A multi-mode optical fibre sensing system using white light interferometry

Firstly, the theory of the white light interferometer is presented. This is followed by minimum peak height difference and related experimental results. The curve fitting signal processing scheme and the best order of polynomial for curve fitting are then discussed. Finally, displacement measurement with and without curve fitting signal processing is examined. The results show that, with a two wavelength source, the central fringe can be identified if the sampling gap is smaller than the maximum sampling OPD gap. The noise in the system can be reduced by the curve fitting technique proposed. The best order of the polynomial used to carry out curve fitting is four according to the experimental results and the analysis.