NRZ versus RZ over Absolute Added Correlative coding in optical metro-access networks

•Two novel modulation formats based on partial-response signalling are demonstrated.•Working principle of NRZ- and RZ-AACC are investigated in dispersive medium.•NRZ- and RZ-AACC are evaluated for both optical metro and access networks.

This paper comparatively investigates the transmission performance of absolute added correlative coding (AACC) using non-return-to-zero (NRZ) and return-to-zero (RZ) pulse shapes with a binary intensity modulation direct detection receiver in 40 Gb/s optical metro-access networks operating at 1550 nm. It is shown that, for AACC transmission, the NRZ impulse shaping is superior in comparison to RZ in spectral efficiency, dispersion tolerance, residual dispersion and self-phase modulation (SPM) tolerance. However, RZ-AACC experiences a ~1-2 dB advantage in receiver sensitivity over NRZ-AACC for back-to-back configuration as well as after 300-km single-mode fiber delivery.