wavelength-division multiplexed (CWDM) systems. A 10-nm spacing of chan-
nel wavelengths in a CWDM system drives down the cost of pluggable transceivers by
eliminating component cooling requirements, and simplifies optical filter design and
manufacture. These systems also tend not to have optical amplification. Optical
channel data rates in the access network today are predominantly at or below
2.48 Gb/s, with 4 and 10 Gb/s gaining some recent deployments.
Metro systems may be classified by reaches typically below 300 km, with
currently typical node traffic capacities of one to several 10’s Gb/s. Given the
reach, number of nodes and optical add/drop granularity, Metro networks are
typically equipped with optical amplifiers and support DWDM with