City of Light: The Story of Fiber Optics

114 CITY OF LIGHT
that fiber-optic communications could work. But like Heinrich Lamm, they
knew they could not develop a whole new technology by themselves. They
needed to interest others. Convinced they had ‘‘enough evidence to commit
our findings to paper,’’ 34 Kao and Hockham sent an article to the Proceedings
of the Institution of Electrical Engineers in November 1965.
Their analysis was careful, but their conclusions were daring. The decibel
scale (see box, pages 115–116) understates the immense gap between the
best existing fibers and their goal because it’s logarithmic. In 1965, the best
fibers had attenuation of 1000 decibels per kilometer; their goal was 20 decibels
per kilometer. Twenty decibels is a factor of 100; lose 20 decibels and
you have one percent of the original light left. A thousand decibels is 10 100 ;
lose a thousand decibels and you have only 1/10 100 of the original light.
Actually, you have no light, because you lost it all long ago. That drop in
intensity is worse than starting with the mass of the whole universe and
ending up with one atom.
That didn’t discourage the editors, who probably had seen crazier schemes.
They asked for revisions, which Kao and Hockham completed in February.
The final version runs eight printed pages, packed with equations and charts
and thick with electronic jargon. 35 The details were central to convincing
their fellow engineers that their new communications medium could offer
huge transmission capacity at low cost.
Published papers mark milestones, but they take months to reach print.
Kao wasn’t about to wait; he launched the proposal with a January 27, 1966,
talk at the London headquarters of the Institution of Electrical Engineers,
which counts Sir Francis Bolton, the impresario of illuminated fountains, as
one of its founders. STL management thought it worthy of a press release,
which announced: ‘‘Short-distance experimental runs of these optical waveguides
have been operated successfully. They have exhibited an informationcarrying
capacity of one gigacycle, which is equivalent to about 200 television
channels or over 200,000 telephone channels.’’ 36 The release soberly summarized
the state of the art, but closed with what must have seemed a wildly optimistic
prediction: ‘‘When these methods are perfected, it will be possible to
transmit very large quantities of information (telephone, television, data, etc.)
between say, the Americas and Europe, along a single undersea cable.’’ That
was impossible with hollow structures like millimeter waveguide or light pipes.
The British magazine Wireless World allocated the bottom part of one page
to Kao’s talk in March. 37 A small American newsletter named Laser Focus
also took note. 38 Yet otherwise it sank without a trace. Scans through a
sampling of major American science and technology magazines, the New York
Times index, and the Reader’s Guide to Periodical Literature show nary a word
about Kao’s proposal. 39 If the editors noticed it at all, they probably dismissed
it as just another crazy scheme, hardly likely to be practical in the twentieth
century. After all, in 1966 satellites were the future of telecommunications.
The role of light would be to travel through confocal waveguides or gas lenses
as was spelled out in the lead article of the January Scientific American 40 —
then the semipopular journal of record for American science—by Stew Miller