POLARIZATION MODE DISPERSION OF SHORT AND LONG SINGLE-MODE FIBERS

Polarization mode dispersion (PMD) in short and long single-mode fibers is measured by a polarization maintaining Michelson interferometer. We found a nonnegligible PMD in some standard fibers. The sensitivity enables us to measure the bend induced PMD of a fiber rolled on a 28-cm diameter drum. A theoretical model for polarization mode dispersion with random mode coupling is developed and an explicit equation for the time of flight distribution is presented. Comparison between measurements on short and long fibers with residual birefringence leads to an estimation of the coupling length of the order of 20-30 m.