1000 micron core plastic fiber optic cable.

Typical Lumileen plastic optical fiber (POF) consists of an inner plastic core with a thin cladding of fluorinated polymer. Since the refractive index of the outer cladding is lower than the core, light entering one end of a fiber reflects along the interior core material at the interface of the core and cladding. Light passes through the length of the fiber in a zigzag path on its way to the other end.