Frequency conversion in a hydrogen-filled hollow-core fiber using continuous-wave fields

TL;DR

This paper demonstrates polarization-preserving quantum frequency conversion in a hydrogen-filled hollow-core fiber using continuous-wave fields, offering a promising alternative to crystal-based methods for fiber network integration.

Contribution

It introduces a novel continuous-wave pump scheme for frequency conversion in a hydrogen-filled fiber, enhancing integration potential and preserving polarization.

Findings

Successful polarization-preserving frequency conversion

Use of continuous-wave pump fields in hydrogen-filled fiber

Potential for seamless fiber network integration

Abstract

In large-area quantum networks based on optical fibers, photons are the fundamental carriers of information as so-called flying qubits. They may also serve as the interconnect between different components of a hybrid architecture, which might comprise atomic and solid state platforms operating at visible or near-infrared wavelengths, as well as optical links in the telecom band. Quantum frequency conversion is the pathway to change the color of a single photon while preserving its quantum state. Currently, nonlinear crystals are utilized for this process. However, their performance is limited by their acceptance bandwidth, tunability, polarization sensitivity, as well as undesired background emission. A promising alternative is based on stimulated Raman scattering in gases. Here, we demonstrate polarization-preserving frequency conversion in a hydrogen-filled anti-resonant hollow-core fiber. This approach holds promises for seamless integration into optical fiber networks and interfaces to single emitters. Disparate from related experiments that employ a pulsed pump field, we here take advantage of two coherent continuous-wave pump fields.