Liquid level sensor utilising a long period fiber grating


We propose here a liquid level sensor using a long period fiber grating (LPFG) in which direct liquid level measurement is carried out by utilising an LPFG, 100mm in length and a periodicity of 1mm. The LPFG was exposed to liquids with varying levels and the wavelength shift of a selected loss band of the transmission spectra was monitored using a broadband light source and an optical spectrum analyzer. The mechanism of this LPFG sensor is based on the fact that the effective Refractive Index (RI) of a cladding mode is directly dependant on the RI of the surrounding medium, be it air, or in this case water and petrol. As the surrounding RI changes, so does the phase matching condition of the LPFG. The result for the level change of the liquid with a specific RI is both a shift in wavelength and a change in the attenuation level of the selected loss band. For the selected loss band, continuous wavelength shifts of 9.5 nm and 25 nm for 100 mm of water and petrol level change have been observed respectively, with sub-millimetre accuracy.

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Divisions: College of Engineering & Physical Sciences > School of Engineering and Technology > Mechanical, Biomedical & Design
College of Engineering & Physical Sciences > Aston Institute of Photonics Technology (AIPT)
Additional Information: S. Grice ; W. Zhang ; K. Sugden and I. Bennion; "Liquid level sensor utilising a long period fiber grating", Proc. SPIE 7212, Optical Components and Materials VI, 72120C (February 06, 2009). Copyright 2009 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. DOI:
Event Title: Optical Components and Materials VI
Event Type: Other
Event Dates: 2009-01-26 - 2009-01-28
Uncontrolled Keywords: Broad Band Source,liquid level sensing,long period Fiber grating,optical spectrum analyzer,refractive index,LPFG,BBS,Computer Science Applications,Electrical and Electronic Engineering,Electronic, Optical and Magnetic Materials,Applied Mathematics,Condensed Matter Physics
ISBN: 978-0-8194-7458-2
Last Modified: 27 Jun 2024 12:16
Date Deposited: 25 May 2017 12:35
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Conference contribution
Published Date: 2009-02-06
Published Online Date: 2009-01-24
Authors: Grice, Steven
Zhang, Wei (ORCID Profile 0000-0002-3584-8541)
Sugden, Kate (ORCID Profile 0000-0001-6323-1082)
Bennion, Ian



Version: Published Version

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