Dynamic Low-Pressure Measurement Using a Fiber Optic-based Fabry-Perot Interferometer

A dynamic low-pressure measurement using a fiber optic-based Fabry-Perot Interferometer (FFPI) has been demonstrated in this work. The developed system has been divided into 2 main parts: pressure source and sensing system. The former is a chamber comprised of an elastic diaphragm, which proportionally deflects according to input pressure from an air pump. The FFPI, consequently, detects the material deflection and demodulates the parameter into useful pressure value via the fringe counting technique and Kirchhoff-Love’s plate theory. To validate the performance of the developed system, a reference pressure instrument is utilized while the air pump feeds pressure of 0.34–6.57 mbar with 10 times repeatability into the system. The experimental results indicated that the FFPI can measure the pressure of 0.343–6.568 mbar, while the reference instrument showed the output values from 0.343–6.471 mbar, respectively. Moreover, the average and maximum percentage error in measurement is 1.27% and 2.67%, respectively. The resolution of the FFPI sensor is also analyzed to be approximately 0.05% or 0.0382 mbar/μm over all measurement ranges. Therefore, we conclude that the FFPI has high accuracy, resolution, linearity, and reliability in dynamic low-pressure measurements.