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Scientists at leading research labs are starting to push the data-transmission
capabilities of fiber-optic cable into the realm of the mind-boggling.
Setting a new record, researchers at Lucent's Bell Labs have for
the first time managed to push an astonishing 3.28 terabits per
second of data over a long stretch of fiber-optic cable. A terabit
-- that's a trillion bits -- is roughly equal to all of the daily
traffic on the Internet for the entire world. The Lucent fiber could
transmit three times the daily global Internet traffic every second.
However, experts say the Bell Labs breakthrough is just the beginning.
In a matter of years, the fiber-optic cable being laid today by
telecoms across the globe could be transmitting data at a rate of
tens of thousands of terabits per second.
At these speeds, the entire written works of mankind could be beamed
across the globe at the speed of light in just a few seconds.
Optical fiber is made from a silica fiber stretched thinner than
human hair. Information is beamed across it by lasers operating
in the near-infrared range of the light spectrum. More than 215
million kilometers of optical fiber has been laid across the globe,
more than enough to stretch to the moon and back nearly 280 times.
The astonishing advances in bandwidth will largely be driven by
two factors, said David Nagel, president of AT&T Labs: the speed
of lasers used to encode the data, and the number of lasers operating
at different wavelengths that can be carried by a single fiber.
Right now, the number of pulses generated by a single laser roughly
follows Moore's law: The capacity doubles every 18 months. Nagel
said that scientists are developing terabit lasers, which would
be capable of handling all of AT&T's daily telephone traffic
-- more than 3 million calls -- plus all the data traffic, all on
a single laser.
Meanwhile, the number of wavelengths, or colors, a single fiber
can simultaneously carry is doubling every year. At the moment,
optical networks carry 40 wavelengths per fiber, Nagel said. Eighty-wavelength
systems are already available, and 160 wavelength systems will be
introduced next year. Nagel said researchers are already experimenting
with 1,000 wavelength systems.
Today's optical networks are theoretically capable of being upgraded
to transmit several thousand terabits of data per second. The Bell
Labs terabit breakthrough represents less than half a percent of
the potential capacity of today's optical networks. Surprisingly,
the know-how for pushing optical networks to these dizzying heights
was developed 20 years ago. Looking at the commercial deployment
of research technologies historically, it just doesn't happen until
there's a huge demand. And that came from the Internet.
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