The market, rationale and technology options for flexible transparent optical networks

This paper outlines the market for transparent optical networks and how these have developed, from their simple origins of saving the costs of OEO regeneration in point-to-point WDM links, to today´s ring and mesh networks with flexible/reconfigurable nodal traffic access, using multi-way ROADM´s. The paper then reviews and compares the technology options for multi-way ROADM´s and the impact that full optical transparency has on the overall network design. The paper also considers alternative approaches, using OEO conversion and electrical switching, and suggests where these or transparent optical switching may be most applicable in an increasingly cost-sensitive environment.