Optical Fiber Construction

Optical Fiber Construction Points : Optical Fiber Construction, Core and Cladding, Coating Basically optical fibers consist of two parts: 1. Core and Cladding These are made from fused silica glass (SiO²) and are optically transparent. 2. Coating The central portion of the optical fibers is called the core; it is this part in which light rays are guided. That portion which surrounds the core is called cladding. The refractive index of the core is always slightly greater than the refractive index of the cladding. Due to this difference in the refractive indices of the core and cladding, the light rays are always kept within the core of the optical fibers.

During manufacturing of the optical fibers, protective layers of plastic are uniformly applied to the entire length of the fiber. The refractive index of the coating is higher than that of cladding and core, to attenuate any undesirable light in the cladding. This coating can be removed when desired, i.e. (for jointing etc). The coating gives protection to the fibers from external influences and absorbs shear forces. These coatings are usually colored to identify individual fibers in a multi-fibers cable.