Fig. 1. Test device of semiconductor laser

Fig. 2. Test device of fiber laser

Fig. 3. Power attenuation coefficients of CLS for different processes

Fig. 4. Light leakage diagrams of different samples. (a) Sample 4; (b) sample 8; (c) sample 12

Fig. 5. Fiber diameter versus time for different corrosion methods

Fig. 6. Surface structures of fiber under different HF corrosion time

Fig. 7. Surface morphologies of claddings for different samples. (a) Sample 8; (b) sample 12

Fig. 8. Surface morphologies of different fiber parts. (a) First part; (b) second part; (c) third part; (d) fourth part

Fig. 9. CLS test power curves. (a) Semiconductor laser input；(b) fiber laser input

Fig. 10. Laser output spectra before and after filtering cladding light

Fig. 11. Light leakage image and thermal image of CLS. (a) Thermal image; (b) light leakage image