Tunable hybrid silicon nitride and thin-film lithium niobate electro-optic microresonator.

This Letter presents, to the best of our knowledge, the first hybrid Si3N4-LiNbO3-based tunable microring resonator where the waveguide is formed by loading a Si3N4 strip on an electro-optic (EO) material of X-cut thin-film LiNbO3. The developed hybrid Si3N4-LiNbO3 microring exhibits a high intrinsic quality factor of 1.85×105, with a ring propagation loss of 0.32 dB/cm, resulting in a spectral linewidth of 13 pm, and a resonance extinction ratio of ∼27  dB within the optical C-band for the transverse electric mode. Using the EO effect of LiNbO3, a 1.78 pm/V resonance tunability near 1550 nm wavelength is demonstrated.