Low-Cost and High-Performance Optical Fiber-Based Sensor for Liquid Level Monitoring


Liquid level sensing is nowadays a relevant issue in a broad range of applications, forcing the sensors performance and cost to be evaluated in parallel. This paper proposes a fiber optic-based liquid level sensor system using a fiber Fabry-Perot interferometer (FPI) embedded into a polyurethane resin diaphragm. The FPI is based on microcavities generated upon catastrophic fuse effect, enabling the fiber recycling and sensors fabrication in a cost-effective way, compared to traditional methods. To enable the simultaneous temperature control, a fiber Bragg grating was used as thermal reference sensor to compensate the temperature cross-sensitivity. The sensor prototype was tested in a field application, using two different configurations, an open chamber configuration, where the diaphragm is in contact with the atmosphere, and a closed chamber configuration revealing the sensitivities of 4.4 +/- 0.1 pm/mm and 1.57 +/- 0.04 pm/mm, respectively. These sensitivity values are within the figures of merit for diaphragm-based sensors as reported recently.



subject category

Engineering; Instruments & Instrumentation; Physics


Martins, J; Diaz, CAR; Domingues, MF; Ferreira, RAS; Antunes, P; Andre, PS

our authors


This work was supported in part by the Fundacao para a Ciencia e a Tecnologia/Ministerio da Educacao e Ciencia through national funds and in part by FEDER PT2020 Partnership Agreement under Project UID/CTM/50025/2013, Project UID/EEA/50008/2019, and Project UID/CTM/50011/2013-POCI-01-0145-FEDER-007679. The associate editor coordinating the review of this paper and approving it for publication was Prof. Agostino Iadicicco.

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