Abstract: The preparation technics of periodically poled LiNbO₃ crystal (PPLN) was studied and the effects of external field characteristics including magnitude, duration of voltage pulse on periodic poling process were investigated. Improving magnitude of pulse could accelerate the poling process. After a detailed study of all technological steps, a resolution to overvcoming fringe breakdown is proposed, i.e. appropriate electrode figure and optimum waveform must be selected. By using the technics proposed, ratio of finished product reaches 90%. To eliminate the negative effects of reverse domain side expansion, a thin insulator layer is coated on the samples and the electrode width is optimized. By this method, high-quality periodically poled LiNbO₃, which meets the expected occupation ratio perfectly, is prepared successfully.

Key words: periodically poled LiNbO₃, dielectric breakdown, domain broadening