US3946335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stabilization circuit for radiation emitting diodes
Assignee: AT&T Inc
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Filing: 1975-02-18
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Granted: 1976-03-23
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Expires: 1995-02-18
Abstract
Abstract A particularly important factor limiting the reliability of diode lasers is the catastrophic mirror damage which occurs when the radiated output exceeds a critical value. Experience has shown that this occurs as a result of fluctuations in the drive current, especially in high efficiency diodes. To avoid such damage, a portion of the output radiation from a diode laser, located in the collector circuit of a common emitter drive transistor, is coupled back to a photodetector, located in the base-emitter circuit of the transistor. The resulting negative feedback tends to stabilize the overall operation of the device and maintain the maximum radiated power within safe limits.
Inventors
- 👤 Bernard Collins De Loach, Jr.
- 👤 Mauro DiDomenico, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:36
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/50; H04B10/564; H01; H01S; H01S5/00; H01S5/06; H01S5/068; H01S5/06825; H01S5/30; H03; H03F; H03F17/00; H04B10/501; H04B10/503; H04B10/504; H01S5/0683
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
67 words
The combination comprising: a transistor connected in the common emitter configuration; a radiation emitting diode laser coupled between the collector and emitter electrodes of said transistor; a photodetector coupled between the base and emitter electrodes of said transistor; means for coupling a portion of the radiated output power from said diode to said photodetector; and means for coupling an input signal between said base and emitter electrodes.
Claim 2
Dependent Claim
67 words
The combination comprising: a transistor connected in the common emitter configuration; a radiation emitting diode laser coupled between the collector and emitter electrodes of said transistor; a photodetector coupled between the base and emitter electrodes of said transistor; means for coupling a portion of the radiated output power from said diode to said photodetector; and means for coupling an input signal between said base and emitter electrodes.
Claim 3
Dependent Claim
13 words
The combination according to claim 1 wherein said photodetector is a back-biased photodiode.
Claim 4
Dependent Claim
18 words
The combination according to claim 1 including means for limiting the bias developed across the transistor base-emitter junction.
Claim 5
Dependent Claim
12 words
The combination according to claim 1 including means for prebiasing said diode.
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) | 1979-03-23 | 1979-09-22 | 1980-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-23 | 1983-09-22 | 1984-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-23 | 1987-09-22 | 1988-03-23 | $7700.00 | Window Closed / Lapsed |