Almost all modern communications, including everything from cable television
to the Internet, are carried on digital pulses of focused, high-intensity
light called the "laser." Beginning in the late 1950s, AT&T Labs worked
extensively to develop the laser into a useful device.
The laser couldn't send information anywhere if there wasn't a communications system to carry it. So AT&T coupled the laser with transmission lines of hair-thin, super-transparent, ultra-strong glass fiber which today carry tens of billions of information bits every second.
Lasers and fiber optic cable have been used extensively in the United States since the early 1980s. Over the past decade, AT&T has installed undersea fiber optic cable connecting the United States to most of the industrialized nations of the world.