Study of microwave to optical conversion utilizing a whispering gallery mode ellipsoidal LiNbO 3 resonator, embedded within a microwave elliptical-cylindrical cavity

Conversion of microwave radiation to optical waves is pivotal for optical communication and quantum technologies. Nonlinear crystals as whispering gallery mode (WGM) resonators enable coherent conversion of microwaves into the optical domain. We study a WGM ellipsoidal lithium niobate (LiNbO3) resonator that enables microwave-to-optical conversion. The resonator is embedded in a microwave elliptical-cylindrical cavity. The cavity induces a strong microwave dipole moment in the WGM LiNbO3, while an optical mode at 375 nm generates the WGM around the rim. A Hamiltonian describes their overlap and indicates that interaction between the microwave dipole moment and the optical mode creates an up-converted signal near the optical frequency. Both up- and down-converted signals undergo electro-optic modulation. We study up-conversion around the 800-THz optical carrier under a 10.5-GHz tone. The proposed structure offers a three-dimensional integrated microwave-optical resonator scheme for nonclassical state conversion in communications.