Fig. 1. Optical mode field distribution of (a) 220 nm top silicon modulator in the wavelength of 1.55μm (W_rib=500 nm, H_slab=90 nm); (b) 220 nm top silicon modulator in the wavelength of 2 μm (W_rib=600 nm, H_slab=90 nm); (c) 340 nm top silicon modulator in the wavelength of 2 μm (W_rib=600 nm, H_slab=100 nm)

Fig. 2. Variation of (a) effective refractive index and (b) optical loss with the waveguide width (H_rib=340 nm, H_slab=100 nm) for TE₀ and TE₁ modes

Fig. 3. Schematic diagram of (a) cross section of the modulator and (b) top view of the modulator

Fig. 4. Under (a) −2 V and (b) −4 V bias, the optical loss and modulation efficiency of the modulator as a function of the PN junction offset

Fig. 5. (a) Optical loss and (b) modulation efficiency as a function of doping concentration under −2 V and −4 V bias

Fig. 6. (a) Optical loss and (b) modulation efficiency as a function of the position of the middle-doping region; (c) Optical loss and (d) modulation efficiency as a function of the position of the heavy-doping region

Fig. 7. Distribution of free carriers under (a) 0 V and (b) −4 V bias

Fig. 8. (a) Optical transmission under 0 V and −4 V bias; (b) Phase shift under different bias

Fig. 9. (a) Electrical bandwidth and (b) electro-optical bandwidth of the modulator