Effect of low dose high energy O³⁺ implantation on refractive index and linear electro-optic properties in X-cut LiNbO₃: Planar optical waveguide formation and characterization

X-cut LiNbO₃ crystals were implanted at room temperature by 5.0 MeV O³⁺ ions with doses ranging from 1.0×10¹⁴ to 6.0×10¹⁴ O/cm². Secondary ion mass spectrometry profiles of atomic species migration as well as damage profiles by the Rutherford backscattering channeling technique and refractive index variation were investigated as a function of dose and subsequent annealing conditions. Two different kinds of damage produced by oxygen implantation were seen: near-surface damage correlated to electronic stopping, which causes an increase of the extraordinary refractive index, and end-of-ion range damage generated by collision cascades, which decreases the extraordinary refractive index values. The different nature of the two kinds of damage is also seen by the different temperature conditions needed for recovery. Low loss planar optical waveguides were obtained and characterized by the prism coupling technique. © 2002 American Institute of Physics.