Large effective area fiber with a graded index core that does not include the Ge

摘要

According to some embodiments, there is provided a core having an effective area of 100μm ² ~150μm ² (i) in the wavelength 1550nm, not containing Ge, and to a radius _{r 1} to the outside (a) to the center line A central core region comprises extending radially, having a relative refractive index percent profile Δ _{1 (r)} Percent calculated relative to pure silica, -0.1% ≦ Δ _{1 (r)} ≦ 0 It is .12%, the central core region having a maximum relative refractive index percent Δ _1MAX, the directly adjacent surrounds (b) a central core region, and has an α value 1.5 ≦ α ≦ 10, extends to an outer radius _{r 2} and an annular core region of a first formed by Mashimashi is ₂ ≦ _{10μm 6μm} ≦ r, the relative refractive index percent profile Δ _{2 (r)} Percent calculated relative to pure silica, the minimum relative refractive index Δ _2MIN , and has a maximum relative refractive index Δ _2MAX, -0.45 ≦ Δ ₂ ≦ 0, and -0.25 ≧ Δ _2MIN ≧ -0.45, relative refractive index at radius r = 2μm is Δ _1MAX ≧ Δ ₂ The directly adjacent surrounds the annular core regions (c) and the first annular core region, the first is (r = 2μm), and made ​​to extend to ₃ ≦ _30μm radius 20μm ≦ r, is calculated based on the pure silica It has a minimum relative refractive index percent Δ _3MIN and relative refractive index percent profile Δ ₃ (r) of the negative percentage that was, there Δ _3MIN and -0.25% in Δ _3MIN ≦ Δ _2MIN -0.5% a core consisting of an annular core region of the second doped with fluorine, the minimum relative refractive index delta Δ _4MIN and relative refractive index percent Δ _{4 (r)} Percent which surrounds (ii) a core, was calculated based on the pure silica a, An optical waveguide fiber comprising a cladding -0.4% Δ _4MIN is -0.2%, so that the attenuation at a wavelength of 1550nm is 0.17dB / km or less, the relative refractive index of the fiber an optical waveguide fiber characterized by comprising the profile is selected is provided.