Frequency Stabilization via Backbone Curve Feedback

This is the Author Accepted Manuscript (reprint) of the article published in Applied Physics Letters (AIP Publishing). Please cite the official Version of Record using the following information: Title: Frequency stabilization via backbone curve feedbackJournal: Applied Physics Letters (AIP Publishing)Official Publication DOI: https://doi.org/10.1063/5.0337380 Abstract:High-performance mechanical resonators are essential for precision sensing and time-keeping, yet their performance is fundamentally limited by nonlinear mechanical effects at high oscillation amplitudes. Existing strategies—such as zero-dispersion engineering or mode coupling—are restricted to specific operating points or require complex structural redesigns, and hence only partially mitigate nonlinear frequency shifts. In this work, we propose and experimentally validate a general nonlinear control strategy that restores linear resonator characteristics at amplitudes significantly exceeding the conventional linear regime. Our scheme cancels parasitic nonlinearities by utilizing the feedback loop phase as the primary control input, making it widely applicable across resonator designs. Our results demonstrate a robust path toward enhancing the dynamic range and signal-to-noise ratio of resonator devices.