Patent ID: 8145174

Claim:
An orthogonal cross-polarization interference compensating device, which compensates for orthogonal cross-polarization interference of other polarization signals with an own polarization signal, comprising: a compensator that generates a compensation signal for compensating phase noise included in the own polarization signal; a demodulator that compensates for the orthogonal cross-polarization interference of the other polarization signals with the own polarization signal by suppressing phase noise included in the own polarization signal based on the compensation signal; an error detector that generates an error signal indicating phase difference between the own polarization signal compensated by the demodulator and a proper own polarization signal; a phase detector that generates a differential signal indicating phase difference between the own polarization signal and the other polarization signals based on the compensation signal and the error signal; an integrator that generates an integration signal by integrating the differential signal generated by phase detector; a shifter that adjusts the compensation signal based on the integration signal generated by the integrator; and a controller that determines whether or not the orthogonal cross-polarization interference is present based on the compensation signal adjusted by the shifter, and if no orthogonal cross-polarization interference is present, adjusts an integration value indicated by the integration signal to a predetermined value.