DISTRIBUTED MEASUREMENT OF BIREFRINGENCE IN POLARIZATION-MANTAINING FIBERS

In this paper a technique to perform a distributed measurement of the birefringence of an optical fiber is proposed. The method relies on the correlation of the spectra of two orthogonal polarization states, which reveals a side peak at a frequency shift proportional to the local difference between the group refractive indexes of the two orthogonal birefringence axes. This allows to perform local birefringence measurement with a spatial resolution in the order of the centimetres using a single OFDR acquisition. While some theoretical aspects need further investigation, preliminary experiments, performed on both single and concatenated polarization maintaining fibers, confirm the viability of the proposed technique.