Thermal annealing of Ge-Se thin films and its influence on waveguide performance

Abstract

Ge-Se thin film waveguide is used in optical devices because of its excellent optical properties. We investigated the structural and optical properties of as-deposited and thermally annealed Ge18Se82 films and the associated waveguides. The optimized annealing condition at 170 °C was determined for Ge18Se82 films. This study reveals that the annealing process can reduce the density of homopolar bonds and voids in the films. After the annealing process, Ge18Se82 waveguides with the dimensions of 1.0 µm×4.0 µm and 1.5 µm×4.0 µm present 0.22 dB/cm and 0.26 dB/cm propagation loss reduction, respectively. This finding suggests that thermal annealing is an appropriate method for improving the performance of chalcogenide glass devices.