Abstract: In a polarimetric fibre-optic sensor using a polarization-maintaining optical fibre with two light propagation modes, a reference light signal is fed to propagate along the optical fibre in accordance with one propagation mode, a series of measurement light signals being induced by a series of optical fibre deformation elements, to propagate along the optical fibre in accordance with the other propagation mode, each being unbalanced in time with respect to the reference light signal by an amount which is different from that of the other measurement light signals; by using particular interferometric techniques, compensating the unbalances and analyzing the signals resulting from the interference between the measurement light signals and the reference light signal it is possible to determine and locate a physical phenomenon which disturbs the optical fibre.