Sumitomo Electric Industries, Limited

Koji Shimoda

Takashi Hasegawa

Makoto Shimizu

Haruhiko Aikawa

Yuji Kubo

Motohide Yoshida

An optical fibercomprising a glass portionhaving a coreand a cladding, and one or more covering layersformed around the glass portion, in which an arrangement form of the covering layerwith respect to the glass portionin cross section perpendicular to a longitudinal direction thereof is changed continuously in the longitudinal direction thereof.

Optical fiber and method of manufacturing the optical fiber

The present invention relates to a method of making an optical fiber product. In particular, this manufacturing method is characterized in that, between a drawing step in which a coated optical fiber comprising a glass fiber and a primary coating layer disposed around the outer periphery of the glass fiber is wound around a reel and a processing step in which the coated optical fiber wound around the reel is rewound around a bobbin, a control step is provided for holding the coated optical fiber wound around the reel in a place with a mean atmospheric temperature T (>0&deg; C.) for at least 30,000/T (hr) and, in the case where a coloring layer or the like is disposed around the outer periphery of the coated optical fiber, for at least 30,000/T (hr) but not longer than 210,000/T (hr). The optical fiber product such as a ribbon-type optical fiber obtained in consequence of this control step, effectively suppressed are increase in transmission loss caused by delamination between the glass fiber and the primary coating layer disposed around its outer periphery, and delamination of the coloring layer disposed around the outer periphery of the coated optical fiber or the like.

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Yokohama, Japan

Koji Shimoda