High brightness 2.2-12 μm mid-infrared supercontinuum generation in a nontoxic chalcogenide step-index fiber

An environment friendly nonlinear chalcogenide glass fiber with a Ge-Sb-Se core and a Ge-Se cladding is fabricated for bright broadband mid-infrared (MIR) supercontinuum (SC) generation. The fabricated Ge-Sb-Se/Ge-Se fiber with a core diameter of 6 μm shows zero group velocity dispersion at ~4.2 μm and ~7.3 μm. By pumping the fiber with a length of 11 cm at 4.485 μm with 330 fs pulses, we achieve a SC covering the 2.2–12 μm spectral range and with an output average power of ~17 mW. This bright broadband SC source is promising for high-resolution MIR spectroscopy.This work was supported by the National Natural Science Foundation of China (51303072, 61405080, and 61575086), the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the Jiangsu Collaborative Innovation Centre of Advanced Laser Technology and Emerging Industry. This work was also supported by the Australian Research Council Centre of Excellence for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS, Project number CE110001018). Yi Yu acknowledges the financial support from the China Scholarship Council (CSC) for her PhD Scholarship No. 201206110048