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Proceedings Paper

Spontaneous Brillouin-based distributed temperature fiber sensor with 35-cm spatial resolution
Author(s): Huai H. Kee; Gareth P. Lees; Trevor P. Newson
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Paper Abstract

Certain distributed sensing applications require sub-meter spatial resolution accuracy, and there is interest as to whether the Brillouin linewidth ultimately limits the spatial resolution that can be achieved. We present a single-ended, spontaneous Brillouin-based distributed temperature fiber sensor with measurements operating with a spatial accuracy of 35 cm. The sensor consists of two main components, a laser source to generate the Brillouin backscattered signal and a low cost filtering system which comprises an all-fiber Mach-Zehnder interferometer connected to a InGaAs detector and computer based averaging system. The sensing fiber was 1 km in total, consisting of three sections of conventional single-mode fiber spliced together with lengths of 600 m, 200 m and 200 m respectively. The second drum was at 67 degree(s)C, an increase of 44 degree(s)C from the two other drums at room temperature of 23 degree(s)C. The results show a rise in the Brillouin signal in the heated section. To take absolute measurements independent of fiber attenuation and localized splice/bend losses, the Brillouin signal has to be referenced to the Rayleigh backscattered signal that is independent of temperature fluctuations. The ratio of the Brillouin and Rayleigh signals (Landau-Placzek ratio) provides a temperature dependent signal which is corrected for splice/bend losses and fiber attenuation.

Paper Details

Date Published: 31 August 2000
PDF: 8 pages
Proc. SPIE 4074, Applications of Optical Fiber Sensors, (31 August 2000); doi: 10.1117/12.397889
Show Author Affiliations
Huai H. Kee, Univ. of Southampton (United Kingdom)
Gareth P. Lees, Univ. of Southampton (United Kingdom)
Trevor P. Newson, Univ. of Southampton (United Kingdom)

Published in SPIE Proceedings Vol. 4074:
Applications of Optical Fiber Sensors
Alan J. Rogers, Editor(s)

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