Photonic Logic Operations with Nonlinear Semiconductor Etalons Exploiting Saturable Absorption in Multiple Quantum Wells

摘要

Photonic logical gates, enabling ultra-fast All-Optical Signal Processing (AOSP), will play a key role in next generation optical networking and computing. Semiconductor technology offers the advantages of compact size and low operating power. In the past years, semiconductor optical amplifiers [1], and microring resonators [2] have been exploited to perform several different operations. On the other hand, Saturable Absorbers (SAs) were only used to perform AND operation [3], due to their typical nonlinear behavior exhibiting low throughput at low powers and high throughput at high powers. Here, we propose the use of a SA-based nonlinear etalon for realizing NAND and NOR logical functions. The device, exhibiting inverse SA behavior, is investigated through numerical modeling. The nonlinear gate consists of an asymmetric Fabry-Perot (FP) cavity formed between a highly reflecting bottom mirror (which is assumed to have 100% reflectivity) and a top mirror with reflectivity R{sub}t. Saturable losses in the cavity can be provided by placing semiconductor Multiple Quantum Wells (MQWs) between the two mirrors. The MQWs nonlinear intensity absorption coefficient α[m{sup}(-1)] can be expressed as: α=α{sub}(ns)+α{sub}0/(1+1/I{sub}(sat)), (1).