WDM optical communication networks: Progress and challenges

While optical-transmission techniques have been researched for quite some time, optical networking studies have been conducted only over the past dozen years or so. The held has matured enormously over this time: many papers and Ph.D. dissertations have been produced, a number of prototypes and testbeds have been built, several books have been written, a large number of startups have been formed, and optical WDM technology is being deployed in the marketplace at a very rapid rate. The objective of this paper is to summarize the basic optical-networking approaches, briefly report on the WDM deployment strategies of two major U.S. carriers, and outline the current research and development trends on WDM optical networks.