A fiber is a very thin glass strand that can carry a very large amount of telecommunications traffic. Before the use of fiber, copper pairs were used for terrestrial applications. Electrical signals over the copper were used for transmission. With fiber, the electronic signal gets converted to optical and the light transports the information from one end to another. Fiber has lots of advantages over copper: much greater capacity, more lightweight, no electrical magnetic interference, and greater security. Fiber optics were initially installed for long-distance applications whereby greater volume led to lower user costs. Eventually, fiber penetrated the metropolitan, access, and enterprise markets. Literally hundreds of fibers can be found in a cable installation. It is currently not known what the theoretical limitations are on a fiber in terms of capacity. Dense Wavelength Division Multiplexing (DWDM) is used to break down the light into various individual channels to multiply the amount of traffic transported. For example, if a 10-gigabit per second signal is being sent down a fiber, and the light is broken down into 16 wavelengths, one can achieve 160 gigabits per second capability on the single fiber.

Contributed By:

Samuel Greenholtz
Principal
Telecom Pragmatics