Optical bistability in a multiple-quantum-well structure with Fabry-Pérot and distributed-feedback resonators

The system we analyze has the structure of a planar optical waveguide containing a multiple quantum well, with the planes of the wells parallel to the direction of propagation. We consider the two different configurations of a Fabry-Pérot cavity and distributed-feedback device. The optical nonlinearities are described by means of the first-principles theory developed by Haug, Koch, Schmitt-Rink, and co-workers, generalized to include the finite width of the wells. The dynamics of the system is described by the equations that govern the evolution of the two counterpropagating fields, coupled with the carrier-density equation, and accompanied by the appropriate boundary conditions. The steady-state behavior is analyzed as a function of the control parameters of the system for the case of a GaAs/${\mathrm{Al}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$As/AlAs structure. The system develops bistability even when the input field is in resonance with the excitonic peak, but the phenomenon becomes more pronounced in the detuned configuration. The hysteresis cycles obtained in the case of distributed-feedback device turn out to be competitive with those displayed by the Fabry-Pérot system.