Or Fibre Optics
A method of transmitting light beams along optical fibres (which are actually bundles of glass). Optical fibres are intended to replace the copper wires employed in electronic networks. A light beam, such as that produced by a laser, can be modulated to carry data (information), and the result is very effective: high-speed transmission, clear signals, multiple streams of data, cost-effective performance. In fact, it's been said that fibre-optic technology is the greatest transmission medium currently known