Optical networking update

This paper presents an inventory of the current state and future prospects for networks in which signal paths between end user nodes remain entirely in optical form without intervening electronic conversions. The emphasis is on wavelength-division multiplexing (WDM). The applications and system aspects are stressed relative to details of the supporting technologies. The case to be made for optical networks as the basis of an entire possible future generation of networking is examined, after which the various architectural choices are discussed. Next, the limits on what can be achieved, mostly arising from limitations within the available technology, are treated. After a review of the history of all-optical networking, the paper concludes with speculations about where the applications, the technology and the architectural character of these systems will be going in the years ahead.