An optical fiber , or optical fibre in Commonwealth English, is a
flexible glass or plastic fiber that can transmit light from one end to the
other. Such fibers 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.