title: 50 μm core diameter Yb³⁺Al³⁺/F⁻ codoped silica fiber with M²<1.1 beam quality.
abstract: This paper reports, for the first time to our best knowledge, a nearly diffraction-limited output in a Yb(3+)/Al(3+)/F(-) codoped double cladding silica fiber with a 50 μm core diameter and 0.02 core NA. The core glass with a diameter >6  mm was fabricated through solgel process combined with high temperature sintering. Laser performances of this fiber at different bend diameters were studied. The mean M2<1.1 in this 50 μm core diameter fiber was achieved at a bend diameter of 0.35 m. The core glass with the refractive index nearly equal to pure silica glass is suitable for the fiber design, such as large-mode-area photonic crystal fiber.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Xu
authors.forename: Zhiquan
authors.initials: Z
authors.lastname: Lin
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.forename: Suya
authors.initials: S
authors.lastname: Feng
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Qinling
authors.initials: Q
authors.lastname: Zhou
authors.forename: Danping
authors.initials: D
authors.lastname: Chen
authors.forename: Liyan
authors.initials: L
authors.lastname: Zhang
authors.forename: Shikai
authors.initials: S
authors.lastname: Wang
authors.forename: Chunlei
authors.initials: C
authors.lastname: Yu
authors.forename: Lili
authors.initials: L
authors.lastname: Hu