We study the coherent scattering process of photons in two waveguides chiral coupling to a Λ-type three-level system (3LS). The 3LS acts as a few-photon router that can direct photons with unity. By adjusting the classical field applied to the 3LS, the tunneling paths between two waveguides can be turned off and on, but two photons can not be routed simultaneously from one port of the incident waveguide to an arbitrarily selected port of the other waveguide. Moreover, driven field controls the number of the bi-photon bound states and the interference pattern of the bi-photon bound states.