A new method incorporating biased clipping orthogonal frequency division multiplexing （OFDM） is presented, which mitigates fiber nonlinear effects in a long-haul coherent optical OFDM （CO-OFDM） system. Under the s...A new method incorporating biased clipping orthogonal frequency division multiplexing （OFDM） is presented, which mitigates fiber nonlinear effects in a long-haul coherent optical OFDM （CO-OFDM） system. Under the scheme of the method, the wanted signal carried by odd subcarriers is orthogonal to clipping noise and a Mach-Zehnder modulator （MZM） performs the optimal OFDM signal up-converter from the radio frequency （RF） domain to the optical domain. Analysis and simulation results show that fiber non- linear effects can be effectively mitigated by reducing the peak-to-average power ratio （PAPR） in biased clipping CO-OFDM system. The nonlinearity threshold （NLT） is improved by 5 dB with a reach of 240 km. With a fiber length up to 800 km, system Q value is improved by approximately 2.3, 1.2, and 0.6 dB at a chromatic dispersion of 6, 12, and 16 ps/（nm.km）, respectively. Additionally, system Q reaches the maximum when direct currect （DC） bias is equal to the mean value of the OFDM waveform.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.60871075
文摘A new method incorporating biased clipping orthogonal frequency division multiplexing （OFDM） is presented, which mitigates fiber nonlinear effects in a long-haul coherent optical OFDM （CO-OFDM） system. Under the scheme of the method, the wanted signal carried by odd subcarriers is orthogonal to clipping noise and a Mach-Zehnder modulator （MZM） performs the optimal OFDM signal up-converter from the radio frequency （RF） domain to the optical domain. Analysis and simulation results show that fiber non- linear effects can be effectively mitigated by reducing the peak-to-average power ratio （PAPR） in biased clipping CO-OFDM system. The nonlinearity threshold （NLT） is improved by 5 dB with a reach of 240 km. With a fiber length up to 800 km, system Q value is improved by approximately 2.3, 1.2, and 0.6 dB at a chromatic dispersion of 6, 12, and 16 ps/（nm.km）, respectively. Additionally, system Q reaches the maximum when direct currect （DC） bias is equal to the mean value of the OFDM waveform.
