All-optical networks

Reviewer: George Michael White

This well-written, succinct introduction to optical networks discusses the implications of extremely high (by current standards) bandwidths and the applications that can be realized with them. It is unfortunate that a typo in a footnote containing Shannon's theorem may lead the reader astray in the discussion of the achievable bandwidth. Apart from this, the authors summarize fiber optics, and its use in cables to realize data networks, well. They suggest that the technology will be extensively used for Web browsing, miscellaneous visualization applications, medical imaging, multimedia conferencing, and other broadband services to the home and office. The components of optical systems are discussed next, with sections devoted to fiber principles and light transmitters and receivers. Networking technology, optical amplification, and wavelength division multiplexing (WDM) contrasted with time division multiplexing are all covered. Three classes of optical nets—the WDM point-to-point link, the broadcast and select, and the wavelength router—are compared. The authors briefly explain how existing services—POTS, T-1, SONET, IP, and ATM networks—can be handled with optical networks. The paper concludes with a listing of some current research projects in industry and academia and some speculation as to what the next steps may be. The treatment of all subjects is nontechnical, and those already working in the field will learn little that is new. Everyone else working in communications will find the paper interesting, enlightening, and important.