  We investigate the routing of a single-photon in a modulated cavity
optomechanical system, in which the cavity is driven by a strong coupling
field, and the mechanical resonator (MR) is modulated with a weak coherent
field. We show that, when there is no a weak coherent field modulating the MR,
the system cannot act as a single-photon router, since the signal will be
completely covered by the quantum and thermal noises. By introducing the weak
coherent field, we can achieve the routing of the single-photon by adjusting
the frequency of the weak coherent field, and the system can be immune to the
quantum and thermal noises.
