VCSEL enabled active resonator gyroscope
AssigneeHoneywell International Inc.
InventorWei Yang
Life of this patent
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Abstract
A interferometric optical gyroscope includes an active resonator comprising a half cavity vertical cavity surface emitting laser (half-VCSEL) operating as one of the mirrors that form the ring resonator. The half-VCSEL includes a bottom mirror stack and active layers formed on the bottom mirror stack and has a surface opposite the bottom mirror stack. Lack of a top mirror stack typically found in a VCSEL prevents the half-VCSEL from lasing, thus the half-VCSEL forms a reflective amplifier for the light circulating in the resonator. A single or multiple external light sources can be used to induce two counter-propagating beams in the resonator. Higher finesse due to the internal gain in the resonator enhances the sensitivity of the gyroscope.
Claims20
An active resonator gyroscope apparatus, comprising:
- an active ring resonator comprising at least three mirrors wherein at least one of the at least three mirrors comprises a half vertical cavity surface emitting laser operating as an active mirror and the rest the at least three mirrors comprise passive mirrors and wherein energy is supplied to said half vertical cavity surface emitting at such an intensity that said active ring resonator is below its lasing threshold;
- external light beam 1 at optical frequency f1;
- external light beam 2 at optical frequency f2;
- and
- means to feed light beam 1 and light beam 2 into said active ring resonator to propagate in counter-rotating directions within the active ring resonator;
- and
- photo detectors D1 and D2 for detecting intensity of the two beams via one or two of the passive mirrors;
- wherein f1and f2 are locked-in with one or two different resonant frequencies of the active ring resonator using outputs from the photo detector D1 and D2, and rotation rate of the gyroscope is correlated to f1-f2.
An active ring resonator gyroscope apparatus, comprising:
- an active ring resonator comprising at least three mirrors wherein at least one of the at least three mirrors comprises a half vertical cavity surface emitting laser operating as an active mirror and the rest the at least three mirrors comprise passive mirrors and wherein energy is supplied to said half vertical cavity surface emitting at such an intensity that said active ring resonator is below its lasing threshold;
- external light beam 1 at optical frequency f1;
- external light beam 2 at optical frequency f2;
- and
- means to feed light beam 1 and light beam 2 into said active ring resonator to propagate in counter-rotating directions within the active ring resonator;
- and
- photo detectors D1 and D2 for detecting intensity of the two beams via one or two of the passive mirrors;
- wherein f1and f2 are locked-in with one or two different resonant frequencies of the active ring resonator using outputs from the photo detector D1 and D2, and rotation rate of the gyroscope is correlated to f1-f2;
- wherein optical gain is attained for the active resonator gyroscope when light passes through the active layers located above the bottom mirror stack and exits through the surface of the half vertical cavity surface emitting laser.
An active ring resonator gyroscope apparatus, comprising:
- an active ring resonator comprising at least three mirrors wherein at least one of the at least three mirrors comprises a half vertical cavity surface emitting laser operating as an active mirror and the rest the at least three mirrors comprise passive mirrors and wherein energy is supplied to said half vertical cavity surface emitting at such an intensity that said active ring resonator is below its lasing threshold;
- external light beam 1 at optical frequency f1;
- external light beam 2 at optical frequency f2;
- and
- means to feed light beam 1 and light beam 2 into said active ring resonator to propagate in counter-rotating directions within the active ring resonator;
- and
- photo detectors D1 and D2 for detecting intensity of the two beams via one or two of the passive mirrors;
- wherein f1 and f2 are locked-in with one or two different resonant frequencies of the active ring resonator using outputs from the photo detector D1 and D2, and rotation rate of the gyroscope is correlated to f1-f2;
- and
- wherein f1-f2, is measured by extracting and combining the two counter-propagating beams via one of the mirrors and measuring a beat frequency produced by the two beams.
Dependencies are inferred from the claim text.