Optical fiber

An optical fiber, or optical fibre, is a flexible <a href="/facts/Glass/hezRsAGf">glass</a> or plastic <a href="/facts/Fiber/ttkxAFBu">fiber</a> that can transmit <a href="/facts/Light/jeofpMn4">light</a> from one end to the other. Such fibers find wide usage in <a href="/facts/Fiber-optic_communication/dc6S0Hg5">fiber-optic communications</a>, where they permit transmission over longer distances and at higher <a href="/facts/Bandwidth_(computing)/lY6Tb4gX">bandwidths</a> (data transfer rates) than electrical cables. Fibers are used instead of metal <a href="/facts/Wire/yyy05H1S">wires</a> because signals travel along them with less <a href="/facts/Attenuation/XP4vX360">loss</a> and are immune to <a href="/facts/Electromagnetic_interference/gv3DlKNr">electromagnetic interference</a>. Fibers are also used for <a href="/facts/Illumination_(lighting)/Gk54r8xE">illumination</a> 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 <a href="/facts/Fiberscope/pWwg3nm6">fiberscope</a>. Specially designed fibers are also used for a variety of other applications, such as <a href="/facts/Fiber_optic_sensor/SpTS0mTX">fiber optic sensors</a> and <a href="/facts/Fiber_laser/JrNSrAyY">fiber lasers</a>.
Glass optical fibers are typically made by <a href="/facts/Drawing_(manufacturing)/rKIV60Gm">drawing</a>, while plastic fibers can be made either by drawing or by <a href="/facts/Extrusion/wM2kJ6wc">extrusion</a>. Optical fibers typically include a <a href="/facts/Core_(optical_fiber)/31ThGPA2">core</a> surrounded by a transparent <a href="/facts/Cladding_(fiber_optics)/URSEucdL">cladding</a> material with a lower <a href="/facts/Index_of_refraction/yjkzvgeE">index of refraction</a>. Light is kept in the core by the phenomenon of <a href="/facts/Total_internal_reflection/Tm0M62NQ">total internal reflection</a> which causes the fiber to act as a <a href="/facts/Waveguide_(optics)/CQ6AnRAl">waveguide</a>. Fibers that support many propagation paths or <a href="/facts/Transverse_mode/nCIl5D6a">transverse modes</a> are called <a href="/facts/Multi-mode_fiber/tgSR57m6">multi-mode fibers</a>, while those that support a single mode are called <a href="/facts/Single-mode_fiber/tVgBIPLp">single-mode fibers</a> (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 1,050 meters (3,440 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 <a href="/facts/Cleave_(fiber)/HgT1kv2m">cleaving</a> of the fibers, precise alignment of the fiber cores, and the coupling of these aligned cores. For applications that demand a permanent connection a <a href="/facts/Fusion_splicing/NnpEuonW">fusion splice</a> is common. In this technique, an electric arc is used to melt the ends of the fibers together. Another common technique is a <a href="/facts/Mechanical_splice/y8mCGEY4">mechanical splice</a>, where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made by means of specialized <a href="/facts/Optical_fiber_connector/uIC3170n">optical fiber connectors</a>. 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 <a href="/facts/Narinder_Singh_Kapany/wwWYFYAp">Narinder Singh Kapany</a>.

Optical fiber open-in-new

Optical fiber