will counteract the lower birefringence of deployed transmission fibers. The
natural tendency to “cherry pick” better fibers on existing routes and economic
constraints on new fiber deployment will stress the utility of existing fiber plants.
In short, one can reasonably view the last several years as a hiatus, not as a
permanent victory over PMD impairments.
Balanced against these potentially troubling forces are a mature understanding
of the basic physical processes, and an increasingly comprehensive view of how
fibers react in installed networks. Future research to attain more sophisticated
understanding of the interplay between the various impairments, will undoubtedly
result in better modeling, emulation, and mitigation of PMD-related impairments ...