US4406516A
Expired / Lapsed
US
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Monomode fiberguide telecommunication system utilizing soliton pulses
Assignee: AT&T Inc
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Filing: 1981-04-27
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Granted: 1983-09-27
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Expires: 2001-04-27
Abstract
Abstract The data transmission rate link length product of monomode fiberguide telecommunication systems can be increased above values possible in "linear" systems by appropriate use of the non-linear dependence of the fiber refractive index on electric field. In particular, selecting the appropriate pulse peak power and center wavelength can result in creation of a soliton, i.e., a pulse capable of substantially dispersionless transmission. The center wavelength is to be close to, but larger than, the wavelength of zero first-order chromatic dispersion of the fiberguide, and the latter wavelength is to be within the anomalous dispersion regime of the fiberguide. Criteria for determining the appropriate peak power, center wavelength, fiber loss, and minimum link length, as well as the asymptotic pulse width and soliton spread due to the power loss in the fiber are given, and facilitate design of a system according to the invention.
Inventors
- 👤 Akira Hasegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:43
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
166 words
A fiberguide telecommunication system comprising (a) a source of pulsed electromagnetic radiation, the pulses having a peak power, a center wavelength, and a spectral width, (b) a monomode fiberguide link having a length, first-order zero chromatic dispersion at a first wavelength in the anomalous dispersion regime of the fiberguide, and a loss at the center wavelength to result in a decrease of the pulse amplitude by about 63% in a first fiberlength, and (c) means for coupling at least a part of the pulsed radiation into the core of the fiberguide, characterized in that (d) the peak power of the radiation coupled into the core is between about 1/4 and 9/4 of the balanced peak power, (e) the link length is at least approximately as large as the soliton formation length, (f) the first fiberlength is at least approximately as large as the soliton formation length, and (g) the center wavelength exceeds the first wavelength by at least about the spectral width of the radiation pulse.
Claim 2
Dependent Claim
166 words
A fiberguide telecommunication system comprising (a) a source of pulsed electromagnetic radiation, the pulses having a peak power, a center wavelength, and a spectral width, (b) a monomode fiberguide link having a length, first-order zero chromatic dispersion at a first wavelength in the anomalous dispersion regime of the fiberguide, and a loss at the center wavelength to result in a decrease of the pulse amplitude by about 63% in a first fiberlength, and (c) means for coupling at least a part of the pulsed radiation into the core of the fiberguide, characterized in that (d) the peak power of the radiation coupled into the core is between about 1/4 and 9/4 of the balanced peak power, (e) the link length is at least approximately as large as the soliton formation length, (f) the first fiberlength is at least approximately as large as the soliton formation length, and (g) the center wavelength exceeds the first wavelength by at least about the spectral width of the radiation pulse.
Claim 3
Dependent Claim
227 words
A fiberguide telecommunication system comprising (a) a source of pulsed electromagnetic radiation, the pulses having a peak power, a center wavelength λ, and a pulse width 2t o , (b) a monomode fiberguide link of length L, the fiberguide having a core of effective cross section S, zero first-order chromatic dispersion at wavelength λ c , in the anomalous dispersion regime of the fiberguide, loss at wavelength λ to result in a decrease of the amplitude of the pulse by 1/e in a distance γ -1 , index of refraction n, and quadratic coefficient of the index n 2 , and (c) means for coupling at least a part of the pulsed electromagnetic radiation into the core of the fiberguide, characterized in that (d) the peak power P of the pulsed electromagnetic radiation coupled into the fiber is adjusted to be between about 1/4 and about 9/4 times a balanced peak power P o , (e) the link length L is selected to be at least approximately as large as a soliton formation length L o , (f) the fiber is selected to have a loss at the wavelength λ such that the distance γ -1 is at least approximately as large as L o , and (g) the center wavelength λ is selected to be at least as large as λ c +Δλ min , ##EQU9##
Claim 4
Dependent Claim
227 words
A fiberguide telecommunication system comprising (a) a source of pulsed electromagnetic radiation, the pulses having a peak power, a center wavelength λ, and a pulse width 2t o , (b) a monomode fiberguide link of length L, the fiberguide having a core of effective cross section S, zero first-order chromatic dispersion at wavelength λ c , in the anomalous dispersion regime of the fiberguide, loss at wavelength λ to result in a decrease of the amplitude of the pulse by 1/e in a distance γ -1 , index of refraction n, and quadratic coefficient of the index n 2 , and (c) means for coupling at least a part of the pulsed electromagnetic radiation into the core of the fiberguide, characterized in that (d) the peak power P of the pulsed electromagnetic radiation coupled into the fiber is adjusted to be between about 1/4 and about 9/4 times a balanced peak power P o , (e) the link length L is selected to be at least approximately as large as a soliton formation length L o , (f) the fiber is selected to have a loss at the wavelength λ such that the distance γ -1 is at least approximately as large as L o , and (g) the center wavelength λ is selected to be at least as large as λ c +Δλ min , ##EQU9##
Claim 5
Dependent Claim
22 words
System according to claim 1 or 2 wherein the fiberguide comprises silica, and λ c is near or equal to 1.55 μm.
