Low half-wave-voltage and high-bandwidth thin-film lithium niobate electro-optic modulator

Hybrid silicon and lithium niobate (LN) photonic integration platform has emerged as a promising candidate to combine the scalability of silicon photonic with the high modulation performance of LN. With the rapid development of virtual reality, data communication, and high-definition video, the core optical modulator has been upgraded to ultrahigh-bandwidth (BW) and low half-wave voltage ( $V_{\pi }$). Low $V_{\pi }$ and high-BW LN modulators have been demonstrated, with applications ranging from microwave photonics to quantum interfaces. However, due to the simulation design, material selection, and preparation process, the values of BW and voltage are not satisfactory, whose $V_{\pi }$ of 2.2 V and BW of 67 GHz indicators are not excellent. We successfully prepared monolithically integrated TFLNM that feature a CMOS-compatible bias voltage, support data rates up to 110 GHz and half-wave-voltage down to 2 V. We achieve this by designing high BW and low voltage, high-quality preparation, advanced testing, and characterization platform. Notably, the results from physical objects align closely with those from Lumerical INTERCONNECT simulations. Overall, our study has almost doubled the BW of TFLNM reported so far, and $V_{\pi }$ has decreased from 2.2 to 2 V.