Giant Brillouin amplification in gas using hollow-core waveguides

TL;DR

This paper demonstrates giant Brillouin amplification in gas-filled hollow-core fibres, surpassing solid-core fibres, enabling efficient optical amplification, lasing, and sensing applications with high pressure and tight light confinement.

Contribution

It introduces a novel high-pressure gas-filled hollow-core fibre platform achieving unprecedented Brillouin gain, enabling new photonic functionalities.

Findings

Brillouin gain exceeds solid silica core fibres by 6 times

Demonstration of a low-threshold gas Brillouin fibre laser

Implementation of a strain-insensitive distributed temperature sensor

Abstract

Stimulated Brillouin scattering (SBS) offers among the highest nonlinear gains in solid materials and has demonstrated advanced photonics functionalities in waveguides. The large compressibility of gases suggests that SBS may gain in efficiency with respect to condensed materials. Here, by using a gas-filled hollow-core fibre at high pressure, we achieve a strong Brillouin amplification per unit length, exceeding by 6 times the gain observed in fibres with a solid silica core. This large amplification benefits from a higher molecular density and a lower acoustic attenuation at higher pressure, combined with a tight light confinement. Using this approach, we demonstrate the capability to perform large optical amplifications in hollow-core waveguides. The implementations of a low-threshold gas Brillouin fibre laser and a high-performance distributed temperature sensor, intrinsically free of strain cross-sensitivity, illustrate the large perspectives for hollow-core fibres, paving the way to their integration into lasing, sensing and signal processing.