Telecom-to-Visible Quantum Frequency Converter on a Silicon Nitride Chip

TL;DR

This paper demonstrates the first silicon nitride chip-based quantum frequency converter that links visible and telecom wavelengths, enabling hybrid quantum networks with improved efficiency and noise suppression.

Contribution

It introduces a novel on-chip quantum frequency converter on SiN that bridges visible and telecom wavelengths using four-wave mixing, with noise suppression strategies and 5% efficiency.

Findings

Achieved 5% on-chip conversion efficiency.

Successfully upconverted photons from 1260 nm to 698 nm.

Identified noise sources and devised suppression methods.

Abstract

Quantum frequency conversion serves a key role in the realization of hybrid quantum networks by interfacing between wavelength-incompatible platforms. Here we present the first quantum frequency converter connecting visible and telecom domains on a silicon nitride (SiN) chip, using Bragg-scattering four-wave mixing to upconvert heralded single photons from 1260 to 698 nm, which covers a 192 THz span. We examine the noise sources in SiN and devise approaches to suppress noise photons at the source and target frequencies to enable measurements at the single-photon level. We demonstrate an on-chip conversion efficiency of 5% in photon flux and describe design modifications that can be implemented to significantly improve it. Our results pave the way for the implementation of CMOS-compatible devices in quantum networks.