Fig. 1. Low loss adiabatic tapering process of fiber bundle

Fig. 2. The experimental scheme of preparation of sulfide fiber combiner

Fig. 3. The fiber bundle structure after tapering

Fig. 4. Power variation of LP_0，1-4 modes in input fiber core with transmission distance

Fig. 5. Output optical field of 7×1 sulfide fiber bundle

Fig. 6. Relationship between the total power loss in the taper region and the taper ratio

Fig. 7. Home-made As₂S₃ multimode fiber and loss spectrum of fiber

Fig. 8. Tapering and fusion experiments of sulfide fiber

Fig. 9. Tapering of sulfide fiber bundle

Fig. 10. End face of 7×1 sulfide fiber bundle under different tapering effects

Fig. 11. End face of 7×1 sulfide fiber bundle after polishing

Fig. 12. Fusion of 7×1 sulfide fiber bundle and output fiber

Fig. 13. 7×1 sulfide fiber combiner device

Fig. 14. Transmission efficiency of 7×1 sulfide fiber combiner at 4.778 μm wavelength

Fig. 15. The relationship between transmission efficiency and wavelength of the 7×1 sulfide fiber combiner

Fig. 16. The transmission efficiency corresponding to different input power of the 7×1 sulfide fiber combiner

Fig. 17. Optical field distribution of the 7×1 sulfide fiber combiner under different tapering effects

Fig. 18. Optimal beam quality of the 7×1 sulfide fiber combiner

Fig. 19. Power damage threshold test of the 7×1 sulfide fiber combiner

Fig. 20. Heat distribution in the 7×1 sulfide fiber combiner at different transmission wavelengths