Abstract

With the recent developments in tunable lasers and filters, star couplers, wavelength-routing multiplexers, low-noise optical amplifiers, and even wavelength changers, optical WDM technology is now emerging as the most flexible and efficient technique for accessing the vast bandwidth of the optical fiber. It permits a large number of independent users to communicate over the same network at a staggering overall throughput without a significant degree of coordination. When envisioning the use of this technology to construct an optical network of national or international extent, it is desirable to keep the signal path all optical from source to destination to offer the network users the flexibility of using virtually arbitrary signaling formats and modulation rates. To realize this goal efficiently it is essential that the network architecture be hierarchical, e.g., local area networks (LANs) interconnected by metropolitan area networks (MANs), which, in turn, are interconnected by a wide area network (WAN) of possible global extent. The subnetworks in such a hierarchy should be decoupled in such a way as to allow optical frequency reuse. Thus, optical frequencies used for local communications within a given LAN could be reused within any other LAN without interference. This increases the overall network capacity, conserves signal power, and simplifies network management and fault isolation.

© 1992 Optical Society of America