Frequency conversion in a hydrogen-filled hollow-core fiber: power scaling, background, and bandwidth

TL;DR

This paper confirms that hydrogen-filled hollow-core fibers enable efficient, broadband quantum frequency conversion with minimal background noise, overcoming limitations of traditional crystal-based methods.

Contribution

The study validates that hydrogen-filled hollow-core fibers provide high-efficiency, broadband quantum frequency conversion with negligible background noise at strong pump powers.

Findings

Conversion efficiency remains high at strong pump powers

Background noise is effectively eliminated in the fiber-based process

The bandwidth of conversion is intrinsically broadband

Abstract

Large-area quantum networks based on optical fibers allow photons at near-infrared wavelengths to travel with minimal loss. Quantum frequency conversion is a method to alter the wavelength of a single photon while maintaining its quantum state. Most commonly, nonlinear crystals are employed for this conversion process, where near-unity conversion efficiency at high fidelity has been demonstrated. Still, the crystal-based conversion process is plagued by strong background noise, very limited spectral bandwidth, and inhomogeneous temperature profiles at strong pump fields. In previous work, we have demonstrated frequency conversion in hydrogen-filled hollow-core fibers and claimed that this conversion process does not compromise performance at strong pump fields, is essentially free of background noise, and intrinsically broadband. Here, we demonstrate that these three claims are justified.