Patent US3575668A successfully refreshed from Google Patents.
US3575668A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser frequency standard employing an optical limiter
Assignee: AT&T Inc
•
Filing: 1968-03-18
•
Granted: 1971-04-20
•
Expires: 1988-03-18
Abstract
Abstract The disclosed laser has, within its resonator, an active medium and an optical limiter adapted to limit at very low levels in order to provide a very narrow effective linewidth at the peak of the atomic gain-versus-frequency curve. The optical resonator is made sufficiently long, for example, by including therein a subsidiary folded resonator, to have a resonance within the narrow effective linewidth. The limiter provides the laser with a self-stabilizing characteristic that minimizes the effects of random fluctuations in the cavity loss or in the gain of the active medium.
Inventors
- 👤 Peter W Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:08
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/05; H01S3/08; H01S3/08018; H01S3/0804; H01S3/0805; H01S3/02; H01S3/03; H01S3/08022; H01S3/08031; H01S3/10; H01S3/106; H01S3/1061
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
66 words
A laser comprising first and second reflectors forming a resonator, an active laser medium disposed within said resonator, means for pumping said active medium, and an optical power limiter disposed within said resonator for providing a loss approaching the peak gain of said active medium with respect to frequency for a power level below that at which the gain of said medium would begin to saturate.
Claim 2
Dependent Claim
66 words
A laser comprising first and second reflectors forming a resonator, an active laser medium disposed within said resonator, means for pumping said active medium, and an optical power limiter disposed within said resonator for providing a loss approaching the peak gain of said active medium with respect to frequency for a power level below that at which the gain of said medium would begin to saturate.
Claim 3
Dependent Claim
43 words
A laseR according to claim 1 in which the resonator includes an optical delay line of length making the overall longitudinal mode frequency spacing of the laser equal to or less than the effective linewidth of said laser, as affected by the limiter.
Claim 4
Dependent Claim
94 words
A laser comprising an optical resonator of path length L, an active laser medium disposed within said resonator, means for pumping said active medium, and means for limiting the power level within said resonator with a loss substantially equal to the unsaturated peak gain of said active medium with respect to frequency, whereby the laser has an effective linewidth suitable for a source of standard frequency, said path length L being selected to make the overall longitudinal mode frequency spacing of the laser equal to or less than said effective linewidth of said laser.
Claim 5
Dependent Claim
94 words
A laser comprising an optical resonator of path length L, an active laser medium disposed within said resonator, means for pumping said active medium, and means for limiting the power level within said resonator with a loss substantially equal to the unsaturated peak gain of said active medium with respect to frequency, whereby the laser has an effective linewidth suitable for a source of standard frequency, said path length L being selected to make the overall longitudinal mode frequency spacing of the laser equal to or less than said effective linewidth of said laser.
Claim 6
Dependent Claim
26 words
A laser according to claim 3 in which the resonator includes a nonreentrant folded optical delay line providing a major portion of the path length L.
References Cited (Backward Citations)
US3434779A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |