Efficient high-quality photon pair generation in modal phase-matched thin-film lithium niobate micro-ring resonators

TL;DR

This paper presents a scalable, cost-effective method for high-quality photon pair generation using modal phase-matched thin-film lithium niobate micro-ring resonators, achieving high rates and ratios suitable for quantum photonics.

Contribution

It introduces a novel modal phase matching approach in TFLN micro-ring resonators that simplifies fabrication and maintains high efficiency for photon pair generation.

Findings

Achieved pair generation rates up to 40.2 MHz/mW.

Coincidence-to-accidental ratios exceeded 1200.

Reduced device size and fabrication cost while maintaining efficiency.

Abstract

Efficient generation of high-quality photon pairs is essential for modern quantum technologies. Micro-ring resonator is an ideal platform for studying on-chip photon sources due to strong nonlinear effect, resonant-enhanced optical fields, and high integration. Thin-film lithium niobate (TFLN) micro-ring resonators with periodically poled quasi-phase matching have shown high-quality photon pair generation. However, periodic poling technology remains expensive and requires complex fabrication hindering its scalability and capability for practical application in nonlinear photonic devices. To address this, we propose a scalable approach using TFLN micro-ring resonators based on modal phase matching to achieve cost-effective, efficient high-quality photon-pair generation, significantly simplifying fabrication. We achieved pair generation rates up to 40.2 MHz/mW through spontaneous parametric down-conversion, with coincidence-to-accidental ratios exceeding 1200. By combining micro-ring resonance enhancement with modal phase matching, our approach reduces device size and fabrication cost while maintaining high nonlinear efficiency. These results advance the development of compact, efficient on-chip photon sources for next-generation nonlinear and quantum photonic applications.