In the coherent optical communication systems at 100 Gbit/s and higher rates using high-order phase modulation

laser phase noise and dispersion effects in fiber-optic transmissions are the major factors that affect the system performance.To compensate for these effects

this paper proposes a method for the combined use of electric channel equalization and carrier phase estimation modules in the electric domain.The phase estimation is completed after the electric channel equalization

the results of which are also used in updating the tap coefficients of the equalizer.This method can effectively reduce the requirements for the step-size in the equalization

conducive to acquiring lower bit error rate

more stable error performance and longer transmission distance.