Strain sensors are a valuable tool for assessing the health of structures. The University of New Brunswick, in conjunction with ISIS Canada, is developing a distributed fibre optic strain sensor based on Brillouin scattering. This sensor can provide a virtually unlimited number of measurement points using a single optical fibre. A description of the operating principles of the system is given, along with a summary of laboratory test results. Strain measurement accuracy as high as approximately ±11 µε has been demonstrated at 1 m spatial resolution. Spatial resolutions as short as 100 mm can be used, although with decreased strain measurement accuracy. Future development of the technology will include an enhancement allowing both strain and temperature to be measured simultaneously.Key words: strain sensor, fibre optics, distributed sensing, structural monitoring, Brillouin scattering.
Simultaneous distributed strain and temperature sensing based on combined Raman–Brillouin scattering using Fabry–Perot lasers