  We propose a scheme to enhance quantum entanglement in an optomechanical
system by exploiting the so-called Duffing nonlinearity. Our model system
consists of two mechanically coupled mechanical resonators, both driven by an
optical field. One resonator supports Duffing nonlinearity, while the other
does not. The resonators are coupled to each other via the so-called phonon
hopping mechanism. The hopping rate is $\theta$-phase-dependent that induces
Exceptional Points (EPs) singularities in the system. Interestingly, while the
resonator with Duffing nonlinearity exhibits vanishing bipartite entanglement,
we observe an entanglement transfer phenomenon into the other mechanical
resonator. This nonlinearly induced entanglement demonstrates superior
robustness against thermal fluctuations compared to entanglement generated
without the nonlinearity. Additionally, this entanglement features the sudden
death and revival phenomenon, where the peaks happen at the multiple of
$\theta=\frac{\pi}{2}$. This work opens a new avenue for exploiting nonlinear
resources to generate robust quantum entanglement, paving the way for
advancements in quantum information processing, quantum sensing, and quantum
computing within complex systems.
