Triaxial fiber optic Sagnac interferometer with single source and detector
AssigneeLitton Systems, Inc.
InventorEric L. Goldner
Life of this patent
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Abstract
A triaxial Sagnac interferometer employs a single source of optical energy and a single photodetector. An optical fiber network interconnects the source and the photodetector with three fiber optic gyroscopes. A phase modulator is associated with each of the gyroscopes for applying a phase difference bias. The modulators are controlled by a common control circuit. The outputs of the modulators are divided into three distinct modes. During any one mode, two of the three gyroscopes are blanked so that the composite output comprises a readily interpreted serial presentation of individual gyroscope data.
Claims9
A triaxial fiber optic Sagnac interferometer for measuring rotation rates about three axes comprising, in combination:
- a) a source of optical energy;
- b) a first, a second and a third gyroscope for measuring rotation rates about a first, a second and third axis respectively;
- c) each of said gyroscopes comprising a coil of optical fiber;
- d) means for launching said optical energy into each of said coils as counterpropagating waves;
- e) phase modulators located in each of said coils for artificially modulating the phase difference between said counterpropagating waves;
- f) a single detector for receiving the outputs of each of said gyroscopes;
- g) an optical network for receiving the output of said source, distributing said output to said gyroscopes, receiving the output of said gyroscopes and transmitting said outputs to said single detector;
- and
- h) means for driving said phase modulators so that the outputs of said gyroscopes are distinguishable at said detector, said means including means for modulating said gyroscopes in accordance with three mutually out-of-phase modulation sequences, each of said modulation sequences comprising a measuring period and two blanking periods.
A triaxial fiber optic Sagnac interferometer for measuring rotation rates about three axes comprising, in combination;
- a) a source of optical energy;
- b) a first, a second and a third gyroscope for measuring rotation rates about a first, a second and a third axis respectively;
- c) each of said gyroscopes comprising a coil of optical fiber;
- d) means for launching said optical energy into each of said coils as counterpropagating waves;
- e) phase modulators located in each of said coils for artificially modulating the phase difference between said counterpropagating waves;
- f) a single detector for receiving the output of each of said gyroscopes;
- g) an optical network for receiving the output of said source, distributing said output to said gyroscopes, receiving the output of said gyroscopes and transmitting said outputs to said single detector;
- and
- h) means for driving said phase modulators with three mutually out-of-phase modulation sequences of common frequency so that the outputs of said gyroscopes are distinguishable at said detector.
Dependencies are inferred from the claim text.