Si2+ ion implanted into stoichiometric lithium niobate crystals: Waveguide characterization and lattice disorder analysis

z-Cut stoichiometric lithium niobate crystals are implanted by 3.6 MeV Si2+ ions at doses of 3-10 × 1013 ions/cm2 at room temperature. Planar waveguides are formed by the ion irradiation induced extraordinary refractive index enhancement in the near surface regions. The waveguide properties are characterized by prism coupling and finite difference method. The effective refractive indices of the TM modes increase when implantation of higher doses is performed. It is found that the lattice damage could be considerably reduced or even almost removed by suitable annealing treatment.