An optical fiber is a flexible, transparent fiber made of very pure glass (silica) not much wider than a human hair that acts as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. It consists of a central core that is surrounded by a cladding. Then a layer of coating formed of one or many concentric layers of materials is applied to protect the fiber optic, avoid its breakage and to ascertain its long-term stability. For standard telecom fibers, the typical diameters of the core and the cladding are 10µm and 125µm respectively.
Contributor: Antoine Bassil (ESR2)