Patent ID: 6668121
Filing Date: 2003-12-23
Classification: G02B

Abstract:
An optical fiber comprising a refractive index profile structure constructed by at least three core layers and a clad outside these core layers;wherein said three core layers are arranged in an order of first, second and third layers from an inside to an outside; conditions of 0.8%&lE;&Dgr;1&lE;3.0%, âˆ’0.7%&lE;&Dgr;2&lE;âˆ’0.4%, and 0.2%&lE;&Dgr;3&lE;0.5% are satisfied when a relative refractive index difference of the first core with respect to said clad is set to &Dgr;1, a relative refractive index difference of the second core with respect to said clad is set to &Dgr;2, and a relative refractive index difference of the third core with respect to said clad is set to &Dgr;3; a cable cutoff wavelength is equal to or less than 1520 nm; relations of D<0, S<0, and 02/km); and conditions of 2.5&lE;a&lE;7, 0.3&lE;(a/b)&lE;0.6, and 1.2&lE;(c/b)&lE;2.0 are satisfied when an outside diameter of the first core is set to a (&mgr;m), an outside diameter of the second core is set to b (&mgr;m) and an outside diameter of the third core is set to c (&mgr;m).