Periodically poled LiNbO3 (PPLN) has been fabricated with a 16.6 mu m domain-inverted period, a 3.0 mu m thick photoresist grating, and a 3.3 mu m pattern open width through the electric field poling process using the liquid electrode technique. The average duty cycle for the fabricated PPLN was measured to be 49.9 +/- 3.3%. The effect of annealing temperatures on the domain shape of PPLN was investigated in the range of 300 to 800 degrees C. At 300 degrees C, residual stress was not relieved completely. As the annealing temperature increases above 800 degrees C, the domain shape changes. However, no domain damage was observed for annealing temperatures from 400 to 700 degrees C. The best annealing temperature for the suppression of domain damage and the improvement in the crystalline quality was found to be 400 degrees C. (c) 2006 Elsevier B.V. All rights reserved.