Patent US3840738A successfully refreshed from Google Patents.
US3840738A
Expired / Lapsed
US
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Optical communications system with means for minimizing material dispersion
Assignee: AT&T Inc
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Filing: 1973-05-09
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Granted: 1974-10-08
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Expires: 1993-05-09
Abstract
Abstract The bandwidth of an optical communications system utilizing a transmission line constructed of a dispersive medium is significantly increased by use of a particular type of repeater and/or detector. This element is of such design as to be sensitive to a spectral width which is only a minor fraction of the total spectral width of originally launched pulses or other amplitude peaks representing information introduced into the transmission line. An exemplary element utilizes a prism or grating which angularly displaces different frequency components of the peak together with a sensor of sufficiently small aperture to respond only to the energy contained in a small angular portion of the spread energy. The dispersion limit on bandwidth capability on a given transmission medium is accordingly increased by a factor equal to the reciprocal of the fraction represented by the spectral portion sensed.
Inventors
- 👤 G Indig
- 👤 P Rentzepis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:57
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/2513
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
249 words
Optical communications system including generating means comprising first means for producing electromagnetic waVe energy with a center frequency within the wave length range of 500 Mu m to 1,000 Angstrom units, including second means for modulating such energy so as to alter a parameter of such wave energy, said parameter being selected from the group consisting of amplitude, frequency, and phase, said first and second means being adapted for generating envelopes of electromagnetic wave energy, said envelopes being definable by a spectral width having a length measurable in time, said length corresponding with at least one of the said parameters; a transmission line of a real medium evidencing a variation in velocity dependent upon wavelength; means for introducing envelopes of electromagnetic wave energy as produced by said first and second means into said line at a first position; and at least one detector responsive to envelopes extracted from said transmission line at a position in the transmission line spaced from the said first position, characterized in that at least one sampling means is provided for extracting sample envelopes of electromagnetic wave energy from unsampled envelopes, said samples envelopes being characterized by a spectral width which is less than but contained within that of the said unsampled envelopes as produced by said first and second means; whereby the unsampled pulse during traversal within the said real medium is increased in time length due to the said wavelength dependent velocity variation and a sampled pulse of lessened time length is produced.
Claim 2
Dependent Claim
249 words
Optical communications system including generating means comprising first means for producing electromagnetic waVe energy with a center frequency within the wave length range of 500 Mu m to 1,000 Angstrom units, including second means for modulating such energy so as to alter a parameter of such wave energy, said parameter being selected from the group consisting of amplitude, frequency, and phase, said first and second means being adapted for generating envelopes of electromagnetic wave energy, said envelopes being definable by a spectral width having a length measurable in time, said length corresponding with at least one of the said parameters; a transmission line of a real medium evidencing a variation in velocity dependent upon wavelength; means for introducing envelopes of electromagnetic wave energy as produced by said first and second means into said line at a first position; and at least one detector responsive to envelopes extracted from said transmission line at a position in the transmission line spaced from the said first position, characterized in that at least one sampling means is provided for extracting sample envelopes of electromagnetic wave energy from unsampled envelopes, said samples envelopes being characterized by a spectral width which is less than but contained within that of the said unsampled envelopes as produced by said first and second means; whereby the unsampled pulse during traversal within the said real medium is increased in time length due to the said wavelength dependent velocity variation and a sampled pulse of lessened time length is produced.
Claim 3
Dependent Claim
34 words
System of claim 1 in which the said parameter is amplitude and the said sampling means has a spectral response which has a maximum half as great as that of the envelopes before sampling.
Claim 4
Dependent Claim
13 words
System of claim 2 in which the said first means includes a laser.
Claim 5
Dependent Claim
13 words
System of claim 3 in which the said laser has a pulsed output.
Claim 6
Dependent Claim
28 words
System of claim 3 in which the said sampling means has a spectral response which centers about a wavelength defining a predominant wavelength mode of the said laser.
Claim 7
Dependent Claim
24 words
System of claim 5 in which the spectral response of the said sampling means is a maximum of one-tenth that of the unsampled envelopes.
Claim 8
Dependent Claim
18 words
System of claim 6 in which a said sampling means is at least a portion of a detector.
Claim 9
Dependent Claim
19 words
System of claim 7 in which the said detector includes an amplifier for increasing the amplitude of sampled envelopes.
Claim 10
Dependent Claim
12 words
System of claim 8 in which the said amplifier includes a laser.
Claim 11
Dependent Claim
13 words
System of claim 9 in which the said laser is a laser oscillator.
Claim 12
Dependent Claim
17 words
System of claim 1 in which a said sampling means is included in the said generating means.
Claim 13
Dependent Claim
14 words
System of claim 11 in which a said detector comprises a said sampling means.
Claim 14
Dependent Claim
33 words
System of claim 1 including at least two said sampling means and at least two said detectors, at least one of said detectors including an amplifier for increasing the amplitude of sampled envelopes.
Claim 15
Dependent Claim
25 words
System of claim 1 in which a said detector is at least part of a terminal receiver at the end of the said transmission line.
Claim 16
Dependent Claim
34 words
System of claim 1 in which unsampled envelopes as introduced into the said transmission line from the said generating means are separated by an interval which is a maximum of about 10 6 second.
Claim 17
Dependent Claim
24 words
System of claim 1 in which the unsampled envelopes have a spectral content only sufficient to satisfy the Fourier requirement for defining time duration.
Claim 18
Dependent Claim
27 words
System of claim 1 in which the spectral content of unsampled envelopes exceeds the Fourier requirement for defining time duration by at least one order of magnitude.
Claim 19
Dependent Claim
55 words
System of claim 1 in which the said detector includes at least one prism or grating for producing an angular spread in the extracted envelopes in terms of wavelength, and in which the said detector is provided with an aperture of such physical dimensions as to limit its response to the desired narrowed spectral width.
Claim 20
Dependent Claim
30 words
System of claim 1 in which the said transmission line has a frequency dispersion of at least 1 percent over the wavelength range of from 0.3 to 0.7 Mu m.
Claim 21
Dependent Claim
22 words
System of claim 1 in which the spectral response of a said sampling means is a maximum of about ten wave numbers.
Claim 22
Dependent Claim
22 words
System of claim 20 in which the spectral response of a said sampling means is a small fraction of a wave number.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |