A Robust and Efficient Frequency Offset Correction Algorithm With Experimental Verification for Coherent Optical OFDM System

Frequency offset correction (FOC) is essential for a coherent optical orthogonal frequency-division multiplexing (CO-OFDM) system. In this paper, we proposed a robust and efficient FOC algorithm by designing training symbols in frequency domain. This algorithm has an advantage in overcoming imperfect frequency response induced by transmitter devices and physical channel implementations. To further improve the stability of the FOC algorithm against the optical signal-to-noise ratio degradation, a two-step iterative operation is introduced. The proposed algorithm has been utilized in a practical 100-km 16QAM-CO-OFDM transmission system to compensate the frequency offset dynamically. The efficiency and robustness of the algorithm have been validated by outstanding and stable experimental results.