Claim 6
Dependent Claim
17 words
System according to claim 1 or 2 wherein the source of pulsed electromagnetic energy is a laser.
Claim 7
Dependent Claim
256 words
A fiberguide telecommunication system comprising (a) a laser source of pulsed electromagnetic radiation, the pulses having a peak power, a center wavelength λ, and a pulse width 2t o , (b) a monomode fiberguide link of length L, the fiberguide comprising silica and having a core of effective cross section S, zero first-order chromatic dispersion at wavelength λ c in the anomalous dispersion regime of the fiberguide, and loss at wavelength λ to result in a decrease of the amplitude of the pulse by 1/e in a distance γ -1 , and (c) means for coupling at least a part of the pulsed electromagnetic energy into the core of the fiberguide, characterized in that (d) the fiberguide is selected to have zero first-order chromatic dispersion wavelength λ c near or equal to 1.55 μm, (e) the peak power P of the pulsed electromagnetic radiation coupled into the fiber is adjusted to be between about 1/4 and about 9/4 times a balanced peak power P o , (f) the link length L is selected to be at least approximately as large as a soliton formation length L o , (g) the fiber is selected to have a loss at λ such that the distance γ -1 is at least approximately as large as L o , and (h) the carrier wavelength λ is selected to be close to λ c , but at least as large as λ c +Δλ min , ##EQU10## where 2t.sub.∞ is the width of the pulse after transmission through the fiber link.
Claim 8
Dependent Claim
256 words
A fiberguide telecommunication system comprising (a) a laser source of pulsed electromagnetic radiation, the pulses having a peak power, a center wavelength λ, and a pulse width 2t o , (b) a monomode fiberguide link of length L, the fiberguide comprising silica and having a core of effective cross section S, zero first-order chromatic dispersion at wavelength λ c in the anomalous dispersion regime of the fiberguide, and loss at wavelength λ to result in a decrease of the amplitude of the pulse by 1/e in a distance γ -1 , and (c) means for coupling at least a part of the pulsed electromagnetic energy into the core of the fiberguide, characterized in that (d) the fiberguide is selected to have zero first-order chromatic dispersion wavelength λ c near or equal to 1.55 μm, (e) the peak power P of the pulsed electromagnetic radiation coupled into the fiber is adjusted to be between about 1/4 and about 9/4 times a balanced peak power P o , (f) the link length L is selected to be at least approximately as large as a soliton formation length L o , (g) the fiber is selected to have a loss at λ such that the distance γ -1 is at least approximately as large as L o , and (h) the carrier wavelength λ is selected to be close to λ c , but at least as large as λ c +Δλ min , ##EQU10## where 2t.sub.∞ is the width of the pulse after transmission through the fiber link.
References Cited (Backward Citations)
US4099835A
Cited
US4070091A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1986-09-26 | 1987-03-28 | 1987-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-26 | 1991-03-28 | 1991-09-27 | $3760.00 | Window Closed / Lapsed |
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