Polymer optical fiber grating as water activity sensor


Controlling the water content within a product has long been required in the chemical processing, agriculture, food storage, paper manufacturing, semiconductor, pharmaceutical and fuel industries. The limitations of water content measurement as an indicator of safety and quality are attributed to differences in the strength with which water associates with other components in the product. Water activity indicates how tightly water is "bound," structurally or chemically, in products. Water absorption introduces changes in the volume and refractive index of poly(methyl methacrylate) PMMA. Therefore for a grating made in PMMA based optical fiber, its wavelength is an indicator of water absorption and PMMA thus can be used as a water activity sensor. In this work we have investigated the performance of a PMMA based optical fiber grating as a water activity sensor in sugar solution, saline solution and Jet A-1 aviation fuel. Samples of sugar solution with sugar concentration from 0 to 8%, saline solution with concentration from 0 to 22%, and dried (10ppm), ambient (39ppm) and wet (68ppm) aviation fuels were used in experiments. The corresponding water activities are measured as 1.0 to 0.99 for sugar solution, 1.0 to 0.86 for saline solution, and 0.15, 0.57 and 1.0 for the aviation fuel samples. The water content in the measured samples ranges from 100% (pure water) to 10 ppm (dried aviation fuel). The PMMA based optical fiber grating exhibits good sensitivity and consistent response, and Bragg wavelength shifts as large as 3.4 nm when the sensor is transferred from dry fuel to wet fuel.

Publication DOI: https://doi.org/10.1117/12.2054207
Divisions: College of Engineering & Physical Sciences > Aston Institute of Photonics Technology (AIPT)
Additional Information: Wei Zhang and David J. Webb, "Polymer optical fiber grating as water activity sensor", Micro-structured and Specialty Optical Fibres III, Kyriacos Kalli; Alexis Mendez, Editors, Proc. SPIE 9128 (2014). Copyright 2014 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: http://dx.doi.org/10.1117/12.2054207
Event Title: Micro-structured and specialty optical fibres III
Event Type: Other
Event Dates: 2014-04-14 - 2014-04-15
Uncontrolled Keywords: equilibrium relative humidity,fiber Bragg grating,PMMA,polymer optical fiber,water activity,Applied Mathematics,Computer Science Applications,Electrical and Electronic Engineering,Electronic, Optical and Magnetic Materials,Condensed Matter Physics
ISBN: 978-1-62841076-1
Last Modified: 08 Jul 2024 08:36
Date Deposited: 19 Jan 2015 16:48
Full Text Link: http://proceedi ... ticleid=1868436
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Conference contribution
Published Date: 2014-05-19
Authors: Zhang, Wei (ORCID Profile 0000-0002-3584-8541)
Webb, David J. (ORCID Profile 0000-0002-5495-1296)



Version: Published Version

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