WDM devices and systems: a network operator perspective

There is enormous interest in wavelength division multiplexing (WDM) on the part of long-distance network operators. This technology allows fibers which a few years ago carried just 1-2 Gb/s to be upgraded using recently announced systems to carry a few hundred Gb/s. This huge increase in capacity can be accomplished without installation of new fiber. Since a national scale fiber plant is a multi-billion dollar investment, network operators are understandably enthused about WDM.