Experimental demonstration of pseudo-pilots-aided Gaussian basis expansion-based phase noise suppression scheme for CO-OFDM

In this paper, we propose a novel phase noise suppression scheme called pseudo-pilots-aided Gaussian basis expansion (PS-GBE) for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. Integrating with the pseudo-pilots, the Gaussian basis can suppress and fit phase noise effectively with high spectral efficiency (SE). We experimentally demonstrate the proposed scheme in 200-Gb/s optical QPSK-OFDM superchannel and 400-Gb/s optical 16QAM-OFDM superchannel. According to the experimental results, the proposed PS-GBE has a phase noise suppression performance similar to the GBE scheme. However, different from the GBE scheme, fewer pilots are needed for phase noise estimation in PS-GBE. Hence, the proposed PS-GBE can achieve higher SE. Compared to the pseudo-pilots-aided orthogonal basis expansion-based (PS-OBE) phase noise suppression and traditional common phase noise compensation (CPEC) methods, the proposed PS-GBE can get a significant performance enhancement. In the QPSK-OFDM system, a Q-factor improvement of 1.1 dB is obtained compared to the PS-OBE method. In the 16QAM-OFDM system, the BER is enhanced from 1.00E-03 to 2.05E-04. Further simulation results indicate that our proposed PS-GBE scheme can effectively increase laser linewidth tolerance. The proposed scheme can be applied to CO-OFDM and extended to coherent optical filterbank multicarrier (CO-FBMC) and coherent optical single carrier frequency domain multiplexing (CO-SCFDM) transmission system.