Frequency Diversity MIMO Detection for DP- QAM Transmission

Dual-carrier 10-GBaud DP-16QAM transmission system with frequency diversity multiple-input multiple-output (FD-MIMO) detection is described. In transmission over 800 km of standard single-mode fiber, with a dual-carrier spacing of 0.8× symbol rate, a Q²-factor penalty of only 1.7 dB, relative to single-carrier performance, is achieved. The performance of FD-MIMO for linear crosstalk mitigation is experimentally demonstrated by varying the channel spacing from 0.4 to 1.2× symbol rate in a dual-carrier DP-16QAM and DP-QPSK back-to-back configuration. Three-channel FD-MIMO equalization for both modulation formats is also studied in the same configuration. In addition, the combination of optical filtering and FD-MIMO indicates that a guard band of 10% of the symbol rate is sufficient to avoid additional linear crosstalk from neighboring WDM channels.