Measurement and analysis on polarization properties of backward Rayleigh scattering for single-mode optical fibers

Abstract

Fluctuation components on a backward Rayleigh scattered signal measured by the polarization optical time domain reflectometer (POTDR) have been investigated in detail by means of the least squares method and the power spectra. As a result, it is revealed that the fluctuation component for the single-mode optical fibers is attributable to the inherent polarization beat length determined by the difference of the phase velocities between the orthogonal <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</tex> HE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</tex> HE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> modes. The power spectrum of the fluctuation is sharply peaked at the Fourier frequency determined by the polarization beat length of approximately 15 m, which is in good agreement with the analysis. The utilization of the power spectrum presents a new method to diagnose the polarization properties along the optical fiber.