A polarization stabilizing device and method based on controlling the
phase retardations of a pair of variable rotators with an optically
interposed quarter-wave plate, with a controller such that the first of
the variable rotators has its phase retardation switched between first
and second values whenever the phase retardation of the second of the
variable rotators reaches an upper or a lower limit. The upper and lower
limits of the second rotator and the first and second values of the first
rotator are chosen so that discontinuities in the power of the output
optical radiation are avoided when the first variable rotator is
switched, thereby providing endless polarization stabilization using
rotators that themselves may have limited retardation ranges.