Fig. 1. Fabrication of fiber components. (a) Micro-nanofiber drawing equipment based on fused tapering method; (b) silica microfiber; (c) microfiber red light characterization; (d) D-shaped fiber polishing equipment;(e) SMF-D-shaped fiber; (f) red light characterization of SMF-D-shaped fiber[33,38]

Fig. 2. Composite waveguide fabrication process. (a) Micro-fiber attached graphene; (b) graphene-coated micro-fiber; (c) graphene-based D-shaped fiber composite waveguide; (d) fiber end-face attached graphene[59,70-74]

Fig. 3. Fiber temperature sensors. (a) D-shaped fiber temperature sensor structure; (b) optical transmission power in D-shaped fiber coated with rGO film as a function of temperature; (c) FP cavity temperature sensor structure; (d) FP cavity resonance wavelength as a function of temperature[75-76]

Fig. 4. Graphene-based fiber current sensors. (a) Sensor structure and sensing current response curve of suspension graphene film on end face of single mode fiber; (b) sensor structure and sensing current response curve of suspension graphene film on end face of etched fiber; (c) sensor structure and sensing current response curve of micro-fiber coil resonator[80-83]

Fig. 5. Graphene-based physical quantity sensors. (a) Graphene-based fiber refractive index sensor; (b) graphene-based fiber magnetic field sensor; (c) graphene-based fiber pressure sensor[84,88,90]

Fig. 6. Graphene-based microfiber gas sensors. (a) Light intensity detection type gas sensor used for acetone gas sensing; (b) interference demodulation type gas sensor used for ammonia gas sensing; (c) graphene coated microfiber ammonia sensor; (d) GO coated microfiber Bragg grating NO2 sensor[59,62,97-98]

Fig. 7. Gas sensors with composite structures. (a) Multimode interference sensor; (b) SPR gas sensor; (c) fiber knot resonant sensor; (d) gas sensor with Brillouin whispering gallery mode cavity[19,101-103]

Fig. 8. Graphene-based fiber biochemical sensors. (a) Micro-nanofiber ethanol sensor; (b) D-shaped fiber red blood cell sensor; (c) hollow fiber humidity sensor; (d) diagram of SPR sensing structure of graphene-encapsulated fiber core; (e) diagram of SPR sensing structure of graphene-on-gold attached D-shaped fiber; (f) diagram of SPR sensing structure of silver-graphene encapsulated photonic crystal fiber[106-107,110-111,115,118]

Fig. 9. Fiber mode locked lasers. (a) End-face attached fiber mode locked lasers; (b) D-shaped fiber mode locked lasers; (c) micro-nanofiber mode locked lasers; (d) active mode locked lasers based on graphene electro-optic modulators[65,127,130,132]

Fig. 10. Fiber Q-switched lasers. (a) TDFL passive Q-switched laser; (b) Q-switched laser based on distributed feedback Bragg grating fiber; (c) EDFL active Q-switched fiber laser[135,139-140]

Fig. 11. Graphene-based nonlinear optical devices. (a) Graphene-based all-optical modulator; (b) electrical heating method to regulate Fermi-Dirac distribution of graphene; (c) DFG plasmon excitation; (d) gate tunable optical frequency comb[32,66-68]