total internal reflection

1. Reflection that occurs when an electromagnetic wave propagating in a material medium, such as the glass core of an optical fiber, with a higher refractive index strikes the interface surface of a lower refractive-index medium, such as the cladding of an optical fiber or air, at an incidence angle equal to or greater than the critical angle. Note 1: At incidence angles greater than the critical angle, all of the incident power is reflected and there is no refracted wave. At the critical angle, the incident ray will propagate along the interface surface. At incidence angles less than the critical angle there will be a reflected ray and a refracted ray, i.e., a transmitted ray, in accordance with Snell's laws of reflection and refraction. Note 2:In optical fibers, total internal reflection allows signal transmission over long distances by confining certain modes to the core because light rays in the core that approach the core-cladding interface at angles greater than the critical...