  We propose a scheme to suppress the laser phase noise without increasing the
optomechanical single-photon coupling strength. In the scheme, the parametric
amplification terms, created by Kerr and Duffing nonlinearities, can restrain
laser phase noise and strengthen the effective optomechanical coupling,
respectively. Interestingly, decreasing laser phase noise leads to increasing
thermal noise, which is inhibited by bringing in a broadband-squeezed vacuum
environment. To reflect the superiority of the scheme, we simulate quantum
memory and stationary optomechanical entanglement as examples, and the
corresponding numerical results demonstrate that the laser phase noise is
extremely suppressed. Our method can pave the way for studying other quantum
phenomena.
