Fig. 4

Numerical optimization of a PZT-on-SiN phase modulator. Simulation of the waveguide loss α (a), the half-wave voltage-length product V_πL (b), and their product V_πLα (c) of a PZT-covered SiN waveguide modulator of the type shown in Fig. 1c, for a wavelength of 1550 nm. Waveguide height, width, and intermediate layer thickness are, respectively, 300 nm, 1.2 μm, and 20 nm. The intrinsic waveguide loss (in the absence of electrodes) was taken to be 1 dB cm⁻¹, and the effective electro-optic Pockels coefficient was 67 pm V⁻¹. The circles show the approximate parameters used in this work, and the diamonds show the optimal point with respect to V_πLα