US4674881A
Expired / Lapsed
US
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Open loop thin film laser gyro
Assignee: NOC (DELAWARE) Corp A CORP OF
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Filing: 1984-04-25
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Granted: 1987-06-23
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Expires: 2004-04-25
Abstract
Abstract The laser gyro includes a laser and a ring resonator. Apparatus is provided for coupling counter-propagating beams of light from the laser into the resonator. The frequency of the laser is scanned across the resonance frequency of the resonator in steps superimposed on a dc level. The intensity of light in one of the counter-propagating beams is detected during each of the steps and the difference in intensity of the detected light is determined. The difference in the intensity of the detected light is used to alter the dc level of the steps so as to drive the difference to zero. The intensity of light in the other of the counter propagating beams is detected during each of the steps and the difference in intensity is also detected. This difference is indicative of the rotation rate of the gyro.
Inventors
- 👤 Anthony W. Lawrence
- 👤 John R. Haavisto
- 👤 Timothy Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:21
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/58; G01C19/64; G01C19/72; G01C19/727
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
150 words
Open loop laser gyro comprising: a laser; a ring resonator; means for coupling counter-propagating beams of light from said laser into said resonator; means for scanning the frequency of said laser across the resonance frequency of said resonator in steps superimposed on a dc level; means for detecting the intensity of light in one of said counter propagating beams during said steps; means for determining a first difference in intensity of the detected light during said steps; means responsive to said first difference of the detected light intensity to alter the dc level of said steps to drive said first difference to zero; means for detecting the intensity of light in the other of said counter-propagating beams during said steps; and means for determining a second difference in intensity during said steps of light in said other counter-propagating beam, said second difference indicative of the rotation rate of said gyro.
Claim 2
Dependent Claim
150 words
Open loop laser gyro comprising: a laser; a ring resonator; means for coupling counter-propagating beams of light from said laser into said resonator; means for scanning the frequency of said laser across the resonance frequency of said resonator in steps superimposed on a dc level; means for detecting the intensity of light in one of said counter propagating beams during said steps; means for determining a first difference in intensity of the detected light during said steps; means responsive to said first difference of the detected light intensity to alter the dc level of said steps to drive said first difference to zero; means for detecting the intensity of light in the other of said counter-propagating beams during said steps; and means for determining a second difference in intensity during said steps of light in said other counter-propagating beam, said second difference indicative of the rotation rate of said gyro.
Claim 3
Dependent Claim
33 words
The laser gyro of claim 1 wherein said means for determining said first and second differences in intensity of the detected light during said steps comprises a pair of sample and hold elements.
Claim 4
Dependent Claim
47 words
The laser gyro of claim 1 wherein said means for determining said first and second differences in intensity of the detected light during said steps comprises a voltage to frequency converter driven by the detector signal, the voltage to frequency output being counted in an up-down counter.
Claim 5
Dependent Claim
14 words
The laser gyro of claim 1 including two input couplers and one output coupler.
Claim 6
Dependent Claim
32 words
The laser gyro of claim 1 including a substrate having a single polished edge for mounting said laser and for mounting detectors for detecting the intensity of light in said counter-propagating beams.
Claim 7
Dependent Claim
25 words
The laser gyro of claim 1 wherein said steps have an extent equal to the width of a resonator line at the 3/4 power points.
Claim 8
Dependent Claim
14 words
The apparatus of claim 1 wherein said laser is a gallium aluminum arsenide laser.
Claim 9
Dependent Claim
11 words
The apparatus of claim 1 wherein said detectors are silicon detectors.
Claim 10
Dependent Claim
15 words
The apparatus of claim 1 wherein said laser is a gallium indium arsenide phosphorous laser.
Claim 11
Dependent Claim
17 words
The apparatus of claim 1 further including a thermoelectric device for controlling the temperature of said laser.
Claim 12
Dependent Claim
157 words
Open loop laser gyro comprising: a laser; a ring resonator; first and second input waveguide couplers for coupling counter-propagating beams of light from said laser into said resonator; means for scanning the frequency of said laser across the resonance frequency of said resonator in steps superimposed on a dc level; means for detecting the intensity of light in one of said input couplers during said steps; means for determining a first difference in intensity of the detected light in said one of said couplers during said steps; means responsive to said first difference to alter the dc level of said steps to drive said first difference to zero; means for detecting the intensity of light in the other of said input couplers during said steps; and means for determining a second difference in intensity of light in said other of said input couplers during said steps, said second difference indicative of the rotation rate of said gyro.
Claim 13
Dependent Claim
157 words
Open loop laser gyro comprising: a laser; a ring resonator; first and second input waveguide couplers for coupling counter-propagating beams of light from said laser into said resonator; means for scanning the frequency of said laser across the resonance frequency of said resonator in steps superimposed on a dc level; means for detecting the intensity of light in one of said input couplers during said steps; means for determining a first difference in intensity of the detected light in said one of said couplers during said steps; means responsive to said first difference to alter the dc level of said steps to drive said first difference to zero; means for detecting the intensity of light in the other of said input couplers during said steps; and means for determining a second difference in intensity of light in said other of said input couplers during said steps, said second difference indicative of the rotation rate of said gyro.
Claim 14
Dependent Claim
190 words
Open loop laser gyro comprising: a laser; a ring resonator; first and second input waveguide couplers for coupling counter-propagating beams of light from said laser into said resonator; an output coupler; means for scanning the frequency of said laser across the resonance frequency of said resonator in steps superimposed on a dc level; means for detecting the intensity of light in one of said input couplers during said steps and for detecting the intensity of light in said output coupler; means for determining a first difference in intensity of detected light in said one of said input couplers and said output coupler during said steps; means responsive to said first difference to alter the dc level of said steps to drive said first difference to zero; means for detecting the intensity of light in the other of said input couplers during said steps and for determining the intensity of light in said output coupler; and means for determining a second difference in intensity of light in said other of said input couplers and said output coupler during said steps, said second difference indicative of the rotation rate of said gyro.
Claim 15
Dependent Claim
190 words
Open loop laser gyro comprising: a laser; a ring resonator; first and second input waveguide couplers for coupling counter-propagating beams of light from said laser into said resonator; an output coupler; means for scanning the frequency of said laser across the resonance frequency of said resonator in steps superimposed on a dc level; means for detecting the intensity of light in one of said input couplers during said steps and for detecting the intensity of light in said output coupler; means for determining a first difference in intensity of detected light in said one of said input couplers and said output coupler during said steps; means responsive to said first difference to alter the dc level of said steps to drive said first difference to zero; means for detecting the intensity of light in the other of said input couplers during said steps and for determining the intensity of light in said output coupler; and means for determining a second difference in intensity of light in said other of said input couplers and said output coupler during said steps, said second difference indicative of the rotation rate of said gyro.
References Cited (Backward Citations)
US3890047A
Cited
US4326803A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-22 | 1990-12-22 | 1991-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-22 | 1994-12-22 | 1995-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-22 | 1998-12-22 | 1999-06-23 | $7700.00 | Window Closed / Lapsed |