Optical Fiber

An optical fiber is a flexible glass or plastic fiber that carries light from one end to the other, widely used in fiber optic communication because a signal traveling through it loses less strength and resists electromagnetic interference better than one traveling through an electrical cable, permitting transmission over longer distances at higher bandwidth. Fibers are also bundled for illumination and imaging, as in a fiberscope, and specially designed fibers serve as sensors and fiber lasers. A glass fiber typically consists of a core surrounded by a transparent cladding of lower refractive index, so that light stays inside the core through total internal reflection and the fiber acts as a waveguide, with single mode fibers carrying one light path used for most communication links longer than about a kilometer and multi mode fibers carrying many paths used for shorter links or higher power applications. The field concerned with designing and applying optical fibers is called fiber optics, a term coined by the physicist Narinder Singh Kapany.