City of Light: The Story of Fiber Optics

16
The Last Mile
An Elusive Vision
These days when I watch television here at home, I have
my choice of four channels that I can get with reasonable
clearness and audibility. Even with only four channels at
their disposal, however, the television moguls can supply
me with a tremendous quantity of rubbish.
Imagine what the keen minds of our entertainment industry
could do if they realized they had a hundred million
channels [the number of standard television channels that
he calculated could fit in the visible spectrum] into which
they could funnel new and undreamed-of varieties of trash.
Maybe we should stop right now!’’
—Isaac Asimov, 1962 1
T he last mile has been the hardest for fiber optics. Optical fibers carry both
telephone and cable television signals to your town or neighborhood, but
except for a few experimental systems, the threads of glass do not reach
homes. Somewhere within few miles of your home the fibers end in a box,
which converts their optical signals into electrical form and sends them to
copper wires. Telephone calls go over simple pairs of wires; cable television
uses coaxial cable, a thin central wire surrounded by an insulator, which in
turn is sheathed within a metal tube, then covered by protective plastic. Those
wires connect to your phone and television.
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