Chromatic dispersion monitoring by extended Kalman filter for coherent optical OFDM systems

Abstract

This paper proposes to monitor the total accumulated chromatic dispersion (CD) by using extended Kalman filter (EKF) for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems. Accurate estimation performance can be achieved by only one OFDM training symbol. Simulations results show that the proposed EKF method can quickly converge to the exact dispersion value within 40 subcarriers. Besides, the influence of inter-carrier interference (ICI) induced by the carrier frequency offset (CFO) and laser phase noise (LPN) on the CD monitoring performance is also investigated. Even with the appearance of 3 GHz CFO and 200 kHz combined laser linewidth (CLW) and without compensation, the mean square error (MSE) and bit error rate (BER) of the proposed method vary little, which illustrate its good tolerance to the ICI.