Mid-infrared generation beyond 3.5 µm in a graded-index silica fiber Karolina Stefanska, Pierre Bejot, Julien Fatome, Guy Millot, Karol Tarnowski and Bertrand Kibler EPJ Web Conf., 287 (2023) 06026 Published online: 18 October 2023 DOI: 10.1051/epjconf/202328706026