  We study the photon statistics properties of few-photon transport in an
optomechanical system where an optomechanical cavity couples to two empty
cavities. By analytically deriving the one- and two-photon currents in terms of
a zero-time-delayed two-order correlation function, we show that a photon
blockade can be achieved in both the single-photon strong-coupling regime and
the single-photon weak-coupling regime due to the nonlinear interacting and
multipath interference. Furthermore, our systems can be applied as a quantum
optical diode, a single-photon source, and a quantum optical capacitor. It is
shown that this the photon transport controlling devices based on photon
antibunching does not require the stringent single-photon strong-coupling
condition. Our results provide a promising platform for the coherent
manipulation of optomechanics, which has potential applications for quantum
information processing and quantum circuit realization.
