Subsurface disorder and electro-optical properties of proton-exchanged LiNbO3 waveguides produced by different techniquesS. M. Kostritskii, Y. N. Korkishko, V. A. Fedorov, V. P. Mitrokhin, O. G. Sevostyanov, I. M. Chirkova, O. Stepanenko and M. De MicheliJ. Eur. Opt. Soc.-Rapid Publ., 9 (2014) 14055DOI: https://doi.org/10.2971/jeos.2014.14055