US4655588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Injection controlled laser transmitter with twin local oscillators
Assignee: RTX Corp
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Filing: 1985-02-25
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Granted: 1987-04-07
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Expires: 2005-02-25
Abstract
Abstract A heterodyne CO 2 optical Doppler radar comprising a ring type of traitter laser and twin local oscillator lasers which are automatically controlled to operate at a difference frequency equal to the intermediate frequency of the radar, which may be in the VHF band. The output of one of the twin lasers is injected into the transmitter laser for stabilization purposes and the output of the other of the twin lasers is heterodyned with the received target return signals to form the radar's intermediate frequency signal.
Inventors
- 👤 Peter P. Chenausky
- 👤 William J. Green, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:05
CPC Classifications
G; G02; G02F; G02F2/00; G02F2/002; G01; G01S; G01S17/00; G01S17/02; G01S17/50; G01S7/00; G01S7/48; H; H01; H01S; H01S3/00; H01S3/05; H01S3/08; H01S3/081; H01S3/083
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
123 words
A heterodyne CO 2 Doppler radar comprising a frequency-stabilized first local oscillator laser and a second local oscillator laser automatically controlled to operate at a frequency offset from that of said first local oscillator laser by the amount of the desired intermediate frequency of the said radar, said radar further comprising an inherently unstable, high powered CO 2 transmitter laser which is injection-stabilized for single frequency operation by said first local oscillator laser, said radar further comprising a mixer and heterodyne receiver connected to said mixer, the received target echoes and a portion of the output of said second local oscillator laser being applied to said mixer, and wherein said heterodyne receiver comprises an intermediate frequency channel plus intermediate frequency signal processing circuitry.
Claim 2
Dependent Claim
123 words
A heterodyne CO 2 Doppler radar comprising a frequency-stabilized first local oscillator laser and a second local oscillator laser automatically controlled to operate at a frequency offset from that of said first local oscillator laser by the amount of the desired intermediate frequency of the said radar, said radar further comprising an inherently unstable, high powered CO 2 transmitter laser which is injection-stabilized for single frequency operation by said first local oscillator laser, said radar further comprising a mixer and heterodyne receiver connected to said mixer, the received target echoes and a portion of the output of said second local oscillator laser being applied to said mixer, and wherein said heterodyne receiver comprises an intermediate frequency channel plus intermediate frequency signal processing circuitry.
Claim 3
Dependent Claim
43 words
The radar of claim 1 wherein said transmitter laser is a ring laser which produces continuous wave power of approximately 90 watts and said first and second local oscillators are lower powered CO 2 lasers of high inherent frequency, mode and temporal stability.
Claim 4
Dependent Claim
21 words
The radar of claim 2 wherein said ring laser comprises a ring control servo system for maximizing the power output thereof.
Claim 5
Dependent Claim
29 words
The radar of claim 1 wherein said first local oscillator laser is frequency stabilized by means of a servo system which includes a Stark cell as a frequency reference.
Claim 6
Dependent Claim
124 words
A heterodyne CO 2 optical radar comprising a high powered, inherently unstable transmitter laser of the ring type, a mixer, and twin local oscillator lasers, the first of which has a portion of its output injected into said transmitter laser for stabilization purposes, and wherein the outputs of both of said twin lasers are applied to a detector which derives the difference or beat frequency of said twin lasers, said beat frequency being applied to a frequency control system which maintains the difference frequency of said twin lasers at the desired intermediate frequency of said radar, and wherein the output of the second of said twin lasers is applied to said mixer together with the received target echoes to produce the radar's intermediate signal.
Claim 7
Dependent Claim
124 words
A heterodyne CO 2 optical radar comprising a high powered, inherently unstable transmitter laser of the ring type, a mixer, and twin local oscillator lasers, the first of which has a portion of its output injected into said transmitter laser for stabilization purposes, and wherein the outputs of both of said twin lasers are applied to a detector which derives the difference or beat frequency of said twin lasers, said beat frequency being applied to a frequency control system which maintains the difference frequency of said twin lasers at the desired intermediate frequency of said radar, and wherein the output of the second of said twin lasers is applied to said mixer together with the received target echoes to produce the radar's intermediate signal.
Claim 8
Dependent Claim
39 words
The radar of claim 5 wherein the cavities of said twin lasers are formed by two parallel channels machined into a single block of ceramic material and wherein said parallel channels are energized from a single electrical excitation source.
References Cited (Backward Citations)
US3740664A
Cited
US4515471A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |