US4009385A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser control circuit
Assignee: AT&T Inc
•
Filing: 1976-03-22
•
Granted: 1977-02-22
•
Expires: 1996-03-22
Abstract
Abstract A control circuit for an injection laser includes a driver circuit which applies a driving current to the laser in response to an electrical modulating signal. A prebias circuit applies a prebias current to the laser in response to the difference between a signal derived from the electrical modulating signal and a signal derived from the laser light output.
Inventors
- 👤 Darrell Dean Sell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:05
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/50; H04B10/501; H04B10/503; H04B10/504; H01; H01S; H01S5/00; H01S5/06; H01S5/068; H01S5/0683; H04B10/29
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
51 words
A control circuit for an injection laser, the circuit comprising: means for driving the laser in response to an electrical modulating signal, and means for prebiasing the laser in response to the difference between a signal derived from the electrical modulating signal and a signal derived from the laser light output.
Claim 2
Dependent Claim
51 words
A control circuit for an injection laser, the circuit comprising: means for driving the laser in response to an electrical modulating signal, and means for prebiasing the laser in response to the difference between a signal derived from the electrical modulating signal and a signal derived from the laser light output.
Claim 3
Dependent Claim
19 words
The circuit as defined in claim 1, wherein the prebiasing means always biases the laser below its threshold current.
Claim 4
Dependent Claim
25 words
The circuit as defined in claim 1, wherein the driving means include a symmetric emitter-coupled pair of transistors conducting a driving current through the laser.
Claim 5
Dependent Claim
88 words
A control circuit for an injection laser comprising: means for conducting a driving current through the laser in response to the electrical modulating signal, amplifier means having input and output terminals, means for deriving a first voltage input to the amplifier from an electrical modulating signal, means for deriving a second voltage input to the amplifier from the laser optical output, and means for conducting a current through the laser and the amplifier in response to the difference between the first and second voltage inputs to the amplifier.
Claim 6
Dependent Claim
88 words
A control circuit for an injection laser comprising: means for conducting a driving current through the laser in response to the electrical modulating signal, amplifier means having input and output terminals, means for deriving a first voltage input to the amplifier from an electrical modulating signal, means for deriving a second voltage input to the amplifier from the laser optical output, and means for conducting a current through the laser and the amplifier in response to the difference between the first and second voltage inputs to the amplifier.
Claim 7
Dependent Claim
23 words
The circuit as defined in claim 4, wherein the current conducted through the amplifier means always prebiases the laser below its threshold current.
Claim 8
Dependent Claim
41 words
The circuit as defined in claim 4, wherein the means for deriving the first voltage input to the amplifier includes a symmetric emitter-coupled pair of transistors responsive to the electrical modulating signal for establishing a prebias current of a predetermined magnitude.
References Cited (Backward Citations)
US3931512A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-02-22 | 1980-08-23 | 1981-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-22 | 1984-08-23 | 1985-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-22 | 1988-08-23 | 1989-02-22 | $7700.00 | Window Closed / Lapsed |