TAG: Optical fibers
An optical fiber or optical fibre is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage 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 lesser amounts of loss; in addition, fibers are also immune to electromagnetic interference, a problem from which metal wires suffer excessively. 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, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, some of them being fiber optic 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 the phenomenon of total internal reflection which 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 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).
An important aspect of a fiber optic communication is that of extension of the fiber optic cables such that the losses brought about by joining two different cables is kept to a minimum. Joining lengths of optical fiber often proves to be more complex than joining electrical wire or cable and involves careful cleaving of the fibers, perfect alignment of the fiber cores, and the splicing of these aligned fiber cores. For applications that demand a permanent connection a mechanical splice which holds the ends of the fibers together mechanically could be used or a fusion splice that uses heat to fuse the ends of the fibers together could be used. Temporary or semi-permanent connections are made by means of specialized optical fiber connectors.
The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. The term was coined by Narinder Singh Kapany who is widely acknowledged as the father of fiber-optics.
From Wikipedia, the free encyclopedia
Projects with this TAG (2)
TV signals on ultra-wideband optical fibre networks
Optical fibres are now increasingly popular in telecommunications, due to their extremely high bandwidth, their very low attenuation, their complete immunity to electromagnetic interference and their reduced diameter and weight.
For these reasons, they are playing an increasing role in trasporting TV content, both for in-building TV signal distribution within the multi-service optical infrastructure, which is mandated in all new buildings (Italian Law 164, 2014) and for TV consumption via broadband networks, which will benefit from ongoing investments in FTTH (Fiber to The Home) architectures, where the fibre is terminated at each building. In Italy, network operators are launching massive optical fiber investment plans over the next five years, not only to cover the most densely populated areas (A and B) but also for less profitable areas (C and D).
Networks and Protocols
The television signal that we can see in our living room, after being generated in a TV studio or in an external shooting site, in order to reach our TV set, makes use of a rather complex and articulated telecommunications network. Broadcasting from the closest TV transmitter represents only the last part of this network.
The “Networks and Protocols” project has the task of studying the transport networks for TV signals from the shooting point up to the transmitters, with the purpose of guiding and accompanying the technological evolution of Rai networks.