Fiber nonlinearity limits the use of coherent optical orthogonal frequency division multiplexing (CO- OFDM) to upgrade wavelength-division multiplexing (WDM) systems using legacy non-return-to-zero-on- off-keying ...Fiber nonlinearity limits the use of coherent optical orthogonal frequency division multiplexing (CO- OFDM) to upgrade wavelength-division multiplexing (WDM) systems using legacy non-return-to-zero-on- off-keying (NRZ-OOK) channels. This letter proposes to compensate for the fiber nonlinearity of COOFDM with NRZ-OOK neighbors by combining digital signal processing (DSP)-based self-phase modulation (SPM) post-compensation with pilot-tone-based cross-phase modulation (XPM) compensation. The simulation results demonstrate that the optimum low-pass filter bandwidth for pilot-tone-based XPM compensation depends on the pilot-to-signal ratio value and launch optical power. Our method allows a 4-dB increase in the launch power for a 40-Gb/s single polarization CO-OFDM channel placed in the middle of six 10.7-Gb/s NRZ channels in a 50-GHz space and 1 200-km WDM system.展开更多
基金supported by the National Natural Sci-ence Foundation of China(Nos.61071097and61107060)the State Key Laboratory of Advanced Optical Com-munication Systems and Networks
文摘Fiber nonlinearity limits the use of coherent optical orthogonal frequency division multiplexing (CO- OFDM) to upgrade wavelength-division multiplexing (WDM) systems using legacy non-return-to-zero-on- off-keying (NRZ-OOK) channels. This letter proposes to compensate for the fiber nonlinearity of COOFDM with NRZ-OOK neighbors by combining digital signal processing (DSP)-based self-phase modulation (SPM) post-compensation with pilot-tone-based cross-phase modulation (XPM) compensation. The simulation results demonstrate that the optimum low-pass filter bandwidth for pilot-tone-based XPM compensation depends on the pilot-to-signal ratio value and launch optical power. Our method allows a 4-dB increase in the launch power for a 40-Gb/s single polarization CO-OFDM channel placed in the middle of six 10.7-Gb/s NRZ channels in a 50-GHz space and 1 200-km WDM system.