Fig. 1. The effect of the laser linewidth on the signal in the OFDM-OQAM system. The line width is (a) 0; (b) 0.1 MHz; (c) 0.2 MHz; (d) 0.3 MHz; (e) 0.5 MHz; (f) 1 MHz

Fig. 2. Pilot structure diagram of the proposed phase noise compensation method

Fig. 3. The AM signal loaded in the pilot

Fig. 4. Flowchart of the proposed phase noise compensation algorithm

Fig. 5. Schematic diagram of PDM CO-OFDM-OQAM system, with insets showing its optical spectra and compensation process

Fig. 6. The bit error rate performance of different laser linewidths with the subcarrier number 256 when light is back-to-back

Fig. 7. The bit error rate performance of different laser linewidths with subcarrier number 512 when light is back-to-back

Fig. 8. The bit error rate performance for proposed method under different subcarrier numbers with OSNR 25 dB when light is back-to-back

Fig. 9. The influence of different pilot groups on bit error rate performance

Fig. 10. Experimental scheme to validate the method proposed in this paper. Acronym key: AWG, Arbitrary Waveform Generator; I, In-phase; Q, quadrature; DSO, digital storage oscilloscope; ECL, External Cavity Laser.