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Background[ edit ] First developed in the s, fiber-optics have revolutionized the telecommunications industry and have played a major role in the advent of the Information Age. Because of its advantages over electrical transmissionoptical fibers have largely replaced copper wire communications in core networks in the developed world.
The process of communicating using fiber-optics involves the following basic steps: Due to much lower attenuation and interferenceoptical fiber has large advantages over existing copper wire in long-distance, high-demand applications. However, infrastructure development within cities was relatively difficult and time-consuming, and fiber-optic systems were complex and expensive to install and operate.
Due to these difficulties, fiber-optic communication systems have primarily been installed in long-distance applications, where they can be used to their full transmission capacity, offsetting the increased cost. The prices of fiber-optic communications have dropped considerably since The price for rolling out fiber to the home has currently become more cost-effective than that of rolling out a copper based network.
Sincewhen optical-amplification systems became commercially available, the telecommunications industry has laid a vast network of intercity and transoceanic fiber communication lines.
Bell considered it his most important invention. The device allowed for the transmission of sound on a beam of light. On June 3,Bell conducted the world's first wireless telephone transmission between two buildings, some meters apart.
The Photophone's first practical use came in military communication systems many decades later. In Harold Hopkins and Narinder Singh Kapany showed that rolled fiber glass allowed light to be transmitted. Initially it was considered that the light can traverse in only straight medium.
After a period of research starting fromthe first commercial fiber-optic communications system was developed which operated at a wavelength around 0.
These early systems were initially limited by multi mode fiber dispersion, and in the single-mode fiber was revealed to greatly improve system performance, however practical connectors capable of working with single mode fiber proved difficult to develop. Inthey had already developed a fiber optic cable that would help further their progress toward making fiber optic cables that would circle the globe.
The first transatlantic telephone cable to use optical fiber was TAT-8based on Desurvire optimised laser amplification technology.
It went into operation in Third-generation fiber-optic systems operated at 1. This development was spurred by the discovery of Indium gallium arsenide and the development of the Indium Gallium Arsenide photodiode by Pearsall. Engineers overcame earlier difficulties with pulse-spreading at that wavelength using conventional InGaAsP semiconductor lasers.
Scientists overcame this difficulty by using dispersion-shifted fibers designed to have minimal dispersion at 1. These developments eventually allowed third-generation systems to operate commercially at 2. The fourth generation of fiber-optic communication systems used optical amplification to reduce the need for repeaters and wavelength-division multiplexing to increase data capacity.
The conventional wavelength window, known as the C band, covers the wavelength range 1. Other developments include the concept of " optical solitons ", pulses that preserve their shape by counteracting the effects of dispersion with the nonlinear effects of the fiber by using pulses of a specific shape.
In the late s throughindustry promoters, and research companies such as KMI, and RHK predicted massive increases in demand for communications bandwidth due to increased use of the Internetand commercialization of various bandwidth-intensive consumer services, such as video on demand.
Internet protocol data traffic was increasing exponentially, at a faster rate than integrated circuit complexity had increased under Moore's Law. From the bust of the dot-com bubble throughhowever, the main trend in the industry has been consolidation of firms and offshoring of manufacturing to reduce costs.
Technology[ edit ] Modern fiber-optic communication systems generally include an optical transmitter to convert an electrical signal into an optical signal to send through the optical fiber, a cable containing bundles of multiple optical fibers that is routed through underground conduits and buildings, multiple kinds of amplifiers, and an optical receiver to recover the signal as an electrical signal.
The information transmitted is typically digital information generated by computers, telephone systems and cable television companies. Transmitters[ edit ] A GBIC module shown here with its cover removedis an optical and electrical transceiver.
The electrical connector is at top right and the optical connectors are at bottom left The most commonly used optical transmitters are semiconductor devices such as light-emitting diodes LEDs and laser diodes.
The difference between LEDs and laser diodes is that LEDs produce incoherent lightwhile laser diodes produce coherent light.Technical Questions and Answers Archive.
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History The American Reusable Textile Association (ARTA) was formed in to help the textile services industry compete with the disposable nonwovens industry. When disposable, single-use products first made an appearance, they were not considered a threat to the textile services industry for two main reasons - expense and environmental concerns.
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