Fig. 1. (a) Constellation of 16QAM; (b) time evolution of carrier phases (blue line) and linear fitting of phase noise by using the symbols in first and third rings of X polarization (red line); (c) time evolution of carrier phases (blue line) and linear fitting of phase noise by using the symbols in first and third rings of Y polarization (red line); (d) time evolution of carrier phases (blue line) and linear fitting of phase noise by using the symbols in first and third rings of both X and Y polarizat

Fig. 2. Schematic diagram of dual-polarization carrier phase recovery algorithm based on Kalman filter

Fig. 3. BER performance of PDM-16QAM system with different linewidths

Fig. 4. BER performance of PDM-16QAM for different linewidths with different OSNRs. (a) 200 kHz; (b) 500 kHz

Fig. 5. BER performance of PDM-16QAM for various algorithms with different block lengths

Fig. 6. Experimental setup of PDM-16QAM system

Fig. 7. (a) Estimated phase noise of X polarization and Y polarization;(b) estimated phase offset of two polarizations with different steps

Fig. 8. BERs of two algorithms change with OSNR. (a) 100 kHz; (b) 2 MHz

Fig. 9. BERs of two algorithms change with block length