Low-pressure and liquid level fiber‐optic sensor based on polymeric Fabry–Perot cavity

Abstract

An experimental study of the interaction between a Mylar® polymer film and a multimode fiber-optic is presented for the simultaneous fiber-optic detection of low-pressure and liquid levels. The junction between the polymer and optical fiber produces an interference spectrum with maximal visibility and free spectral range around 9 dB and 31 nm, respectively. Water pressure, which is controlled by the liquid level, stresses the polymer. As a result, the spectrum wavelength shifts to the blue region, achieving high sensitivities around 2.49 nm/kPa and 24.5 nm/m. The polymeric membrane was analyzed using a finite element model; according to the results, the polymer shows linear stress response. Furthermore, the membrane material is operated below the yielding point. Moreover, the finite analysis provides information about the stress effect over the thickness and the birefringence changes. This sensor exhibits a quadratic polynomial fitting with an adjusted R-squared of 0.9539. The proposed sensing setup offers a cost-effective alternative for liquid level and low-pressure detection.

Investigation by simulation of the highest sensitivity interferometric pressure sensor at the end of a micro-structured optical fiber

“…Polymers have low moduli of elasticity, which allows them to provide adequate sensitivities for fiber optic pressure sensors [10]. Usually, we use a chemical process to form the cone [11], in which we insert a quantity of polymer of type (PDMS) [12], and then we proceed to a chemical vapor deposition (CVD) [13] of gold, and this, to form the reflecting surface.…”

“…D. Jauregui Vazquez and al, have proposed an extrinsic fiber optic pressure sensor based on a silica diaphragm made by electric discharge, the sensor was designed to respond over a measurement range from 0 to 6.89KPa, and it has a sensitivity of around 2.49 nm KPa, this was also tested for a distance range from 0.14 to 0.7 m. The sensitivity obtained is 24.5 nm m −1 [16].…”

High-Sensitivity Liquid Level Sensor Based on the Balloon-Shaped Fiber Optic MZI

“…Among them, the liquid level sensor based on Fabry-Perot Interferometer (FPI) has been studied to a certain extent because of the advantage of non-direct contact with liquid measurement [15]- [17]. Jauregui-Vazquez et al reported a liquid level fiber-optic sensor based on polymeric FPI with a sensitivity of 24.5 nm/m [16]. In addition, MZI and Michelson interferometer-based fiber optic level sensors have also been studied by many researchers.…”