Mode-dispersion phase matching single photon source based on thin-film lithium niobate

In the domain of integrated quantum photonics, the burgeoning superiority of lithium niobate's second order nonlinearity in electro-optic modulation makes thin-film lithium niobate a leading quantum photonic platform after silicon. To date, single-photon sources using thin-film lithium niobate has mainly adopted periodic polarization quasi-phase matching technology, which requires the preparation of complex electrodes for domain inversion in the waveguide to realize quasi-phase matching. This method inevitably introduces complexity, such as complex processing methods, enlarged polarization regions, and compromised integration density. With the development of quantum information technology, the ever-increasing degree of integration constantly creates new demands. Consequently, the development of a streamlined, high-efficiency quantum light source on a lithium niobate platform is a pressing issue. In this study, we propose a novel thin-film lithium niobate parametric down-conversion single-photon source based on mode dispersion phase matching theory. The strategy is different from conventional strategies that utilize periodic polarization to generate single-photon sources in thin-film lithium niobate devices. In contrast to traditional quasi-phase matching techniques that utilize the phase matching between pump fundamental mode light and parametric fundamental mode light, our method employs the phase matching between the pump light's higher-order mode and the parametric light's fundamental mode. The pump light' s higher-order mode is obtained by designing an asymmetric directional coupler. The device's single-photon yield can attain /(s & BULL;mW), satisfying the requirements for optical 3.8 x 107 quantum information processing. This innovative solution is expected to replace the traditional quasi-phase matching single-photon sources, thus further promoting the study of optical quantum information based on thin-film lithium niobate chips.

Automated summary

This study proposes a novel thin-film lithium niobate parametric down-conversion single-photon source based on mode dispersion phase matching theory, which differs from traditional periodic polarization quasi-phase matching technology. Instead of matching the pump and parametric light in their fundamental modes, this method matches the pump light's higher-order mode with the parametric light's fundamental mode using an asymmetric directional coupler. This innovative solution is expected to replace traditional quasi-phase matching single-photon sources and further promote optical quantum information research based on thin-film lithium niobate chips.