Fig. 1. Structure diagram of electro-optic modulation module based on photonic crystal

Fig. 2. Theoretical model of side coupling structure

Fig. 3. Electrical structure diagram of electro-optic modulation module based on photonic crystal

Fig. 4. Structure diagram of silicon-based mode-division-multiplexing module

Fig. 5. Theoretical model of silicon-based mode-division-multiplexing module

Fig. 6. Silicon-based integrated device for electro-optic modulation assembly with mode-division multiplexing. (a) Overall structure diagram; (b) tapered structure diagram

Fig. 7. TE mode effective refractive index change with waveguide width

Fig. 8. Relationship between coupling length and coupling efficiency of single-mode waveguide w₁ corresponding to different waveguide spacing g

Fig. 9. Transmittance of electro-optic modulation module after direct cascade

Fig. 10. Transmittance of the electro-optic modulation module under “on” state when c is 2 to 11, respectively

Fig. 11. Transmittance of the integrated device under “on” state when c is 2 to 11, respectively

Fig. 12. Carrier concentration distribution of electro-optic modulation module.(a)n-type carrier concentration distribution under modulation voltage of 1.24 V; (b)p-type carrier concentration distribution under modulation voltage of 1.24 V

Fig. 13. Transmittance of electro-optic modulation module of the integrated device under “off” and “on” states

Fig. 14. Steady-state field distribution of the integrated device. (a) “off” state; (b) “on” state

Fig. 15. Extinction ratio and insertion loss of the integrated device. (a) As a function of air hole radius; (b) as a function of air holes number in tapered region c

Fig. 16. Insertion loss as a function of coupling distance g