High-Speed Thin-Film Lithium Niobate Modulator Based on Novel Dual-Capacitor Electrode Design

This work introduces a dual-capacitance upper and lower T-electrode structure for high-performance silicon-based thin-film lithium niobate electro-optic modulators. Employing this structure reduces the distributed capacitance per unit length, suppresses the slow light effect, and lowers the microwave refractive index, consequently achieving group velocity matching between optical and microwave waves. For a 1 cm long device, this design simulates a half-wave voltage of 1.18 V, an electro-optic bandwidth exceeding 70 GHz, and an optical loss of 0.1 dB/cm. Furthermore, the proposed modulator demonstrates compatibility with standard photonic integrated circuit fabrication processes, indicating strong potential for large-scale manufacturing.