Multi-harmonic phononic frequency comb generation in capacitive CMOS-MEMS resonators

Phononic frequency combs (PFCs) have emerged as a pivotal technology in precision measurements and advanced signal processing, harnessing the power of discrete, evenly spaced frequency lines. Their expansion into the realm of microelectromechanical systems (MEMS) presents potential opportunities for enhanced control in various applications, from telecommunications to quantum computing. This work presents an experimental study on the generation of PFCs at the fundamental frequency and its higher harmonics in a complementary metal oxide semiconductor based electrostatic MEMS resonator measured under an open-loop configuration. The phenomenon is attributed to nonlinear mode coupling and 1:2 internal resonance between two eigenmodes and their harmonics when the resonator operates in nonlinear resonance. The experimental approach employs a combination of optical and electrical characterization techniques. This study, primarily experimental in nature, provides crucial insights into the behavior of PFCs in MEMS resonators, suggesting possible multi-harmonic internal resonance as the underlying mechanism. These findings contribute significantly to the field of MEMS research, offering potential applications in high-precision frequency control for telecommunications, sensor technology, and quantum computing.