Optomechanical Synchronization across Multi-Octaves Frequency Spans

TL;DR

This paper demonstrates the first purely optomechanical RF frequency divider and explores synchronization of a silicon-nitride oscillator up to the fourth harmonic, advancing frequency control and signal processing capabilities.

Contribution

It introduces a novel optomechanical frequency divider and experimentally investigates multi-harmonic synchronization in silicon-nitride oscillators.

Findings

Achieved entrainment up to the fourth harmonic of a 32 MHz oscillator.

Demonstrated frequency division up to a 4:1 ratio from 128 MHz to 32 MHz.

Showcased potential applications in frequency synthesis and nonlinear sensing.

Abstract

Experimental exploration of synchronization in scalable oscillator micro systems has unfolded a deeper understanding of networks, collective phenomena, and signal processing. Cavity optomechanical devices have played an important role in this scenario, with the perspective of bridging optical and radio frequencies through nonlinear classical and quantum synchronization concepts. In its simplest form, synchronization occurs when an oscillator is entrained by a signal with frequency nearby the oscillator's tone, and becomes increasingly challenging as their frequency detuning increases. Here, we experimentally demonstrate entrainment of a silicon-nitride optomechanical oscillator driven up to the fourth harmonic of its 32 MHz fundamental frequency. Exploring this effect, we also experimentally demonstrate for the first time a purely optomechanical RF frequency divider, where we performed frequency division up to a 4:1 ratio, i.e., from 128 MHz to 32 MHz. Further developments could harness these effects towards frequency synthesizers, phase-sensitive amplification and nonlinear sensing.