Signal processing treatments for static and dynamic Brillouin distributed sensing

Abstract

The Brillouin frequency spectrum profile is characterised by the Lorentzian or the Gaussian function, which is identical to the reflection spectrum of a fibre Bragg grating (FBG), while similarly the Brillouin frequency is linearly dependent on the amount of applied strain or the ambient temperature of the fibre. In this paper, we used the Zero-Crossing fibre Bragg grating demodulation algorithm to optimise the Brillouin frequency shift of a typical single-mode optical fibre, SMF28, in which static and dynamic strain steps are applied. We showed that the FBG demodulation algorithms could be used and improve the response from a Brillouin system even though the strain levels are below the measuring capability of the system.