151 /spl times/ 43 Gb/s transmission over 4080 km based on return-to-zero-differential quadrature phase-shift keying

We demonstrate a record distance with N /spl times/ 43 Gb/s RZ-DQPSK modulated channels. More than 1.5 dB margin is measured for all 151 WDM, 50 GHz-spaced channels at the end of the system, based on 70 nm-wide Raman repeaters.