Transmission of 40 Gb/s WDM signals over 6,250 km of conventional NZ-DSF with >4 dB FEC margin

We successfully transmitted 18/spl times/40 Gb/s RZ-DPSK channels over 6,250 km of non-slope-matched-fibers with >4 dB FEC margin using dispersion-slope compensators at the receiver. We demonstrated that 40 Gb/s DPSK worked as well as 10 Gb/s RZ-OOK for the same spectral efficiency.