City of Light: The Story of Fiber Optics

SUBMARINE CABLES 207
Fyne, Scotland in February 1980; later they added a 140 million bit per
second repeater. Careful measurements showed the cable worked well in the
water. 17 The single-mode tests added to the evidence that persuaded the Post
Office to lay single-mode fibers on land as well as at sea.
A Bold Move at Bell Labs
By 1980 the course of the future was clear for AT&T Submarine Systems.
Peter Runge told the world: ‘‘The next generation of coaxial cables will not
be developed because of fibers.’’ When TAT-7 was laid in 1983, it would be
the last coaxial cable to cross the Atlantic. The next transatlantic cable, TAT-
8, would contain two pairs of single-mode fibers each carrying 280 million
bits per second, the combined equivalent of 35,000 phone calls—nearly nine
times the capacity of TAT-7. Plans called for repeaters to be 30 to 35 kilometers
(19 to 22 miles) apart. He said the cost per channel should be only
20 percent that of TAT-6 and only half as much as the partly developed coax
system Bell had abandoned as impractical. 18
Sitting in the audience as Runge spoke to a laser meeting, I recognized
a milestone. AT&T had just announced the Northeast Corridor system, but
that was only one link in a nationwide network. Submarine cables were the
highest-performance telecommunication systems on the planet, and fiber optics
would be the next generation, slated for operation in 1988. Fiber optics
had gone beyond a few guys with a draw tower in an old pickle factory. The
brash upstart had won a starring role.
Bell Labs tackled cable development itself. The submarine systems group
asked the single-mode fiber group at Murray Hill to supply 20 fibers, each 20
kilometers (12 miles) long, for a cable to be tested in the North Atlantic. It
became a crash priority for a growing team that turned their Murray Hill
labs into a small-scale factory. The longest fibers they could draw were five
kilometers. Splicing them together was a challenge, but the canny Paul Lazay
realized it also was an opportunity. He could measure subtle differences
among fibers and predict the results of connecting two slightly different types.
By putting fibers together in the right order, he could fine tune their transmission.
Working intensely, Murray Hill made 22 fibers, each 20 kilometers,
for the submarine cable group.
The Holmdel group testing long-distance single-mode transmission cast
eager eyes at those 400 kilometers (250 miles) of fiber. Lacking that much
fiber, they had been bouncing signals back and forth through shorter fiber
segments. Splicing those long fibers together promised more realistic results,
but Lazay was not thrilled when Holmdel asked to borrow them. He was a
researcher himself—he knew the other researchers would find excuses to play
with the fibers, and he worried about possible damage. That wouldn’t do; the
fibers were committed to the submarine cable experiment. On the other hand,
Lazay didn’t want to be seen as obstructing other Bell research groups. He
decided to let them borrow the fiber, but to protect it he spliced the 20 reels