aspects of commerce, improvements in the quality of life, and our ability to defend ourselves. Optoelectronics is interdependent with electronics, communication and information technology, and computer technology, and shares strategic importance with them.
Optoelectronics is not a new field. Around 1880, Alexander Graham Bell patented the Photophone, a system for voice communication utilizing amplitude-modulated sunlight as the electronic signal carrier. During the 1920s, the initial experiments on television were carried out at the AT&T Bell Labs, and extended and carried into commercial reality by the RCA David Sarnoff Labs and others during the 1930s. The advanced cathode-ray tubes (CRTs) developed during that period at Bell Labs were crucial to the early development of radar, so important for success in World War II. Advanced CRTs were used as the memory elements in the first electronic telephone switching service introduced by AT&T late in the 1950s. The laser was invented at Bell Labs in the mid-1950s, and in 1960 the first working laser was demonstrated at Hughes Aircraft Company. In 1970, the first low-loss fiber-optic transmission medium was demonstrated by Corning Glass, and the first room-temperature, continuously operating semiconductor laser was demonstrated at Bell Labs and in the Soviet Union. These form the heart of the current long-haul terrestrial and oceanic transmission systems for voice and data. For example, the first transoceanic underwater communication cable was installed in the mid-1950s. It utilized low-frequency, electron tube repeater and wire cable technology, and had only a few tens of channels. The first optoelectronic cable, TAT-8, based on semiconductor laser repeaters and fiber-optic transmission paths, was installed in the Atlantic Ocean between the United States and England and France, and operated first in December 1988. It has 40,000 voice channels in a cable the diameter of a finger, about the same size as the original electron tube cable. TAT-9, to be installed in 1992, will have more capacity than all previous cables combined. The semiconductor laser is also used in compact disc recording.
In 1969, the first charge coupled device (CCD), and in 1970 the first miniature color video cameras based on CCDs, were invented and developed at Bell Labs. The CCD has become the sensing element basis for most fax machines, the Camcorder, and many important military applications used in the recent Gulf War. It is often used in commercial television and in surveillance applications. The film-based still camera will eventually be supplanted by a CCD-based camera, and computer-based editing and transmission will change the nature of photography for advanced amateurs and news reporting.
As the name implies, optoelectronics is a part of the broader technological field known as "electronics." In optoelectronics, light rather than electrons plays a role in moving energy or information from one point to another. Actually, all energy and information in electronics is conveyed in