US4447125A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low dispension single mode fiber
Assignee: AT&T Inc
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Filing: 1982-04-01
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Granted: 1984-05-08
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Expires: 2002-04-01
Abstract
Abstract A low-loss single mode fiber with low total dispersion within the wavelength range 1.25-1.385 μm and low added cabling loss is disclosed. The fiber has relatively high Δ to assure low cabling loss. The high Δ is obtained, however, without paying a cost in high material dispersion by providing at least 20 percent of the Δ by down-doping of the fiber cladding.
Inventors
- 👤 Paul D. Lazay
- 👤 Paul J. Lemaire
- 👤 Arthur D. Pearson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:29
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/036; G02B6/03616; G02B6/03622; G02B6/03627; G02B6/02214
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
156 words
A single mode fiber comprising a substrate tube and within said substrate tube: (a) an up-doped core which contributes a refractive index increase relative to that part of the fiber originating in said substrate tube of less than 0.40 percent and greater than 0.30 percent, (b) a down-doped cladding with no abrupt change in index of refraction which contributes a refractive index decrease relative to that part of the fiber originating in said substrate tube of less than 0.22 percent and greater than 0.15 percent, (c) a core diameter of between 8.7 and 7.5 microns and, (d) a ratio of diameter of the down-doped cladding to the diameter of the up-doped core of greater than 5.5, the cutoff wavelength being less than 1.31 μm, the Δ of the fiber being greater than 0.3 percent and less than 0.75 percent, the dispersion of the fiber being less than 5 psec/nm-km within the wavelength range of 1.25-1.385 μm.
Claim 2
Dependent Claim
156 words
A single mode fiber comprising a substrate tube and within said substrate tube: (a) an up-doped core which contributes a refractive index increase relative to that part of the fiber originating in said substrate tube of less than 0.40 percent and greater than 0.30 percent, (b) a down-doped cladding with no abrupt change in index of refraction which contributes a refractive index decrease relative to that part of the fiber originating in said substrate tube of less than 0.22 percent and greater than 0.15 percent, (c) a core diameter of between 8.7 and 7.5 microns and, (d) a ratio of diameter of the down-doped cladding to the diameter of the up-doped core of greater than 5.5, the cutoff wavelength being less than 1.31 μm, the Δ of the fiber being greater than 0.3 percent and less than 0.75 percent, the dispersion of the fiber being less than 5 psec/nm-km within the wavelength range of 1.25-1.385 μm.
Claim 3
Dependent Claim
149 words
The fiber of claim 1 comprising (a) an up-doped core which contributes a refractive index increase relative to that part of the fiber originating in said substrate tube of 0.38 percent plus or minus 0.02 percent, (b) a down-doped cladding with no abrupt change in index of refraction which contributes a refractive index decrease relative to that part of the fiber originating in said substrate tube of 0.19 percent plus or minus 0.02 percent, (c) a core diameter of 8.3 microns plus or minus 0.2 microns, (d) a ratio of diameter of the down-doped cladding to the diameter of the up-doped core of 6.0 plus or minus 0.2, the Δ of the fiber being greater than 0.3 percent and less than 0.75 percent, the dispersion of the fiber being less than 5 psec/nm-km within the wavelength range of 1.25-1.385 μm, and the cutoff wavelength being less than 1.31 μm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-08 | 1987-11-07 | 1988-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-08 | 1991-11-07 | 1992-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-08 | 1995-11-07 | 1996-05-08 | $7700.00 | Window Closed / Lapsed |