Sumitomo Electric Industries, Limited

Fumiaki Satou

Takashi Sasaki

Atsushi Inoue

Tetsuya Nakanishi

Katsuyuki Aihara

Hiroshi Miyano

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.

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Yokohama, Japan

Fumiaki Satou