Fibre optic spectral polarimetry for sensing multiple stress-loaded locations along a length of fibre

The authors describe a novel fibre optic sensor detecting multiple stress-loaded locations, where cross-coupling takes place in a length of birefringent single-mode fibre. The information about the cross-coupled locations and the distances between them can be obtained from the modulated spectrum due to the interference between the uncross- and cross-coupled modes along the fibre. In the experiment, the determination of only the cross-coupled locations is demonstrated by the processing of the spectral interferences. The performance principle based on spectral polarimetry is described together with experimental demonstrations. The limitation to the spectral polarimetric technique is also discussed for the view of the sensor use