Patent ID: 7613366
Filing Date: 2009-11-03
Classification: H04B

Abstract:
1. A polarization mode dispersion compensator comprising: a polarization controller rotating a polarization angle of an input optical signal and outputting polarization controlled light; a polarization mode dispersion (PMD) compensating device compensating a polarization mode dispersion of the polarization controlled light and outputting a PMD compensated light; a signal quality monitor measuring a degree of polarization (DOP) of the PMD compensated light and generating a feedback signal indicating the measured DOP of the PMD compensated light; and a control unit controlling the polarization controller and PMD compensating device based on the measured DOP, wherein the control unit determines an amount of change of a control signal applied to the polarization controller for a feedback loop, by evaluating a DOP in response to the control signal using a plurality of feedback signals generated in the past feedback loops, changes the control signal by the determined amount, applies a changed control signal to the polarization controller, the compensating device is an optical element with a variable and adjustable amount of differential group delay, and the control unit determines an amount of change of the differential group delay for each feedback loop by evaluating a past trend of changes of the differential group delay of the compensating device.