Light-based information systems for the businessman

ABSTRACT

The rapid advances in light-based information transfer have left many awed, both engineers and end users. Articles and books for the former are highly technical, while information for the latter discusses the results without an explanation of the principles. This paper seeks to bridge that gap.Examined first is the conceptual difference between the two primary transfer methods --- copper coaxial cable and fiber optic cable. Next, attenuation and noise are discussed as the primary factors encouraging the development of glass fibers. The following section uses this information to look at a few example systems (like Bell's transatlantic underwater system) and the benefits derived from the installation of fiber optic cable.The LED transmitter is examined, and particularly the special LED: the laser. The development and structure of injection lasers are described, from the simple diffused-junction lasers (like GaAs-GaAs lasers), to the complex double-heterojunction lasers (like AlGaAs-GaAs lasers). Examples are considered to see benefits brought by lasers.With the terms set, the paper delves into the technical specifications which might confront a decision maker, and concludes by listing the potential benefits and drawbacks of a light-based communication system.