Dissipation-assisted few-photon optical diode

We studied the coherent transport of one or two photons in a one-dimensional waveguide chirally coupled to a dissipative nonlinear cavity. The scattering amplitudes were derived analytically. With the assist of dissipation, we can realize an ideal optical diode at the single-photon level, i. e., the transmittance is unity from one side and zero form the other side. The working area and properties of the two-photon diode are also found. This work details the relation between the diode effect and our system parameters, especially dissipation, which may find it applications in nonreciprocal quantum devices and quantum networks.