A parametric study of laser induced-effects in terbium-doped borosilicate glasses: Prospects for compact magneto-optic devices

We report a study of ultrafast laser waveguide inscription in two magneto-optical glasses. Two types of femtosecond laser systems operating in kHz and MHz repetition rate regimes are used for waveguide fabrication. Single mode waveguides in the visible are obtained in both writing regimes and exhibit distinct optical properties depending on laser writing conditions and the nature of glasses. Photodarkening, produced as a fabrication byproduct and associated with waveguide propagation loss, is shown to be reversible via annealing. Photodarkening behaves differently in the magneto-optical glasses studied, most likely due to large differences in the concentration of lanthanum and/or gallium in the materials.