  The ability to engineer entangled states that involve macroscopic objects is
of particular importance for a wide variety of quantum-enabled technologies,
ranging from quantum information processing to quantum sensing. Here we propose
how to achieve coherent manipulation and enhancement of quantum entanglement in
a hybrid optomechanical system, which consists of a Fabry-P\'{e}rot cavity with
two movable mirrors, an optical parametric amplifier (OPA), and an injected
squeezed vacuum reservoir. We show that the advantages of this system are
twofold: (i) one can effectively regulate the light-mirror interactions by
introducing a squeezed intracavity mode via the OPA; (ii) when properly
matching the squeezing parameters between the squeezed cavity mode and the
injected squeezed vacuum reservoir, the optical input noises can be suppressed
completely. These peculiar features of this system allow us to generate and
manipulate quantum entanglement in a coherent and controllable way. More
importantly, we also find that such controllable entanglement, under some
specific squeezing parameters, can be considerably enhanced in comparison with
those of the conventional optomechanical system. Our work, providing a
promising method to regulate and tailor the light-mirror interaction, are
poised to serve as a useful tool for engineering various quantum effects which
are based on cavity optomechanics.
