The apparatus and methods disclosed herein are directed to detecting the presence of a whipping tail when using a fiber winding system to wind a fiber onto a rotating spool. The fiber is guided onto the rotating spool through a containment region between the spool and a whip shield to create the wound fiber. The whipping tail outwardly extends from the wound fiber and periodically or quasi-periodically passes through a light beam to create a series intensity dips in the light beam, thereby forming a modulated light beam. The modulated light beam is converted into a digital electrical signal made up of electrical pulses having a timing defined by the intensity dips. The measured timing of the electrical pulses is compared to an estimated timing based on the rotating spool to ascertain the presence of a whipping tail.