Low-loss heterogeneously integrated barium-titanate-on-silicon-nitride photonics

We present a hybrid barium titanate photonics platform exhibiting exceptionally low losses of 0.7 dB/cm and realize ring resonators with intrinsic quality factors exceeding 6 × 105. Measurement of VπL = 0.56 Vcm in electro-optic modulation experiments demonstrates the platform's potential.