In an optical fiber, anything used to convert cladding modes to radiation modes, thus removing them from the fiber. Note: In practice, the fiber's polymer overcoat (which is also used to protect it from mechanical damage and to isolate it optically from other fibers) is used as a cladding mode stripper. The refractive index of the coating material is made to be slightly higher than that of the cladding. This forces optical energy in the cladding modes to radiate into the relatively lossy coating, from which it quickly dissipates.