All-optical logic gates with quantum-dot semiconductor optical amplifiers

In this invited paper we review the progress on all-optical gates that exploit quantum-dot semiconductor optical amplifiers (QD-SOAs) as nonlinear elements. In particular we focus on our research conducted in this cutting-edge technological field, which relies on QD-SOAs incorporated in a Mach-Zehnder Interferometer (MZI). We present results on an extensive set of Boolean operations executed in the optical domain by properly configuring and driving the QD-SOA-based MZI. We address the feasibility of these logic gates and we give guidelines for their design so that they can be realized with logical correctness and high performance. Finally we report on some characteristic applications of enhanced functionality where these fundamental gates are employed as core logic units to form complex all-optical circuits.