Fabrication of channel waveguides in Er3+-doped tellurite glass via N+ ion implantation

Er3+-doped tellurite glasses are of great interest for the fabrication of active integrated optical circuits because of their unique properties in terms of bandwidth and rare-earth solubility. Multimode channel waveguides in a glass of this family, namely, a sodium–tungsten–tellurite glass, have been realized with high-energy ion irradiation, where the ion beam size in one dimension was reduced to a few tens of micrometers by a silicon mask. This approach makes possible the fast fabrication of waveguides with high aspect ratio (∼103). The 24 μm wide and 10 mm long waveguide stripes achieved by 1.5 MeV N+ irradiation with fluences between 5 × 1015 and 4.0 × 1016 ions/cm2 were studied using interference phase contrast microscopy and surface profilometry. The waveguiding effect was investigated by the end-fire coupling technique. Multimode light propagation has indeed been observed in these channels, confirming the effectiveness of this method. Dark-line spectroscopy revealed that light propagated in the channel via the optical barrier formed by the N+ implantation.