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Proceedings Paper

Fibre optic/hydrogel probe for distributed chemical measurements
Author(s): W. Craig Michie; Brian Culshaw; I. McKenzie; Chris Moran; Neil B. Graham; F. Santos; Peter T. Gardiner; Erik Bergqvist; B. Carlstrom
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Paper Abstract

This paper reports on the basic design and preliminary evaluation of an entirely novel cable configuration which enables the detection of water, pH or similar variables as a function of position along the length of an optical fibre. This sensing capability is realised through a combination of Optical Time Domain Reflectometry (OTDR) and a microbend transducer activated by chemically sensitive water swellable polymers (hydrogels). Experiments with a water sensor prototype have demonstrated the detection of wetted sections of less than 25 cm length in cables longer than 100 m and indicate that interrogation of sensors several kilometres long is possible. The present experiments have demonstrated the principal of measurement through the development of a distributed water detector. However the technique can be used to monitor various chemical parameters such as pH or ionic concentration by selecting the appropriate gel as the responsive medium.

Paper Details

Date Published: 14 September 1994
PDF: 4 pages
Proc. SPIE 2360, Tenth International Conference on Optical Fibre Sensors, (14 September 1994); doi: 10.1117/12.185022
Show Author Affiliations
W. Craig Michie, Univ. of Strathclyde (United Kingdom)
Brian Culshaw, Univ. of Strathclyde (United Kingdom)
I. McKenzie, Univ. of Strathclyde (United Kingdom)
Chris Moran, Univ. of Strathclyde (United Kingdom)
Neil B. Graham, Univ. of Strathclyde (United Kingdom)
F. Santos, Univ. do Porto (Portugal)
Peter T. Gardiner, Univ. of Strathclyde (United Kingdom)
Erik Bergqvist, Ericsson Cables Co. (Sweden)
B. Carlstrom, Ericsson Cables Co. (Sweden)

Published in SPIE Proceedings Vol. 2360:
Tenth International Conference on Optical Fibre Sensors
Brian Culshaw; Julian D. C. Jones, Editor(s)

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