The phenomena of excitability and coherent resonance
in a nonlinear ring cavity in the presence of
excitons and biexcitons are considered. A bifurcation
analysis of the dynamics of the nonlinear ring cavity indicates
that both self-pulsation and excitability can exist
in the system. It is demonstrated that coherent resonance
can be observed in an excitable exciton-biexciton system
in the ring cavity. The optimum conditions