Long-Term PMD Characterization of a Metropolitan G.652 Fiber Plant

Using the Jones matrix eigenanalysis method, the differential group delay (DGD) behavior of a metropolitan G.652 buried operational cable plant of a major Italian telecom operator in the city of Torino was characterized. The measurement campaign lasted 73 consecutive days. An extremely stable DGD behavior was found, despite the fact that the cables run across a very densely built city environment. On the other hand, it was also found that routine maintenance on the infrastructure, although indirect and nondisruptive, repeatedly altered this picture. Based on these results, it is argued that the recently introduced "hinge" model describes the plant DGD statistical behavior better than the traditional description. This argument is also supported by the close fit that was obtained with a theoretical hinge-model DGD probability density function of the measured DGD data histogram. It is also argued that in this kind of scenario fast adaptive compensation is most likely the only realistic solution for avoiding sudden performance degradation or out-of-service