| BUSINESSWEEK ONLINE : JANUARY 31, 2000 ISSUE | ||||||||
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| INFORMATION TECHNOLOGY
Blinded by the Light Since the invention of the telephone, AT&T and other telecom companies have used electrical networks that convert voice and data into pulses of electrons that travel over copper wires. Now, phone companies are switching to optical networks that convert data into bits of light-- photons--that travel over optical fibers made of glass. The reason: Copper wires can carry only a few million bits per second, while optical lines transport up to 1 billion times as much data. TODAY'S TELEPHONE NETWORKS LOCAL NETWORKS A local call or e-mail is transmitted in electrical format through the local copper network until it is handed off to an optical system on its way to the long-distance network. That has made the local-phone network a bottleneck. REGENERATORS When signals travel through the long-distance network, they only have enough power to go 125 miles or so at a time. So, they need a power boost from something called a regenerator. That means phone companies need thousands of expensive regenerators throughout their networks. CAPACITY When long-distance companies started using optical fibers in the early 1980s, each fiber could carry 120,000 calls. That began to change in 1995 as equipment makers learned how to split one fiber into four channels, each capable of carrying 120,000 calls. NEXT-GENERATION NETWORKS LOCAL NETWORKS The Bells and GTE are starting to bring optical technology into the local networks. That means a company's Net traffic could hit fiber-optic cables in the basement of its office building instead of near the long-distance network. That will boost capacity up to 1 billion times. REGENERATORS A new generation of optical equipment that will gain momentum this year will drive signals for thousands of miles, not 125. That will reduce the need for so much expensive equipment, dropping the cost of a long-distance network up to 85%. Savings could be passed along to long-distance customers. CAPACITY Optical technology called dense wave division multiplexing (DWDM) now allows companies to split each strand of fiber into 40 channels, and that could grow to more than 1,000 channels in the years ahead. Then, one fiber could carry 122 million calls, instead of the current 5 million. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ BACK TO TOP |
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