Optical waveguides fabricated by transition element ions exchange in some commercial and special optical glasses

Abstract

We present a fabrication and properties study of planar optical waveguides fabricated in a variety of commercially available as well as non-commercial special silicate-based optical glasses. The exchanged ions coming from external sources were Ag+, Cu+, Cu2+ and Er3+. The reduction of Ag+ to Ag0 from which the high optical losses of waveguides may originate was strongly enhanced when the glass contained reducing fining agents as As2O3 or Sb2O3. The Cu2+ ion-exchange proceeded very quickly and resulted in the fabrication of waveguides with negligible birefringence. The samples containing exclusively Cu+ exhibited very strong blue–green luminescence even in the cases of very low copper content in the exchanged surface layers. The purely thermal erbium ion-exchange was successful only in lithium containing glasses; when using the electric-field-assisted ion-exchange the erbium containing waveguides were fabricated also in several sodium-rich and sodium–potassium glasses. The shallow erbium-containing surface layers were deepened by the post-exchange annealing of the as-exchanged samples. The properties of the fabricated waveguides are discussed from the point of view of the composition of substrate glasses, taking into account the ratios of the bridging and non-bridging oxygen atoms in the glass matrices and the presence of fining agents.