US4177436A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for controlling the differential output power of a semiconductor laser
Assignee: AT&T Inc
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Filing: 1977-12-05
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Granted: 1979-12-04
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Expires: 1997-12-05
Abstract
Abstract The apparent differential output power or quantum efficiency of a semiconductor laser, such as a double heterostructure laser diode, is reduced by means of a circuit which shunts the laser and includes a threshold device. The I-V characteristic of the shunt circuit intersects that of the laser at V x such that at voltages below V x the current through the laser exceeds that through the shunt, and conversely above V x . Specific embodiments of the shunt circuit include a resistor in series with either a zener diode or one or more forward-biased conventional diodes.
Inventors
- 👤 Richard W. Dixon
- 👤 Joseph F. Svacek, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:03
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/06; H01S5/068; H01S5/06812
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
78 words
A circuit for controlling the output of a semiconductor laser comprising, in parallel with said laser, a circuit branch including a threshold device and having a current-voltage characteristic which intersects that of said laser at a cross-over voltage V x such that, for voltages less than V x the current through said laser exceeds that through said branch, whereas for voltages greater than V x the current through said laser is less than the current through said branch.
Claim 2
Dependent Claim
78 words
A circuit for controlling the output of a semiconductor laser comprising, in parallel with said laser, a circuit branch including a threshold device and having a current-voltage characteristic which intersects that of said laser at a cross-over voltage V x such that, for voltages less than V x the current through said laser exceeds that through said branch, whereas for voltages greater than V x the current through said laser is less than the current through said branch.
Claim 3
Dependent Claim
26 words
The circuit of claim 1 wherein said laser comprises a laser diode and said threshold device comprises a zener diode poled opposite to said laser diode.
Claim 4
Dependent Claim
25 words
The circuit of claim 2 including a first resistor in series with said zener diode and a second resistor in series with said laser diode.
Claim 5
Dependent Claim
21 words
The circuit of claim 3 wherein the resistance of said second resistor is much greater than that of said first resistor.
Claim 6
Dependent Claim
31 words
The circuit of claim 1 wherein said laser comprises a laser diode and said threshold device comprises at least one forward-biased diode poled in the same direction as said laser diode.
Claim 7
Dependent Claim
16 words
The circuit of claim 5 wherein said threshold device comprises a plurality of series-connected forward-biased diodes.
Claim 8
Dependent Claim
28 words
The circuit of claim 5 including a first resistor in series with said diode of said threshold device and a second resistor in series with said laser diode.
Claim 9
Dependent Claim
21 words
The circuit of claim 7 wherein the resistance of said second resistor is much greater than that of said first resistor.
Claim 10
Dependent Claim
101 words
A circuit comprising a first laser branch including a semiconductor laser diode, a second shunt branch, in parallel with said first branch, including a threshold device, means for applying voltage and current to said branches, said branches being mutually adapted so that the current-voltage characteristic of said shunt branch intersects that of said laser branch at a cross-over voltage V x such that for voltage below V x the current through said shunt branch is less than that through said laser branch, whereas for voltages greater than V x the current through said shunt branch exceeds that through said laser branch.
Claim 11
Dependent Claim
101 words
A circuit comprising a first laser branch including a semiconductor laser diode, a second shunt branch, in parallel with said first branch, including a threshold device, means for applying voltage and current to said branches, said branches being mutually adapted so that the current-voltage characteristic of said shunt branch intersects that of said laser branch at a cross-over voltage V x such that for voltage below V x the current through said shunt branch is less than that through said laser branch, whereas for voltages greater than V x the current through said shunt branch exceeds that through said laser branch.
Claim 12
Dependent Claim
32 words
The circuit of claim 9 wherein said threshold device comprises a zener diode poled opposite to said laser diode and said shunt branch includes a resistor in series with said zener diode.
Claim 13
Dependent Claim
24 words
The circuit of claim 9 wherein said threshold device comprises at least one forward-biased diode poled in the same direction as said laser diode.
Claim 14
Dependent Claim
16 words
The circuit of claim 11 wherein said threshold device comprises a plurality of series-connected, forward-biased diodes.
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) | 1982-12-03 | 1983-06-04 | 1983-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-03 | 1987-06-04 | 1987-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-03 | 1991-06-04 | 1991-12-04 | $7700.00 | Window Closed / Lapsed |