneous measurement of temperature and refractive index (RI). The system was tested under real industrial conditions, and enables temperature-compensated online measurement of emulsion concentration with a high resolution of 0.03 Brix. The measuring system was equipped with filtering of the emulsion and automatic cleaning of the sensor, which proved to be essential for successful implementation of a fiber optic RI sensor in machining emulsion monitoring applications.

1 Laboratory for Electro Optics and Sensor Systems, Faculty of Electrical Engineering and Computer Science, University of Maribor, Koroska Cesta 46, 2000 Maribor, Slovenia

2 Marovt d.o.o., Stranice 55, 3206 Stranice, Slovenia

Sensors 2023, 23(4), 1905;

Received: 22 December 2022 / Revised: 24 January 2023 / Accepted: 4 February 2023 / Published: 8 February 2023