US3670165A
Expired / Lapsed
US
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Optical time demultiplexer utilizing a single control pulse per frame
Assignee: AT&T Inc
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Filing: 1970-12-09
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Granted: 1972-06-13
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Expires: 1990-12-09
Abstract
Abstract A single optical control pulse per frame is utilized to spatially separate the linearly polarized channel pulses of time multiplexed optical PCM signal in an optical time demultiplexer, the basic unit of which comprises an active medium in which birefringence can be optically induced, a polarization separator in optical series therewith to deflect out of the unit channel pulses to be detected, and a delay device which selectively delays the control pulse and causes it to by-pass the separator. A plurality of such units, equal in number to the number of channels to be demultiplexed, are disposed in optical series in the transmission path of the signal.
Inventors
- 👤 Tracy Stewart Kinsel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:59
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/35; H; H04; H04J; H04J14/00; H04J14/08
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
266 words
An optical time demultiplexing system utilizing a single optical control pulse per frame for spatially separating into separate optical detection paths a plurality of sequential, linearly polarized optical channel pulses comprising a plurality of gating units equal in number to the number of channels per frame to be separated, said units being disposed optically in series with one another in the transmission path of said channel pulses, each of said units comprising an active medium in which birefringence can be optically induced, a polarization separator in optical series with said medium for deflecting selected ones of said channel pulses into a selected detection path, a differential delay device for delaying said channel and control pulses with respect to one another and for causing said control pulse to by-pass said separator, and a detector for receiving channel pulses deflected from said transmission path by said separator, means for applying to the active medium of one of said units a high intensity, linearly polarized optical control pulse coincident and collinear with the passage of a corresponding channel pulse therethrough to rotate by substantially 90* the polarization of said channel pulse, thereby causing said channel pulse to be deflected by the polarization separator of said one unit to incidence on the detector of said unit, said delay device of said one unit being effective to delay selectively said control pulse by an amount substantially equal to the spacing of said channel pulses, thereby to cause the next one of said units to deflect said next channel pulse from said transmission path into the next one of said detection paths.
Claim 2
Dependent Claim
266 words
An optical time demultiplexing system utilizing a single optical control pulse per frame for spatially separating into separate optical detection paths a plurality of sequential, linearly polarized optical channel pulses comprising a plurality of gating units equal in number to the number of channels per frame to be separated, said units being disposed optically in series with one another in the transmission path of said channel pulses, each of said units comprising an active medium in which birefringence can be optically induced, a polarization separator in optical series with said medium for deflecting selected ones of said channel pulses into a selected detection path, a differential delay device for delaying said channel and control pulses with respect to one another and for causing said control pulse to by-pass said separator, and a detector for receiving channel pulses deflected from said transmission path by said separator, means for applying to the active medium of one of said units a high intensity, linearly polarized optical control pulse coincident and collinear with the passage of a corresponding channel pulse therethrough to rotate by substantially 90* the polarization of said channel pulse, thereby causing said channel pulse to be deflected by the polarization separator of said one unit to incidence on the detector of said unit, said delay device of said one unit being effective to delay selectively said control pulse by an amount substantially equal to the spacing of said channel pulses, thereby to cause the next one of said units to deflect said next channel pulse from said transmission path into the next one of said detection paths.
Claim 3
Dependent Claim
23 words
The system of claim 1 wherein said channel and control pulses are linearly polarized at an angle of about 45* to one another.
Claim 4
Dependent Claim
13 words
The system of claim 1 wherein said polarization separator comprises a Rochon prism.
Claim 5
Dependent Claim
32 words
The system of claim 1 including a separate filter disposed between each of said detectors and each of said separators to prevent spurious control pulse radiation from being incident on said detectors.
Claim 6
Dependent Claim
123 words
The system of claim 1 wherein said delay device comprises a first dichroic surface disposed in said transmission for selectively reflecting said control pulse into a separate, optically longer delay path, said first surface being highly transmissive to said channel pulses, a second dichroic surface disposed in said transmission path in spaced relation to said first surface, means for reflecting said control pulse from said delay path to incidence on said second surface, said second surface being highly transmissive to said channel pulses and highly reflective to said control pulse and being disposed so as to reflect said control pulse to propagation along said transmission path, and said polarization separator being disposed in said transmission path between said first and second dichroic surfaces.
Claim 7
Independent Claim
159 words
A method of spatially separating into separate optical detection paths a plurality of sequential, linearly polarized optical channel pulses by means of a single optical control pulse per frame comprising the steps of a. making a preselected channel pulse incident upon a medium in which birefringence can be optically induced, b. making a high intensity, linearly polarized optical control pulse coincident and collinear with said channel pulse in said medium to rotate by substantially 90* the polarization of said channel pulse, c. making said channel pulse incident on a polarization sensitive device to deflect said channel pulse to a detector, d. causing said control pulse to by-pass said device and to be delayed in time by an amount substantially equal to the channel pulse spacing, thereby to cause said control pulse to be coincident and collinear with the next one of said channel pulses, and e. repeating steps (a)-(d) until all such channel pulses are spatially separAted and detected.
Claim 8
Independent Claim
159 words
A method of spatially separating into separate optical detection paths a plurality of sequential, linearly polarized optical channel pulses by means of a single optical control pulse per frame comprising the steps of a. making a preselected channel pulse incident upon a medium in which birefringence can be optically induced, b. making a high intensity, linearly polarized optical control pulse coincident and collinear with said channel pulse in said medium to rotate by substantially 90* the polarization of said channel pulse, c. making said channel pulse incident on a polarization sensitive device to deflect said channel pulse to a detector, d. causing said control pulse to by-pass said device and to be delayed in time by an amount substantially equal to the channel pulse spacing, thereby to cause said control pulse to be coincident and collinear with the next one of said channel pulses, and e. repeating steps (a)-(d) until all such channel pulses are spatially separAted and detected.
Claim 9
Dependent Claim
23 words
The method of claim 6 wherein said control and said channel pulses are polarized at an angle of about 45* to one another.
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) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |