Adjustable slow light via the electro-optic effect in periodically poled thin-film lithium niobate

This study introduces and comprehensively investigates a novel tunable slow-light (SL) photonic crystal, the modindex modulation in periodically poled thin-film LN via the linear electro-optic effect. To optimize performance, we establish a theoretical model and utilize numerical simulations to analyze the device, focusing on its bandgap wavelength lambda BG and maximum group index ngmax. Based on these findings, we propose two design options, demonstrating the following advantages: at 200 V, we achieve a ngmaxof approximately 4.7 along with a low propagation loss alpha of 0.29 dB/cm, significantly surpassing conventional SL devices, and a group velocity dispersion GVD of 0.0073 ns2 /m. By increasing the voltage to 300 V, we attain a nmax g of approximately 7.4, enabling tunable SL without affecting lambda BG-a feat difficult to accomplish with the devices-while maintaining similar alpha but significantly affecting GVD (0.022 ns2/m). (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.