Ti-diffused planer waveguides have been fabricated on pure and Mg-doped near stoichiometric lithium niobate (SLN). Secondary ion mass spectroscopy method was applied to study the Ti diffusion in 1 mol% Mg-doped Z-cut SLN crystal. 100nm Ti film has been deposited on LN substrate by e-beam evaporation at room temperature. Diffusion constant value for Mg-doped SLN is lower (1.84 x 10(-13) cm(-2)/S) than that of pure SLN. Mg-doped CLN also possesses low diffusion constant value of 1.27 x 10(-13) cm(-2)/s due to higher doping concentration of Mg (5 mol%). AFM topographic observation reveals that Mg-doped SLN shows lower surface roughness than Mg-doped CLN. The roughness (peak to valley) of the Ti-diffused Mg:SLN is 20 nm compared to 62 nm for the congruent LN waveguide. These features make Mg:SLN highly attractive for the fabrication of efficient waveguides. (c) 2005 Elsevier B.V. All rights reserved.