Patent ID: 7085052

Claim:
A polarization controller, comprising: a succession of optical elements arranged along a path of a light beam between an input and an output; wherein the succession of optical elements includes a predetermined number of optical elements in said succession, that are each controllable for determining a polarization state of the output, at least one of the optical elements in the succession comprising a device having a tuning range with maximum and minimum endpoint limits for determining said polarization state, which limits cannot be exceeded; wherein the succession of optical elements has a predetermined minimum number of said optical elements such that said succession of optical elements is configured to obtain a unique polarization alteration; wherein the succession of optical elements further comprises at least one additional optical element that is controllable for determining the polarization state of the output, wherein interaction of the predetermined number of optical elements with the additional element is such that a given polarization state of the output can be achieved by choosing one of a plurality of alternative sets of values of control settings applied to the predetermined number of optical elements and the additional optical element; a controller operable to select among said alternative sets of values, wherein the controller is operable to select among the alternative sets so as to minimize at least one error function; and, wherein the at least one error function favors values of the control settings at a predetermined area within a range of possible values of the control settings.