http://www.ck12.org Chapter 20. Geometric Optics
An important technological use of total internal reflection today is in the field of communications. Fiber optic cables
are quickly replacing much of the copper wire used to carry cable television and telephone signals. Light signals
in fiber optics are used in place of an electrical current in a copper wire because of their low energy losses and
their ability to transmit much more information. There is practically no transmission of the light wave to the air
because of the tiny fiber and index of refraction of the fiber optic cable. Almost all of the light is internally reflected
as it is transmitted. A small amount of energy is absorbed by the cable and there is a very small amount of light
that is lost at the ends of the cable. Fiber optic cables are also used in medical applications to transmit video from
difficult-to-access areas during surgery and as diagnostic probes.