| CPC G02B 6/023 (2013.01) [G02B 6/02023 (2013.01); G02B 6/02285 (2013.01); G02B 6/02395 (2013.01)] | 12 Claims |
|
1. An optical fiber comprising:
a core extending along a fiber axis and comprised of silica glass;
a cladding provided on an outer peripheral surface of the core, comprised of silica glass, and having a maximum refractive index lower than a maximum refractive index of the core; and
a resin coating provided on an outer peripheral surface of the cladding, wherein
the optical fiber has a mode field diameter of 8.2 μm or more and 9.6 μm or less at a wavelength of 1310 nm, a cable cutoff wavelength of an LP11 mode of 1060 nm or more and 1260 nm or less, and a cable cutoff wavelength of an LP02 mode of 1060 nm or less, wherein
mode dispersion between an LP01 mode and the LP11 mode is 1000 ps/km or less in a wavelength range of 850 nm or more and 1060 nm or less, wherein
a radius of the core defined along a radial direction orthogonal to the fiber axis is 3 μm or more and 10 μm or less,
the core includes an inner region surrounded by an outer peripheral surface that is around the fiber axis as a center and is separated from the fiber axis by 0.2 times the radius of the core, and in the inner region, a refractive index profile of the core has a shape in which a relative refractive index at a core center coinciding with the fiber axis is 0.8 times or more a maximum refractive index difference of the core,
in an outer region of the core surrounding the inner region, the refractive index profile of the core has a shape in which a relative refractive index difference Δ0 defined in the inner region in which a distance r0 along the radial direction satisfies a relationship of 0≤r0/r1≤0.2 with respect to a distance r1 corresponding to the radius of the core, the relative refractive index difference Δ0 being a refractive index difference at a portion separated from the fiber axis by the distance r0, a relative refractive index difference Δ1 at a portion separated from the fiber axis by the distance r1, and a relative refractive index difference Δr at a portion separated from the fiber axis by a distance r equal to or greater than the distance r0 and equal to or less than the distance r1 satisfy a relationship approximated by the following formula including an exponent α of 2.0 or more and 20 or less:
Δr=Δ0+(Δ1−Δ0)×((r−r0)/(r1−r0))α, and
the mode field diameter at the wavelength of 1310 nm is 8.2 μm or more and 9.6 μm or less, the cable cutoff wavelength of the LP11 mode is 1060 nm or more and 1260 nm or less, and the cable cutoff wavelength of the LP02 mode is 1060 nm or less.
|