Abstract: An apparatus and method for reducing or preventing fiber entry whip as the loose end of a fiber being wound on a spool enters a fiber winding device. A fiber winding device includes a spool winder entrance, a winding spool and a fiber whip shield substantially surrounding the winding spool. A fiber entry whip reducer positioned in front of the fiber winding device includes at least one pulley and a guide channel including a straight entry section and a curved section leading to the fiber winding device. The guide channel is formed and positioned such that the loose end of the fiber is maintained against the guide channel by centrifugal force imparted onto the fiber by the curvature of the channel and forward motion of the fiber produced by the rotating spool, thereby producing a trajectory such that the loose end of the fiber enters the fiber winding device and is maintained against the whip shield.

Abstract: The invention provides improved methods for reducing polarization mode dispersion (PMD) in single mode fiber by spinning the fiber during the drawing process in accordance with a spin function having sufficient harmonic content to achieve low levels of PMD for commercial fibers for which the beat lengths of the fibers, including the beat lengths of different portions of the fibers, are variable and thus not readily known in advance. The spin functions of the invention take advantage of certain resonances in energy transfer between polarization modes to achieve substantial reductions in PMD for a wide range of beat lengths. Examples of suitable spin functions include frequency-modulated and amplitude-modulated sine waves.