Periodically poled lithium niobate whispering gallery mode microcavities on a chip

In this study, we investigate the fabrication of periodically poled lithium niobate (PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using conventional microfabrication techniques. The quality factor of the PPLN microdisk resonators with a 40-μm radius and a 700-nm thickness is 6.7×105. Second harmonic generation (SHG) with an efficiency of 2.2×10−6 mW−1 is demonstrated in the fabricated PPLN microdisks. The nonlinear conversion efficiency could be considerably enhanced by optimizing the period and pattern of the poled structure and by improving the cavity quality factors.