Optical fiber having negative dispersion and low slope in the erbium amplifier region

摘要

A optical fiber [30] is disclosed that is suitable for use in a dispersion-compensated, optical communication system [700] that is served by Erbium-doped fiber amplifiers. The fiber has a negative chromatic dispersion that is more negative than -0.8 ps/(nm-km) over the wavelength region 1530 - 1565 nm, and has a dispersion slope that is less than 0.05 ps/(nm2-km). This fiber exhibits an average optical transmission loss that is less than 0.21 dB/km; and its effective area exceeds 50 µm2, which renders it relatively insensitive to bending loss. The optical fiber includes a core [31] of germanium-doped silica whose refractive index is n1, and a layer of cladding material [34] that surrounds the core. The cladding comprises approximately pure silica, whose refractive index is n2. Between the core and the cladding, the fiber further includes first and second annular rings of doped silica. The first annular ring [32] has a width of 4.5 ±1.5 microns, is doped with fluorine, and has a refractive index n3. The second annular ring [33] is doped with germanium and has a refractive index n4. These indexes are constrained by the following equations:0.45 (n1 - n2)/n2 0.58;-0.09 (n3 - n2)/n2 -0.05; and0.02 (n4 - n2)/n2 0.28.