FIBER OPTICS

Improving Telephones

Beginning in the mid 1960s researchers began to explore the possibilities of fiber-optic technology. By the beginning of the 1970s it was apparent that fiber optics had tremendous potential to improve the clarity and speed of telephone signals. A single hair-thin optical fiber could carry as many messages as a thick copper-wire cable containing 512 wires. Unlike copper wires, the glass fiber is unaffected by motors, electrical generators, power lines, or lightning storms—common causes of static on the line.

How It Works

The thin, extremely pure glass of an optical fiber, surrounded by a reflective casing, can bend light. This makes it possible to use light, specifically light generated by lasers, in place of electricity. Light can be carried faster, more cheaply, and more efficiently than electrical signals. Sounds are converted into a pattern of light, transmitted, received at the other end, then converted back into sound.

Putting It to Use

One of the first uses of fiber optics was in 1977 in Chicago. There two offices of Bell Telephone and a third for customers were successfully connected by light-carrying glass fibers. In 1978 the phones at Disney World were linked through fiber optics, and Disney also used them for video transmission, lighting, and alarm systems. They also built an intriguing two-way video-speaker arrangement, like a phone with a picture, for use at their EPCOT Center. Fiber optics have made possible fax technology, laser printers, high-quality copy machines, new medical tools that allow surgeons to see inside a patient using a tiny incision, and the rapid modem links between computers.

THE COMPACT DISC

Ever since the phonograph was developed in 1877, recordings have been made by the vibrations of a needle on a groove. Eventually, the groove and the needle wear out, and the sound quality deteriorates.

In 1972 optoelectronics made the development of the compact disk, or CD, practical. Lasers could convert sound into microscopic traces on the surface of a disk. Other lasers could detect them and convert them back into sound. The recordings came out stunningly clear, more information could be packed in than before, and there was almost no wear. The first commercially successful audio CDs were introduced in Japan and Europe in 1982 and in the United States the following year.