Sumitomo Electric Industries, Limited

Toyokuni Electric Cable Co., Ltd.

Katsuyuki Aihara

Takashi Sasaki

Atsushi Inoue

Tetsuya Nakanishi

Hiroshi Miyano

Fumiaki Satou

Kenichiro Ohtsuka

Keisuke Okada

Hiroshi Nagai

Kenichi Suzuki

Daizo Nishioka

Yukihiro Yokomachi

Takayasu Yamauchi

Hideaki Tajima

Masaji Yahagi

Kimio Ito

Toshiyuki Igarashi

An optical fiber that has a small bending loss can be securely prevented from being fractured due to accidental bending during installation or other operations. The optical fiber includes a core, a first cladding, a second cladding, and a third cladding. The relative refractive index difference &#x394;of the core is in the range of 0.3% to 0.38%, the relative refractive index difference &#x394;of the first cladding is equal to or smaller than 0%, and the relative refractive index difference &#x394;of the second cladding is in the range of &#x2212;1.8% to &#x2212;0.5%. The inner radius rand the outer radius rof the second cladding satisfy the expression '0.4r+10.5&#x3c;r&#x3c;0.2r+16', and the inner radius rof the second cladding is equal to or greater than 8 &#x3bc;m.

Optical cable and optical transmission system

An optical fiber that has a small bending loss can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. The optical fiber includes a core, a first cladding, a second cladding and a third cladding. The relative refractive index difference &#x394;of the core is in the range of 0.3% to 0.38%, the relative refractive index difference &#x394;of the first cladding is equal to or smaller than 0%, and the relative refractive index difference &#x394;of the second cladding is in the range of &#x2212;1.8% to &#x2212;0.5%. The inner radius rand the outer radius rof the second cladding satisfy the expression '0.4r+10.5&#x3c;r&#x3c;0.2r+16', and the inner radius rof the second cladding is equal to or greater than 8 &#x3bc;m.

Optical fiber and optical cable

Provided is an optical fiber that has a small bending loss, can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. An optical fiberincludes a core, a first cladding, a second cladding, and a third cladding. The relative refractive index difference &#x394;of the coreis in the range of 0.3% to 0.38%, the relative refractive index difference &#x394;of the first claddingis equal to or smaller than 0%, and the relative refractive index difference &#x394;of the second claddingis in the range of &#x2212;1.8% to &#x2212;0.5%. The inner radius rand the outer radius rof the second claddingsatisfy the expression '0.4r+10.5&#x3c;r&#x3c;0.2r+16', and the inner radius rof the second claddingis equal to or greater than 8 &#x3bc;m. The bending loss at a wavelength of 1550 nm and at a radius of curvature of 7.5 mm is smaller than 0.1 dB/turn, and the bending loss at a wavelength of 1625 nm and at a radius of curvature of 4 mm is greater than 0.1 dB/turn.

An optical fiber branch cable is provided that comprises a branch portion disposed stably with respect to a multi-core optical fiber cable of a trunk line from which branching is performed, that is excellent in handleability as a cable, and that exhibits high workability. In the optical fiber branch cable of the invention, in a middle of a multi-core optical fiber cableof a trunk line, a branch portionis disposed. The branch portionhas: a base memberwhich is attached so as to cover a tensile-strength wirein a portion where a cable jacketof the multi-core optical fiber cableis removed away; a multi-core optical connectorwhich is connected to the tip end of a tape unitdrawn out from the multi-core optical fiber cable; an extra-length housing portionwhich houses an extra length of the tape unitto which the multi-core optical connectoris connected; and a connector attaching portionto which the multi-core optical connectoris attachable in a plural number.

Optical fiber branch cable, method of wiring the same, and method of providing the same

An optical connector has a simple structure and a method of attaching an optical fiber cord to the connector is easy. The connectorincludes: a plug partwhich has a capillaryprovided at the front and containing a built-in optical fiberand which includes a mechanical splicing portioncapable of allowing an optical fiberto be inserted from the rear so as to be fixed therein; a caulking standcapable of holding a sheath by radially contracting in a state in which the optical fiber cordis inserted therein; a caulking ringprovided outside the cylindrical portionof the standso as to hold the tension memberbetween the ringand the standand a coupling bodyprovided behind the plug partand accommodating the standand the ring

Optical connector and method of attaching optical fiber cord to optical connector

Growing community of inventors

Yokohama, Japan

Katsuyuki Aihara