Comparison between as-built data and field measurements of PMD in OPGW cabled fibres

Factory measurements of polarisation mode dispersion (PMD) on optical ground wire cabled fibres are compared with field measurements of the installed span links. Analysis of the expected PMD values calculated from the factory measurements and the as-built reports reveal a systematic overestimation of the PMD in installed links, mitigated by correction of the limited sensitivity of commercial equipments. Unexpectedly high PMD values are observed, indicating that important changes on the PMD characteristics of the fibres may occur during cable installation