Multi-core optical fiber and method of manufacturing the same
First Claim
1. A multi-core optical fiber comprising:
- a plurality of core portions; and
a cladding portion positioned so as to surround an outside of each of the core portions,whereineach of the core portions includes a center core portion that is positioned at a center of that core portion and that has a refractive index which is greater than that of the cladding portion, a second core portion that is formed so as to surround an outside of the center core portion and that has a refractive index which is less than that of the center core portion, and a depressed portion that is formed so as to surround an outside of the second core portion and that has a refractive index which is less than those of the second core portion and the cladding portion,a relative refractive-index difference of the center core portion with respect to the cladding portion is Δ
1, a relative refractive-index difference of the second core portion with respect to the cladding portion is Δ
2, a relative refractive-index difference of the depressed portion with respect to the cladding portion is Δ
3, a diameter of the center core portion is 2A, an outside diameter of the second pore portion is 2B, an outside diameter of the depressed portion is 2C, B/A is Ra2, and C/A is Ra3,Δ
1 is from 0.05% to 1.2%, Δ
2 is almost 0%, Δ
3 is equal to or greater than −
0.7%, 2A is from 4 μ
m to 14 μ
m, Ra2 is 1 to 3, (Ra3−
Ra2) is equal to or less than 2, a cut-off wavelength is from 1 μ
m to 1.53 μ
m, and an effective core area at a wavelength of 1.55 μ
m is from 30 μ
m2 to 180 μ
m2, andan interval distance between each of the core portions and another one of the core portions positioned adjacent thereto is set such that optical cross-talk between the core portions for a total length of the multi-core optical fiber is equal to or less than −
30 dB at a wavelength of 1.55 μ
m.
1 Assignment
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Accused Products
Abstract
A multi-core optical fiber includes: a plurality of core portions; and a cladding portion positioned so as to surround each of the core portions, wherein each core portion includes a center core portion that has a refractive index greater than that of the cladding portion, a second core portion that is formed so as to surround the center core portion and that has a refractive index less than that of the center core portion, and a depressed portion that is formed so as to surround the second core portion and that has a refractive index less than those of the second core portion and the cladding portion, and an interval distance between the adjacent core portions is set such that optical cross-talk between the core portions for a total length of the multi-core optical fiber is equal to or less than −30 dB at a wavelength of 1.55 μm.
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Citations
7 Claims
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1. A multi-core optical fiber comprising:
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a plurality of core portions; and a cladding portion positioned so as to surround an outside of each of the core portions, wherein each of the core portions includes a center core portion that is positioned at a center of that core portion and that has a refractive index which is greater than that of the cladding portion, a second core portion that is formed so as to surround an outside of the center core portion and that has a refractive index which is less than that of the center core portion, and a depressed portion that is formed so as to surround an outside of the second core portion and that has a refractive index which is less than those of the second core portion and the cladding portion, a relative refractive-index difference of the center core portion with respect to the cladding portion is Δ
1, a relative refractive-index difference of the second core portion with respect to the cladding portion is Δ
2, a relative refractive-index difference of the depressed portion with respect to the cladding portion is Δ
3, a diameter of the center core portion is 2A, an outside diameter of the second pore portion is 2B, an outside diameter of the depressed portion is 2C, B/A is Ra2, and C/A is Ra3,Δ
1 is from 0.05% to 1.2%, Δ
2 is almost 0%, Δ
3 is equal to or greater than −
0.7%, 2A is from 4 μ
m to 14 μ
m, Ra2 is 1 to 3, (Ra3−
Ra2) is equal to or less than 2, a cut-off wavelength is from 1 μ
m to 1.53 μ
m, and an effective core area at a wavelength of 1.55 μ
m is from 30 μ
m2 to 180 μ
m2, andan interval distance between each of the core portions and another one of the core portions positioned adjacent thereto is set such that optical cross-talk between the core portions for a total length of the multi-core optical fiber is equal to or less than −
30 dB at a wavelength of 1.55 μ
m. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification