Mid-infrared supercontinuum in well-structured As[sbnd]Se fibers based on peeled-extrusion.

Abstract High quality large-core As Se chalcogenide fiber was fabricated via a novel extrusion method to peel off the out-layer of the core glass, and thus all the defects, such as deformations, interface bubbles between the core and cladding can be eliminated effectively. The raw materials were purified by the dynamic distilling and the glasses were prepared by the melt-quenching method. The preform was prepared by an improved isolated stacked homemade extrusion (ISE) machine. The fibers coated with polymer protection were drawn out with a core diameter of ∼240 μm. The core/cladding ratio of the fiber were kept approximately 1:2, and the optical loss was generally lower than 1.5 dB/m in a wavelength range of 5.6–9.7 μm, with a minimum value of 0.6 dB/m at 8.3 μm. The calculated fiber numerical aperture was approximately 0.55. Supercontinuum (SC) generation experiments of fiber at different wavelengths and pump powers were performed. A flattened SC spectrum can be obtained in this large-core fiber with femtosecond pumping. Highlights • A peeled-off extrusion technique was presented for chalcogenide glass fiber. • This step-index As-Se fiber shows a low optical loss in midinfrared with a minimum value of 0.6 dB/m at 8.3 μm. • A flatness supercontinuum spectrum covering 1.5-13.3 μm can be obtained in this As-Se fiber pumped with a femtosecond laser. [ABSTRACT FROM AUTHOR]