Low-Pressure Measurement using an Extrinsic Fiber-Based Fabry-Perot Interferometer for Industrial Applications

Abstract

The development of an extrinsic fiber-based Fabry-Perot interferometer (EFFPI) for low-pressure measurement in the industry applications has been studied in this work. Monochromatic light from a laser diode with a wavelength of 1310 nm is operated as a source for illuminating the EFFPI sensor. A 30 mm diameter PVC pipe is utilized as a target, of which one end is sealed with a rubber balloon and the end is connected to the air pressure flow controlling system. Furthermore, the center point of the balloon is secured with a reflective thin film, which has a reflectance of ~55%. For the performance validation of the fiber sensor, a low-pressure range from 5 to 50 mBar is released onto the target. With 12 rounds repeatability, the experimental results reported that the average measured pressure values from the EFFPI sensor are 4.915 – 50.988 mBar. When compared to the reference instrument, the maximum and average errors in percentage terms are, however, 3.77% and 1.45%, respectively. In addition, results showed that the measured pressure value is directly proportional to the number of interference fringes, giving a sensitivity in the pressure measurement of the EFFPI sensor of 0.248 mBar/fringe.