Sumitomo Electric Industries, Limited

Takeshi Kyogoku

Masumi Ito

Sumio Hoshino

Futoshi Mizutani

Shigeki Endoh

Takehiko Kito

Tatsuo Saitoh

For an index change of an interfacial region which is formed in a boundary between core region and cladding region and which decreases its refractive indices from the core region side to the cladding region side, a change rate in relative index difference (0.5&times;&Dgr;n)/(d/r) normalized by a core radius r, obtained for a domain of change from 0.8&times;&Dgr;n to 0.3&times;&Dgr;n relative to a relative index difference &Dgr;n of the core region , is used as an index for evaluation of refractive index change and an allowable range of values thereof is set to a range of the lower limit of 0.4% to the upper limit of 4.0%, whereby a single-mode optical fiber capable of low loss phototransmission can be realized while reducing influence of a tail spread and strain in the optical fiber.

Single-mode optical fibers and fabrication methods thereof

A method of manufacturing a glass fiber preform in which a quartz glass rod having an outer coating containing chlorine and a core doped for higher refractive index has blown thereon a soot formed by a burner fed with quartz glass raw material and a chlorine group gas undergoing flame hydrolysis. The resulting composite is the heated and fused to collapse.

Method of manufacturing fiber preform for single-mode fibers

Growing community of inventors

Yokohama, Japan

Takeshi Kyogoku