City of Light: The Story of Fiber Optics

A VISION OF THE FUTURE 87
caused by uneven settling of the soil. Like a high-speed railroad line or interstate
highway, it required broad, sweeping curves. That would make installation
costly, but AT&T could accept that. Waveguides promised tremendous
capacity, and they were to run mostly between cities, not within them.
After two years of tests, Bell Labs settled on a design for 50.8 millimeter
(2-inch) waveguides each carrying 80,000 conversations at frequencies between
35 and 75 gigahertz. The signals would be digitized and transmitted
by pulse-code modulation, as Reeves had proposed 21 years earlier. 28 The
overall data rate would be a then-staggering 160 million bits per second.
Meanwhile, Bell Labs was also pursuing another long-distance alternative,
the communications satellite. Arthur C. Clarke, a British engineer and writer,
had come up with the idea during World War II as an alternative to radio
relays and coaxial cables. Both of those systems required chains of repeaters
to span long distances. However, Clarke realized that a satellite with an orbit
lasting exactly one day would stay continually over the same place on the
equator, so a transmitter on board could relay signals between any two points
on its side of the Earth. 29 John R. Pierce, a top Bell Labs communications
engineer who also worked on millimeter waveguides, picked up on the idea
in the 1950s and pushed it as the Space Age emerged. Like Clarke, Pierce
had published science-fiction stories, but Pierce was primarily an engineer
and saw the practical potential of satellite communications, which became
the first important civilian use of space technology. 30
Standard Telecommunication Labs concentrated on millimeter waveguides,
but Reeves was not impressed by early trials. Congested Britain didn’t
have room to bury pipes with sweeping curves, small irregularities caused
disturbing losses, and no technology was available for the amplifiers needed
to compensate for the inevitable losses. He didn’t like the costly, brute-force
approach, so he considered a bolder alternative—moving all the way to light.
The gap between microwave and optical frequencies is a factor of 100,000.
That seemed overwhelming to most, but Reeves realized the difference was
the same as the gap from long waves to microwaves he had seen crossed in
his 35 years of engineering. He had a hunch light would work better, and
he was a man who listened to his hunches because they often were right. 31
Reeves hoped that mental telepathy might be the ultimate communications
technology, 32 but he didn’t know how to tame that, so light would have to
suffice.
A Pioneering Effort
Reeves knew little about light until STL landed a military contract in the field
in 1952. The contract required a working knowledge of optics, so he hired
Murray Ramsay, a young physics graduate from University College London,
who had been a scout in Reeves’s troop before the war. The ever-curious
Reeves pumped the young Ramsay for information and pondered the prospects
for optical communications in his smoke-filled office at STL. He tested