Polarimetric optical fiber sensor with compensated birefringence for dynamic strain measurement

Polarimetric fiber optic sensors belong to phase sensors, in which phase shift between two electric field components of beam passing through a high birefringent optical fibers responsible for a change in polarization state of the light. The paper presents polarimetric fiber sensor for dynamic strain measurements. In order to measure the strain in several points of the rail a relatively long, of length of few meters, measuring fiber was used. It causes problems with coherence of light passing through the fiber and hence the compensation of the birefringence was introduced.