An optical fiber is a flexible, transparent fiber made of extruded glass or polymer. It functions as a waveguide to transmit light, wave and ditgital data . Optical fibers typically include a transparent core surrounded by a transparent layer with a lower index of refraction. Light is contained in the core by means of total internal reflection and causes the fiber to act as a waveguide. OF is used for microscope and fiberscope to transmit light. They are largely used as a medium in telecommunication. Optical fibers is used as sensors to measure strain, temperature and pressure.