Highly efficient interaction of a tubular-lattice hollow-core fiber and flexural acoustic waves: design, characterization and analysis

TL;DR

This paper investigates the acousto-optic interaction in tubular-lattice hollow-core fibers using simulations and experiments, revealing high modulation efficiency and potential for tunable fiber devices.

Contribution

It provides the first detailed analysis of acousto-optic modulation in HCFs, combining modeling and experimental validation to guide device design.

Findings

Higher modulation performance in HCFs compared to standard fibers

Effective coupling of modes within 743-1355 nm wavelength range

Insights into design and fabrication for all-fiber acousto-optic devices

Abstract

The modulation efficiency of a tubular-lattice hollow-core fiber (HCF) by means of flexural acoustic waves is investigated in detail for the first time. The main acousto-optic properties of the HCF are evaluated employing 2D and 3D models based on the finite element method. The induced coupling of the fundamental and first higher-order modes is simulated in the wavelength range from 743 to 1355 nm. Significant acoustic (amplitude, period, strain, energy) and optical parameters (effective index, beat length, birefringence, coupling coefficient) are analyzed. The simulations are compared to experimental results, indicating higher modulation performance in HCFs compared to standard optical fibers. In addition, useful insights into the design and fabrication of all-fiber acousto-optic devices based on HCFs are provided, enabling potential application in tunable spectral filters and mode-locked fiber lasers.