Analysis of polarization fluctuation in single-mode optical fibers with continuous random coupling

A new analysis method is developed to study the polarization fluctuation in conventional single-mode optical fibers. A random partial differential equation is derived to describe the continuous random coupling between two eigenpolarization modes caused by the perturbation of permittivity along fibers. The calculation formulas for the polarization fluctuation are given. By these formulas, it is proved that the average noise power of the fluctuation at the fiber output depends on the fiber length, the correlation length of perturbation, and the variance of disturbances.