Experimental Observation of Noise Reduction in Weakly Coupled Nonlinear MEMS Resonators

In this paper, we present the strongly nonlinear behavior of a 2-degree-of-freedom weakly coupled microelectromechanical systems (MEMS) resonator system in a mixed nonlinear regime, using a closed-loop phase feedback oscillator approach. Three out of four nonlinear bifurcation points within a strongly nonlinear coupled resonator system, with both electrical and mechanical nonlinearities, were revealed. Furthermore, we are able to study the amplitude and frequency stabilities of the resulting system when biased at the bifurcation points. Specifically, we discover that, as compared with the linear case, orders of magnitude improvement in amplitude and frequency signal resolution can be observed at the nonlinear bifurcation points, demonstrating that coupled nonlinear MEMS resonators can be useful for enhancing the amplitude and frequency stability for relevant applications.