Conventional and unconventional photon blockade with cross-Kerr nonlinearity

We investigate the use of the cross-Kerr nonlinearity to realize strong photon blockade in a weakly driven, three-mode system. The results show that the conventional photon blockade induced by the strong nonlinearities and the unconventional photon blockade induced by quantum interference effects exist in our system. In particular, we find that the CPB only appears in the strong cross-Kerr coupling regime, while the UPB can occur in the weak or strong cross-Kerr coupling regime. For the strong cross-Kerr nonlinearities, both CPB and UPB exhibit strong antibunching features. Furthermore, the switch between CPB and UPB can be achieved with different detunings. Our work paves the way to study two different physical mechanisms behind CPB and UPB.