Optical characterization of buried planar waveguides created by stoichiometric implantation of Ti and O into LiNbO3

Subsurface optical waveguides created in x-cut LiNbO3 by the stoichiometric implantation of Ti and O at 500 degrees have been characterized for optical losses at 672 nm. Implant doses were 2.5 x 1017 /cm2 and 7.5 x 1017 /cm2 for Ti and O respectively at Ti energies of 320 keV and 5.5 MeV and at O energies of 120 keV and 3.0 MeV. These implants produced waveguides from 0.2 μm and 1.8 μ m below the surface. The optical losses at 672 nm were determined using end-fire coupling techniques due to the inability of prism couplers to couple to the subsurface guides. The keV regime implants yielded single mode waveguides while the high energy implants created multimode guides due to greater straggling