коэффициент рассеивания от режима поляризации(The "PMD coefficient", with units of ps/km1/2, indicates the rate at which PMD builds up along the fiber length.
For a fixed length, a "PMD value", with units of ps, can be measured. Test sets have a minimum measurable PMD value. For fiber with a low PMD coefficient, a long fiber length is required for accurate measurement.
For example, if a 0.02 ps/km1/2 fiber is measured using an interferometric test set with a minimum PMD of 0.1 ps, one would requires 25 km of fiber. SleepyDude)
