Optical fibers are often used to transmit signal (for example, some internet service providers connect homes to their network via optical fibers). These fibers are thin transparent fibers clad with a protective outer layer. Signals of light are sent inside the fiber, repeatedly bouncing off of the fiber walls via total internal reflection until they reach their destination. However, for this total internal reflection to occur, the light must enter the fiber at an appropriate angle. If a fiber has an index of refraction n1 = 1.59 and is clad with a material of index of refraction n2 = 1.43, what is the minimum angle of incidence, Īi, for light entering the fiber to undergo total internal reflection once inside? Assume the incoming light is coming from air n = 1.00, and is refracted upon entering the fiber (not shown in diagram).
