Thermal Stability of the Proton-Implanted Ce3+-Doped Phosphate Glass Waveguide

Abstract

A waveguide is fabricated in the Ce³⁺-doped phosphate glass by the 400 keV proton implantation with a dose of 8.0 × 10¹⁶ ions/cm². The simulation conducted with the SR and TRIM reveals the presence of an optical barrier at 3.32 µm, which corresponds to the maximum nuclear energy loss. The measurements by the prism coupler confirm that the barrier-type waveguide supports guided modes. The thermal stability of the waveguide is characterized via a 1 h thermal annealing at 310°C. Both the refractive index and the optical mode profiles demonstrate negligible changes after annealing, revealing resistance to modification induced by heat. The minimal difference in the reconstructed refractive index distributions and the consistent agreement between experimental and simulated indices of the modes further confirm the optical stability of the waveguide. These results demonstrate the remarkable thermal stability of the proton-implanted Ce³⁺-doped phosphate glass and its suitability as a robust material platform for integrated photonic applications.