Fiber-optic communication is a method of transmitting information from one place to another, sending a pulse of light through an optical fiber. Light forms a carrier signal in the form of electromagnetic radiation, which is modulated to transmit information.
In the 1970s, originally developed into optical fiber communication systems, they reconstructed the telecommunications industry and began to play a major role in the advent of the Information Age. Due to its advantages over electrical transmission in the developed world, optical fibers have largely replaced copper wire communications in major networks.
Introduction
Optical fiber is used by many telecommunication companies to transmit telephone signals, Internet communications, and cable television signals. Due to the much lower attenuation and interference, the optical fiber has great advantages over the existing copper wire over long distances and in maintaining high transmission information requirements. However, developing infrastructure within cities was relatively difficult and time-consuming. Optical fiber systems were complex and expensive to install and operate. Due to these difficulties, optical fiber systems in communication communications were primarily installed in places with large distances, where they are used to ensure the transfer of the full amount of necessary information, compensating for the increased cost. Since 2000, prices for optical fiber-optic communications have dropped significantly. Fiber connection to the house is now more cost-effective than using copper cables in the network.
In 1990, the fiber-optic communication systems begin to be commercially convenient, the telecommunications industry expended networks of long-distance optical fiber communication lines. By 2002, the intercontinental communications network had reached 250,000 km of submarine cable with a carrying capacity of 2.56 Tb / s.
History
In 1966, Charles K. Kao and George Hawham proposed optical fibers at STC Labs (STL), Harlow, when they showed that losses of 1000 decibels/km in existing glass (compared to 5-10 decibels/km in coaxial cable) came from - for contaminants that could potentially be removed.
The optical fiber was successfully developed in 1970, in the work “Glass-granular work,” wherewith low signal attenuation in communications (20 dB / km ) and at the same time, GaAs semiconductor lasers were developed so that they were compact and therefore suitable for transmitting light through fiber optic cables over long distances.
This first-generation system worked with a small transfer rate of 45 Mbps with a relay interval of up to 10 km. Shortly thereafter, on April 22, 1977, a shared telephone and electronic system sent the first live video via telephone via fiber optics with a resolution of 6 Mbps in Long Beach, California. {km}
The second generation of fiber-optic communications was developed for commercial use in the early 1980s, operated with a 1.3-micron wavelength, and used InGaAsP semiconductor lasers. Although these systems were initially limited to dispersion, in 1981 a single-mode fiber was shown to greatly improve system performance. By 1987, these systems were operating at bit rates of up to 1.7 Gb / s with relay interval up to 50 km.
The first transatlantic telephone cable that uses optical fiber-based on the TAT-8 Deserver optimized laser signal magnification technology. It went into operation in 1988.
Third generation optical fiber systems that conduct a wavelength of 1.55 μm have a loss of approximately 0.2 decibels/km. They achieved this despite earlier difficulties with the propagation of the pulse at that wavelength using conventional InGaAsP semiconductor lasers. Scientists have overcome this difficulty by using dispersion-moving fibers designed to have a minimum dispersion of 1.55 microns or by limiting the laser spectrum to a single longitudinal method. These advances ultimately enabled third-generation systems to operate commercially at 2.5 Gbit / s with relay spans in excess of 100 km.
The 4th generation of fiber-optic communication systems applied optical signal amplification to bring down the requirement for repeaters and wavelength division multiplexing to increase data magnitude. These two enhancements triggered a revolution that doubled the capacity of the system every 6 months, starting in 1992, until it was above 10 Tb / s by 2001. Recently, 14 Tbit / s bit rates have been achieved over the only 160 km line using optical amplifiers.
The development center for the fifth generation of fiber-optic communications is spreading the wavelength range over which the WDM system can operate. A conventional wavelength window, known as band C, covers a wavelength range of 1.53-1.57 microns, and the new dry fiber has a low loss window promising to expand that range to 1.30-1.65 microns. Other events include the concept of “ optical solitons, ” the pulsation of which preserves their shape, counteracting the effects of dispersion with non-linear effects of the fiber when using a pulsation of a certain shape.
Technology
twenty-first-century fiber-optic communication systems contain an optical transmitter to transfigure an electrical signal into an optical and forward into an optical fiber cable holding bundles of multiple optical fibers that are split by underground pipelines and buildings, as well as multiple kinds of amplifiers, an optical receiver to return the signal as electric. The transmitted information is typically digital information produced by computers, telephone systems and cable television companies.
