Methods and apparatus for optical polarization control

A method of polarization control of an optical signal by a polarization controller, the polarization controller comprising a first polarization rotator and a second polarization rotator controlled by control settings, comprising:

• generating a monitoring value indicating a performance of the polarization controller;
• determining from the monitoring value if the polarization controller is operating in a selected one of a plurality of optimal performance states;
• and if not,
• selecting different control settings to select an alternate one of the plurality of optimal performance states for the polarization controller.

A controller configured to control a polarization controller having a first polarization rotator and a second polarization rotator controlled by control settings,

• the controller comprising a processor and a memory, said memory containing instructions executable by said processor whereby said controller is operative to:
• obtain a monitoring value indicating a performance of the polarization controller;
• determine from the monitoring value if the polarization controller is operating in a selected one of a plurality of optimal performance states;
• and if not,
• select different control settings to select an alternate one of the plurality of optimal performance states for the polarization controller.

A controller configured to control a polarization controller having a first polarization rotator and a second polarization rotator controlled by control settings, the controller comprising:

• a monitoring module configured to obtain a monitoring value indicating a performance of the polarization controller;
• a comparison module configured to determine from the monitoring value if the polarization controller is operating in a selected one of a plurality of optimal performance states;
• and
• a processing module configured, if the comparison module indicates operating not in an optimal performance state, for selecting different control settings to select an alternate one of the plurality of optimal performance states for the polarization controller.

A computer program product for controlling a polarization controller having a first polarization rotator and a second polarization rotator controlled by control settings, said computer program product comprising a non-transitory computer readable medium storing a computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to:

• obtain a monitoring value indicating a performance of the polarization controller;
• determine from the monitoring value if the polarization controller is operating in a selected one of a plurality of optimal performance states;
• and if not,
• select different control settings to select an alternate one of the plurality of optimal performance states for the polarization controller.