A novel and highly sensitive liquid level sensor based on a polymer optical fiber Bragg grating (POFBG) is experimentally demonstrated. Two different configurations are studied and both configurations show the potential to interrogate liquid level by measuring the strain induced in a POFBG embedded in a silicone rubber diaphragm, which deforms due to hydrostatic pressure variations. The sensor exhibits a highly linear response over the sensing range and a good repeatability. For comparison, a similar sensor using a FBG inscribed in silica fiber is fabricated, which displays a sensitivity that is a factor of 5 smaller than the POFBG. The temperature sensitivity is studied and a novel multi-sensor arrangement proposed which has the potential to provide level readings independent of temperature and the liquid density.
Bibliographical noteFunding: Marie Curie Intra European Fellowship included in the 7th
Framework Program of the European Union (POSSIBLE PIEF-GA-2013-628604 project).
Marques, C. A. F., Peng, G-D., & Webb, D. J. (2015). Highly sensitive liquid level monitoring system utilizing polymer fiber Bragg gratings. Optics Express, 23(5), 6058–6072. https://doi.org/10.1364/OE.23.006058