Single-photon router utilizing whispering-gallery resonator coupled with atoms

We examine the routing scheme of single photons in a photonic quantum network. The configuration of the proposed router consists of two one-dimensional waveguides and a whispering-gallery-mode resonator interacting with two-level atoms. The study shows that the quantum interference caused by atoms can be used to control the transport of a single photon in the waveguides. When only one atom is considered, by adjusting the amplitude of the intermode backscattering strength and the position of the atom, perfect transmission and reflection of single photon can be realized. For the case of two atoms, by properly designing the distance between the two atoms, nonresonant photon inputting from one port of the first waveguide can be deterministically transferred to one of the selected output ports of the second waveguide. We also examine how the routing properties are influenced by the losses of the atoms and resonator.