Multicore optical fiber with reduced cross talk
A multicore optical fiber including four cores arranged in a linear configuration, the centerline of each core being spaced from the centerline of an adjacent core by a distance x of about 30 microns or less, and each core having a relative refractive index Δ 1 . A cladding surrounding each of the four cores, the cladding including an inner cladding region with a relative refractive index Δ 2 , a depressed-index cladding region with a relative refractive index Δ 3 , and an outer cladding region with a relative refractive index Δ 4 , wherein Δ 1 >Δ 2 >Δ 3 and Δ 1 >Δ 4 >Δ 3 . Furthermore, each core of the four cores has a mode field diameter, at a wavelength of 1310 nm, of about 8.1 microns or less, and cross talk between adjacent cores is about −18 dB or less at wavelengths of 1310 nm and 1550 nm per 2 km fiber length.
1 . A multicore optical fiber comprising:
four cores arranged in a linear configuration such that a centerline of each core is arranged along axis A,
the centerline of each core being spaced from the centerline of an adjacent core by a distance x of about 30 microns or less, and
each core having a relative refractive index Δ 1 ; and
a cladding surrounding each of the four cores, the cladding comprising:
an inner cladding region with a relative refractive index Δ 2 ,
a depressed-index cladding region with a relative refractive index Δ 3 and a volume V 3 of 20% Δmicron 2 or greater, and
an outer cladding region with a relative refractive index Δ 4 ,
wherein:
Δ 1 >Δ 2 >Δ 3 and Δ 1 >Δ 4 >Δ 3 ,
the multicore optical fiber has an outer diameter of about 125 microns or less,
each core of the four cores has a mode field diameter, at a wavelength of 1310 nm, of about 8.07 microns or less,
each core of the four cores has a cable cutoff of about 1260 nm or less, and
cross talk between adjacent cores of the four cores is about −18 dB or less at wavelengths of 1310 nm and 1550 nm per 2 km fiber length.
2 . The multicore optical fiber of claim 1 , wherein the distance x is between about 22 microns and about 28 microns.
3 . The multicore optical fiber of claim 2 , wherein the distance x is between about 24 microns and about 26 microns.
4 . The multicore optical fiber of claim 1 , wherein a centerline of the multicore optical fiber is positioned along the axis A.
5 . The multicore optical fiber of claim 1 , wherein the four cores are arranged in a linear 1×4 configuration.
6 . The multicore optical fiber of claim 1 , wherein each core of the four cores has a mode field diameter, at a wavelength of 1310 nm, of about 8.0 microns or less.
7 . The multicore optical fiber of claim 1 , wherein an effective area of the multicore optical fiber, at a wavelength of 1310 nm, is about 55.0 micron 2 or less.
8 . The multicore optical fiber of claim 1 , wherein an effective area of the multicore optical fiber, at a wavelength of 1550 nm, is about 30 micron 2 or greater.
9 . The multicore optical fiber of claim 1 , wherein a minimum distance y between the centerline of an outermost core of the four cores and an outer diameter of the cladding is between about 15 microns and about 30 microns.
10 . The multicore optical fiber of claim 9 , wherein the minimum distance y is between about 22 microns and about 26 microns.
11 . The multicore optical fiber of claim 1 , wherein the cross talk between adjacent cores of the four cores is about −20 dB or less at wavelengths of 1310 nm and 1550 nm per 2 km fiber length.
12 . The multicore optical fiber of claim 11 , wherein the cross talk between adjacent cores of the four cores is about −25 dB or less at wavelengths of 1310 nm and 1550 nm per 2 km fiber length.
13 . The multicore optical fiber of claim 12 , wherein the cross talk between adjacent cores of the four cores is about −30 dB or less at wavelengths of 1310 nm and 1550 nm per 2 km fiber length.
14 . The multicore optical fiber of claim 13 , wherein the cross talk between adjacent cores of the four cores is about −50 dB or less at wavelengths of 1310 nm and 1550 nm per 2 km fiber length.
15 . The multicore optical fiber of claim 14 , wherein the cross talk between adjacent cores of the four cores is about −55 dB or less at wavelengths of 1310 nm and 1550 nm per 2 km fiber length.
16 . The multicore optical fiber of claim 1 , wherein the cable cutoff of each core is about 1240 nm or less.
17 . The multicore optical fiber of claim 16 , wherein the cable cutoff of each core is about 1230 nm or less.
18 . The multicore optical fiber of claim 1 , wherein the cladding comprises a marker that is not located on a line of symmetry of the multicore optical fiber.
19 . The multicore optical fiber of claim 1 , wherein an alpha value of each core is about 10 or greater.
20 . The multicore optical fiber of claim 1 , wherein the volume V 3 is about 40% Δmicron 2 or greater.