Fig. 1. Schematic diagram of optical system

Fig. 2. Experimental holograms and frequency spectrograms

Fig. 3. Phase distribution diagram of unwrapping of eccentric fiber optic

Fig. 4. Measurement results of refractive index of eccentric optical fiber

Fig. 5. Digital hologram of sample after welding

Fig. 6. Refractive index distribution and radial refractive index profile of different columns from welding point