City of Light: The Story of Fiber Optics

88 CITY OF LIGHT
ways to modulate and guide light from special high-performance lamps. 33
About 1958, he assembled a small team to study optical communications,
including Ramsay, an older engineer named Charles C. Eaglesfield, and four
others who reported to Len Lewin, a senior manager. 34 Reeves monitored their
work and added his own ideas, although he had many other projects to distract
him.
The millimeter waveguide project continued under Lewin, developing a 7centimeter
(2.8-inch) waveguide Barlow had proposed. In 1958, Lewin put
that project under Antoni E. Karbowiak, a microwave engineer who had
earned a doctorate under Barlow. Born in 1923 in Poland, Karbowiak fought
with British troops during World War II, earning British residence and an
education. 35 Quiet and reserved, he combined a mastery of mathematical waveguide
analysis and a fertile imagination with a solid physical intuition missing
in many theorists. 36 His grasp of advanced mathematics complemented nicely
Reeves’s less mathematical intuition, enthusiasm, and drive.
Working in the same department as the millimeter waveguide project, the
little optics team began thinking of optical waveguides. That was an innovation.
Since the days of Alexander Graham Bell, most people had automatically
assumed optical communication would go through open air. Yet living
near London, notorious for its murky smogs, the STL team needed only look
out their windows to see the problems of sending light through the atmosphere.
A few people had had similar ideas before, but none had gotten far. Both
Bell Labs 37 and RCA 38 had patented schemes for sending light signals through
transparent rods or hollow pipes, but neither did anything with the idea. 39
At the end of the war, R. V. L. Hartley, a Bell Labs scientist, concluded that
transparent rods did not transmit light well enough for communications, and
that hollow reflective metal pipes were too sensitive to bends. 40 Those were
reasonable conclusions in 1945, but times were changing.
Light Pipes
At STL, Eaglesfield proposed a disarmingly simple idea: an optical ‘‘pipeline’’
of one-inch steel pipe coated inside with silver, the most reflective metal available.
‘‘It is a little strange that this subject has received apparently no published
treatment,’’ he wrote, 41 evidently unaware of the patent William
Wheeler had received 80 years earlier.
On paper the idea looked good. If light passing down the pipe spread out
at an angle of no more than half a degree, in theory only about 0.05 percent
would be lost at each reflection. Eaglesfield calculated the loss in terms of
decibels, a logarithmic scale handy for measuring loss because you can add
the decibel losses of two segments to get total loss, or multiply the transmission
distance by the loss per unit length to get total loss. The lower the loss
in decibels, the better the transmission line (see box, pages 115–116). Eaglesfield
calculated that loss should be 2.5 decibels per mile, meaning 56 percent