ARRAW: Anti-resonant reflecting acoustic waveguides

TL;DR

This paper introduces ARRAWs, a novel type of acoustic waveguide inspired by optical ARROWs, which suppress radiative losses and enable co-localization of optical and acoustic waves in silicon-on-insulator systems.

Contribution

The paper proposes the design principles for ARRAWs and demonstrates silicon/silica platforms that support optical guidance and backward Brillouin scattering.

Findings

ARRAWs effectively suppress radiative dissipation.

Silicon/silica ARRAWs support strong backward Brillouin scattering.

Guidelines for designing efficient ARRAWs are established.

Abstract

Development of acoustic and optoacoustic on-chip technologies calls for new solutions to guiding, storing and interfacing acoustic and optical waves in integrated silicon-on-insulator (SOI) systems. One of the biggest challenges in this field is to suppress the radiative dissipation of the propagating acoustic waves, while co-localizing the optical and acoustic fields in the same region of an integrated waveguide. Here we address this problem by introducing Anti-Resonant Reflecting Acoustic Waveguides (ARRAWs) -- mechanical analogues of the Anti-Resonant Reflecting Optical Waveguides (ARROWs). We discuss the principles of anti-resonant guidance and establish guidelines for designing efficient ARRAWs. Finally, we demonstrate examples of the simplest silicon/silica ARRAW platforms that can simultaneously serve as near-IR optical waveguides, and support strong backward Brillouin scattering.