System and method for enhancing signal-to-noise ratio of a resonator fiber optic gyroscope
First Claim
1. A fiber optic gyroscope comprising:
- a first laser source configured to produce a first laser beam having a first frequency;
a second laser source configured to produce a second laser beam having a second frequency;
a sensing resonator having a first input coupled to the first laser source and a second input coupled to the second laser source such that the first laser beam propagates through the sensing resonator in a first direction and the second laser beam propagates through the sensing resonator in a second direction;
first resonance tracking electronics (RTE) configured to generate a first control signal that indicates when the first laser beam is off resonance;
second resonance tracking electronics (RTE) configured to generate a second control signal that indicates when the second laser beam is off resonance;
a first intensity modulator coupled between a first output of the sensing resonator and an input of the first resonance tracking electronics, the first intensity modulator configured to modulate the intensity of a signal from the first output of the sensing resonator at a first intensity modulation frequency such that the first resonance tracking electronics is able to discriminate between the signal from the first output of the sensing resonator and electronic noise, wherein the first intensity modulation frequency is different from a resonance tracking modulation frequency of the first RTE; and
a second intensity modulator coupled between a second output of the sensing resonator and an input of the second resonance tracking electronics, the second intensity modulator configured to modulate the intensity of a signal from the second output of the sensing resonator at a second intensity modulation frequency such that the second resonance tracking electronics is able to discriminate between the signal from the second output of the sensing resonator and electronic noise, wherein the second intensity modulation frequency is different from a resonance tracking modulation frequency of the second RTE.
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Abstract
A resonator fiber optic gyroscope includes a sensing resonator having a first resonance frequency for a first laser beam propagation direction and a second resonance frequency for a second laser beam propagation direction; an intensity modulator coupled to an output of the sensing resonator and configured to modulate the intensity of a signal output from the sensing resonator, wherein the intensity modulator modulates the output signal at an intensity modulation frequency; and resonance tracking electronics coupled to an output of the intensity modulator and configured to demodulate the intensity modulated signal output from the intensity modulator at a resonance tracking modulation frequency to produce a first demodulated signal; the resonance tracking electronics further configured to demodulate the first demodulated signal at the intensity modulation frequency, wherein the intensity modulation frequency is different from the resonance tracking modulation frequency.
72 Citations
20 Claims
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1. A fiber optic gyroscope comprising:
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a first laser source configured to produce a first laser beam having a first frequency; a second laser source configured to produce a second laser beam having a second frequency; a sensing resonator having a first input coupled to the first laser source and a second input coupled to the second laser source such that the first laser beam propagates through the sensing resonator in a first direction and the second laser beam propagates through the sensing resonator in a second direction; first resonance tracking electronics (RTE) configured to generate a first control signal that indicates when the first laser beam is off resonance; second resonance tracking electronics (RTE) configured to generate a second control signal that indicates when the second laser beam is off resonance; a first intensity modulator coupled between a first output of the sensing resonator and an input of the first resonance tracking electronics, the first intensity modulator configured to modulate the intensity of a signal from the first output of the sensing resonator at a first intensity modulation frequency such that the first resonance tracking electronics is able to discriminate between the signal from the first output of the sensing resonator and electronic noise, wherein the first intensity modulation frequency is different from a resonance tracking modulation frequency of the first RTE; and a second intensity modulator coupled between a second output of the sensing resonator and an input of the second resonance tracking electronics, the second intensity modulator configured to modulate the intensity of a signal from the second output of the sensing resonator at a second intensity modulation frequency such that the second resonance tracking electronics is able to discriminate between the signal from the second output of the sensing resonator and electronic noise, wherein the second intensity modulation frequency is different from a resonance tracking modulation frequency of the second RTE. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system comprising:
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a resonator fiber optic gyroscope configured to measure rotation rate; and a processing unit coupled to the resonator fiber optic gyroscope and configured to perform calculations based on the rotation rate measured by the resonator fiber optic gyroscope; wherein the resonator fiber optic gyroscope includes; a sensing resonator having a first resonance frequency for a first laser beam propagation direction and a second resonance frequency for a second laser beam propagation direction; an intensity modulator coupled to an output of the sensing resonator and configured to modulate the intensity of a signal output from the sensing resonator, wherein the intensity modulator modulates the output signal at an intensity modulation frequency; and resonance tracking electronics coupled to an output of the intensity modulator and configured to demodulate the intensity modulated signal output from the intensity modulator at a resonance tracking modulation frequency to produce a first demodulated signal;
the resonance tracking electronics further configured to demodulate the first demodulated signal at the intensity modulation frequency, wherein the intensity modulation frequency is different from the resonance tracking modulation frequency. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of enhancing signal-to-noise ratio for measuring rotation rate in a resonator fiber optic gyroscope, the method comprising:
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modulating intensity of a signal output from a sensing resonator, wherein the intensity is modulated at an intensity modulation frequency that is different from a resonance tracking modulation frequency; demodulating the intensity modulated signal at the intensity modulation frequency and at the resonance tracking modulation frequency to produce a double demodulated signal; and generating a signal related to rotation rate based on the double demodulated signal. - View Dependent Claims (18, 19, 20)
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Specification