Acousto-optic and opto-acoustic modulation in piezo-optomechanical circuits

TL;DR

This paper demonstrates integrated piezo-optomechanical circuits that enable efficient RF-to-optical coupling and modulation at 2.4 GHz and 1550 nm, using both piezoelectric and photoelastic effects for acousto-optic and opto-acoustic control.

Contribution

It introduces a novel chip-scale platform combining piezoelectric and photoelastic coupling for RF-optical interactions in integrated circuits.

Findings

Achieved acousto-optic modulation with waveform mapping from RF to optical signals.

Demonstrated opto-acoustic gating of propagating acoustic waves.

Modeled the system dynamics using coupled mode equations of cavity optomechanics.

Abstract

Acoustic wave devices provide a promising chip-scale platform for efficiently coupling radio frequency (RF) and optical fields. Here, we use an integrated piezo-optomechanical circuit platform that exploits both the piezoelectric and photoelastic coupling mechanisms to link 2.4 GHz RF waves to 194 THz (1550 nm) optical waves, through coupling to propagating and localized 2.4 GHz acoustic waves. We demonstrate acousto-optic modulation, resonant in both the optical and mechanical domains, in which waveforms encoded on the RF carrier are mapped to the optical field. We also show opto-acoustic modulation, in which the application of optical pulses gates the transmission of propagating acoustic waves. The time-domain characteristics of this system under both pulsed RF and pulsed optical excitation are considered in the context of the different physical pathways involved in driving the acoustic waves, and modeled through the coupled mode equations of cavity optomechanics.