Lasing in a femtosecond-laser-written single-scan waveguide fabricated in Tm-doped BGG glass

We report lasing action in a femtosecond-laser-inscribed waveguide in thulium-doped barium-gallium-germanium oxide (BGG) glass. A laser cavity was assembled with this waveguide that provided a single-mode output of 62 mW when pumped at 1.6 mu m. The waveguide was fabricated using a single laser scan to create a near-circular cross section with a positive refractive index change of approximately 3.5 x 10-3. Analysis of the laser-modified region was performed using electron-probe microanalysis and Raman spectroscopy. These findings establish BGG glass as a promising platform for the fabrication of mid-infrared integrated photonic devices. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.