Mandrel wrapping 41351 85436221 2006-11-03T08:20:04Z Srleffler 252195 Light-emitting diode In multimode [[fiber optics]], '''mandrel wrapping''' is a technique used to modify the [[modal distribution]] of a propagating optical [[Signalling (telecommunication)|signal]]. A '''cylindrical rod wrap''' consists of a specified number turns of fiber on a [[mandrel]] of specified size, depending on the fiber characteristics and the desired modal distribution. It has application in optical [[transmission (telecommunications)|transmission]] performance tests, to simulate (or establish) [[equilibrium mode distribution]] in a launch fiber (a fiber used to inject a test signal in another fiber that is under test). If the launch fiber is fully filled ahead of the mandrel wrap, the higher-order [[Transverse mode|mode]]s will be stripped off, leaving only lower-order modes. If the launch fiber is underfilled, for example as a consequence of being energized by a [[laser diode]] or [[Light-emitting diode|edge-emitting LED]], there will be a redistribution to higher-order modes until modal equilibrium is reached. ==See also== *[[Mode scrambler]] {{FS1037C}} {{optics-stub}} [[Category:Fiber optics]]