Comparison of coherent optical single-carrier and multi-carrier superchannel with FDM and FDE

• We thoroughly compare performances of coherent optical SC and MC superchannels with FDM and FDE with uniform design rule.
• DAC & ADC resolution and laser phase noise effects on SCFDM and OFDM superchannels with 4 to 256-QAM formats are compared.
• Impact of dispersion accumulation and polarization effects on both superchannels is shown.
• Nonlinear performances of both superchannels with higher-order QAM formats are discussed.
• Investigation on heterogeneous superchannel employing interleaved SCFDM/OFDM subbands is presented.

Optical superchannel employing single-carrier (SC) and multi-carrier (MC) subband modulation techniques have been widely discussed for high-speed coherent optical transmission and networks. In this paper, we establish uniform system design based on frequency-domain equalization (FDE) and carry out a thorough study on orthogonal frequency division multiplexing (OFDM) superchannel versus SC frequency division multiplexing (SCFDM, also named as DFT-spread-OFDM) superchannel. The baseband signal characteristics of SCFDM and OFDM are analyzed. SCFDM and OFDM superchannel systems with 4-, 16-, 64- and 256-QAM formats and polarization division multiplexing (PDM) are numerically investigated against various impairments. The results show that SCFDM superchannel outperforms its MC counterpart against finite DAC&ADC resolution and fiber nonlinearities, while suffers more penalty when very large dispersion or laser phase noise exists.