Fig. 1. Sensing schematic diagram of the FBG^[14]

Fig. 2. FBG based force sensing microsurgical pliers for minimally invasive retinal surgery. (a) One-dimensional and two-dimensional structure^[18]; (b) improved two-dimensional structure^[19]; (c) three-dimensional structure^[20]

Fig. 3. FBG based electrically inductive micropliers used to peel the retina^[21]

Fig. 4. Two-dimensional force sensing positioning hook based on FBG for artificial lens^[22]

Fig. 5. FBG based sensor for radiofrequency cardiac ablation^[23]

Fig. 6. FBG based three-dimensional force sensor for ablation surgery^[24]

Fig. 7. FBG based three-dimensional force sensor for coronary intervention^[25]

Fig. 8. Single FBG based three-dimensional force sensor^[26]

Fig. 9. FBG based one dimensional force sensor array^[27]

Fig. 10. FBG sensor based on the sarrus structure^[28]

Fig. 11. Three-dimensional force sensing probe based on FBG^[30]

Fig. 12. Three-dimensional force sensing biopsy probe based on FBG^[31-32]

Fig. 13. Force sensing oblique needle based on FBG^[33]

Fig. 14. Force sensing drainage needle with embedded FBG based on cross elastic beam structure^[34]

Fig. 15. Three-dimensional force and torque sensor based on FBG^[35]

Fig. 16. Six-dimensional force and torque micro-sensor based on FBG^[36]

Fig. 17. One-dimensional remote force sensor based on FBG^[37]

Fig. 18. A probe fixing the FBG to the outer surface of the capillary with epoxy adhesive^[38]

Fig. 19. Temperature sensing technology based on FBG^[39]

Fig. 20. Tumor ablation temperature monitoring system based on FBG^[40]

Fig. 21. Closed-loop temperature control system for liver tissue laser ablation based on FBG^[41]

Fig. 22. A temperature monitoring system based on FBG thermal sensing^[42]