The technology of the periodic poling LiNbO 3 (PPLN) by applying external field was experimentally studied. A periodic Al electrode was formed on one side of Z cut LiNbO 3 and uniform electrode on the other side by photolithographic in 0.5 mm thick samples. A series of high voltage pulses was applied between the electrodes at room temperature. The voltage application was performed under various conditions including magnitude, duration of voltage pulse and the peak current. The third quasi phase matched periodic poling LiNbO 3 (PPLN) with periods of 9.5 μm was fabricated.