A joint recovery scheme for carrier frequency offset and carrier phase noise using extended Kalman filter

• Published in: Optical fiber technology Vol. 36; pp. 438 - 446
• Main Authors: Li, Linqian, Feng, Yiqiao, Zhang, Wenbo, Cui, Nan, Xu, Hengying, Tang, Xianfeng, Xi, Lixia, Zhang, Xiaoguang
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.07.2017
• Subjects: Carrier frequency offset (CFO) estimation; Carrier phase noise (CPN) recovery; Extended Kalman filter (EKF); Extended Kalman filter (EKF); Carrier frequency offset (CFO) estimation; Carrier phase noise (CPN) recovery
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2017.06.004

•A joint recovery scheme for CFO and CPN by extended Kalman filter is proposed.•The proposed scheme behaves high and stable CFO estimation accuracy.•The proposed scheme can enhance the laser linewidth tolerance.•The proposed scheme shows a fast convergence speed and low computational complexity.•The proposed scheme is implemented and verified in the PDM-QPSK system and PDM-16QAM system. A joint carrier recovery scheme for polarization division multiplexing (PDM) coherent optical transmission system is proposed and demonstrated, in which the extended Kalman filter (EKF) is exploited to estimate and equalize the carrier frequency offset (CFO) and carrier phase noise (CPN) simultaneously. The proposed method is implemented and verified in the PDM-QPSK system and the PDM-16QAM system with the comparisons to conventional improved Mth-power (IMP) algorithm for CFO estimation, blind phase search (BPS) algorithm or Viterbi-Viterbi (V-V) algorithm for CPN recovery. It is demonstrated that the proposed scheme shows high CFO estimation accuracy, with absolute mean estimation error below 1.5MHz. Meanwhile, the proposed method has the CFO tolerance of [±3GHz] for PDM-QPSK system and [±0.9GHz] for PDM-16QAM system. Compare with IMP/BPS and IMP/V-V, the proposed scheme can enhance the linewidth symbol duration product from 3×10−4 (IMP/BPS) and 2×10−4 (IMP/V-V) to 1×10−3 for PDM-QPSK, and from 1×10−4 (IMP/BPS) to 3×10−4 for PDM-16QAM, respectively, at the 1dB optical signal-to-noise ratio (OSNR) penalty. The proposed Kalman filter also shows a fast convergence with only 100 symbols and much lower computational complexity.