Waveguide in Tm3+-Doped Chalcogenide Glass Fabricated by Femtosecond Laser Direct Writing

We fabricated a buried single line waveguide within a depth of 100 μm below the Tm³⁺-doped 75GeS₂15Ga₂S₃10CsI (GGSI) glass substrate surface using a single line approach by femtosecond laser direct writing. The near field profile of the guided modes and the propagation loss of the fabricated waveguides were measured and discussed. Single mode guidance at 1039 nm has been demonstrated. The writing parameters for the minimum propagation loss of 0.86 dB/cm are 0.8-μJ pulse energy and 100-μm/s scanning speed. This waveguide will be a good candidate for the waveguide laser and passive optical components in the mid-infrared application field.