Chalcogenide glass fibers with a rectangular core for polarized mid-infrared supercontinuum generation

A step-index chalcogenide fiber with a rectangular core and a circular cladding was fabricated through an approach that combines an extrusion technique and a multiple-stage rod-in-tube method. This fiber has a Ge12As24Se64 glass core with a size of ~2.8 μm × 5.9 μm, and a Ge10As24S66 glass cladding with a diameter of ~220 μm, and shows a relatively large birefringence. When ~10 cm long fiber was pumped at 4.0 μm with 330 fs pulses, ~2.2–9.5 μm supercontinuum with a flatness of 20 dB and a polarization extinction ratio of ~10 dB was generated.This work was financially supported by the National Natural Science Foundation of China (61575086, 61805109), The Priority Academic Program Development of Jiangsu Higher Education Institutions, The Jiangsu Collaborative Innovation Centre of Advanced Laser Technology and Emerging Industry, and The Australian Research Council (110001018CE)