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Optical communication is any form of telecommunication that uses light as the transmission medium. Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700

An optical communication system is nothing consists of a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal. For biologic transmitters see Transmitter substance. A transmitter is an electronic device which usually with the aid of an antenna In the fields of communications, Signal processing, and in Electrical engineering more generally a signal is any time-varying or spatial-varying quantity Channel, in communications (sometimes called communications channel) refers to the medium used to convey Information from a

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Forms of optical communication

There are many forms of non-technological optical communication, including body language and sign language. Body language is a term for Communication using Body movements or Gestures instead of or in addition to sounds verbal language or other communication A sign language (also signed language) is a Language which instead of acoustically conveyed Sound patterns uses visually transmitted sign patterns

Techniques such as semaphore lines, ship flags, smoke signals, and beacon fires were the earliest form of technological optical communication. A semaphore telegraph, optical telegraph, shutter telegraph chain, Chappe telegraph, or Napoleonic semaphore is a system The smoke signal is one of the oldest forms of communication in recorded history Beacons are aids to Navigation devices Intentionally conspicuous beacons help guide navigators to their destinations

The heliograph uses a mirror to reflect sunlight to a distant observer. A Heliograph (from the Greek Helios ( Ἥλιος meaning "sun" and graphein (γραφειν = write is a wireless A mirror is an object with a surface that has good Specular reflection; that is it is smooth enough to form an Image. Reflection is the change in direction of a Wave front at an interface between two different media so that the wave front returns into the medium from which By moving the mirror the distant observer sees flashes of light that can be used to send a prearranged signaling code. Navy ships often use a signal lamp to signal in Morse code in a similar way. A ship /ʃɪp/ is a large vessel that floats on water Ships are generally distinguished from Boats based on size Signal lamp, also called Aldis lamp, is a visual signaling device for Optical communication (typically using Morse code) &ndash essentially a focused lamp Morse code is a Character encoding for transmitting telegraphic information using standardized sequences of short and long elements to represent the letters numerals

Distress flares are used by mariners in emergencies, while lighthouses and navigation lights are used to communicate navigation hazards. A flare gun is a gun that fires flares. They are typically used as a distress signal as well as other signaling purposes at sea and between aircraft and people on the ground A lighthouse is a Tower, building or framework designed to emit light from a system of lamps and lenses or in older times from a fire and used as an A Navigation light is a coloured source of illumination on an Aircraft, spacecraft or waterborne vessel, used to signal a craft's position Heading

Aircraft use the landing lights at airports to land safely, especially at night. Landing lights are lights used on Aircraft to illuminate the terrain and Runway ahead during Takeoff and Landing. An airport is a location where Aircraft such as airplanes, Helicopters and blimps take off and land Aircraft landing on an aircraft carrier use a similar system to land correctly on the carrier deck. An aircraft carrier is a Warship designed with The light systems communicate the correct position of the aircraft relative to the best landing glideslope. The Instrument Landing System (ILS is a ground-based Instrument approach system that provides precision guidance to an Aircraft approaching a Runway

Optical fiber is the most common medium for modern digital optical communication. An optical fiber (or fibre) is a Glass or Plastic fiber that carries Light along its length

Free-space optical communication is also used today in a variety of applications. In Telecommunications Free Space Optics (FSO is an Optical communication technology that uses light propagating in free space to transmit data between two points

Optical fiber communication

Main article: Fiber-optic communication. Fiber-optic communication is a method of transmitting information from one place to another by sending Light through an Optical fiber.

Optical fiber is the most common type of channel for optical communications, however, other types of optical waveguides are used within communications gear, and have even formed the channel of very short distance (e. An optical fiber (or fibre) is a Glass or Plastic fiber that carries Light along its length A waveguide is a structure which guides waves such as Electromagnetic waves Light, or Sound waves 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. A laser diode is a Laser where the active medium is a Semiconductor similar to that found in a Light-emitting diode. Infrared light, rather than visible light is used more commonly, because optical fibers transmit infrared wavelengths with less attenuation and dispersion. Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of In Physics, attenuation (in some context also called extinction) is the gradual loss in intensity of any kind of Flux through a medium The signal encoding is typically simple intensity modulation, although historically optical phase and frequency modulation have been demonstrated in the lab. In Optical communications, intensity modulation ( IM) is a form of Modulation in which the optical power output of a source is varied in accordance 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. An optical amplifier is a device that amplifies an Optical signal directly without the need to first convert it to an electrical signal

Free-space optical communication

Main article: Free space optical communication. In Telecommunications Free Space Optics (FSO is an Optical communication technology that uses light propagating in free space to transmit data between two points

IrDA is an example of low-data-rate, short distance free-space optical communications using LEDs. The Infrared Data Association ( IrDA) defines physical specifications Communications protocol standards for the short-range exchange of Data RONJA is an example of 10Mbit/s 1. RONJA ( Reasonable Optical Near Joint Access) is a Free Space Optics device originating in the Czech Republic. In telecommunications Bit rate or Data transfer rate is the average number of Bits characters or blocks per unit time passing between equipment in a data transmission 4 km full-duplex optical point-to-point link.

See also

References

In Electronics, an opto-isolator (or optical isolator, optocoupler, photocoupler, or photoMOS) Fiber tapping is a method to extract signal from an Optical fiber without breaking the connection Overview According to the US Navy's Naval Research Laboratory, a modulating retro-reflector (MRR system combines an optical Retro-reflector and an electro-optic
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