The Furukawa Electric Co., Ltd.

Jun Terada

Ryuichi Sugizaki

Shinichi Arai

Hisashi Koaizawa

Keiichi Aiso

Naoto Oyama

Katsunori Inoue

Tadashi Takahashi

Kazuyuki Umeno

Tomomichi Yasuoka

Toshiaki Sakai

Daeyoul Yoon

Hideaki Chiba

Masamitsu Kaneko

Fumika Nishino

Mituhiro Kawasaki

Sayo Suga

Nobuyasu Matsumoto

A welding method includes: irradiating a plurality of metal foils stacked on a first surface of a metal member in a first direction with laser light to weld the metal member and the plurality of metal foils to each other, the laser light including first laser light having a wavelength of 800 [nm] or more and 1200 [nm] or less and second laser light having a wavelength of 550 [nm] or less, a second surface of a metal foil farthest from the metal member in the first direction among the plurality of metal foils, on a side opposite to the metal member, being irradiated with the laser light.

Welding method, welding device, metal stacked body, electrical component, and electrical product

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.

Preform for optical fiber and method of producing optical fiber

Growing community of inventors

Chiyoda-ku, Japan

Jun Terada