# Ultrafast Laser Inscription of High Performance Mid-Infrared Waveguides in Chalcogenide Glass

## TL;DR

This paper demonstrates the fabrication of high-performance mid-infrared waveguides in chalcogenide glass using ultrafast laser inscription, achieving low losses and high coupling efficiency for potential mid-IR applications.

## Contribution

It introduces a multicore waveguide design with different refractive index contrasts fabricated by ultrafast laser inscription in chalcogenide glass, advancing mid-IR waveguide technology.

## Key findings

- Propagation losses of 0.20 ± 0.05 dB/cm at 4.5 μm
- Coupling efficiencies exceeding 60%
- Successful fabrication of multicore waveguides with different index contrasts

## Abstract

We present the realization of mid-infrared waveguide by ultrafast laser inscription technique in a chalcogenide glass. Our approach is based on multicore waveguide that consists in an alignment on a mesh of positive refractive index channels placed parallel to each other. Two different meshes are investigated with different refractive index contrasts between the channel and the glass matrix. A detailed analysis of the performances at a wavelength of 4.5 $\mu$m shows propagation losses of 0.20 $\pm$ 0.05 dB/cm and coupling efficiencies higher than 60 %.