Logic unit for CSRZ-OOK signals with the capability of simultaneously realizing logic OR and AND gates

To cope with the development of Carrier-suppressed-return-to-zero-on-off-keying (CSRZ-OOK) modulation format, it is of great significance to investigate all-optical logic gates to process CSRZ-OOK format signals. To the best of our knowledge, for CSRZ-OOK signals, only logic AND gate has been demonstrated while other logic functions haven't been explored until now. In this paper, an all-optical logic unit to process CSRZ-OOK signals based on four-wave mixing (FWM) arising in a semiconductor optical amplifier (SOA) is proposed. A logic OR gate and two logic AND gates with the CSRZ-OOK format unchanged could be simultaneously achieved without reconfiguration in this single unit. The performance of 40 Gb/s logic operation is firstly evaluated with numerical simulations by a comprehensive dynamic model considering three-input induced FWM in an SOA. Then, experimental demonstrations at 10 Gb/s with clear waveforms and high extinction ratios (ERs) further verify the logic integrity of this scheme.