Thin Film LiNbO3 Modulator Based on LiNbO3-Silica Hybrid Waveguide with Narrow Electrode Gap

A novel thin-film lithium niobate (TFLN) electro-optic modulator with low half-wave-voltage length product is designed and fabricated. LiNbO
3
-Silica hybrid waveguide is adopted to achieve an electrode gap as narrow as 3 μm without deterioration of optical transmission, resulting in a high electric field loading efficiency and a low half-wave-voltage length product. Furthermore, periodically loaded T-rail electrodes are employed to ensure a large modulation bandwidth. Experiment results show a half-wave-voltage length product as low as 1.8 V·cm. RF performance has also been preliminarily verified and the device is expected to achieve a large modulation bandwidth.