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The remarkable thing about the hair-thin strands of optical fiber

By Steve Rogers,


The remarkable thing about the hair-thin strands of optical fiber that Corning and other companies sell today is that any single strand of glass can carry many different beams of light at the same time, each beam wobbling at its own frequency and using its own method of encoding information. This is the enormous advantage of fiber: Its overall bandwidth potential (how many different signals it can transmit and how fast you can encode or modulate them) is much higher than any other transmission medium. Unless the transmission medium itself somehow gets in the way, as a deep pothole or a truck might block the road when a car wants to go by, a single fiber-optic cable could carry the entire weight of data on the internet.

Image render with a strand of human hair on the left with a shorter piece of an optical fiber to the right of the strand...
cfot
As the saying goes, one strand of optical fiber is about the diameter of a human hair.CORNING
It’s an amazing idea. Now, copper wires—sometimes called “twisted pair” because they are made of pairs of strands of copper twisted around one another—also carry data and telephone signals to homes and farms in much of rural America. But because of the characteristics of copper as a transmission medium, signals that travel over copper don’t have the extraordinary frequency range that light signals do, are subject to interference from other signals, and in general degrade very quickly over more than a short distance. That’s why if you have a copper-wire DSL (digital subscriber line) subscription, you have to be very close to the phone company’s “central office” to get a download signal into your house. A DSL house is connected to a copper wire, not a fiber-optic cable.

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