No abstract

We have made continual, multiple-day measurements of the polarization dependent loss of multiple C-band channels in an installed 1800 km terrestrial link. The PDLs of individual channels varied on the time-scale of hours, while the temporal variations of the PDLs of adjacent channels often tracked. The probability densities of the field measurements of PDL were not Maxwellian and instead were truncated, consistent with the limited number of elements in the link having appreciable PDL. A new model for the statistics of PDL in systems with few PDL elements is proposed, where a lower bound of the distribution exists if there is a dominant PDL element. The probability distributions from measurement and theory show good agreement.

No abstract

Reconfigurable amplifiers are presented that allow the extension of link lengths in wavelength-division multiplexing (WDM) systems. Standard amplifiers meet the fundamental requirement for a flat gain spectrum at multiple gains by introducing variable optical losses by means of a variable optical amplifier. However, this technique results in strong noise figure degradation at small gain values. Modifying the length of the active erbium-doped fiber by means of optical switches avoids this problem.