Patent ID: 7212717
Filing Date: 2007-05-01
Classification: C03B,G02B

Abstract:
1. An optical fiber comprising: a solid core region extending along a predetermined axis; and a cladding region provided on an outer periphery of said core region, said cladding region being provided with plural holes that extend along said core region and that are arranged so as to constitute plural layers about said core region in a cross-section orthogonal to the predetermined axis, wherein, in the cross-section orthogonal to the predetermined axis, at least the holes, that are among said plural holes in said cladding region and constitutes the innermost layer closest to said core region, are arranged such that the arrangement thereof has N-fold rotational symmetry about said core region (N is an integer of three or more) while the holes constituting the respective layers except the innermost layer are arranged such that the arrangement thereof has 2N-fold rotational symmetry about said core region, wherein the holes constituting one of the plural layers are arranged with a pitch of L, and the ratio (d/L) between the pitch L and the hole diameter d is 0.55 or more, and wherein said optical fiber has a chromatic dispersion between −20 ps/nm/km and +20 ps/nm/km over an entire wavelength range of 900 nm to 1200 nm.