Fiber Optic Tutorials

In its simplest form an optical fiber consists of a cylindrical core of silica glass surrounded by a cladding whose refractive index is lower than that of the core. Because of an abrupt index change at the core-cladding interface, such fibers are called step-index fibers. In a different type of fiber, known as graded-index fiber, the refractive index decreases gradually inside the core.  This figure shows schematically the index profile and the cross section for the two kinds of fibers. Considerable insight in the guiding properties of optical fibers can be gained by using a ray picture based on geometrical...