Flat-top Spectrum Data Format for Nx40 Gbit/s WDM Transmission with 0.8 bit/s/Hz Spectral Efficiency

We examine a signal format with flat-top spectrum and corresponding sinc temporal profile resonancely placed over few time slots. A feasibility of WDM transmission at 40 Gbit/s channel rate over 1200 km without FEC with spectral efficiency of 0.8 bit/s/Hz (without polarization division multiplexing) is confirmed by numerical modelling.