White-light spectral interferometry with the equalization wavelength determination used to measure distances and displacements

Two new white-light interferometric techniques employing a low-resolution spectrometer in the equalization wavelength determination are proposed to measure distances and displacements. The techniques use a dispersive Michelson interferometer alone or a tandem configuration of a non-dispersive Michelson interferometer and a two-mode optical fibre when the dispersion in the interferometer and the intermodal dispersion in the optical fibre are known. We demonstrate experimentally that these known dispersions affect the range of measurable distances and the sensitivity of the displacement measurements.