  Quantum superposition in mechanical systems is not only key evidence for
macroscopic quantum coherence, but can also be utilized in modern quantum
technology. Here we propose an efficient approach for creating macroscopically
distinct mechanical superposition states in a two-mode optomechanical system.
Photon hopping between the two cavity modes is modulated sinusoidally. The
modulated photon tunneling enables an ultrastrong radiation-pressure force
acting on the mechanical resonator, and hence significantly increases the
mechanical displacement induced by a single photon. We study systematically the
generation of the Yurke-Stoler-like states in the presence of system
dissipations. We also discuss the experimental implementation of this scheme.
