Encyclopedia > Optical communications

  Article Content

Optical communication

Redirected from Optical communications

Optical communication is any form of telecommunication that uses light as the transmission medium. Techniques such as semaphore, ship flags[?], smoke signals, and beacons; fires were the earliest form.

The heliograph[?] uses a mirror to reflect sunlight to a distant observer. By moving the mirror the distant observer sees flashes of light that can be used to send a prearranged signalling code. Navy ships often use a signal lamp[?] to signal in Morse code in a similar way.

Distress flares[?] are used by mariners in emergencies, while lighthouses and navigation lights[?] are used to communicate navigation hazards.

Aircraft use the landing lights[?] at airports to land safely, especially at night. Aircraft landing on an aircraft carrier use a similar system to land correctly on the carrier deck. The light systems communicate the correct position of the aircraft relative to the best landing glideslope[?].

In modern communications, lasers are often used as a light source. Often the light is in the infra-red spectrum, rather than being visible light, because the glass fibers transmit those frequencies better. By using different light frequencies (or colours) multiple communications can be sent optically.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
BBC News 24

... the BBC News Centre in BBC Television Centre, West London. See also: List of British television channels External Links BBC News 24 live video streaming at 34Kbps ...

 
 
 
This page was created in 35.5 ms