Design of X-Cut and Z-Cut Lithium Niobate Whispering-Gallery-Mode Disk-Resonators With High Quality Factors

We demonstrate the fabrication process of millimeter-size lithium niobate (LiNbO
$_3$
) whispering-gallery-mode (WGM) disk-resonators. We fabricate both
$x$
- and
$z$
-cut disk-resonators, starting from commercially available LiNbO
$_3$
disks with diameters of 12 mm and thicknesses of 1 mm. We characterize these two WGM resonators using a prism coupling configuration. We find that both resonators feature high loaded quality factors, in both cases higher than
$10^7$
at 1550 nm. We also investigate the polarization and thermal effects in these disk-resonators. The design of high-
$Q$
LiNbO
$_3$
disk-resonators with different orientations using the same platform will allow for a wide variety of potential applications in nonlinear and quantum photonics.