Where did fiber optics come from?

In the late 1960s in the UK, Dr. Charles Kuen-Kao and his colleague were instrumental in determining that fiber optic cables of that era were unusable due to impurities in their glass. These early fiber optic cables only carried telephone and television signals through pulses of light for about 20 meters before almost all of the light was scattered. But by 1970, communications researchers had created ultrapure optical fiber more than 800 meters long.

Fiber optics, resembling fishing line, later enabled broadband communications, biomedical informatics, and a host of other digital applications. By 2009, when Dr. Kao received the Nobel Prize in Physics, it was estimated that the number of fiber optic cables in use around the world was over 600 million miles of fiber optic installation.

By 2019, fiber optic cables exist for almost any task and environment. For example, DEPS fiber optic cable is available in various versions for buried , sewer, suspended between poles.

How does fiber optics work?

Fiber optics send encoded information through a beam of light down a glass or plastic pipe. In the 1960s, engineers used it to transmit phone calls at the speed of light.

Each cable contains incredibly thin strands of glass or plastic: optical fibers. Each cable can have two or several hundred conductors. The strands, each one-tenth the width of a human hair, are capable of carrying about 25,000 phone calls each. Thus, a cable consisting of hundreds of strands is capable of carrying millions of calls.

Light reflects off the walls of the cable tube. Each photon bounces down the pipe like a bobsled on an icy track. Although you can expect light to seep through the edges of the glass tube, it is directed at small angles (no more than 42 degrees) that reflect it back into the tube. This is known as total internal reflection.

The cable also keeps light in the tube. The core of the cable is a strand of glass or plastic through which light passes. A second layer, called a shell, is wrapped around the outside of the core. The sheath holds the light signals inside the core.