Fibre optic strain analysers and specifications
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Published:2016
Cedric Kechavarzi, MSc, PhD, FHEA, Kenichi Soga, FREng, FICE, Nicholas de Battista, BE&A (Hons), MSc, PhD, MASCE, A&CE, Loizos Pelecanos, MEng(Hons), ACGI, PhD, DIC, Mohammed Z E B Elshafie, BSc (Hons), MPhil, PhD, Robert. J Mair, CBE FREng, FICE, FRS, 2016. "Fibre optic strain analysers and specifications", Distributed Fibre Optic Strain Sensing for Monitoring Civil Infrastructure: A Practical Guide, Cedric Kechavarzi, MSc, PhD, FHEA, Kenichi Soga, FREng, FICE, Nicholas de Battista, BE&A (Hons), MSc, PhD, MASCE, A&CE, Loizos Pelecanos, MEng(Hons), ACGI, PhD, DIC, Mohammed Z E B Elshafie, BSc (Hons), MPhil, PhD, Robert J Mair, CBE FREng, FICE, FRS
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A distributed fibre optic (FO) strain sensing system is composed of two fundamental elements: (i) an FO to measure strain and another to measure temperature (or a network of FO cables) installed within the structure to be monitored; and (ii) an optical spectrum analyser designed to characterise the Brillouin spectrum of the backscattered light from the fibres (see Figure 1.8) in order to measure central frequency shifts from which strain and temperature are derived.
Brillouin spectrum analysers and the measurement system specifications are introduced. It should be noted that, although this guide focuses predominantly on Brillouin optical time domain reflectometry (BOTDR) and Brillouin optical time domain analysis (BOTDA), the list of system specifications described here would remain valid for most distributed fibre optic sensing (DFOS) systems.
