Ultra-Long-Haul, Dense WDM Using Dispersion-Managed Solitons in an All-Raman System

Abstract

In the late 1990s, the telecommunications industry began to see dense WDM as the way to provide for the seemingly explosive growth in demand for transmission capacity. The usual industry practice of using electronic regeneration at every node point (typically, once every 400 to 600 km; see Fig. 18.1), however, promised to use far too much capital equipment and office space, especially if the net transmission rates were to be at terabit levels. For example, a system carrying one terabit/s in each direction, at the practical and increasingly popular per-channel rate of 10 Gbit/s, would require no less than 200 (expensive and bulky) regenerators, or OT units per node (one for each direction and channel). In the meantime, it was already well known, principally from undersea practice, that such dense WDM could be successfully carried out, without regeneration, over transoceanic distances, at least under the special conditions of the undersea environment. Thus the idea of developing an all-optical terrestrial system (which had in fact been advanced many years ago [1-3]) began to take root and to undergo engineering development by many firms.