By Peter Weiss
As a heavy rod of glass sinks into a searing furnace, a wheel below it whirs. Every second that the drum turns, it pulls almost another meter of glass fiber off the softened end of the translucent shaft.
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The fiber then races through lasers that measure its hair-thin diameter and through a cup of liquid polymer, which adds a protective skin. In the cavernous Corning plant in Wilmington, N.C., a row of these fiber-drawing towers operates nonstop, 24 hours per day. They crank out millions of kilometers of optical fiber every year.