Beat length characterization based on backscattering analysis in randomly perturbed single-mode fibers

This paper presents analytical and numerical results on the statistical properties of the backscattering signal of a randomly perturbed, linearly birefringent, single-mode fiber. Our theory is based on the study of amplitude evolution of the backscattered field passed through a linear polarizer, aligned with the state of polarization of the input signal. In particular, we show that the mean value of the beat length can be calculated using two methods based, respectively, on a level crossing rate analysis of the backscattered signal and on the evaluation of the standard deviation of its spectral density.