A method for screening fiber polarization mode dispersion using a
polarization optical time domain reflectometer. A pulse radiation is
emitted into the fiber under test, and the backscattered radiation is
measured by the POTDR and used to obtain a POTDR trace. A composite trace
of more than one POTDR trace is obtained. The composite trace is then
analyzed to compare the variation of signals along the length of the
fiber, the variation in signals relating to the level of PMD along the
length of the fiber. Because high levels of PMD correspond to localized
levels of low variability, by setting the variability of signal threshold
sufficiently low, fibers having unacceptably high localized PMD can be
identified and removed.