A type of glass optical fiber (GOF) characterized by a sharp difference, or step, in the index of refraction (IOR) at the interface between the core and the cladding.The layer of cladding has a uniform IOR that is sharply lower (typically one percent or more), which causes errant light rays striking the interface to reflect back into the core, which is the primary light-conducting medium. Light rays striking the interface at extreme angles less than the critical angle can be lost in the cladding, as illustrated in Figure S-11. Multi-step fibers comprise multiple layers of cladding with sharp steps in IOR to compound the effect. See also critical angle, GOF, graded-index fiber, IOR, reflection, and total internal reflection. ......3464748...123464748Frame 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1