Investigation of LiNbO3 waveguide fabricated by helium implantation and combined proton and copper exchange

We report an experimental observation of propagation of light in waveguide formed on Y-cut LiNbO3 crystal by helium implantation and combined proton and copper exchange. The buffer layer formed in result of ion implantation enjoys depolarization properties and provides intermode energy exchange. The parameters of this buffer layer is defined from mode spectroscopy. Mode diffraction on the 2-D grating-like periodical structure formed by defects of layer is observed. Appearance of such defects we explain by features of copper-doped helium-implanted optical LiNbO3 waveguide fabrication process.