Regulation of Periodic Poling in KTP Crystals via Electrode Pattern and Connection Design

Periodically poled potassium titanyl phosphate (PPKTP) crystals, engineered based on the ferroelectric domain structure of KTP, have emerged as a core component for generating entangled quantum light sources in quantum optics.This is attributed to the entangled photon sources they produce, which exhibit superior performance such as low power consumption, compact size, and high entanglement quality.During the preparation of PPKTP crystals via the electric field poling method, inhomogeneous electric fields can lead to irregular domain structures, adversely affecting their nonlinear optical properties.Therefore, electric field uniformity is a critical control factor in the poling process.To improve the electric field homogeneity during the polarization of PPKTP crystals, this study systematically optimized both the electrode pattern and the electrode connection structure through simulation and experimental validation.Using finite element analysis, the spatial electric field distributions of different electrode patterns were simulated.A doublesided rounded electrode pattern was proposed to mitigate edge electric field concentration, while a parallel multi-contact electrode connection method was introduced to further enhance the uniformity of the electric field distribution.The