Fabrication by H+ or He+ ion implantation in lithium niobates and tantalates doped with rare earths and optical characterization

By using a Van de Graaff accelerator, optical waveguides are fabricated in rare earth ions-doped LiNbO3, LiNbO3 (MgO) and LiTaO3 crystals, by thermally controlled He+ or H+ implantation. The Rare earth ions used as dopants are either the Nd3+ laser ion or the Eu3+ structural probe. The mode spectra of the various waveguides are investigated by dark lines spectroscopy. The effective indices are used to reconstruct the refractive index profiles. The latter depend, whatever the material composition, on the implantation parameters only. Moreover, the emission spectra of Eu3+ in LiNbO3 waveguides is found very similar to the bulk fluorescence. Light ion implantation is therefore a convenient technique for tailoring active waveguides in optical material.