All-optical set–reset flip–flop based on the passive microring-resonator bistability

In this paper, we propose a design for an all-optical R–S flip–flop with separate set and reset inputs, which is based on the optical bistability due to Kerr and two-photon absorption (TPA) effects in the microring resonators. Based on the steady state analysis of the light propagation in nonlinear microrings, variations of hysteresis parameters versus the system variables, such as transmission coefficient, nonlinear refractive index and detuning angle, are analyzed. The switching temporal behavior of the proposed flip–flop is obtained by the microring transient analysis. It is shown that the contrast ratio parameter and the switching power of the proposed all-optical flip–flop can be controlled by system parameters.