Polarization optical fiber sensor for distributed current monitoring

A new technique to distributedly monitor intense current along high energy electric cables is presented and experimentally validated. The new technique is based on the distributed polarization measurement of Rayleigh backscattered light and on Faraday rotation of polarization induced by the electric current flowing in the cable. While current monitoring by Faraday rotation in optical fibers is among the first examples of optical fiber sensors, this is the first time, to best of our knowledge, that a distributed current sensor is implemented. Preliminary experimental tests have been performed on a 40-m-long electric cable, with currents varying from 0 kA to 2.5 kA, using standard telecommunication fibers non-optimized to the specific aim. Results confirm the viability of the approach.