We report the fabrication and optical properties of planar and channel waveguides on z-cut near-stoichiometric LiNbO(3) crystal formed by 6.0 MeVO(3+) implantation at a dose of 5x10(14) ions/cm(2). The properties of the planar waveguide are characterized by use of prism coupling and the reflectivity calculation method. It is found that the effective refractive indices of the transverse magnetic modes increase but the transverse electric ones decrease when an appropriate heat annealing treatment is performed. We also find that only transverse magnetic polarized light could be guided in this waveguide effectively, although the dark mode could be detected in both the transverse electric and the transverse magnetic directions.