Abstract: The invention relates to a polarization scrambler comprising a controllable optical phase retardation element for retarding with respect to one another components of a light beam with a different state of polarization, the light beam propagating through the element, and a control arrangement for controlling the phase retardation element, said control arrangement being adapted to supply a control signal so that as a function of time the phase retardation is controlled in such a way that with a given state of polarization (SOP) of the light entering the polarization scrambler varying states of polarization occur at its output in such a way that, averaged in time, the light intensities emerging in each SOP are at least substantially equal.