Optical Fiber Communication
Main article: Fiber-optic communication.
Optical fiber is the most common type of channel for optical communications, however, other types of optical waveguides are used within computers or communications gear, and have even formed the channel of very short distance (e.g. chip-to-chip, intra-chip) links in laboratory trials. The transmitters in optical fiber links are generally light-emitting diodes (LEDs) or laser diodes. Infrared light, rather than visible light is used more commonly, because optical fibers transmit infrared wavelengths with less attenuation and dispersion. The signal encoding is typically simple intensity modulation, although historically optical phase and frequency modulation have been demonstrated in the lab. The need for periodic signal regeneration was largely superseded by the introduction of the erbium-doped fiber amplifier, which extended link distances at significantly lower cost.
Read more about this topic: Optical Communication
Famous quotes containing the words optical and/or fiber:
“It is said that a carpenter building a summer hotel here ... declared that one very clear day he picked out a ship coming into Portland Harbor and could distinctly see that its cargo was West Indian rum. A county historian avers that it was probably an optical delusion, the result of looking so often through a glass in common use in those days.”
—For the State of New Hampshire, U.S. public relief program (1935-1943)
“I taught school in the early days of my manhood and I think I know something about mothers. There is a thread of aspiration that runs strong in them. It is the fiber that has formed the most unselfish creatures who inhabit this earth. They want three things only; for their children to be fed, to be healthy, and to make the most of themselves.”
—Lyndon Baines Johnson (1908–1973)