Chemical Etching Technique for Investigations of a Structure of Annealed and Unannealed Proton Exchange Channel LiNbO3 Waveguides

The proton exchanged channel waveguides are actively used for different integrated-optic components. There is a problem of the channel waveguide characterization because the single-mode channel waveguides for infrared region have the cross section about several microns. The wet etching and noncontact profilometry were used to investigate phase composition in proton exchanged channel waveguide. It has been found the known phases of H x Li 1−x NbO 3 have noticeably different etching rates. So, obtained experimental data gives the possibility of phase composition identification for channels with cross-section down to ∼ 2 μm.