| Universal Filter Multi-Carrier(UFMC)is promising in high-speed PONs and mobile fronthaul networks due to its high spectrum utilization,low out-of-band leakage and robustness of time-frequency offset.The transmission capacity of the UFMC system can be effectively increased by increasing the signal baud rate or the modulation order of the signal.However,for the transmission system with the limited bandwidth,more inter-symbol interference(ISI)and fiber dispersion distortion appear in the high baud-rate signal.Meanwhile,higher-order QAM signals require higher signal-to-noise ratios(SNRs)and are susceptible to more nonlinear noise in long-distance fiber transmission.To solve the above issues,in this work,the 25-GBd probabilistic shaping(PS)64-QAM UFMC signal and the 12.5-GBd PS 1024-QAM QAM signal in intensity modulation direct detection(IM/DD)UFMC system with 10-GHz bandwidth have been investigated theoretically and experimentally.First,the 25-GBd PS 64-QAM UFMC transmission system over 30-km SSMF has been experimentally achieved with improved bit error ratio(BER)performance by optimizing the allocation of data subbands to mitigate ISI caused by the fiber chromatic dispersion.Second,in the PS 1024-QAM UFMC system,a truncated probabilistic shaping(TPS)1024-QAM UFMC transmission scheme with the entropy of 9 bits/symbol is proposed and experimentally demonstrated,where the precoding is exploited to eliminate the large ripples of SNRs and suppress peak to average power ratio(PAPR)simultaneously.The BER performance is improved within the soft-decision FEC threshold. |
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