City of Light: The Story of Fiber Optics

BREAKTHROUGH 143
piece of luggage, and London was going through a bomb scare when they
arrived. A bobby inspecting incoming luggage looked long and hard at the
strange package. Worried about ruining the fragile fiber, Maurer took off the
lid and showed the bobby the optical fiber wound on the can.
The bobby looked and replied, ‘‘Oh yes, they use them in medicine.’’
Amazed that a policeman would recognize such novel technology, Maurer
explained he was going to the British Post Office to measure it. That satisfied
the bobby, who sighed and said, ‘‘You Yanks will probably be selling them
to us one of these days,’’ before moving on to other luggage. 36
Maurer and Lucy arrived at Dollis Hill late in the morning of Monday,
November 9, 1970. After the Post Office team installed the fiber in their
apparatus, Dyott suggested they break for lunch and do the measurements
after returning. Maurer insisted he had to stay with the fiber. Dyott displayed
a large key for the 1920s vintage lock and offered to lock the lab, but Maurer
refused to budge, even when Dyott said he could hold the key. Not about to
be denied their lunch, the British left Maurer behind, returning with a cup of
coffee and a cheese sandwich for him.
They spent the afternoon making measurements with a helium-neon laser.
Several tests confirmed that attenuation was ‘‘an astonishing 15 decibels per
kilometer,’’ 37 as Maurer had claimed. Each time he carefully cleaved a piece
of fiber off the reel, Maurer retrieved it and taped the piece onto the side of
his drum. Then a short piece broke with an audible ping and fell to the floor.
The horrified Maurer searched for it on a floor sprinkled with pieces of British
fiber left from earlier tests. Corning’s fiber was larger, and heat treating gave
it a distinctive curve. Nonetheless, he couldn’t find the missing piece and had
to leave without it after the day’s measurements were done.
As soon as Maurer was gone, Dyott stopped everything to sweep up the
fiber fragments on the floor. The Post Office crew sifted carefully through the
debris and, Dyott recalls, ‘‘in no time we found the piece of larger-diameter
slightly curved fiber, about 1 1 ⁄2 to 2 inches long. I handed it to George Newns
to see what he could make of it.’’ 38
Dyott and Newns knew the secret of Corning’s fiber lay in its composition,
so Newns immediately took the little piece to British Titan Products, which
had a neutron activation system that could sensitively analyze composition
of even tiny samples. Within hours, British Titan reported back that it was
the purest form of silica they had ever encountered. Dyott knew the fiber had
to contain something else, either to dope the core to increase its refractive
index, or to reduce the index of the cladding. He asked what else was in the
glass, but the neutron activation specialists said they had found only pure
silica. Dyott insisted there had to be something else. Reluctantly, British Titan
admitted there was one possibility. The company specialized in titanium products,
so traces of the metal were everywhere, and that background contamination
could conceal small quantities of titanium from their instruments.
That hinted at the identify of the magic ingredient, but a definitive answer
was out of reach. The test had consumed the tiny piece of fiber. 39