Fig. 1. Diagram of Yb3+ doped chaotic fiber laser

Fig. 2. Experimental setup for chaotic correlation detection

Fig. 3. Plastic circular plate

Fig. 4. Detection with circular foreign object. (a) Amplitude of voltage; (b) correlation function peak

Fig. 5. Correlation function curve of different areas. (a) Without circular plate area; (b) circular plate area

Fig. 6. Hot melt glue

Fig. 7. Two-dimensional scanning image of hot melt glue. (a) Amplitude of voltage; (b) correlation function peak

Fig. 8. Correlation function curves of different areas. (a) Without hot melt glue area; (b) middle area of hot melt glue; (c) other areas of hot melt glue