Single-mode optical fiber
AssigneeDraka Comteq B.V.
InventorsLouis-Anne de Montmorillon, Simon Richard, Pierre Sillard
Life of this patent
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Abstract
The present invention embraces a single-mode optical fiber typically having reduced bending losses. The optical fiber includes a central core, an intermediate cladding, a buried trench, and an outer cladding. The optical fiber typically has (i), at a wavelength of 1310 nanometers, a mode field diameter with a nominal value of between about 8.6 microns and 9.5 microns (and a tolerance of ±0.4 micron), (ii) a cable cut-off wavelength of no more than 1260 nanometers, and (iii), for a bending radius of 15 millimeters at a wavelength of 1550 nanometers, bending losses of no more than 0.03 dB/turn.
Claims30
A single-mode optical fiber, comprising:
- a central core surrounded by an outer cladding, said central core having (i) a radius r1, (ii) a positive, maximum refractive-index difference Δn1 with respect to said outer cladding, and (iii) an alpha refractive-index profile with an alpha parameter α of between 1.5 and 2.5;
- an intermediate cladding positioned between said central core and said outer cladding, said intermediate cladding having a radius r2 and a refractive-index difference Δn2 with respect to said outer cladding;
- and
- a buried trench positioned between said intermediate cladding and said outer cladding, said buried trench having a radius r3 and a negative refractive-index difference Δn3 with respect to said outer cladding;
- wherein the optical fiber has (i), at a wavelength of 1310 nanometers, a mode field diameter with a nominal value of between 8.6 microns and 9.5 microns and a tolerance of ±0.4 micron, (ii) a cable cut-off wavelength of 1260 nanometers or less, and (iii), for a bending radius of 15 millimeters at a wavelength of 1550 nanometers, bending losses of 0.003 dB/turn or less.
A single-mode optical fiber comprising:
- a central core surrounded by an outer cladding, said central core having (i) a radius r1 of between 4.9 microns and 6.6 microns, (ii) a maximum refractive-index difference Δn1 with respect to said outer cladding of between 5.3×10−3 and 7.0×10−3, and (iii) an alpha refractive-index profile with an alpha parameter α of between 1.5 and 2.5;
- an intermediate cladding positioned between said central core and said outer cladding, said intermediate cladding having a radius r2 and a refractive-index difference Δn2 with respect to said outer cladding of between −1×10−3 and 1×10−3;
- and
- a buried trench positioned between said intermediate cladding and said outer cladding, said buried trench having a radius r3 and a negative refractive-index difference Δn3 with respect to said outer cladding of between −10×10−3 and −1.4×10−3.
A single-mode optical fiber comprising:
- a central core surrounded by an outer cladding, said central core having (i) a radius r1, (ii) a positive, maximum refractive-index difference Δn1 with respect to said outer cladding, (iii) an alpha refractive-index profile with an alpha parameter α of between 1.5 and 2.5, (iv) a surface integral V01 of between 22×10−3 micron and 25×10−3 micron, and (v) a volume integral V11 of between 87×10−3 μm2 and 103×10−3 μm2, the surface integral V01 and the volume integral V11 being defined according to the following equations:
- V
- 01
- =
- ∫
- 0
- r
- 1
-
- Δ
-
-
- n
-
- (
- r
- )
- ·
- ⅆ
- r
- ≈
- r
- 1
- ×
- (
- alpha
- ·
- Δ
-
-
- n
- 1
- +
- Δ
-
-
- n
- 2
- )
- /
- (
- alpha
- +
- 1
- )
- V
- 11
- =
- 2
- ·
- ∫
- 0
- r
- 1
-
- Δ
-
-
- n
-
- (
- r
- )
- ·
- r
- ·
- ⅆ
- r
- ≈
- r
- 1
- 2
- ×
- (
- alpha
- ·
- Δ
-
-
- n
- 1
- +
- 2
- ·
- Δ
-
-
- n
- 2
- )
- /
- (
- alpha
- +
- 2
- )
- ;
- an intermediate cladding positioned between said central core and said outer cladding, said intermediate cladding having a radius r2 and a refractive-index difference Δn2 with respect to said outer cladding;
- and
- a buried trench positioned between said intermediate cladding and said outer cladding, said buried trench having (i) a radius r3, (ii) a negative refractive-index difference Δn3 with respect to said outer cladding, (iii) a surface integral V03 of between −45×10−3 micron and −25×10−3 micron, and (iv) a volume integral V13 of between −1020×10−3 μm2 and −500×10−3 μm2, the surface integral V03 and the volume integral V13 being defined according to the following equations:
- V
- 03
- =
- ∫
- r
- 2
- r
- 3
-
- Δ
-
-
- n
-
- (
- r
- )
- ·
- ⅆ
- r
- ≈
- (
- r
- 3
- -
- r
- 2
- )
- ×
- Δ
-
-
- n
- 3
- V
- 13
- =
- 2
- ·
- ∫
- r
- 2
- r
- 3
-
- Δ
-
-
- n
-
- (
- r
- )
- ·
- r
-
- ⅆ
- r
- ≈
- (
- r
- 3
- 2
- -
- r
- 2
- 2
- )
- ×
- Δ
-
-
- n
- 3
- .
Dependencies are inferred from the claim text.