The objective is to achieve a nonlinear crystal with periodically modified domain structure which is applied to the light frequency conversion in optical measuring devices. We use a ferroelectric crystal called lithium niobate to create PPLN (periodically polarised lithium-niobate) crystal. There are several techniques to produce PPLN: one of these is the electron beam bombardment. We generate the surface charge pattern with the help of the electron beam of a SEM (scanning electron microscope) where the electron beam deflection is controlled by a microcontroller to produce the necessary surface charge pattern The applied tool is ADuC841 microcontroller from the family 80C51. The control program was written in C programming language and was simulated by Keil μVision software. In this paper we will show how to model the domain kinetics of a periodically poling electric field. The model is developed to examine the behaviour of the electric field variation and the domain formation during the polarization and to determine the main parameters of the poling technique like SEM parameters (accelerating voltage, charge density) etc The poling process is modeled by a 3D finite element numerical program FlexPDE 5.0 to clarify the role of the dielectrical properties of the crystal. With the simulation of the process we can optimise the domain inversion process to achieve high spatial resolution and contrast of the produced PPLN device.