Lattice disorder, refractive index changes and waveguides in LiNbO3 formed by H+-implantation

H + -implantation in LiNbO 3 induces radiation damage, lattice disorder and corresponding refractive index changes. The refractive index decreases in the nuclear stopping region at the end of the implanted ion's track, but changes very little in the electronic stopping region. Thus, these characteristics can be used for fabrication of planar waveguides. The waveguide fabrication process comprises a furnace annealing in flowing oxygen to remove the damage and optical absorption from the guiding layer as well as to compensate oxygen loss during ion implantation. The damaged buried layer together with electronic excitement forms an optical “well”, which confines optical mode propagation. The results of this work show that H + -implantation can be a promising technique for fabrication of low-loss waveguides.