阅读说明：本技术 基于光学谐振腔游标效应的光学陀螺 (Optical gyroscope based on vernier effect of optical resonant cavity ) 是由 王金芳 刘瑞鑫 朱一 王妍 薛永强 于浩泽 陈上碧 李家韡 于 2020-04-03 设计创作，主要内容包括：本发明涉及基于光学谐振腔游标效应的光学陀螺,包含宽带光源、分束器、第一耦合器、第一环形波导、第二耦合器、第二环形波导、合束器、光谱仪、处理系统；本发明具有两个独立的光学谐振腔：第一耦合器、第一环形波导构成第一环形谐振腔,第二耦合器、第二环形波导构成第二环形谐振腔；利用两光学谐振腔的输出光的干涉所产生的光学游标效应,同时获得旋转速度大小和旋转速度方向。本发明体积小、结构简单、精度高,不包含相位调制器件及相关的电信号产生和处理系统,不对光信号进行相位调制就能分辨旋转速度方向。(The invention relates to an optical gyroscope based on optical resonant cavity vernier effect, which comprises a broadband light source, a beam splitter, a first coupler, a first annular waveguide, a second coupler, a second annular waveguide, a beam combiner, a spectrometer and a processing system, wherein the broadband light source is connected with the beam splitter; the invention has two independent optical resonant cavities: the first coupler and the first annular waveguide form a first annular resonant cavity, and the second coupler and the second annular waveguide form a second annular resonant cavity; and simultaneously obtaining the rotation speed and the rotation speed direction by utilizing the optical vernier effect generated by the interference of the output light of the two optical resonant cavities. The invention has small volume, simple structure and high precision, does not contain a phase modulation device and a related electric signal generating and processing system, and can distinguish the rotating speed direction without carrying out phase modulation on optical signals.)

1. An optical gyroscope based on vernier effect of an optical resonant cavity is characterized by comprising a broadband light source (1), a beam splitter (2), a first coupler (3), a first annular waveguide (4), a second coupler (5), a second annular waveguide (6), a beam combiner (7), a spectrometer (8) and a processing system (9);

the optical output end of the broadband light source (1) is connected with the optical input end of the beam splitter (2), and the first optical output end of the beam splitter (2) is connected with the first optical input end of the first coupler (3); a first optical output end and a second optical input end of the first coupler (3) are connected with the first annular waveguide (4), and a second optical output end of the first coupler (3) is connected with a first optical input end of the beam combiner (7); the second light output end of the beam splitter (2) is connected with the first light input end of the second coupler (5); a first optical output end and a second optical input end of the second coupler (5) are connected with the second annular waveguide (6), and a second optical output end of the second coupler (5) is connected with a second optical input end of the beam combiner (7); the optical output end of the beam combiner (7) is connected with the optical input end of the spectrometer (8), the electrical output end of the spectrometer (8) is connected with the electrical input end of the processing system (9), and the electrical output end of the processing system (9) outputs a gyro output signal;

the first coupler (3) and the first annular waveguide (4) form a first annular resonant cavity; the second coupler (5) and the second annular waveguide (6) form a second annular resonant cavity; the output light of the broadband light source (1) is divided into a first beam of light and a second beam of light after passing through the beam splitter (2), the first beam of light enters the first annular resonant cavity through the first coupler (3), enters the beam combiner (7) through the first coupler (3), and is output by the light output end of the beam combiner (7); the second beam of light enters the second ring-shaped resonant cavity through the second coupler (5), enters the beam combiner (7) through the second coupler (5) and is output by the light output end of the beam combiner (7), the first beam of light and the second beam of light meet and interfere at the light output end of the beam combiner (7), the interference light output by the beam combiner (7) enters the spectrometer (8), the spectrum of the interference light is collected by the spectrometer (8), the spectrum of the interference light is converted into a spectrum voltage signal, the spectrum voltage signal is input into the processing system (9), and a gyro output signal output by the processing system (9) comprises the rotating speed and the rotating direction.

