Although satellite systems are expected to be the dominant communications medium for long distance during the rest of the 90s, fiber-optics technology is revolutionizing the communications industry because of its low cost, height transmission volume, low error rate, and message security. Fiber optic communication cable are replacing copper wire as the major communications medium in buildings and cities; major communications companies are currently investing huge sums of money in fiber optic communication cable networks that can carry digital signals, thus increasing communications capacity. (Computers connected by fiber-optic cables do not need to use modems.)
In fiber-optics communications, signals are converted to light form and fired by laser in bursts through insulated, very thin (2/1000 of an inch) glass or plastic fibers, The pulses of light represent the “on” state in electronic data transmission and can occur nearly 1 billion times per second – up to 80 gigabytes of digital data per second can be sent through a fib er-optic cable. Equally important, fiber optic communication cable aren’t cumbersome in size; a fiber optic communication cable (insulated fibers bound together) that is only 0.12 inch thick is capable of supporting nearly 250000 voice conversations at the same time (soon to be doubled to 500000). However, since the data is communicated in the form of pulses of light, specialized communications equipment must be used.
Fiber optic communication cable are not susceptible to electronic noise and so have much lower error rates than normal telephone wire and cable. In addition, their potential speed for data communications is up to 10000 times faster than that of microwave and satellite systems. Fiber-optic communications is also resistant to illegal data theft, because it is almost impossible to tap into it to listen to the data being detected; in fact, it is currently being used by the Central Intelligence Agency. Another advantage to fiber-optic transmission is that electrical signals don’t escape from the cables- in other words, the cables don’t interfere with sensitive electrical equipment that may be nearby. Given its significant advantages, it is not surprising that fiber-optic cable is much more expensive than telephone wire and cable. (A twisted- pair telephone wire of 4 megahertz might send only 1 kilobyte of data in a second. A coaxial cable of 100 megahertz might send 10 megabytes. And a fiber-optic cable of 2 billion megahertz might send 1 gigabyte.)
AT&T has developed undersea optical fiber cables for transatlantic use in the belief that fiber optics will eventually replace satellite communication in terms of cost-effectiveness and efficiency. Japan has already laid an underwater fiber-optic cable. Sprint uses a fiber-optic communications network laid along railroad rights-of –way in the United States that carries digital signals at company switching stations). Most of the “information superhighway” covered so much in the mass media today involoves fiber-optic connections.