Planar optical waveguide in Cu-doped potassium sodium strontium barium niobate crystal formed by mega-electron-volt...

The first planar optical waveguide to the authors' knowledge has been formed in Cu-doped potassium sodium strontium barium niobate crystal by mega-electron-volt He(+) implantation. Both TE and TM modes are observed. The profiles of the ordinary and the extraordinary refractive indices are deduced from dark-line mode spectroscopy. The results show that the mega-electron-volt He implantation results in a decrease in refractive index in barriers for both n(o) and n(e), but for n(e) there is an obvious increase in the waveguide region. From an experiment in photorefractive two-wave mixing, it is found that the erasure time for two-wave mixing is prolonged by ion implantation.