Optic fiber is widely used in
communication. It consists of a core and cladding. Core refractive index is
always greater than cladding refractive index. Some of the main types of optic
fibers are Erbium doped fiber, termination fiber, photonic crystal fiber,
photosensitive fiber, bend-insensitive fiber, high-index fiber and
polarization-preserving fiber. In photosensitive fibers, refractive index is
subjected to a change on an exposure to ultraviolet light. By doping proper
amount of germanium and boron ions, sensitivity can be increased which finds
immediate application in Bragg grating. Bragg grating is a periodic variation
of the refractive index along the fiber axis. This is used in pump lasers, optical filters
etc. Bend-insensitive fibers are fabricated by increasing the numerical
aperture. This reduces bending loss.
