US5140656A
Expired / Lapsed
US
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Soliton optical fiber communication system
Assignee: Nokia Bell Labs
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Filing: 1991-08-12
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Granted: 1992-08-18
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Expires: 2011-08-12
Abstract
Abstract In soliton optical fiber communication systems that comprise a multiplicity of spaced-apart intermediate non-electronic amplifiers, pulse arrival time jitter can be substantially reduced by incorporation into the transmission path of spaced-apart bandwidth-limiting elements. Exemplarily, the bandwidth-limiting elements are optical filters of bandwidth B f , with a filter associated with each intermediate amplifier, and with B f chosen to fall within the range B sol (N f /3) 1/2 , where B sol is the FWHM spectral width of the soliton pulses, and N f is the number of intermediate filters in the system. More generally, the bandwidth-limiting elements are selected such that >δt 2 >, the variance of the jitter, is at most 90% of the variance associated with an, otherwise identical, comparison system that does not contain the bandwidth-limiting elements. Systems according to the invention thus can overcome the Gordon-Haus limit on the bit rate/distance product.
Inventors
- 👤 Akira Hasegawa
- 👤 Yuji Kodama
- 👤 Dietrich Marcuse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:56
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/25077
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
179 words
A first optical fiber communication system comprising a) means for generating optical pulses, associated with said pulses being a center frequency ω o and a bandwidth B sol ; b) means responsive to the optical pulses, said responsive means being spaced apart from said generating means; c) a length L of transmission path pulse-transmissively connecting said generating means and said responsive means, said length of transmission path comprising single mode optical fiber and a multiplicity N amp of spaced-apart non-electronic amplifiers, the first communication system being adapted for operation as a soliton fiber communication system; CHARACTERIZED IN THAT d) the transmission path comprises a multiplicity N f of spaced-apart bandwidth-limiting elements, associated with said elements being a nominal gain characteristic g(ω), with g(ω) selected such that the variance of the arrival time jitter (<δt 2 >) at the responsive means is at most 90% of <δt 2 > associated with a comparison optical fiber communication system which is identical to the first communication system except that the transmission path of the comparison system does not comprise said bandwidth-limiting elements.
Claim 2
Dependent Claim
179 words
A first optical fiber communication system comprising a) means for generating optical pulses, associated with said pulses being a center frequency ω o and a bandwidth B sol ; b) means responsive to the optical pulses, said responsive means being spaced apart from said generating means; c) a length L of transmission path pulse-transmissively connecting said generating means and said responsive means, said length of transmission path comprising single mode optical fiber and a multiplicity N amp of spaced-apart non-electronic amplifiers, the first communication system being adapted for operation as a soliton fiber communication system; CHARACTERIZED IN THAT d) the transmission path comprises a multiplicity N f of spaced-apart bandwidth-limiting elements, associated with said elements being a nominal gain characteristic g(ω), with g(ω) selected such that the variance of the arrival time jitter (<δt 2 >) at the responsive means is at most 90% of <δt 2 > associated with a comparison optical fiber communication system which is identical to the first communication system except that the transmission path of the comparison system does not comprise said bandwidth-limiting elements.
Claim 3
Dependent Claim
44 words
A system according to claim 1, wherein 0.1N amp ≦N f ≦10N amp , wherein said bandwidth-limiting elements comprise optical filters, said optical filters having a center frequency nominally equal to ω o and a bandwidth B f in the range 5-20B sol .
Claim 4
Dependent Claim
17 words
A system according to claim 2, wherein B f is in the range 8-15 B sol .
Claim 5
Dependent Claim
29 words
A system according to claim 1, wherein said bandwidth-limiting elements have bandwidth B f , selected such that 0.1≦×≦10, where x=N f (B sol /B f ) 2 .
Claim 6
Dependent Claim
46 words
A system according to claim 1, comprising optical filters having a bandwidth B f selected such that a jitter reduction function f(x)<0.9, where x=N f (B sol /B f ) 2 and f(x) is at least approximately equal to (3/2x 3 )(2x-3+4e -x -e -2x ).
Claim 7
Dependent Claim
8 words
A system according to claim 5, wherein f(x)<0.5.
Claim 8
Dependent Claim
14 words
A system according to claim 5, wherein f(x)=(3/2x 3 )(2x-3+4e -x -e -2x ).
Claim 9
Dependent Claim
45 words
A system according to claim 1, wherein associated with each amplifier is an optical filter having a center frequency nominally equal to ω o and a bandwidth B f selected such that B f is in the range B sol (N f /3) 1/2 ±30%.
Claim 10
Dependent Claim
13 words
A system according to claim 1, wherein the responsive means are receiver means.
Claim 11
Dependent Claim
24 words
A system according to claim 1, wherein each of the multiplicity of non-electronic amplifiers comprises a length of rare earth-doped single mode optical fiber.
Claim 12
Dependent Claim
25 words
A system according to claim 1, wherein each of said bandwidth-limiting elements has a bandwidth in the range B sol (N f /3) 1/2 ±30%.
Claim 13
Dependent Claim
17 words
A system according to claim 1, wherein the system is a wavelength division multiplexed (WDM) soliton system.
Claim 14
Dependent Claim
25 words
A system according to claim 1, wherein the nominal center frequency of the bandwidth-limiting elements, ω f , is essentially equal to ω o .
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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) | 1995-08-18 | 1996-02-17 | 1996-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-18 | 2000-02-17 | 2000-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-18 | 2004-02-17 | 2004-08-18 | $7700.00 | Window Closed / Lapsed |