5        The Magic Light: Fiber-Optic Systems

The concept of harnessing light as a modern communications tool stretches back to the late nineteenth century. Alexander Graham Bell, the inventor of the telephone, patented an invention in 1880 that used light to transmit sound.1 Bell’s invention, the photo-phone, employed sunlight and a special light-sensitive device in the receiver to relay and subsequently reproduce a human voice.

It wasn’t until the twentieth century, though, that the idea for such a tool could be transformed into a practical communications system. Two developments helped bring about this advance: the perfection of the laser and the manufacturing of hair-thin glass lines called fiber-optic (FO) lines. When combined, they helped ...

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