Proposal for noise-free visible-telecom quantum frequency conversion through third-order sum and difference frequency generation

TL;DR

This paper proposes a noise-reducing quantum frequency conversion method using third-order sum and difference frequency generation in silicon nitride microring resonators, enabling efficient, low-noise conversion between visible and telecom wavelengths.

Contribution

It introduces a novel third-order frequency conversion approach using microring resonators, addressing broadband noise issues in quantum networks.

Findings

Achieves >80% conversion efficiency at 50 mW pump power.

Demonstrates potential for compact, scalable quantum frequency converters.

Reduces broadband noise compared to existing methods.

Abstract

Quantum frequency conversion (QFC) between the visible and telecom is a key functionality to connect quantum memories over long distances in fiber-based quantum networks. Current QFC methods for linking such widely-separated frequencies, such as sum/difference frequency generation and four-wave mixing Bragg scattering, are prone to broadband noise from the pump laser(s). To address this issue, we propose to use third-order sum/difference frequency generation (TSFG/TDFG) for an upconversion/downconversion QFC interface. In this process, two pump photons combine their energy and momentum to mediate frequency conversion across visible and telecom bands, bridging a large spectral gap with long-wavelength pump pho-tons, which is particularly beneficial from the noise perspective. We show that waveguide-coupled silicon nitride microring resonators can be designed for efficient QFC between 606 nm and 1550 nm via a 1990 nm pump through TSFG/TDFG. We simulate the device dispersion and coupling, and from the simulated parameters estimate that the frequency conversion can be efficient (>80 %) at 50 mW pump power. Our results suggest that microresonator-based TSFG/TDFG is promising for compact, scalable, and low power QFC across large spectral gaps.