Beyond Two-Octave Coherent OAM Supercontinuum Generation in Air-Core As<sub>2</sub>S<sub>3</sub> Ring Fiber
Yingning Wang, Yuxi Fang, Wenpu Geng, Jicong Jiang, Zhi Wang, Hao Zhang, Changjing Bao, Hao Huang, Yongxiong Ren, Zhongqi Pan, Yang Yue
Abstract
In this work, we designed and simulated a novel air-core As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ring fiber that supports orbital angular momentum (OAM) modes. By optimizing the structure parameters of the designed fiber to effectively tailor its chromatic dispersion, a near-zero flat dispersion profile with a total of <; ±30 ps/nm/km variation over 3380-nm bandwidth from 2025 nm to 5405 nm is achieved for OAM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1,1</sub> mode. After launching a 100-fs 70-kW hyperbolic secant pulse into an 8-mm air-core As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ring fiber, a light-carrying OAM supercontinuum is numerically formed beyond two-octave range, covering 5717nm bandwidth from 1182 nm to 6897 nm at -30dB. Furthermore, the generated supercontinuum is highly coherent across the whole spectral range. This can serve as an effective manner to expand the spectral coverage of the OAM beams for various applications.