  We develop a new approach for controllable single-photon transport between
two remote one-dimensional coupled-cavity arrays, used as quantum registers,
mediated by an additional one-dimensional coupled-cavity array, acting as a
quantum channel. A single two-level atom located inside one cavity of the
intermediate channel is used to control the long-range coherent quantum
coupling between two remote registers, thereby functioning as a quantum switch.
With a time-independent perturbative treatment, we find that the leakage of
quantum information can in principle be made arbitrarily small. Furthermore,
our method can be extended to realize a quantum router in multi-register
quantum networks, where single-photons can be either stored in one of the
registers or transported to another on demand. These results are confirmed by
numerical simulations.
