Nonlinear Interactions Between 10Gb/s NRZ Channels and 40Gb/s Channels with RZ-DQPSK or PSBT Format, over Low-Dispersion Fiber

RZ-DQPSK and PSBT are seen as promising modulation formats for upgrading 10Gb/s networks to 40Gb/s. We show that cross non-linear effects make the upgrade more challenging for RZ-DQPSK than for PBST over low-dispersion fibre.