| 摘要 |
An optical fiber comprising: (i) a glass core (20) extending from a centerline and including a central core region (22) with an alpha value of less than 2, a first annular core region (24)surrounding the central core region (22), and a second annular core region (26) surrounding the first annular core region (24), wherein the second annular core region (26) has a higher maximum relative refractive index percent &Dgr;26MAX than that maximum relative refractive index percent &Dgr;24MAX of the first annular core region (24); and (ii) a glass cladding (30) surrounding and in contact with the core (20), the cladding comprising: (a) a first annular cladding region (32) extending from a radius RC3 to a radius R32, (b) a second annular cladding region (34) extending from the radius R32 to a radius R34, (c) a third annular cladding region (36) surrounding the second annular region (34) and extending from the radius R34 to an outermost glass radius R36; wherein the core (20) comprises a maximum relative refractive index percent &Dgr;CMAX; wherein said first annular cladding region (32) comprises relative refractive index percent &Dgr;32(r) % the second annular cladding region (34) comprises a minimum relative refractive index percent, &Dgr;34 MIN, wherein &Dgr;CMAX>&Dgr;32MAX>&Dgr;34MIN, and &Dgr;34MIN<−0.1; and wherein the core and the cladding provide a fiber with cable cutoff less than 1500 nm, dispersion at 1550 nm 3 to 6 ps/nm/km, and an effective area at 1550 nm greater than 75 μm2. The second annular cladding region may contain a plurality of randomly dispersed holes.
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