Patent US3579145A successfully refreshed from Google Patents.
US3579145A
Expired / Lapsed
US
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Modulator stabilization circuits
Assignee: AT&T Inc
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Filing: 1969-03-21
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Granted: 1971-05-18
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Expires: 1989-03-21
Abstract
Abstract The operating point of a modulator is stabilized by superimposing a pilot signal upon the information bearing modulating signal. The resulting modulation produced by the pilot signal is compared with a reference signal in a phase detector and a control signal generated which is used to counteract any drift of the operating point. Alternatively, the average intensity of the modulator output signal is detected and used to alter the net bias applied to the modulator as a means of stabilization.
Inventors
- 👤 Owen E De Lange
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:38
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/09; G02F1/092; G02F1/0121; G02F1/0123; G02F2203/00; G02F2203/19
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
171 words
In combination: an optical wave amplitude modulator whose output wave intensity varies in response to an information bearing modulating signal; said modulator comprising an electro-optical material and means for impressing said moduLating signal across said material in a direction transverse to the direction of optical wave propagation through said material; means for establishing a bias in said modulator, thereby defining a preferred operating point; and means for stabilizing the bias of said modulator at said preferred operating point comprising: a pilot signal generator; means for coupling said generator to said modulator to modulate the output wave intensity of said modulator; means coupled to the output of said modulator for detecting the modulation produced by said pilot signal; a phase detector; means for coupling the detected modulation produced by said pilot signal to said phase detector; means for coupling said pilot signal generator to said phase detector; and means for coupling the output from said phase detector to said modulator to stabilize the operation of said modulator about said preferred operating point.
Claim 2
Dependent Claim
171 words
In combination: an optical wave amplitude modulator whose output wave intensity varies in response to an information bearing modulating signal; said modulator comprising an electro-optical material and means for impressing said moduLating signal across said material in a direction transverse to the direction of optical wave propagation through said material; means for establishing a bias in said modulator, thereby defining a preferred operating point; and means for stabilizing the bias of said modulator at said preferred operating point comprising: a pilot signal generator; means for coupling said generator to said modulator to modulate the output wave intensity of said modulator; means coupled to the output of said modulator for detecting the modulation produced by said pilot signal; a phase detector; means for coupling the detected modulation produced by said pilot signal to said phase detector; means for coupling said pilot signal generator to said phase detector; and means for coupling the output from said phase detector to said modulator to stabilize the operation of said modulator about said preferred operating point.
Claim 3
Dependent Claim
142 words
In combination: an electromagnetic wave amplitude modulator whose output wave intensity varies in response to an information bearing modulating signal; means for biasing said modulator at a minimum point along its output wave intensity versus bias characteristic; and means for stabilizing the bias of said modulator at said minimum point comprising: a pilot signal generator; means for coupling said generator to said modulator to modulate the output wave intensity of said modulator; means coupled to the output of said modulator for detecting the modulation produced by said pilot signal; a phase detector; means for coupling the detected modulation produced by said pilot signal to said phase detector; means for coupling said pilot signal generator to said phase detector; and means for coupling the output from said phase detector to said modulator to stabilize the operation of said modulator about said minimum point.
Claim 4
Dependent Claim
142 words
In combination: an electromagnetic wave amplitude modulator whose output wave intensity varies in response to an information bearing modulating signal; means for biasing said modulator at a minimum point along its output wave intensity versus bias characteristic; and means for stabilizing the bias of said modulator at said minimum point comprising: a pilot signal generator; means for coupling said generator to said modulator to modulate the output wave intensity of said modulator; means coupled to the output of said modulator for detecting the modulation produced by said pilot signal; a phase detector; means for coupling the detected modulation produced by said pilot signal to said phase detector; means for coupling said pilot signal generator to said phase detector; and means for coupling the output from said phase detector to said modulator to stabilize the operation of said modulator about said minimum point.
Claim 5
Dependent Claim
153 words
In combination: an electromagnetic wave amplitude modulator whose output wave intensity varies in response to an information bearing modulating signal; means for biasing said modulator at a preferred operating point in the linear region of its output wave intensity versus bias characteristic; and means for stabilizing the bias of said modulator at said preferred operating point comprising: a pilot signal generator; means for coupling said generator to said modulator to modulate the output wave intensity of said modulator; means coupled to the output of said modulator for detecting the modulation produced by said pilot signal; a phase detector; means for coupling the detected modulation produced by said pilot signal to said phase detector; means including a frequency doubler for coupling said pilot signal generator to said phase detector; and means for coupling the output from said phase detector to said modulator to stabilize the operation of said modulator about said preferred operating point.
Claim 6
Dependent Claim
153 words
In combination: an electromagnetic wave amplitude modulator whose output wave intensity varies in response to an information bearing modulating signal; means for biasing said modulator at a preferred operating point in the linear region of its output wave intensity versus bias characteristic; and means for stabilizing the bias of said modulator at said preferred operating point comprising: a pilot signal generator; means for coupling said generator to said modulator to modulate the output wave intensity of said modulator; means coupled to the output of said modulator for detecting the modulation produced by said pilot signal; a phase detector; means for coupling the detected modulation produced by said pilot signal to said phase detector; means including a frequency doubler for coupling said pilot signal generator to said phase detector; and means for coupling the output from said phase detector to said modulator to stabilize the operation of said modulator about said preferred operating point.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |