Digital communication is information transmitted electronically and is encoded digitally. It is stored and processed by computers. The U.S. military moved quickly to use fiber optics for improved communications and tactical systems. In the early 1970’s, the U.S. Navy installed a fiber optic telephone link aboard the U.S.S. Little Rock. The Air Force followed suit by developing its Airborne Light Optical Fiber Technology (ALOFT) program in 1976. Encouraged by the success of these applications, military R&D programs were funded to develop stronger fibers, tactical cables, ruggedized, high-performance components, and numerous demonstration systems ranging from aircraft to undersea applications. Commercial applications followed soon after. In 1977, both AT&T and GTE installed fiber optic telephone systems in Chicago and Boston respectively. These successful applications led to the increase of fiber optic telephone networks. By the early 1980’s, single-mode fiber operating in the 1310 nm and later the 1550 nm wavelength windows became the standard fiber installed for these networks. Initially, computers, information networks, and data communications were slower to embrace fiber, but today they too find use for a transmission system that has lighter weight cable, resists lightning strikes, and carries more information faster and over longer distances.
The first working fiber-optical data transmission system was demonstrated by German physicist Manfred Börner at Telefunken Research Labs in Ulm in 1965, which was followed by the first patent application for this technology in 1966
Nishizawa invented other technologies that contributed to the development of optical fiber communications, such as the graded-index optical fiber as a channel for transmitting light from semiconductor lasers and this was in 1960s---->2014 (plz wake up a little bit.
Daniel Colladon first described this “light fountain” or “light pipe” in an 1842 article titled On the reflections of a ray of light inside a parabolic liquid stream. This particular illustration comes from a later article by Colladon, in 1884. In 1880 Alexander Graham Bell and Sumner Tainter invented the Photophone at the Volta Laboratory in Washington, D.C., to transmit voice signals over an optical beam.[10] It was an advanced form of telecommunications, but subject to atmospheric interferences and impractical until the secure transport of light that would be offered by fiber-optical systems. In the late 19th and early 20th centuries, light was guided through bent glass rods to illuminate body cavities. Jun-ichi Nishizawa, a Japanese scientist at Tohoku University, also proposed the use of optical fibers for communications in 1963, as stated in his book published in 2004 in India Optical fibers are widely used in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data rates) than wire cables. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. Fibers are also used for illumination, and are wrapped in bundles so that they may be used to carry images, thus allowing viewing in confined spaces. Specially designed fibers are used for a variety of other applications, including sensors and fiber lasers. Optical fibers typically include a transparent core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by total internal reflection. This causes the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are called multi-mode fibers (MMF), while those that only support a single mode are called single-mode fibers (SMF). Multi-mode fibers generally have a wider core diameter, and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,000 meters (3,300 ft). Joining lengths of optical fiber is more complex than joining electrical wire or cable. The ends of the fibers must be carefully cleaved, and then carefully spliced together with the cores perfectly aligned. A mechanical splice holds the ends of the fibers together mechanically, while fusion splicing uses heat to fuse the ends of the fibers together. Special optical fiber connectors for temporary or semi-permanent connections are also available. "An optical fiber (or optical fibre) is a flexible, transparent fiber made of high quality extruded glass (silica) or plastic." Silicon dioxide, also known as silica (from the Latin silex), is a chemical compound that is a dioxide of silicon with the chemical formula SiO2. It has been known since ancient times. Silica is most commonly found in nature as quartz, as well as in various living organisms,[2] Silica is one of the most complex and most abundant families of materials, existing both as several minerals and being produced synthetically. Notable examples include fused quartz, crystal, fumed silica, silica gel, and aerogels. Applications range from structural materials to microelectronics to components used in the food industry. Slightly thicker than a human hair, It can function as a waveguide, or “light pipe”, to transmit light between the two ends of the fiber. Power over Fiber optic cables can also work to deliver an electric current for low-power electric devices. The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics.
Amigos de la lectura y la escritura, sé que nos gustan los talleres, los seminarios, pero también se requiere apoyo para la producción, para los que producen libros que luego compartimos con otros y nos invitan a nuevas experiencias. Si están interesados, aquí hay un lanzamiento interesante. Gracias! Silvia Aquí más información sobre el proyecto : http://www.gentequecamina.com/ Biografía de la autora: http://www.gentequecamina.com/el-libro/autora-2/
Astronomía Didáctica y la Biblioteca Departamental invitan a la conferencia: “La astronomía como fenómeno educativo” El estudio de la Astronomía se remonta a épocas arcaicas, sin embargo en la actualidad esta ciencia está subvalorada por la escuela tradicional, enseñándose en el colegio de manera superficial y abordándose a pasos lentos a nivel profesional. Explicaciones, implicaciones, ventajas, alternativas, antecedentes y propuestas serán introducidas a la comunidad desde la perspectiva de la educación. Conferencista : Lorena Aristizabal Fecha y hora : Jueves 10 de Abril de 2014, 6:30 pm Lugar : Biblioteca Departamental – Cali Colombia Mayores informes : mhguarin@puj.edu.co - 317.5315356 Entrada Libre
Colombia President Santos 9 April, 2013 said hoped talks with ELN will begin “sooner rather than later,” amid increasing speculation that official announcement of negotiations with Colombia’s second guerrilla group will come in May. Peace talks with FARC set to resume 17 April postponed until 23 April for scheduling and logistical reasons; FARC negotiating team joined by 4 new members, including influential Pablo Catatumbo, commander of Alfonso Cano bloc. Sides have yet to announce agreement on any of 5 major agenda items. UN and National University held public forums in Bogotá on potential political participation of FARC 28-30 April; all major political parties participated except supporters of former president Uribe. FARC, ELN 1 April announced cooperation in Arauca dept and elsewhere in east to fight extractive projects, multinational companies. Amid rumours of possible splits within organisation, FARC’s Southern Bloc 9 April said it would comply with possible peace agreement “to the letter”. Killing of prominent land restitution activist Ever Antonio Cordero in Córdoba 9 April prompted widespread condemnation, underscored worries about escalating violence against civil society leaders. Death of “Emerald King” Víctor Carranza 4 April prompted concerns of violent conflict over access to emerald resources.
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