An optical fiber (or optical fibre) is a flexible, transparent fiber made of a pure glass (silica) not much wider than a human hair. It functions as a waveguide, or "light pipe", to transmit light between the two ends of the fiber.Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication. An optical fiber cable is a cable containing one or more optical fibers. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed.