City of Light: The Story of Fiber Optics

238 CITY OF LIGHT
on the overhead cables. Each time I see them working, I ask hopefully if
they’re putting in fiber, but they invariably reply ‘‘no.’’
Erratic, intermittent noise plagues my phone line. It hit when I was talking
to Jason Stark, a Bell Labs scientist who devised an ingenious way to generate
206 wavelengths from a single laser source. He started with a pulse lasting
just a tenth of a trillionth of a second, which contained a wide range of
wavelengths. Passed through a 20-kilometer fiber, it stretched 200,000 times,
with the longer wavelengths leading the shorter ones. Then a modulator
chopped the long rainbow pulse into a couple hundred short ones, each of a
different color. Optics can sort the light, routing each color pulse to a different
destination. Thus, one laser transmitter could deliver signals to a couple hundred
homes.
The technology is not ready yet. Right now, it’s a big box sitting on a
bulky optical table in his lab. Stark has plans to modify it, squeezing the
components down to semiconductor devices that fit on an integrated wafer.
He hopes that would help solve the problem of bringing fibers to homes
economically. 33
I could use it right now. One Friday morning, something knocked out a
cable that runs down my street, and two of my three phone lines died. As a
journalist, I live by the phone; I paced the floor because I couldn’t get urgent
calls returned. After a thoroughly frustrating day, I was surprised to hear the
phone ring about 5:30. Don Keck was returning a call from a few days earlier.
I apologized for my phone problems and complained about the poor service.
He said the phone company should have been working the light harder. ‘‘No,
Don,’’ I replied, ‘‘They’re still using obsolete old electrons.’’ We both laughed.