Abstract

Photonic switching devices are required to route or switch an optical signal without translating it first to an electrical signal. Their main attraction is in the ability to handle optical signals in a transparent way: the format and data are set by the network terminals. Three different families of photonic switches can be defined according to the switching mechanism. Mechanical switches physically move fibers to route a signal. They are inherently slow but can be ideal for specific applications. Electrooptic switches using integrated optics are faster and more versatile. Some integrated optics technologies have been developed to the point that they can be tested in actual system experiments. We review the different kinds of electrooptical switching device, their principle of operation, and their typical parameters. All-optical switches are controlled by the light itself through a nonlinear optical interaction. All-optical devices could be extremely fast, and switching times of the order of 100 fs have been recently demonstrated. However, all-optical switches are still in their infancy. Several concepts have been proposed and demonstrated, yet their potential depends critically on the development of suitable nonlinear media. We describe some of these experiments and the problems facing this technology.

© 1988 Optical Society of America