Fig. 1. EO chromophores with stronger electron-donors.

Fig. 2. High performance chromophores for neat film poling.

Fig. 3. (Color online) (a) Chemical structure for chromophores HLD1, HLD2, cross-linker C1, and polymer P1. (b) Temporal stability of the poled films HLD1/HLD2, HLD2/C1, HLD2/P1, JRD1/APC, and JRD1/PMMA at the curing temperature of 85 °C. Reproduced with permission from Ref. [27]. Copyright 2020, American Chemical Society.

Fig. 4. (Color online) (a) Schematic of the slot-photonic crystal slow-light phase modulator and dominant electric field component Ex at quasi-TE mode. Reprinted with permission from Ref. [70], Copyright 2008, The Optical Society. (b) Scanning electron microscopy (SEM) images of the fabricated device. Reprinted with permission from Ref. [73], Copyright 2016, The Optical Society.

Fig. 5. (Color online) (a) The SOH phase modulator with an SiO₂ film on top of the silicon strips which cover with the gate electrode. Reproduced with permission from Ref. [74]. Copyright 2011, Optical Society of America. (b) 100 GHz SOH phase modulator. Reproduced with permission from Ref. [10]. Copyright 2014, Nature Publishing Group. (c) Ultra-low half-wave voltage of 0.21 V SOH MZM. Reproduced with permission from Ref. [34]. Copyright 2018, Optical Society of America. (d) Capacitivity coupled SOH MZM with high-κ slotlines. Reproduced with permission from Ref.[75]. Copyright 2021, Optical Society of America. (e) High-temperature-resistant SOH MZM working up to 200 Gbit/s over 100 °C. Reproduced with permission from Ref. [77]. Copyright 2020, Nature Publishing Group. (f) The structure of SOH MZM by optimizing the strip-to-slot mode converter. Reproduced with permission from Ref. [78]. Copyright 2020, Optics and Precision Engineering.

Fig. 6. (Color online) (a) The relative size of all-organic, SOH and POH modulator. Reproduced with permission from Ref. [1]. Copyright 2017, American Chemical Society. (b) Variation of halfwave voltage (V_π) with electrode length/device length (L) for various types of devices. Reproduced with permission from Ref. [79]. Copyright 2021, American Chemical Society. (c) Comparison measured (symbols) and computationally predicted (lines)V_πL values for JRD1, DLD164, and BAH13 organic OEO materials at 1550 nm in a POH MZM. Reproduced with permission from Ref. [69]. Copyright 2022, Royal Society of Chemistry.

Fig. 7. (Color online) (a) A high-speed POH phase modulator designed and fabricated. Reproduced with permission from Ref. [11]. Copyright 2014, Nature Publishing Group. (b) POH MZM with metal-insulator-metal plasmonic slot waveguide. Reproduced with permission from Ref. [12]. Copyright 2015, Nature Publishing Group. (c) All-plasmonic MZM using a single metal layer without the silicon waveguide. Reproduced with permission from Ref. [38]. Copyright 2017, Nature Publishing Group. (d) Low-loss plasmonic electro-optic ring modulator. Reproduced with permission from Ref. [40]. Copyright 2018, Nature Publishing Group.

Fig. 8. (Color online) (a) Beyond 500 GHz POH MZM used for sub-THz microwave photonics. Reproduced with permission from Ref. [41]. Copyright 2019. American Institute of Physics. (b) 222 GBd on-off-keying transmitter based on POH MZM. Reproduced with permission from Ref. [80]. Copyright 2020. Optical Society of America. (c) Compact IQ electro-optic modulator operated with sub-1-V driving electronics. Reproduced with permission from Ref. [42]. Copyright 2019. Nature Publishing Group. (d) Symbol rates 100 GBd monolithically integrated electro-optical transmitter based on POH MZM. Reproduced with permission from Ref. [44]. Copyright 2020. Nature Publishing Group.

Table 1. The MZM on various EO platforms with operating principle of Pockels effect. The best result reported is given in parenthesis.