Optical fiber is a single, hair fine filament drawn from molten silca glass. Today, this has replaced metal wires in high speed communication.In a fiber optic communications system, cables made of optical fibers connect datalinks that contain lasers and light detectors. To transmit information, a datalink converts an analog electronic signal into digital pulses of laser light. These travel through the optical fiber to another datalink, where a light detector reconverts them into an electronic signal.