Tilted Fibre Bragg Gratings and Phase Sensitive-Optical Low Coherence Interferometry for refractometry and liquid level sensing

A set-up based on an interferometric technique and including tilted Fibre Bragg Gratings has been used to provide refractive index and liquid level measurements. Such gratings have been investigated using the well-known Phase Sensitive-Optical Low Coherence Interferometry technique. This combination provides very promising refractometry sensing results, as the relative uncertainty on measurement is lower than 0.04% in the range 1.37–1.40 and shows a clear potential in liquid level sensing.