Attenuation occurring as a result of either a bend in an optical fiber that exceeds the minimum bend radius or an abrupt discontinuity in the core/cladding interface.The incident light rays strike the boundary between the core and the cladding at an angle less than the critical angle and enter the cladding, where they are lost. See also attenuation, cladding, core, critical angle, macrobend, microbend, and optical fiber.