Silicon-based thin-film lithium niobate electro-optic modulator with low loss and small V π ·L

Abstract Electro-optic (EO) modulators play a critical role in converting electrical signals into optical signals. With the growing demand for higher data traffic and broader network bandwidth, there is an increasing need for high-performance, highly integrated EO modulators. Thin-film lithium niobate (TFLN) modulators have emerged as a promising solution for next-generation integrated photonic circuits due to their low power consumption, wide bandwidth, compact footprint, and well-established fabrication process. Our research proposes a Mach–Zehnder modulator (MZM) based on silicon-based TFLN, aiming to achieve a balance between low half-wave voltage product (V π ·L), low optical loss, and high bandwidth. Through systematic design of the waveguide geometry and cladding structure, we demonstrate a modulator with a V π ·L of 0.69 V·cm, a propagation loss of 0.578 dB cm −1 , and a 3-dB bandwidth exceeding 110 GHz at 1550 nm.