AVS 49th International Symposium
    Microelectromechanical Systems (MEMS) Wednesday Sessions
       Session MM+NS-WeM

Paper MM+NS-WeM6
Frequency and Phase Entrainment in MEMS Oscillators

Wednesday, November 6, 2002, 10:00 am, Room C-210

Session: Nanotechnology and Nanofabrication in NEMS
Presenter: K.L. Aubin, Cornell University
Authors: M. Zalalutdinov, Cornell University
K.L. Aubin, Cornell University
A.T. Zehnder, Cornell University
B. Ilic, Cornell University
D. Czaplewski, Cornell University
L. Sekaric, Cornell University
J.M. Parpria, Cornell University
H.G. Craighead, Cornell University
Correspondent: Click to Email
Synchronization of light-induced self-sustained vibration of MEMS resonators by external parametric perturbation was demonstrated. Self-oscillation of disc-type MEMS resonators induced by CW laser light has been described earlier.@footnote 1@ In the work presented here, partial modulation of the laser power was used to provide additional parametric excitation through the laser beam induced stress as a physical mechanism to control the parameter - the effective spring constant of the resonator. Modulation depth as low as 5% of CW laser power at frequencies near n times (n=1,2,3...) the natural resonant frequency of the oscillator was shown to cause the frequency and phase of the mechanical motion to become entrained to the modulation frequency (over n). The range of frequencies over which entrainment was possible was shown to vary with modulation amplitude. Once entrainment of the mechanical vibrations is achieved, one can tune the mechanical frequency of vibration by about 10% by changing the modulation frequency. During that tuning, the phase difference between the modulation signal and the mechanical motion was shown to vary as much as 130°. In a synchronized state, stability of the vibrations appears to be limited only by that of the modulation source, allowing us to demonstrate better than 10@super -9@ stability for the frequency of the mechanical motion. Integration of entrained MEMS and NEMS oscillators into a phase-locked loop (PLL) circuit in order to build a high stability reference oscillator is currently under study. @FootnoteText@ @footnote 1@M. Zalalutdinov, A. Zehnder, A. Olkhovets, S. Turner, L. Sekaric, B. Ilic, D. Czaplewski, J. M. Parpia and H. G. Craighead, "Auto-Parametric Optical Drive For Micromechanical Oscillators" Appl. Phys. Lett., Vol. 79, pp 695 (2001).