This document is limited to the statistics of the PMD distribution of cabled fibers. When the relationship between the cabled fiber distribution and uncabled fiber distribution is known and stable, the uncabled fiber data may be used to augment the characterization of the cabled fiber PMD distribution. Methods of doing this are beyond the scope of this document.

This document addresses first-order PMD from the perspective of the polarized view [2], in which the two principal states of polarization at the output are orthogonal and distinct. The relative time delay between the two modes at a given wavelength is the differential group delay (DGD). The average of DGD values across wavelengths yields the PMD value.

This document assumes that the cabled fiber is highly mode coupled. As a result, the distribution of the differential group delay values for a given cabled fiber is assumed to be random across time and wavelength. The random values follow a Maxwell distribution [2].

The statistical limits are given in terms of concatenated links composed of several randomly selected individual cable sections to give them meaning in terms of functionality. The requirements, however, are only applicable to the distribution of PMD coefficients from individual cable sections that are produced by the cabler.