Fabrication and characterization of femtosecond laser written waveguides in chalcogenide glass

TL;DR

This paper reports on the fabrication and optical characterization of femtosecond laser written waveguides in nonlinear chalcogenide glass, revealing a tunneling absorption mechanism and achieving low-loss single-mode guidance at 633 nm.

Contribution

It introduces a novel method for creating buried waveguides in chalcogenide glass using femtosecond laser pulses, with detailed analysis of formation mechanisms and optimized parameters.

Findings

Propagation loss as low as 1.47 dB/cm

Single mode guidance at 633 nm demonstrated

Tunneling identified as dominant nonlinear absorption mechanism

Abstract

The authors describe the fabrication of buried waveguides in a highly nonlinear chalcogenide glass, gallium lanthanum sulfide, using focused femtosecond laser pulses. Through optical characterization of the waveguides, they have proposed a formation mechanism and provide comparisons to previous work. Tunneling has been identified as the dominant nonlinear absorption mechanism in the formation of the waveguides. Single mode guidance at 633 nm has been demonstrated. The writing parameters for the minimum propagation loss of 1.47 dB/cm are 0.36 uJ pulse energy and 50 um/s scanning speed.