Patent ID: 7315677

Claim:
A graded index multimode optical fiber comprising: a core comprising silica doped with germania and fluorine, the core extending from a centerline at r=0 to an outermost core radius, R 1 ; and a cladding surrounding and in contact with the core; wherein the germania is disposed in the core with a germania dopant concentration profile, C 1 (r), and the core has a center germania concentration at the centerline, C 11 , greater than or equal to 0, and an outermost germania concentration C 12 , at R 1 , wherein C 12 is greater than or equal to 0; wherein the fluorine is disposed in the core with a fluorine dopant concentration profile, C 2 (r), and the core has a center fluorine concentration at the centerline, C 21 , greater than or equal to 0, and an outermost fluorine concentration C 22 , at R 1 , wherein C 22 is greater than or equal to 0; wherein C 1 (r)=C 11 −(C 11 −C 12 )(1−x 1 )r α1 −(C 11 −C 12 )x 1 r α2 ; wherein C 2 (r)=C 21 −(C 21 −C 22 )x 2 r α1 −(C 21 −C 22 )(1−x 2 )r α2 ; wherein 1.9<α1<2.1, 1.9<α2<2.1; and wherein −10<x 1 <10 and −10<x 2 <10.