Optical fiber preforms are the starting point behind every kilometer of fiber optic cable. Though rarely seen by end users, these cylindrical glass rods serve as the base material from which high-speed optical fibers are drawn. A TOSLINK optical fiber cable with a clear jacket. These cables are used mainly for digital audio connections between devices. As global communication relies more than ever on fiber networks—from. An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers are widely used in fiber-optic communication, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than. Optical cables are designed to carry data in the form of light through fiber optic technology.