Patent US2419556A successfully refreshed from Google Patents.
US3845294A
Expired / Lapsed
US
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Multiplexed communications system
Assignee: AT&T Inc
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Filing: 1973-05-09
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Granted: 1974-10-29
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Expires: 1993-05-09
Abstract
Abstract A pulsed optical communication system based on use of a pulse train generated, for example, by a Q-switched laser, is frequency multiplexed so as to contain generally upwards of 10 subchannels. Subchannels correspond with frequency spectral portions representative of natural laser modes and are processed by first separating the spectral content of a pulse envelope, for example, by use of a prism, and then modulating such portions individually. Modulation may take any of the usual forms-either quantized or analog. In the usual system, component pulses are reconstituted after modulation perhaps by introduction into a transmission line. Demultiplexing is accomplished by a similar procedure, i.e., by separating spectral components within a pulse envelope and by introducing such components into photomultipliers or other suitable detectors.
Inventors
- 👤 G Indig
- 👤 P Rentzepis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:41
CPC Classifications
H; H04; H04J; H04J14/00; H04J14/02; G; G02; G02B; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0013; G02B6/0015; G02B6/0016
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
139 words
Optical communications system including first means for generating pulsed electromagnetic radiation having a substantial portion of its energy in the wavelength range of 500 Mu m to 100 Angstrom units, second means for modulating such pulsed radiation, and third means for further processing such modulated information, characterized in that separation means is interposed between said first and said second means for separating pulses emanating from said first means into radiation units containing distinct and differing spectral portions, said portions herein designated as component pulses, in which said second means includes a plurality of elements each so arranged as to admit but a Corresponding component pulse so that such component pulses may serve as communications subcarriers and in which said third means includes means for reconstituting said component pulses after passage through said second means so producing a reconstituted pulse.
Claim 2
Dependent Claim
139 words
Optical communications system including first means for generating pulsed electromagnetic radiation having a substantial portion of its energy in the wavelength range of 500 Mu m to 100 Angstrom units, second means for modulating such pulsed radiation, and third means for further processing such modulated information, characterized in that separation means is interposed between said first and said second means for separating pulses emanating from said first means into radiation units containing distinct and differing spectral portions, said portions herein designated as component pulses, in which said second means includes a plurality of elements each so arranged as to admit but a Corresponding component pulse so that such component pulses may serve as communications subcarriers and in which said third means includes means for reconstituting said component pulses after passage through said second means so producing a reconstituted pulse.
Claim 3
Dependent Claim
26 words
System of claim 1 in which said third means includes a transmission line and in which reconstitution results from simultaneously introducing component pulses into such line.
Claim 4
Dependent Claim
32 words
System of claim 1 in which said third means includes at least one demultiplexing apparatus for separating the said reconstituted pulse into portions corresponding in center frequency with the said component pulses.
Claim 5
Dependent Claim
41 words
System of claim 3 in which said demultiplexing apparatus is at least a portion of a receiver and in which it is provided with detection means, so placed and of such aperture as to be exclusively sensitive to such demultiplexed portions.
Claim 6
Dependent Claim
16 words
System of claim 4 in which the said detectors convert the said portions into electrical impulses.
Claim 7
Dependent Claim
43 words
System of claim 3 in which the said demultiplexing apparatus is at least a portion of a repeater and in which there is provided apparatus for reconstituting demultiplexed portions so as to produce a further reconstituted pulse for launching in a transmission medium.
Claim 8
Dependent Claim
13 words
System of claim 1 in which said first means includes a Q-switched laser.
Claim 9
Dependent Claim
13 words
System of claim 1 in which said first means includes a mode-locked laser.
Claim 10
Dependent Claim
23 words
System of claim 8 in which said first means includes a dispersive medium for time spreading pulsed energy produced by said mode-locked laser.
Claim 11
Dependent Claim
32 words
System of claim 1 in which said first means includes a cw laser and shutter means for interrupting a cw beam produced thereby so as to result in a stream of pulses.
Claim 12
Dependent Claim
32 words
System of claim 1 in which said second means comprises at least one prism for producing a diverging wave front characterized by a variation in wavelength from one geometric position to another.
Claim 13
Dependent Claim
19 words
System of claim 11 in which said second means additionally includes a collimating device following the said spreading means.
Claim 14
Dependent Claim
12 words
System of claim 1 in which said second means includes a grating.
References Cited (Backward Citations)
US3506834A
Cited
US3755676A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |