Estimating apparatus for bias drift of transmitting end modulator, compensating apparatus and receiver

A communication system, comprising:

• a transmitting end modulator subject to a bias drift;
• a receiver coupled to the transmitting end modulator;
• and
• a receiving end compensator performing phase recovery on received signals to remove a frequency difference and a phase difference between a transmitting end laser and a receiving end laser to produce phase recovered received signals, estimate the bias drift according to the phase recovered received signals and to compensate the bias drift of the transmitting end modulator according to the estimated bias drift of the transmitting end modulator in the receiver,
• the receiving end compensator is further configured to modify a reference signal used for performing equalization processing according to the estimated bias drift of the transmitting end modulator, and perform equalization processing on the received signals according to the modified reference signal.

A method of estimating and compensating bias drift of a transmitting end modulator contained in received signals, applied in a receiver, the method comprising:

• recovering the received signals by removing a frequency difference and a phase difference between a transmitting end laser and a receiving end laser producing phase recovered received signals;
• estimating the bias drift of the transmitting end modulator according to the phase recovered received signals;
• and
• compensating the bias drift of the transmitting end modulator in the receiver according to the estimated bias drift of the transmitting end modulator,
• the method further comprising:
• modifying a reference signal used for performing equalization processing according to the estimated bias drift of the transmitting end modulator, and performing equalization processing on the received signals according to the modified reference signal.