An optical fibre is a flexible, transparent fibre made of a pure silica glass not much wider than a human hair. An optical fibre functions as a wave-guide, or "light pipe", to transmit light between the two ends of the fibre. Optical fibres are widely used in fibre-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication. These fibres allow the signal to travel with less loss and electromagnetic interference than traditional wires.