Fig. 1. Polarization-independent modulator structure. (a) Total structure (inset is the schematic of the beam splitter and mode converter); (b) cross-sectional view; (c) details of electrode structure

Fig. 2. Simulation results of the beam splitter. (a) Coupling efficiency of TE₀ and TM₀ modes (inset is the schematic of the beam splitter); (b) influence of waveguide width on the coupling efficiency; (c) influence of gap on the coupling efficiency; (d) influence of length on the coupling efficiency

Fig. 3. Simulation results of the mode converter. (a) Simulated effective index of the TFLN rib waveguide with respective to its width under different mode conditions; (b) simulated transmission efficiency of the mode converter under different taper lengths (inset is the schematic of the taper and simulated optical field distribution)

Fig. 4. Simulation design of modulator electric field. (a) Optical and electric field distribution of TE₀ and TE₁ modes in the modulating region of the multimode waveguide; (b)VπLcurves of TE₀ and TE₁ modes with respect to varied waveguide width

Fig. 5. Characteristic value of the modulator. (a) Microwave characteristic impedance; (b) microwave loss; (c) group refractive index for two different modes; (d) electrical-optical bandwidth for two different modes of the modulator