High-power-handling ultra-compact acousto-optic modulators using one-dimensional topological interface states on thin-film lithium tantalate

TL;DR

This paper introduces an ultra-compact, high-power acousto-optic modulator on thin-film lithium tantalate utilizing topological interface states, achieving strong optical confinement, high power handling, and stable operation in a small footprint.

Contribution

First demonstration of a topological interface state-based acousto-optic modulator on thin-film lithium tantalate with high power capacity and ultra-compact size.

Findings

Device footprint of 0.13 x 0.12 mm²

Half-wave voltage-length product of 0.491 Vcm

Stable modulation at 28 dBm (630.9 mW) optical power

Abstract

Recent advances in integrated photonics have enabled on-chip signal modulation and processing through localized photon-phonon interactions. For acousto-optic devices, compact footprint and high efficiency are essential for dense integration, while strong power handling is critical for stable operation in demanding applications. However, it remains challenging to achieve these features simultaneously on existing integrated platforms. Here, we propose and experimentally demonstrate, for the first time on a thin-film lithium tantalate platform, an ultra-compact acousto-optic modulator based on topological interface states. Benefiting from the strong optical confinement of the topological boundary state, the device achieves a footprint of 0.13 by 0.12 mm2 and a half-wave voltage-length product of 0.491 Vcm. We further demonstrate stable acousto-optic modulation at an on-chip optical power of up to 28 dBm (630.9 mW), highlighting the strong power-handling capability of the thin-film lithium tantalate topological structure. This work provides a compact and high-power solution for microwave-to-photonic transduction and shows the potential of the thin-film lithium tantalate for robust integrated photonic systems.