US5013131A
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US
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Single-mode optical, fiber and process for its production
Assignee: Schott AG
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Filing: 1989-04-12
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Granted: 1991-05-07
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Expires: 2009-04-12
Abstract
Abstract A single-mode optical fiber is doped to achieve a number of desired properties and have a refractive index profile n(r). The doped fiber must at least approximate the formula: ##EQU1## in which n o means the refractive index of the matrix material and r i =i·Δr. A process for the production of the single-mode optical fiber is disclosed using at least 100 layers.
Inventors
- 👤 Ulrich Fotheringham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:42
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/02004; G02B6/02009; G02B6/02214; G02B6/02219; G02B6/02228; G02B6/02233; G02B6/036; G02B6/03605; G02B6/03611; G02B6/03616; G02B6/03638; G02B6/03644; G02B6/03661; G02B6/03672; G02B6/03688
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
156 words
A single-mode multiple-layer fiber with a refractive index profile n(r), in which n means the refractive index of the fiber material at distance r from the axis of the fiber, and the refractive index profile is adjusted by doping of matrix material from which the fiber is predominantly made, with at least one dopant with formation of a number of layers having different refractive indices, characterized in that: (a) the refractive index profile n(r) is adjusted for preset values of at least one of the desired properties of chromatic dispersion, mode field diameter, attenuation and overmode cutoff; (b) a number m of layers of thickness Δr is greater than the number of desired properties; and (c) each layer contains just enough dopant so that the relative refractive indices, with the desired properties maintained, meet at least approximately the condition ##EQU16## in which n o means the refractive index of the matrix material and r i =i·Δr.
Claim 2
Dependent Claim
156 words
A single-mode multiple-layer fiber with a refractive index profile n(r), in which n means the refractive index of the fiber material at distance r from the axis of the fiber, and the refractive index profile is adjusted by doping of matrix material from which the fiber is predominantly made, with at least one dopant with formation of a number of layers having different refractive indices, characterized in that: (a) the refractive index profile n(r) is adjusted for preset values of at least one of the desired properties of chromatic dispersion, mode field diameter, attenuation and overmode cutoff; (b) a number m of layers of thickness Δr is greater than the number of desired properties; and (c) each layer contains just enough dopant so that the relative refractive indices, with the desired properties maintained, meet at least approximately the condition ##EQU16## in which n o means the refractive index of the matrix material and r i =i·Δr.
Claim 3
Dependent Claim
17 words
A single-mode optical fiber according to claim 1, wherein the matrix material is glass or quartz glass.
Claim 4
Dependent Claim
18 words
A single-mode optical fiber according to claim 1, wherein number m of the layers is greater than 100.
Claim 5
Dependent Claim
19 words
A single-mode optical fiber according to claim 3, wherein number m of the layers is between 300 and 500.
Claim 6
Dependent Claim
28 words
A single-mode optical fiber according to claim 1, wherein a dopant is present to raise the refractive index and a dopant is present to lower the refractive index.
Claim 7
Dependent Claim
15 words
A single-mode optical fiber according to claim 1, wherein fluorine and germanium dopants are present.
Claim 8
Dependent Claim
30 words
A single-mode optical fiber according to claim 1, wherein the fiber has as a desired property a flattened shape of the chromatic dispersion as a function of the light wavelength.
Claim 9
Dependent Claim
37 words
A single-mode optical fiber according to claim 7, wherein the chromatic dispersion has zero positions at the light wavelengths of about 1,300 and 1,550 nm, and a maximum of 3 ps/nm.km about midway between the zero positions.
Claim 10
Dependent Claim
31 words
A single-mode optical fiber according to claim 1, wherein as a desired property the attenuation of LP mode, taken at the first overmode, is at least 1 dB/m at 1,250 nm.
Claim 11
Dependent Claim
30 words
A single-mode optical fiber according to claim 1, wherein as a desired property the attenuation of fundamental mode (LP 10 ) is at most 10 -6 db/km at 1,600 nm.
Claim 12
Dependent Claim
21 words
A single-mode optical fiber according to claim 1, wherein as a desired property the mode field diameter is about I,300 nm.
Claim 13
Dependent Claim
24 words
A single-mode optical fiber according to claim 1, wherein as a desired property the refractive index has a minimum value as the bottom limit.
Claim 14
Dependent Claim
19 words
An optical fiber according to claim 1, having a refractive index profile shape substantially in accordance with FIG. 7.
Claim 15
Dependent Claim
19 words
An optical fiber according to claim 1, having a refractive index profile shape substantially in accordance with FIG. 8.
Claim 16
Dependent Claim
33 words
An optical fiber according to claim 13, wherein a step occurs in the refractive index profile at approximately the level of undoped matrix material between first maximum (7) and a second minimum (5).
Claim 17
Dependent Claim
21 words
An optical fiber according to claim 4, wherein a third maximum is in the terminal segment of the refractive index profile.
Claim 18
Dependent Claim
139 words
A process for the production of a single-mode multiple-layer optical fiber, in which the fiber is designed with multiple layers having different refractive indices, and the refractive index is adjusted by using at least one dopant in the matrix material from which the fiber is predominantly made, characterized in that: (a) the refractive index profile n(r) is adjusted for preset values of at least one of the desired properties of chromatic dispersion, mode field diameter, attenuation, and overmode cutoff; (b) the number m of layers of thickness Δr is selected large compared with the number of desired properties; and (c) each layer is provided with just enough so that the relative refractive indices while maintaining the desired properties meets approximately the condition ##EQU17## in which n o means the refractive index of the matrix material and r i =i·Δr.
Claim 19
Dependent Claim
139 words
A process for the production of a single-mode multiple-layer optical fiber, in which the fiber is designed with multiple layers having different refractive indices, and the refractive index is adjusted by using at least one dopant in the matrix material from which the fiber is predominantly made, characterized in that: (a) the refractive index profile n(r) is adjusted for preset values of at least one of the desired properties of chromatic dispersion, mode field diameter, attenuation, and overmode cutoff; (b) the number m of layers of thickness Δr is selected large compared with the number of desired properties; and (c) each layer is provided with just enough so that the relative refractive indices while maintaining the desired properties meets approximately the condition ##EQU17## in which n o means the refractive index of the matrix material and r i =i·Δr.
Claim 20
Dependent Claim
13 words
A process according to claim 17, wherein more than 100 layers are selected.
Claim 21
Dependent Claim
14 words
A process according to claim 17, wherein about 300 to 500 layers are selected.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-05-06 | 1994-11-05 | 1995-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-06 | 1998-11-05 | 1999-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-06 | 2002-11-05 | 2003-05-07 | $7700.00 | Window Closed / Lapsed |