An optical space switch based on D-fibers has been fabricated and its use in switching networks investigated. The characteristics of a switching network depend not only on the nature of the switches used, but also on the architecture utilized. In general, architectural complexity can be used in a trade with switch specification to achieve a given network behavior. Several architectures are reviewed and their consequences on the switch specification evaluated. The principles of a D-fiber space switch are described, and the switching characteristics predicted and measured. The characteristics of the switch, within its optimum architecture, enable a fully transparent network, i.e. totally nonblocking with minimum restriction on optical bandwidth, to be realized. The limits to the size of such a network are calculated using the measured characteristics of a switch fabricated in the laboratory.>

A radically new approach to optical fiber cable design and installation is described. Packages containing a number of optical fibers were drawn into preinstalled empty bores (tubes) using the viscous drag of air. The drag force acting on the fiber package is distributed along its length, which makes it possible to introduce fibers into complicated routes, with low strain. In this paper, we will concentrate mainly on the design of the fiber package, first from the point of view of the hydrodynamic forces acting on it during installation. This leads to a theoretical model for the installation process. Second, we shall consider the package as a subminiature optical fiber cable, and examine its optical performance during manufacture and temperature cycling, which leads to a theoretical model of the temperature performance of the package. Finally, we will describe a trial field installation using this cabling technique.