  Quantum steering displays an inherent asymmetric property that differs from
entanglement and Bell nonlocality. Besides being of fundamental interest,
steering is relevant to many asymmetric quantum information tasks. Here, we
propose a scheme to generate and manipulate Gaussian quantum steering between
two spatially distant mechanical modes of two optomechanical cavities coupled
via an optical fiber, and driven by blue detuned lasers. In the unresolved
sideband regime, we show, under realistic experimental conditions, that strong
asymmetric steering can be generated between the two considered modes. Also, we
show that one-way steering can be achieved and practically manipulated through
the lasers drive powers and the temperatures of the cavities. Further, we
reveal that the direction of one-way steering depends on the sign of the
difference between the energies of the mechanical modes. Finally, we discuss
how to access the generated steering. This work opens up new perspectives for
the distribution of long-distance trust which is of great interest in secure
quantum communication.
