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Highly sensitive liquid level monitoring system utilizing polymer fiber Bragg gratings

Marques, C. ; Peng, G. ; Webb, D. J.

Optics Express Vol. 23, Nº 5, pp. 6058 - 6072, February, 2015.

ISSN (print): 1094-4087
ISSN (online):

Journal Impact Factor: 3,488 (in 2014)

Digital Object Identifier: 10.1364/OE.23.006058

Abstract
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.