US4907237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical feedback locking of semiconductor lasers
Assignee: United States Department of Commerce
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Filing: 1988-10-18
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Granted: 1990-03-06
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Expires: 2008-10-18
Abstract
Abstract An optical method and apparatus is disclosed for stabilizing the frequencyf semiconductor lasers. The basic system includes only the optical elements of a conventional semiconductor laser optically coupled to a separate, external resonator having an optical cavity with a particular resonance frequency. The optical geometry is configured such that the output from the resonator is fed back to the laser only when the laser frequency matches or substantially matches the resonance frequency. In other disclosed embodiments, optical electronic feedback loops are used to modulate the laser injection current to stabilize the frequency and to adjust the phase of the optical feedback signal.
Inventors
- 👤 Brahim Dahmani
- 👤 Leo W. Hollberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:08
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/14; H01S5/06; H01S5/065; H01S5/0656; H01S3/00; H01S3/05; H01S3/08; H01S3/08018; H01S3/0804; H01S3/0805; H01S3/081; H01S3/082; H01S5/068; H01S5/0683; H01S5/0687; H01S5/141; H01S5/142
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
158 words
A stabilized semiconductor diode laser system comprising: a semiconductor diode laser that emits a beam along a first axis; said laser having a laser optical field and a carrier density an optical resonator means, located external to said laser, having a resonator frequency, and including an input port for receiving said laser beam and an output port through which a beam exits said resonator means, said resonator means for producing an enhanced optical output at said output port only when an optical beam supplied at said input port has a frequency substantially equal or exactly equal to said resonant frequency; first means for optically coupling at least a portion of said beam to said input port; and second means for optically coupling said output port to said laser as a positive optical feedback thereto whereby inherent coupling of the laser optical field to the carrier density of said laser results in a locking of the laser output frequency.
Claim 2
Dependent Claim
158 words
A stabilized semiconductor diode laser system comprising: a semiconductor diode laser that emits a beam along a first axis; said laser having a laser optical field and a carrier density an optical resonator means, located external to said laser, having a resonator frequency, and including an input port for receiving said laser beam and an output port through which a beam exits said resonator means, said resonator means for producing an enhanced optical output at said output port only when an optical beam supplied at said input port has a frequency substantially equal or exactly equal to said resonant frequency; first means for optically coupling at least a portion of said beam to said input port; and second means for optically coupling said output port to said laser as a positive optical feedback thereto whereby inherent coupling of the laser optical field to the carrier density of said laser results in a locking of the laser output frequency.
Claim 3
Dependent Claim
47 words
A semiconductor laser system as claimed in claim 1 and further including a beam splitter for dividing said emitted beam into a sampled beam and a system output beam; and wherein said first coupling means couples said sampled beam to said input port of said resonator means.
Claim 4
Dependent Claim
19 words
A semiconductor laser system as claimed in claim 2 wherein said input and said output port are the same.
Claim 5
Dependent Claim
22 words
A semiconductor laser system as claimed in claim 3 wherein said first coupling means and said second coupling means are the same.
Claim 6
Dependent Claim
23 words
A semiconductor laser system as claimed in claim 2 wherein said optical resonator means comprises a confocal resonator having an axis of symmetry.
Claim 7
Dependent Claim
31 words
A semiconductor laser system as claimed in claim 5 wherein said first means couples said sampled beam to said resonator at an angle to said axis of symmetry of said resonator.
Claim 8
Dependent Claim
25 words
A semiconductor laser system as claimed in claim 2 and further including means for changing the phase of the optical output of said resonator means.
Claim 9
Dependent Claim
37 words
A semiconductor laser system as claimed in claim 7 wherein said phase changing means comprises means optically coupled to receive optical radiation emitted by said resonator means and to convert said optical radiation into an electronic signal.
Claim 10
Dependent Claim
53 words
A semiconductor laser system as claimed in claim 8 wherein said phase changing means comprises a modulation lock means for receiving said electronic signal and for generating a correction signal; and wherein said second coupling means comprises a direction changing mirror mounted on a piezoelectric transducer means for providing movement of said mirror.
Claim 11
Dependent Claim
51 words
A semiconductor laser system as claimed in claim 7 and further including means optically coupled to receive optical radiation emitted by said resonator means for converting said optical radiation into an electronic signal; and means for changing the laser injection current, said modulating means receiving said electronic signal as an input.
Claim 12
Dependent Claim
73 words
A semiconductor laser system as claimed in claim 7 wherein said resonator has four ports and produces a first output beam that contains a reflected portion of said coupled sample beam as well as an interfering component, and a second output beam that contains only a reflected portion of said sample beam; and wherein said second coupling means only couples said second output beam to said laser and blocks said first output beam.
Claim 13
Dependent Claim
33 words
A semiconductor laser system as claimed in claim 7 and further including means for monitoring the noise on an output from said resonator and for generating a correction signal to reduce said noise.
Claim 14
Dependent Claim
35 words
A semiconductor laser system as claimed in claim 2 and further including means for monitoring an output from said resonator for a frequency imbalance and for generating a correction signal to reduce said frequency imbalance.
Claim 15
Dependent Claim
21 words
A semiconductor laser system as claimed in claim 13 wherein said monitoring and generating means includes an RF heterodyne locking means.
Claim 16
Independent Claim
74 words
A method for stabilizing a semiconductor laser that emits a beam comprising: splitting off a portion of said emitted beam to provide a sample beam; coupling said sampled beam to an optical resonator located external to said laser and having a resonant frequency; coupling the output of said resonator back to said laser as a positive feedback only when the frequency of said laser is equal to or substantially equal to said resonant frequency.
Claim 17
Independent Claim
74 words
A method for stabilizing a semiconductor laser that emits a beam comprising: splitting off a portion of said emitted beam to provide a sample beam; coupling said sampled beam to an optical resonator located external to said laser and having a resonant frequency; coupling the output of said resonator back to said laser as a positive feedback only when the frequency of said laser is equal to or substantially equal to said resonant frequency.
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) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-05 | 2001-09-04 | 2002-03-06 | $7700.00 | Window Closed / Lapsed |