Simultaneous Detection of Liquid Level and Refractive Index with a Long-Period Fiber Grating Based Sensor Device
In this study, a long-period fiber grating (LPFG)-based optical fiber sensor device is proposed for simultaneous detection of liquid level and refractive index (RI). When part of the grating was submerged in an unknown liquid, the resonant wavelength of each cladding mode of the LPFG sensor varied linearly with the submerged length and nonlinearly with the RI of the liquid. By retaining the first-order (sensitivity) and second-order (cross sensitivity) terms of a Taylor expansion of the nonlinear relation, the changes in submerged length (or liquid level) and RI can be simultaneously evaluated from the changes in resonant wavelength of two cladding modes. The sensitivity coefficients to liquid level, RI, their cross effect and environmental effects were studied both analytically and experimentally. The maximum prediction error by the proposed evaluation algorithm was found to be 1 mm for liquid level and 0.005 for RI.
Y. Huang et al., "Simultaneous Detection of Liquid Level and Refractive Index with a Long-Period Fiber Grating Based Sensor Device," Measurement Science and Technology, vol. 24, no. 9, IOP Publishing Ltd., Sep 2013.
The definitive version is available at https://doi.org/10.1088/0957-0233/24/9/095303
Civil, Architectural and Environmental Engineering
Electrical and Computer Engineering
Keywords and Phrases
Multiple Parameter Sensing; Evaluation Algorithm; Liquid Level; Long Period Fiber Grating; Optical Fiber Sensor; Resonant Wavelengths; Sensitivity Coefficient; Simultaneous Detection; Diffraction Gratings; Refractive Index
International Standard Serial Number (ISSN)
Article - Journal
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01 Sep 2013