Patent ID: 6490396
Filing Date: 2002-12-03
Classification: G02B

Abstract:
An optical waveguide fiber comprising:a core region having a refractive index profile and a centerline; a clad layer surrounding and in contact with the core region, said clad layer having a refractive index profile and average refractive index nc; wherein the refractive index profile of said core region is characterized by a relative index percent &Dgr;(r)% which is positive and has a value at each radius point beginning at the centerline where r=0 and &Dgr;(r)%=&Dgr;o% and ending at r=ro at which point &Dgr;(r)%=0; and, wherein relative index percent values, &Dgr;(r)%, for 0&lE;r&lE;ro, are less than or equal to an upper boundary curve and greater than or equal to a lower boundary curve; said upper and lower boundary curves being selected to provide, at 1550 nm, an effective area great than or equal to 80 &mgr;m2 and an attenuation less than 0.20 dB/km; said upper boundary curve having three straight line segments having respective beginning and ending points, (&Dgr;%, r), of (1%, 0) and (0.55%, 0.9 &mgr;m) for the first segment, (0.55%, 0.9 &mgr;m) and (0.45%, 1.5 &mgr;m) for the second segment, and (0.45%, 1.5 &mgr;m) and (0, 9.6 &mgr;m) for the third segment; and, said lower boundary curve having three straight line segments having respective beginning and ending points (&Dgr;%, r) of (0.25%, 0) and (0.30%, 0.28 &mgr;m) for the first segment, (0.30%, 0.28 &mgr;m) and (0.175%, 4.57 &mgr;m) for the second segment, and (0.175%, 4.57 &mgr;m) and (0, 6.5 &mgr;m) for the third segment.