Hybrid thin-film lithium niobate micro-ring acousto-optic modulator for microwave-to-optical conversion

TL;DR

This paper presents a hybrid thin-film lithium niobate micro-ring acousto-optic modulator with low voltage operation and enhanced microwave-to-optical conversion efficiency, advancing quantum information transduction technologies.

Contribution

The work introduces a novel hybrid TFLN micro-ring AOM with optimized electrode design and demonstrates significantly improved microwave-to-optical conversion efficiency.

Findings

Half-wave-voltage-length product VpaiL as low as 9 mVcm

Microwave-to-optical conversion efficiency of 0.05%

Enhanced coupling strength of 0.48 Hz s^{1/2} at 0.84 GHz

Abstract

Highly efficient acousto-optic modulation plays a vital role in the microwave-to-optical conversion. Herein, we demonstrate a hybrid thin-film lithium niobate (TFLN) racetrack micro-ring acousto-optic modulator (AOM) implemented with low-loss chalcogenide (ChG) waveguide. By engineering the electrode configuration of the interdigital transducer, the double-arm micro-ring acousto-optic modulation is experimentally confirmed in nonsuspended ChG loaded TFLN waveguide platform. Varying the position of blue-detuned bias point, the half-wave-voltage-length product VpaiL of the hybrid TFLN micro-ring AOM is as small as 9 mVcm. Accordingly, the acousto-optic coupling strength is estimated to be 0.48 Hz s1/2 at acoustic frequency of 0.84 GHz. By analyzing the generation of phonon number from the piezoelectric transducer, the microwave-to-optical conversion efficiency is calculated to be 0.05%, approximately one order of magnitude larger than that of the state-of-the-art suspended counterpart. Efficient microwave-to-optical conversion thus provides new opportunities for low-power-consumption quantum information transduction using the TFLN-ChG hybrid piezo-optomechanical devices.