Excitation of coupled phononic frequency combs via two-mode parametric three-wave mixing

This paper builds on the recent demonstration of three-wave mixing based phononic frequency comb. Here, in this process, an intrinsic coupling between the drive and resonant frequency leads to a frequency comb of spacing corresponding to the separation between drive and resonant frequency. In this paper, through the coupling with other identical devices, we demonstrate the emergence of two different frequency comb regimes using a single tone external drive signal. Several interesting features for coupled frequency combs are identified, including the following: (1) the spacing of the component frequency combs are controlled by two different resonant frequencies, each associated with two different modes; (2) the nonlinear drive level dependence is different for the component frequency combs; (3) mutually exclusive well-bounded regimes for each component frequency comb exist, and such regimes are not merely described by well-known parametric resonance thresholds.