Ultratunable quantum frequency conversion in photonic crystal fiber

TL;DR

This paper demonstrates ultrabroadband quantum frequency conversion of single photons using a photonic crystal fiber, enabling flexible wavelength control for quantum networks with moderate efficiency.

Contribution

It introduces a method for quantum frequency conversion over a broad wavelength range in a single fiber, tunable by a single pump laser, with potential for quantum networking applications.

Findings

Achieved conversion over 1226-1408 nm range covering 150+ frequency bins.

Internal conversion efficiency of 12%, total efficiency 1.4%.

Maintained low $g^{(2)}(0)$ indicating high single-photon purity.

Abstract

Quantum frequency conversion of single photons between wavelength bands is a key enabler to realizing widespread quantum networks. We demonstrate the quantum frequency conversion of a heralded 1551 nm photon to any wavelength within an ultrabroad (1226 - 1408 nm) range in a group-velocity-symmetric photonic crystal fiber (PCF), covering over 150 independent frequency bins. The target wavelength is controlled by tuning only a single pump laser wavelength. We find internal, and total, conversion efficiencies of 12(1)% and 1.4(2)%, respectively. For the case of converting 1551 nm to 1300 nm we measure a heralded $g^{(2)}(0) = 0.25(6)$ for converted light from an input with $g^{(2)}(0) = 0.034(8)$. We expect that this PCF can be used for a myriad of quantum networking tasks.