LAUSR

A novel robust tri-cladding stepped fiber structure has been proposed for the dispersion tuning, and a systematic simulation has been given for the fibers with different sizes of claddings and cores. The results show that double zero-dispersion wavelength (ZDW) points can be obtained, and the first ZDW is shorter at 3.3 µm and the second ZDW at 9.9 µm. Based on the simulation of the structural optimization, we have prepared a well-structured tri-cladding fiber with a minimum loss of 1.55 dB/m at 6.77 µm by a novel continuous two-stage extrusion method. Moreover, a flattened supercontinuum extending from 1.3 to 12.9 µm pumping at anomalous dispersion wavelength of 5 µm between the two ZDWs can be achieved, which fits well with the simulated results. After all, the optimized fiber consisting of As2Se3, Ge10As22Se68, As2S3 exhibits excellent properties that demonstrate the potential for a simple way to prepare high quality fiber with a tri-cladding structure.