On the Feasibility of 320 Gb/S All-Optical and Gate Using Quantum-Dot Semiconductor Optical Amplifier-Based Mach-Zehnder Interferometer

The feasibility of realizing an all-optical AND gate for 320 Gb/s return-to-zero data by incorporating quantum-dot semiconductor optical amplifiers (QD-SOAs) in a Mach-Zehnder interferometer (MZI) is theoretically investigated and demonstrated. The proposed scheme employs the QD-SOA-based MZI in a configuration where the QD-SOA in one MZI arm is subject to the first data sequence, the QD-SOA in the other MZI arm receives no such input but is constantly held in the small signal gain regime, and the second data stream is inserted from the common MZI port acting as enabling or disabling signal. Compared to other approaches adopted for the same purpose this implementation is more general, direct, flexible and affordable as only one strong data signal is required to control switching. By conducting numerical simulation the impact of the critical parameters on the Q-factor is thoroughly assessed. The obtained results are interpreted with the help of a complete characterization of the QD-SOA response to an ultrafast data pulse stream. This allows to specify the requirements that the critical parameters must satisfy to achieve acceptable performance. The extracted design rules are technologically realistic and ensure AND operation both with logical correctness and high quality. The outcome of the numerical treatment extends the range of Boolean functions executed with the QD-SOA-MZI module at sub-Tb/s data rates.