US 2017/0248755 A1Published application

Multimode Optical Fiber with High Bandwidth, and Corresponding Multimode Optical System

AssigneeDraka Comteq B.V.

InventorsMarianne Bigot, Denis Molin, Pierre Sillard

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Abstract

The invention concerns a multimode optical fiber, with an ct-profile graded-index core with an a-value between 1.96 and 2.05 and a N value defined as N=(R1/λ)2(n12−n02) between 7 and 52, where R1 is the multimode core radius, n1 is the maximum index of the multimode core and n0 is the minimum index at the outer edge of the graded index core. According to the invention, a depressed region directly surrounds the graded/index core and satisfies the criteria: −2.20<Dn2<0, where Dn2 is the index difference of depressed region with external cladding, and 220 Ln(N)−1100<V2<220Ln(N)−865, where V2 is the volume of the depressed region. Such a multimode fiber shows an increased OFL-bandwidth above 10000 Hz·km at an operating wavelength between 950 nm and 1310 nm.

Claims17

Dependent claims

A multimode optical fiber, comprising a central core surrounded by an outer optical cladding, said central core having (i) an outer radius R1, (ii) a maximum refractive index n1, (iii) a minimum refractive index n0, and (iv) a graded-index profile n(r) that is a function of the radial distance r from the center of said central core,

said central core's graded-index profile n(r) is defined by the following equation:
n

(
r
)
=
n
1

1
-
2

Δ

(
r
R
1
)
α
where:
Δ
=
(
n
1
2
-
n
0
2
)
2

n
1
2
and α is between 1.96 and 2.05, with α a non-dimensional parameter that is indicative of the shape of the index profile,
with n0 and n1 at an operating wavelength λ,
said central core has an N value between 7 and 52, where N is defined by the following equation:
N
=
(
R
1
λ
)
2

(
n
1
2
-
n
0
2
)
with λ the operating wavelength such that λ≧950 nm,
wherein said optical cladding comprises a trench, a region of depressed refractive index n2, surrounding said central core, said trench having an inner radius R1, an outer radius R2, with R2>R1, a refractive index difference Dn2=(n2−nCl)×1000 with respect to said optical cladding having at its outer edge a refractive index nCl, with n2 and nCl at the operating wavelength λ, and a volume V2=π(R22−R12)×Dn2, where Dn2 is expressed in 10−3 and Vtrench is expressed in 10−3 μm2,
and wherein said trench satisfies the criteria:
−2.20<Dn2<0.0
and
220×Ln(N)−1100<V2<220×Ln(N)−865.

63 more elements

Dependencies are inferred from the claim text.