Highly sensitive liquid-level sensor based on dual-wavelength double-ring fiber laser assisted by beat frequency interrogation


A highly sensitive liquid-level sensor based on dual-wavelength single-longitudinal-mode fiber laser is proposed and demonstrated. The laser is formed by exploiting two parallel arranged phase-shift fiber Bragg gratings (ps-FBGs), acting as ultra-narrow bandwidth filters, into a doublering resonators. By beating the dual-wavelength lasing output, a stable microwave signal with frequency stability better than 5 MHz is obtained. The generated beat frequency varies with the change of dual-wavelength spacing. Based on this characteristic, with one ps-FBG serving as the sensing element and the other one acting as the reference element, a highly sensitive liquid level sensor is realized by monitoring the beat frequency shift of the laser. The sensor head is directly bonded to a float which can transfer buoyancy into axial strain on the fiber without introducing other elastic elements. The experimental results show that an ultra-high liquidlevel sensitivity of 2.12 × 107 MHz/m within the measurement range of 1.5 mm is achieved. The sensor presents multiple merits including ultra-high sensitivity, thermal insensitive, good reliability and stability.

Publication DOI: https://doi.org/10.1364/OE.20.027367
Divisions: Engineering & Applied Sciences > Aston Institute of Photonics Technology
Uncontrolled Keywords: Atomic and Molecular Physics, and Optics
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://www.osa ... =oe-20-25-27367 (Publisher URL)
PURE Output Type: Article
Published Date: 2012-12-03
Published Online Date: 2012-11-21
Authors: Dai, Yi
Sun, Qizhen
Tan, Sisi
Wo, Jianghai
Zhang, Jiejun
Liu, Deming


Item under embargo.

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