We propose a waveguide-cavity coupled system to achieve the routing of photons by the phases of other photons. Our router has four input ports and four output ports. The transport of the coherent-state photons injected through any input port can be controlled by the phases of the coherent-state photons injected through other input ports. This control can be achieved when the mean numbers of the routed and control photons are small enough and require no additional control fields. Therefore, the all-optical routing of photons can be achieved at the single-photon level.
@article{arxiv.1409.6509,
title = {All-optical routing of single photons with multiple input and output ports by interferences},
author = {Wei-Bin Yan and Bao Liu and Ling Zhou and Heng Fan},
journal= {arXiv preprint arXiv:1409.6509},
year = {2014}
}