Fig. 1. Typical application diagram of interventional fiber in vivo in situ diagnosis and treatment. (a) A single lensless multi-mode or multi-core fiber is used to realize early diagnosis and accurate treatment through the auxiliary means of interventional in vivo in situ early microscopic imaging of lesions at any lesion site; (b) Schematic diagram of the application principle of optical fiber probe to achieve interventional in vivo in situ spectral detection

Fig. 2. The number of papers published by Chinese scholars in the field of optical fiber medical applications in the past 25 years has increased year by year

Fig. 3. Illustrates how fiber optic and device root technologies are enabling applications to flourish

Fig. 4. Several typical core-hole combined special fiber cross sections developed in the laboratory of the authors^[12]

Fig. 5. (a) For comparison, an interventional medical catheter capable of delivering multiple fluids^[13]; (b) A multifunctional integrated medical fiber interconnecting with an all-in-fan-in device, which integrates the traditional waveguide fiber, nanoparticle liquid transport capillary, microimaging multimode fiber, metal electrode for electrode pulse signal transmission, etc

Fig. 6. Flowchart of preparation of DIY preform of precision assembled optical fiber

Fig. 7. Photo of a laboratory DIY system for drawing special optical fiber

Fig. 8. Special fiber produced by porous capillary tubes and lab's innovative fiber DIY system

Fig. 9. Fiber end precision polishing technology. (a) The processing principle; (b) Examples of the fiber end structures; (c) The application of fiber end lenses in mode field transforming and efficient coupling between fibers and semiconductor lasers or waveguide chips; (d) Fiber end for surface plasmon resonance (SPR) sensing probes^[17-18]; (e) Fiber end for optical coherence tomography (OCT) probes^[19-20]; (f) Fiber end for multi-core fiber end reflection couplers^[21]; (g) Fiber end for light focusing and particle manipulation; (h) Fiber end polishing benchtop experimental system^[22]

Fig. 10. (a) Schematic diagram of the helical long-period fiber grating; (b) Transmission spectrum of the helical long-period fiber grating; (c) End and side views of the helical offaxis single-core and symmetrical dual-core fibers; (d) Benchtop fiber twisting system; (e) Vortex beam generated by helical long-period fiber grating, interference intensity pattern and corresponding simulation results

Fig. 11. (a) Schematic diagram of polishing fiber on the polishing wheel side; (b) Schematic diagram of a biosensor based on D-shaped optical fiber^[48]; (c) Structural schematic diagram of high birefringence D-shaped microfiber device^[49]; (d) New optical fiber side polishing benchtop experimental system; (e) D-shaped optical fibers prepared using the system; (f) Instrument characterization results of the morphology of the side polishing surface（the roughness is uneven in the order of micrometers）

Fig. 12. (a) Working schematic of a thermal diffusion for optical fiber device; (b) Schematic of the optical fiber device by thermal diffusion; (c) Schematic of a ring waveguide coupler by thermal diffusion; (d) Schematic of a vectorial bending sensor applying thermal diffusion; (e) Differential bending sensitivity of the two sets of orthogonal cores FBGs of the device in (d) corresponding to different bending directions (0°-360°); (f) Benchtop fiber optic thermal diffusion experimental system

Fig. 13. Schematic diagram of three dimensions of realizing fiber optic technology and its application innovation