Multimode mechanical lasing and synchronization in silicon optomechanical crystal oscillators

We present recent advances in the development and control of the nonlinear dynamics of individual and coupled one-dimensional optomechanical oscillators (OMOs), based on silicon optomechanical crystal cavities. These devices exhibit coherent mechanical oscillations at frequencies up to hundreds of MHz, driven by a self-sustained mechanism known as self-pulsing (SP). We experimentally demonstrate several individual and collective dynamical regimes that are essential steps toward realizing networks of weakly interacting OMOs with remotely controllable dynamics. In particular, we observe multimode mechanical lasing in a single OMO, spontaneous synchronization of weakly coupled OMOs, and injection locking of both individual and coupled OMOs to external RF tones. These results open the door to high-performance applications in sensing, time-keeping, and signal processing.