Fig. 1. Atomic structures and band structures of (a) graphene^[27], (b) TMDs^[27], (c) BP^[27]and (d) MXene^[78]. (e) Distribution diagram of the bandgap of each material^[27]. Reprinted by permission from Ref. [27]. Copyright Nature Photonics. Reprinted by permission from Ref. [78]. Copyright Advanced Materials.

Fig. 2. (a) Experimental setup of an MZI all-optical modulator based on MXene materials; (b) high-magnification HRTEM atomic lattice structure of MXene nanosheet; (c) optical microscopy image of microfibers deposited with MXenes; (d) Raman spectrum of Ti₃C₂T_x and Ti₃AlC₂. Reprinted by permission from Ref. [100]. Copyright Advanced Materials.

Fig. 3. (a) Interference spectra of two output ports; (b) interference fringes at a control light (pump) power of 122 mW; (c) phase shift versus different control light (pump) powers. Reprinted by permission from Ref. [100]. Copyright Advanced Materials.

Fig. 4. (a) Waveform of the 980 nm control light (pump); (b) signal light switch conversion and its fitting curve; (c) output breaking; (d) waveforms of signal light at 40 Hz. Reprinted by permission from Ref. [100]. Copyright Advanced Materials.

Fig. 5. (a) All-optical switch experimental device with MI structure; (b) waveforms of control light and signal light and their fitting curves; (c) waveforms of signal light when control light modulation frequency changes. Reprinted by permission from Ref. [104]. Copyright Journal of Materials Chemistry C.

Fig. 6. (a) Schematic diagram of the three-dimensional structure of MI twin-core fiber; (b) cross section of twin-core fiber; (c) cross section and (d) polished surface of the polished area of twin-core fiber; (e) twin-core fiber output light intensity monitoring. Reprinted by permission from Ref. [108]. Copyright Optics Letters.

Fig. 7. (a) PI structure all-optical modulation experimental device; (b) signal light waveform, illustration: control light waveform; (c) single all optical signal switching and corresponding fitting curve; (d) output signal light for long-term measurement. Reprinted by permission from Ref. [106]. Copyright Chinese Optics Letters.

Fig. 8. (a) All-optical switch experimental device; (b) GMFR preparation process; (c) GMFR optical microscope image; (d) GMFR transmission spectrum of controlled light on (black) and controlled light off (blue), the red line represents the reflection peak of FBG filtering. Reprinted by permission from Ref. [107]. Copyright Applied Physics Letters.

Fig. 9. Comparison of signal light and control light waveforms of all-optical switches. Reprinted by permission from Ref. [107]. Copyright Applied Physics Letters.

Fig. 10. (a) Experimental diagram of all-optical thresholder; (b) pulse profile of fiber laser source; (c) noise pulse tracking; (d) merger pulse trajectory includes fiber laser source and noise source. Reprinted by permission from Ref. [76]. Copyright 2D Materials.

Fig. 11. (a) Waveform of light pulse before passing through antimony micro-nano fiber; (b) waveform of light pulse after passing through micro-nano fiber of antimony material. Reprinted by permission from Ref. [76]. Copyright 2D Materials.

Fig. 12. (a) Experimental device of all-optical phase modulator based on graphene optical Kerr effect; (b) optical microscope image of GCM; (c) transmission spectrum of GCM; (d) top: paired switching pulses; middle: pulse modulation signal of GCM fiber; bottom: MZI pulse modulation signal containing GCM; (e) for loss modulation including GCM (solid red line), MZI modulator phase modulation (solid red line) and MZI loss modulation (blue dotted line) output signal modulation depth and peak switching power relationship. Reprinted by permission from Ref. [118]. Copyright Optica.

Fig. 13. Waveforms of the output signal light in different time ranges. Reprinted by permission from Ref. [118]. Copyright Optica.

Fig. 14. (a) Optic microscope image of BP-coated microfiber; (b) schematic diagram of wavelength converter based on BP four-wave mixing; (c) system output spectrum; (d) extinction ratio and conversion at different RF frequencies efficiency; (e) details of the corresponding FWM optical spectrum at different RF frequencies. Reprinted by permission from Ref. [122]. Copyright Acs Photonics.