Proposal for a compact design for real-time optical bistability switching via a semiconductor cavity containing quantum wells.

A compact design for semiconductor cavities including coupled AlGaN/AlGaAs quantum wells is proposed for all-optical switching of the bistability process. First, physical and geometrical parameters are optimized to engineer the conducting electrons' energy levels in the quantum wells. Then, finite element simulations based on Schrödinger equations are executed to estimate the states of the charge carriers for AlGaN/AlGaAs as the active region. Next, the optical coupling and pumping fields are applied to the active region to both initiate the bistability and facilitate its real-time control. The Maxwell-Bloch approach based on rotating-wave approximation is employed to analyze the optimal conditions for controlling the behavior of optical bistability (OB). It is found that the threshold of OB can be optimized to have low values by tuning the intensity of coupling fields and the rate of an incoherent pumping field. This provides a fast real-time switching facility to control output intensity of the systems. The proposed scheme could have potential applications in optical memories, in which it is paramount to have active control over the readout of the system's quantum states. Thanks to the high nonlinear response of semiconductors, the featured device would be a prospective candidate for on-chip ultrasubluminal wave propagation studies and narrowband real-time switching and filtering applications.