The Furukawa Electric Co., Ltd.

Naoto Oyama

Shinichi Arai

Ryuichi Sugizaki

Hisashi Koaizawa

Keiichi Aiso

Jun Terada

Katsunori Inoue

Hirofumi Saito

An optical fiber comprising a core and a cladding region which covers an outer periphery of the core, having a zero-dispersion wavelength in a wavelength range of 1.4 &mgr;m to 1.65 &mgr;m, and being in a single mode in that zero-dispersion wavelength, wherein GeO is doped in the core in a quantity such that a relative refractive index difference of the core becomes not less than 1.8%, the cladding region includes first, second, and third cladding regions, and a refractive index of the second cladding region is smaller than those of the first cladding region and the third cladding region.

Optical fiber, optical fiber component and optical transmission method

A low-dispersion optical fiber provides both reduced chromatic dispersion in a used wavelength band and increased effective core area. The low-dispersion optical fiber is made by covering a center core ( ) with a first side core ( ), covering the first side core ( ) with a second side core ( ), and covering the second side core ( ) with a cladding ( ). When the maximum refractive index of the center core ( ) is written n1, the minimum refractive index of the first side core ( ) is written n2, the maximum refractive index of the second side core ( ) is written n3 and the refractive index of the cladding ( ) is written nc, then n1>n3>nc>n2 is satisfied. Relative refractive index differences &Dgr;1, &Dgr;2 and &Dgr;3 with respect to the cladding ( ) of the maximum refractive index of the center core ( ), the minimum refractive index of the first side core ( ) and the maximum refractive index of the second side core ( ) respectively are made 0.4%&lE;&Dgr;1&lE;0.7%, &minus;0.30%&lE;&Dgr;2&lE;&minus;0.05% and 0.2%&lE;&Dgr;3.

Low-dispersion optical fiber and optical transmission system using the low-dispersion optical fiber

A low-dispersion optical fiber provides both reduced chromatic dispersion in a used wavelength band and increased effective core area. The low-dispersion optical fiber is made by covering a center core ( ) with a first side core ( ), covering the first side core ( ) with a second side core ( ), and covering the second side core ( ) with a cladding ( ). When the maximum refractive index of the center core ( ) is written n the minimum refractive index of the first side core ( ) is written n , the maximum refractive index of the second side core ( ) is written n and the refractive index of the cladding ( ) is written nc, then n n nc>n is satisfied. Relative refractive index differences &Dgr;1, &Dgr;2 and &Dgr;3 with respect to the cladding ( ) of the maximum refractive index of the center core ( ), the minimum refractive index of the first side core ( ) and the maximum refractive index of the second side core ( ) respectively are made 0.4%&lE;&Dgr;1&gE;0.7%, &minus;0.30%&lE;&Dgr;2&lE;&minus;0.05% and 0.2%&lE;&Dgr;3.

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Chiyoda-ku, Japan

Naoto Oyama