Patent EP0598554A1 successfully refreshed from Google Patents.
EP0598554A1
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EP
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Negative dispersion optical fiber
Assignee: AT&T Inc
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Filing: 1993-11-11
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Granted: —
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Expires: 2013-11-11
Abstract
Abstract Disclosed is optical fiber that can advantageously be used to compensate chromatic dispersion in an optical fiber communication system, typically a system that is upgraded from 1.3µm to 1.55µm operating wavelength (λ op ). The fiber typically has a power law core (11) refractive index profile, a refractive index "trench" (12) surrounding the core, and a refractive index "ridge" (13) surrounding the trench. The refractive index profile of the fiber preferably is designed such that the fiber supports the fundamental mode (LP₀₁), does not support the LP₁₁ mode but does support the LP₀₂ mode, all at λ op . A λ op , LP₀₁ has dispersion more negative than -150 ps/nm·km and, in a preferred embodiment, LP₀₁ also has negative dispersion slope at λ op .
Inventors
- 👤 Ashish Madhukar Vengsarkar
- 👤 Kenneth Lee Walker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 04:30
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/036; G02B6/03616; G02B6/03638; G02B6/03644; G02B6/02047; G02B6/02214; G02B6/02219; G02B6/02252; G02B6/02261; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29371; G02B6/29374; H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/2513; H04B10/2525; G02B6/028; G02B6/0281; G02B6/03605; G02B6/03611
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
87 words
An article comprising a length L DC of optical fiber (said fiber to be designated "DC" fiber) designed to support propagation of radiation of wavelength λ op in a fundamental mode and at least one higher order mode, the DC fiber having a refractive index profile, and λ op being about 1.55µm; CHARACTERIZED IN THAT said refractive index profile is selected such that the radiation in the fundamental mode has dispersion D DC (λ op ) at wavelength λ op that is more negative than -150 ps/nm·km.
Claim 2
Dependent Claim
43 words
The article of claim 1, wherein the refractive index profile is selected such that the DC fiber does not support propagation of the LP₁₁ mode of the radiation of wavelength λ op and does support propagation of the LP₀₂ mode of said radiation.
Claim 3
Dependent Claim
132 words
The article of claim 1, wherein the article is an optical fiber communication system that comprises a source (11) of radiation of wavelength λ op , detector means (16) for detecting radiation of wavelength λ op that are spaced from said source of radiation, and an optical fiber transmission path (13, 17 and 18) that radiation-transmissively links said source and said detector means, with said optical fiber transmission path comprising said length L DC of DC fiber (17), and further comprising a length L SM of single mode optical fiber (13) having chromatic dispersion D SM (λ op ) at λ op , with L DC and L SM selected such that L DC ·D DC (λ op ) + L SM ·D SM (λ op ) is approximately equal to zero.
Claim 4
Dependent Claim
61 words
The article of claim 3, wherein the refractive index profile is further selected such that the absolute value of (L DC ·D DC (λ) + L SM ·D SM (λ))/(L DC + L SM ) is less than 1.5 ps/nm · km for all wavelengths λ in a wavelength range that is greater than 50 nm and includes λ op .
Claim 5
Dependent Claim
98 words
An article comprising a length of optical fiber (said fiber to be designated "DC" fiber) designed to support propagation of radiation of wavelength λ op in a fundamental mode and at least one higher order mode, the DC fiber having a refractive index profile; CHARACTERIZED IN THAT said refractive index profile is selected such that the DC fiber does not support propagation of radiation of wavelength λ op in the LP₁₁ mode and supports propagation of radiation of wavelength λ op in at least one other higher order mode (designated LP 0m , m = 2, 3, .......).
Claim 6
Dependent Claim
86 words
The article of claim 5, wherein the DC fiber has a core (11) having normalized maximum refractive index difference Δ c > 0, the core contactingly surrounded by a cladding comprising, in outwardly directed sequence, a first cladding region (the "trench") (12) having normalized refractive index difference Δ₁ < 0, a second cladding region (the "ridge") (13) having normalized refractive index difference Δ₂ selected such that 0 < Δ₂ < Δ c , and a third cladding region having normalized refractive index difference Δ₃ < Δ₂.
Claim 7
Dependent Claim
41 words
The article of claim 6, wherein m = 2, Δ c > 0.015, Δ₁ < -0.003 and Δ₃ = 0, with the refractive index profile selected such that the cut-off wavelength of LP₁₁ is less than the cut-off wavelength of LP₀₂.
Claim 8
Dependent Claim
30 words
The article of claim 6, wherein said third cladding region extends to the surface of the DC fiber, and wherein Δ₃ is substantially constant as a function of radial distance.
Claim 9
Dependent Claim
44 words
The article of claim 1, wherein the DC fiber comprises at least one rare earth species capable of stimulated emission at the wavelength λ op , and wherein the article comprises means for coupling pump radiation of wavelength <λ op into the DC fiber.
Claim 10
Dependent Claim
18 words
The article of claim 9, wherein λ op is about 1.55µm and the rare earth species is Er.
References Cited (Backward Citations)
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