| 摘要 |
An optical waveguide fiber comprising: (i) a Ge free core having an effective area of 90 μm2 to 160 μm2, at a 1550 nm wavelength, and α value 12≦̸α≦̸25, said core comprising: (a) a central core region extending radially outwardly from a centerline to a radius r0≦̸2 μm, and having a relative refractive index percent profile &Dgr;0(r) wherein −0.1% ≦̸&Dgr;0(r) ≦̸0.1%, and wherein the central core region has a maximum relative refractive index, &Dgr;0MAX, (b) a first annular core region surrounding and directly adjacent to the central core region and extending to an outer radius r1, wherein 4.8 μm ≦̸r1≦̸10 μm, and having a relative refractive index percent profile, &Dgr;1(r), and a minimum relative refractive index, &Dgr;2MIN, and the relative refractive index measured at a radius r=2.5 μm being −0.15≦̸&Dgr;1(r=2.5 μm) ≦̸0, and &Dgr;0MAX ≧&Dgr;1(r=2.5 μm); (c) a fluorine doped second annular region surrounding and directly adjacent to the first annular core region and extending to a radius 13 μm ≦̸r2≦̸30 μm and having a negative relative refractive index percent profile, &Dgr;2(r), with a minimum relative refractive index &Dgr;2MIN being: &Dgr;2MIN<&Dgr;1(r=2.5 μm), and −0.7% ≦̸&Dgr;2MIN≦̸−0.28%; and (ii) a cladding surrounding the core and having a relative refractive index percent &Dgr;c (r) in % measured relative to pure silica, and &Dgr;c (r)=&Dgr;2MIN±0.3%; wherein the relative refractive index profile of the optical fiber is selected to provide attenuation of no more than 0.175 dB/km at the wavelength of 1550 nm.
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