Patent US4583228A successfully refreshed from Google Patents.
US4583228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency stabilization of lasers
Assignee: BELL TELPHONE LABORATORIES INCORPARATED
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Filing: 1983-11-21
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Granted: 1986-04-15
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Expires: 2003-11-21
Abstract
Abstract Apparatus including a semiconductor laser source and means for stabilizing the frequency of the laser. A feedback signal is provided by means such as a Fabry-Perot interferometer, which signal is coupled simultaneously to two feedback loops. One loop provides high frequency control of the drive current while the other loop provides low frequency control of the laser temperature.
Inventors
- 👤 Michael G. Brown
- 👤 Richard G. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:56
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/06; H01S5/068; H01S5/0683; H01S5/0687; H01S5/06837
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
120 words
Laser apparatus comprising a semiconductor laser light source; current means for driving the laser source; means for controlling the temperature of the laser; and means for providing a feedback signal to stabilize the frequency of the light output from said laser source comprising: means for producing an electrical output signal in response to changes in the frequency of the output from the light source; and at least two feedback loops electrically coupled to said electrical output signal, one of said feedback loops adapted to couple relatively fast changes in the output signal to the current means driving said laser source and the other feedback loop adapted to couple relatively slow changes in the output signal to the temperature control means.
Claim 2
Dependent Claim
120 words
Laser apparatus comprising a semiconductor laser light source; current means for driving the laser source; means for controlling the temperature of the laser; and means for providing a feedback signal to stabilize the frequency of the light output from said laser source comprising: means for producing an electrical output signal in response to changes in the frequency of the output from the light source; and at least two feedback loops electrically coupled to said electrical output signal, one of said feedback loops adapted to couple relatively fast changes in the output signal to the current means driving said laser source and the other feedback loop adapted to couple relatively slow changes in the output signal to the temperature control means.
Claim 3
Dependent Claim
30 words
Apparatus according to claim 1 wherein the means for producing an electrical output signal in response to changes in laser frequency includes a Fabry-Perot interferometer optically coupled to said laser.
Claim 4
Dependent Claim
49 words
Apparatus according to claim 2 wherein the means for producing an electrical output further includes a first optical detector optically coupled to the output of the Fabry-Perot interferometer, a second optical detector optically coupled to a reference beam, and means for comparing the electrical output of the two detectors.
Claim 5
Dependent Claim
19 words
Apparatus according to claim 3 wherein the means for comparing the output of the detectors comprises a differential amplifier.
Claim 6
Dependent Claim
52 words
Apparatus according to claim 1 wherein the current means is a constant current source and the said one feedback loop is coupled to the current source so that the output of the current source is proportional to the sum of the current from the feedback loop and from a fixed dc voltage.
Claim 7
Dependent Claim
19 words
Apparatus according to claim 1 wherein the feedback loops include means for controlling the voltage of the feedback signals.
Claim 8
Dependent Claim
27 words
Apparatus according to claim 1 wherein the said one feedback loop includes a high pass filter and the said other feedback loop includes a low pass filter.
Claim 9
Dependent Claim
21 words
Apparatus according to claim 1 wherein the short-term and the long-term frequency stabilization of the laser is less than 1 MHz.
Claim 10
Dependent Claim
41 words
Apparatus according to claim 1 wherein the instantaneous changes in frequency of the laser are controlled by the feedback loop coupled to the current means so that the frequency noise amplitude of the laser is reduced by at least 20 dB.
Claim 11
Dependent Claim
22 words
Apparatus according to claim 2 wherein the passband of the interferometer has a full width half maximum of less than 50 MHz.
References Cited (Backward Citations)
JPS57147291A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |