An optical fiber (or fibre in British English) 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[a] 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 transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer. Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of 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 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, 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).
Being able to join optical fibers with low loss is important in fiber optic communication. This is more complex than joining electrical wire or cable and involves careful cleaving of the fibers, precise alignment of the fiber cores, and the coupling of these aligned cores. For applications that demand a permanent connection a fusion splice is common. In this technique, an electric arc is used to melt the ends of the fibers together. Another common technique is a mechanical splice, where the ends of the fibers are held in contact by mechanical force. 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 Indian-American physicist Narinder Singh Kapany, who is widely acknowledged as the father of fiber optics.
Burton upon Trent, also known as Burton-on-Trent or simply Burton, is a market town in Staffordshire, England, close to the border with Derbyshire. In 2011, it had a population of 72,299. The demonym for residents of the town is 'Burtonian'. Burton is 11 miles (18 km) southwest of Derby, 27 miles (43 km) northwest of Leicester, 28 miles (45 km) west-southwest of Nottingham and 20 miles (32 km) south of the southern entrance to the Peak District National Park.
Burton is known for brewing. The town originally grew up around Burton Abbey. Burton Bridge was also the site of two battles, in 1322 when Edward II defeated the rebel Earl of Lancaster and 1643 when royalists captured the town during the First English Civil War. William Lord Paget and his descendants were responsible for extending the manor house within the abbey grounds and facilitating the extension of the River Trent Navigation to Burton. Burton grew into a busy market town by the early modern period.
The town is served by Burton-on-Trent railway station. The town was also the start and terminus of the now defunct South Staffordshire Line which linked it to Lichfield, Walsall, Dudley and Stourbridge.