Fig. 1. Structure of Mach-Zehnder interferometer (MZI)

Fig. 2. Relationship between input and output powers of each signal component in MWP link^[13]

Fig. 3. Dual-tone test output RF spectrum of MWP link^[13]

Fig. 4. Electrical predistortion method^[14]

Fig. 5. Structure of polarization linear modulator^[18]

Fig. 6. Structure diagram of double polarizer MZM^[19]

Fig. 7. Dual polarization parallel MZM modulator^[21]. (a) Model schematic; (b) RF output power as a function of RF input power for dual-polarization modulator and traditional ODSB schemes

Fig. 8. Dual parallel MZI modulator based on polarization multiplexing^[22]. (a) Model schematic; (b) SFDR performance of multi-octave linearized link based on PM-DPMZM

Fig. 9. Enhanced linearized analog photonic link^[23]. (a) Schematic of enhanced linearity link and working points of sub-MZMs; (b) comparison of frequency spectra for two-tone test, where the left is traditional quadrature-biased link and the right is enhanced linearity link; (c) SFDR curves, where the left is traditional quadrature-biased link and the right is enhanced linearity link

Fig. 10. Schematics of double parallel and multistage parallel modulators. (a) Double parallel modulator^[24]; (b) multistage parallel modulator^[25]

Fig. 11. Schematic of proposed linearity analog photonic link based on DPMZM^[29]

Fig. 12. Structure diagram and microscopy image of double-parallel silicon MZM^[30]

Fig. 13. Schematic of single integrated multiplex MZI modulator^[31]

Fig. 14. Dual parallel MZM modulator based on phase shift^[32]

Fig. 15. Schematic of series linearized modulator^[33]

Fig. 16. Schematic and microscopy image of silicon double series MZM^[34]. (a) Schematic; (b) microscopy image

Fig. 17. Structure diagram of micro-ring resonator

Fig. 18. Structure diagram of RAMZM

Fig. 19. Schematic of a RAMZM with push-pull operation^[36]

Fig. 20. Two different configurations of IMPACC^[37]

Fig. 21. CMOS compatible silicon microring-assisted MZM^[38]. (a) Schematic of fabricated ring-assisted MZI modulator；(b) cross-section of waveguide; (c) top-view of fabricated modulator

Fig. 22. Optimized double microring assisted modulator^[39]. (a) Microscopic image; (b) measured SFDR curves at 1 GHz and 10 GHz

Fig. 23. Process flow of heterogeneous-integrated MZM on silicon^[40]. (a) Si-WG etch; (b) materials bonding; (c) Ⅲ-Ⅴ etch and N-contact; (d) metallization

Fig. 24. Structure and technological process of heterogeneous RAMAM on silicon^[41]

Fig. 25. Reconfigurable silicon RAMZM^[12]. (a) Model schematic; (b) modulator chip packaged with a PCB

Fig. 26. Compact thin-film lithium niobate electro-optic modulator on silicon^[47]. (a) 1550 nm TE field; (b) 10 GHz RF field

Fig. 27. Si/LiNbO₃ hybrid ring modulator^[48]. (a) Structure diagram; (b) cross-section of device; (c) top-view optical micrograph of fabricated device; (d) SEM image of electrodes

Fig. 28. Structure schematic of Si/LiNbO₃ hybrid MZM^[49]