Distributed Polarization-Sensitive Reflectometry in Nonreciprocal Single-Mode Optical Fibers

We present a novel theoretical model for the description of round-trip propagation of polarized optical signals in single-mode fibers affected by nonreciprocal birefringence. The model has a general validity, but it has been specialized to the case of Faraday rotation. Building on the theoretical result, we propose also a method to measure both reciprocal and nonreciprocal birefringence of single-mode fibers by means of polarization-sensitive reflectometry. The theoretical model and the measurement technique have been tested in a preliminary experiment, which consisted in measuring the static magnetic field of a 1.5 T magnetic resonance imaging scanner. Experimental results are in agreement with the theory.