Reduction of intra-channel four-wave mixing through pairwise or pulseto- pulse alternate polarization of carrier-suppressed RZ signals

It is shown that a combination of pairwise or pulse-to-pulse alternate polarization and 67% duty cycle carrier-suppressed return-to-zero (CSRZ) achieves additional reduction of intra-channel four-wave mixing compared to bit-to-bit alternate polarization in 40 Gbit/s systems.