Multi-point strain measurement using Fabry–Perot interferometer consisting of low-reflective fiber Bragg grating

A novel simultaneous multi-point strain sensing system based on fiber Bragg grating (FBG) is proposed. In conventional FBG based multi-point sensing systems, the number of measurement points is limited by various factors. For example, in a method based on the wavelength division multiplexing method (WDM), there is a trade-off between the number of the points and dynamic range of measurement. And in a method based on the time division multiplexing (TDM), there is a trade-off between the number of the points and measurement time. The proposed sensing system has a capability of multi-point measurement with high dynamic range and short measurement time. A Fabry–Perot interferometer consisting of low-reflective FBG (FBG-FPI) is introduced as a sensor head. The reflection spectrum from an array of the FBG-FPIs is analyzed using Fourier transform. An experimental demonstration of multipoint strain measurement is reported.