TABLE OF CONTENTS Light-emitting diodes (LEDs) can be used for displays, for signals such as traffic lights, or for sending information at very high frequencies. Of course, all of these applications could be grouped under the heading of communications. LEDs have been made and sold for decades. Recent innovative research has led to dramatic improvements in LED output power and efficiency. The situation has evolved to the point that it is now clear that LEDs will be used in some light-ing applications by displacing the tungsten light bulb. The commercial stakes in this industry are very high; in my opinion, even higher than those in the communications industry. This application of LEDs may solve an important problem faced by engineers in optoelectronics, a marketing problem: how to a chieve product sales volumes that grow faster than product prices decline. This is a requirement for the existence of a business.
The circumstances imposed by the communications industry have led to the simultaneous development of high-reliability lasers with continuously improving bandwidth and, at the same time, optical fibers with reduced loss and dispersion. Initially, a result of this progress was to reduce the need for large numbers of optoelectronic devices in optical fiber telecommunications systems. As a result, making a growing business out of the design and manufacture of optoelectronic components like detectors, LEDs, and lasers for telecommunications has not been a simple task. During the past few years, the explosive growth of the Internet has prompted network equipment installers to develop...
