Ti-diffused near-stoichiometric(NS) LiTaO(3 )multimode planar waveguide was fabricated by diffusion of Ti-film coated onto a congruent LiTaO3 substrate and post Li-rich vapor transport equilibration process. The crystalline phase in the Ti-diffused layer was analyzed by powder x-ray diffraction and the Li2O-content was evaluated from the measured birefringence. The Ti-concentration profile was analyzed by secondary ion mass spectrometry. The modes guided in the planar waveguide were characterized by prism-coupling technique. The refractive index profile was constructed from the measured mode indices, and correlated with the Ti-concentration profile. The results show that the waveguide retains the LiTaO3 phase and is in an NS composition environment. Both the refractive index and Ti-concentration follow Gaussian profile. The extraordinary and ordinary index change profiles are almost same, implying that the electric field profile of the mode guided in the NS Ti:LiTaO3 waveguide would be polarization-insensitive. The ordinary and extraordinary index changes and the Ti-concentration follow a similar exponential relationship with a power index similar to 1.3. Comparison shows that the Ti:LiTaO(3 )waveguide shows considerable differences from the Ti:LiNbO3 in Ti diffusivity, index change profile and its relation to Ti-concentration, and polarization dependence of guided mode. (C) 2017 Elsevier B.V. All rights reserved.