Abstract
Since the collapse of the market for optical communications equipment at the beginning of the millennium, there has been diminished interest and investment in technologies for long‐distance optical transmission. This is largely a result of the enormous capacities afforded by wavelength‐division multiplexed systems; the systems deployed early in the decade had capacities comparable to the total network traffic. This situation is about to change. Those systems are becoming full now, and growth in traffic indicates that capacity of systems will become a crucial factor in the years ahead. This paper examines the technical challenges inherent in scaling network capacity to accommodate traffic growth in the coming decades. © 2010 Alcatel‐Lucent.