Quasi-phase matching (QPM) frequency conversion devices have been studied for applications of highspeed all-optical signal processing due to their ultrafast nonlinear optical response and wide conversion bandwidth. Among several ferroelectric crystals used, MgO-doped near-stoichiometric LiNbO3 (MgSLN) crystals have advantages including low dopant content, low coercive field and high damage threshold. In this work, 2 in boules of MgSLN crystals were grown from Li-rich melts by the melt supplying technique. Then Ti-diffusion waveguides were fabricated on Z-cut plate of as-grown crystals. Finally, periodically poled optical gratings with period of 18 pm were made on the plate by high-voltage electric-field poling process. The compositional uniformity of as-grown crystals was detected by optical spectroscopy and the quality of Ti:PPLN devices was observed by optical microscopy, respectively. The effects of several key parameters including domain structure, compositional uniformity and polish process on the quality of Ti:PPLN devices were discussed. The way to improve the quality of Ti:PPLN devices was proposed. (C) 2008 Elsevier B.V. All rights reserved.