Cavity-enhanced acousto-optic modulators on polymer-loaded lithium niobate integrated platform

TL;DR

This paper demonstrates a polymer-loaded lithium niobate integrated platform with photonic crystal nanobeam cavities that significantly enhances acousto-optic modulation efficiency, enabling low-power, high-extinction on-chip optical modulation for advanced photonic applications.

Contribution

It introduces a novel PCNBCs-based acousto-optic modulator on a polymer-loaded lithium niobate platform with superior performance over traditional micro-ring resonators.

Findings

Achieved 38 dB extinction ratio with low RF power below -50 dBm.

Demonstrated robust digital amplitude shift keying modulations.

Validated the platform's potential for integrated microwave photonics.

Abstract

On chip acousto-optic (AO) modulation represents a significant advancement in the development of highly integrated information processing systems. However, conventional photonic devices face substantial challenges in achieving efficient conversion due to the limited overlap between acoustic waves and optical waves. In this study, we address this limitation by demonstrating an enhanced conversion effect of photonic crystal nanobeam cavities (PCNBCs) in AO modulation on a polymer-loaded lithium niobate integrated platform. Attributed to the high ratio of quality factor (Q) to mode volume (V) and optimal light-sound overlap within the nanocavity, PCNBCs-based AO modulator exhibits a significantly enhanced extinction ratio of 38 dB with a threshold RF power below -50 dBm, which is two orders of magnitude lower than that based on micro-ring resonator (MRRs). In addition, robust digital amplitude shift keying modulations using selected RF and optical channels of the PCNBCs-enhanced AO modulators. These findings validate the compelling properties of the PCNBCs photonic platform, establishing it as a promising candidate for on-chip integrated microwave photonics, optical transceivers, and computing applications.