High sensitivity distributed temperature fiber sensor using stimulated Brillouin scattering

Optical fiber technology has become a very powerful tool for distributed temperature (strain and refractive index) sensing, and can be used to monitor critical infrastructures such as bridges, aircrafts, pipelines, etc. Stimulated Brillouin scattering (SBS) in optical fibers used for distributed sensing utilizing the first Stokes order, is limited to a fixed material property, 1.1 MHz/degrees C for SMF-28. We demonstrate a distributed higher order Stokes SBS temperature fiber-sensor increasing the achievable sensitivity by several folds to over 4 MHz/degrees C. The proposed system uses time-gating for distributed sensing. This allows the increase in sensitivity by the order of the Stokes waves generated while maintaining a fairly normal spatial resolution over a few kilometers of sensing length. Increased sensitivity on these types of sensors may allow an earlier detection which could prevent failure of the monitored structure. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement