A Frequency Offset Estimation and Compensation Scheme for ASCM Systems

ASCM systems implementing subcarriers multiplexing and demultiplexing in the analog domain, could effectively improve the tolerance to fiber nonlinearity and dispersion, and moreover reduce the requirements for sampling rate and bandwidth of DACs/ADCs. However, the integrity of low symbol rate subcarriers in an ASCM system is more sensitive to FO. Aiming at the method of analog domain subcarrier demultiplexing in an ASCM system, this paper proposes a FO estimation and compensation scheme based on spectral dip searching and local subcarrier frequency adjusting. The simulation result shows that the estimation accuracy of proposed scheme can reach the order of 10MHz, and the cost of Q value is less than 0.05dB.