Photonic Crystal Microring Resonators on a Hybrid Silicon Nitride-on-Lithium Niobate Platform

Photonic-crystal resonators (PhCRs) have been widely used in nonlinear integrated photonics for frequency engineering applications. A microwave-assisted frequency converter based on PhCRs highlights its precise control of frequency (enabled by creation of a pair of supermodes by a corrugated PhCR) and bidirectional frequency conversion. In this paper, we demonstrate a high-quality PhCR on a hybrid silicon nitride-on-lithium niobate-on-insulator (SiN-on-LNOI) platform for the first time for voltage-driven flexible frequency conversion using the electro-optic effect (0.85 pm/V). The fabricated PhCR has a large supermode splitting bandwidth = 14.6 GHz and an intrinsic quality factor (Q) = 147,000. Using different periodic corrugation amplitudes in the fabricated PhCRs enables the precise control of mode splitting with a ratio of 93.5 MHz/nm between the mode splitting bandwidth and the corrugation amplitude.