The intracavity power, and hence sensitivity, of optomechanical sensors is commonly limited by parametric instability. Here we characterize the degradation of sensitivity induced by parametric instability in a micron-scale cavity optomechanical system. Feedback via optomechanical transduction and electrical gradient force actuation is applied to suppress the parametric instability. As a result a $5.4$-fold increase in mechanical motion transduction sensitivity is achieved to a final value of $1.9\times {10}^{-18}{\mathrm{mHz}}^{-1/2}$.

• Received 11 September 2011

DOI:https://doi.org/10.1103/PhysRevA.85.061802