2. Optical gyro based on the vernier effect of the optical cavity according to claim 1, characterized in that the coupling coefficient of the first coupler (3) is different from the coupling coefficient of the second coupler (5); the refractive index of the first annular waveguide (4) is the same as that of the second annular waveguide (6); the length of the first ring-shaped resonant cavity is different from that of the second ring-shaped resonant cavity;

the bandwidth of the broadband light source (1) is at least 10 times of the least common multiple of the free spectral width FSR1 of the first ring-shaped resonant cavity and the free spectral width FSR2 of the second ring-shaped resonant cavity;

the first coupler (3) and the second coupler (5) are both 2 x 2 couplers; the beam splitter (2) and the beam combiner (7) are both 1 multiplied by 2 couplers, and the coupling ratio is 50: 50.

3. Optical gyro based on vernier effect of the optical cavity according to claim 1 or 2,

the transmission spectrum of the first ring resonator is a first transmission valley of equal frequency spacing, the frequency spacing is the free spectral width FSR1 of the first ring resonator, and the minimum transmissivity of the first transmission valley is the transmissivity at the resonant frequency of the first ring resonator;

the transmission spectrum of the second ring resonator is a second transmission valley of equal frequency spacing, the frequency spacing being the free spectral width FSR2 of the second ring resonator, and the minimum transmittance of the second transmission valley is the transmittance at the resonant frequency of the second ring resonator; a minimum transmittance of the first transmission valley is different from a minimum transmittance of the second transmission valley;

the transmission direction of the first beam of light in the first ring-shaped resonant cavity is opposite to the transmission direction of the second beam of light in the second ring-shaped resonant cavity; when the gyroscope rotates, the first transmission valley and the second transmission valley move in opposite directions on the frequency axis.

4. The optical gyroscope of claim 3 based on vernier effect of optical resonator,

when the center frequency of the first transmission valley is different from the center frequency of the second transmission valley, the first transmission valley forms a third transmission valley in the spectrum of the interference light, and the second transmission valley forms a fourth transmission valley in the spectrum of the interference light; when the center frequency of the first transmission valley is the same as the center frequency of the second transmission valley, the first transmission valley and the second transmission valley together form a fifth transmission valley in the spectrum of the interference light;

a ratio of a minimum transmittance of the third transmission valley to a minimum transmittance of the fourth transmission valley is the same as a ratio of a minimum transmittance of the first transmission valley to a minimum transmittance of the second transmission valley;

if the minimum transmittance of the first transmission valley is greater than that of the second transmission valley, the minimum transmittance of the fifth transmission valley is the smallest and the minimum transmittance of the third transmission valley is the largest in the spectrum of the interference light; if the minimum transmittance of the first transmission valley is less than that of the second transmission valley, the minimum transmittance of the fifth transmission valley is the smallest and the minimum transmittance of the fourth transmission valley is the largest in the spectrum of the interference light.

5. The optical gyroscope of claim 4 based on vernier effect of optical resonator,

the spectrometer (8) collects the spectrum of the interference light, converts the spectrum of the interference light into a spectrum voltage signal and inputs the spectrum voltage signal into the processing system (9);

when the gyroscope is static, the processing system (9) acquires a first resonance frequency and takes the first resonance frequency as an origin;

when the gyroscope rotates, according to the free spectral width FSR1 of the first ring-shaped resonant cavity, the free spectral width FSR2 of the second ring-shaped resonant cavity, the transmission direction of the first beam of light in the first ring-shaped resonant cavity and the transmission direction of the second beam of light in the second ring-shaped resonant cavity, the processing system (9) obtains the moving direction of the second resonant frequency, the third transmission valley and the fourth transmission valley in the spectrum of the interference light, further obtains the frequency difference x at the second resonant frequency according to the reading method of the vernier caliper, and calculates the rotating speed by utilizing the proportional relation between the frequency difference x and the rotating speed; and, the rotation speed direction is determined according to the moving direction of the third transmission valley or the fourth transmission valley in the spectrum of the interference light.

6. The optical gyroscope of claim 5 based on vernier effect of optical resonator,

when the gyroscope is static, determining the center frequency of any one fifth transmission valley in the spectrum of the interference light, namely the first resonance frequency, and taking the first resonance frequency as an origin;

when the gyroscope rotates clockwise, the transmission direction of the first beam of light in the first annular resonant cavity is clockwise, and the transmission direction of the second beam of light in the second annular resonant cavity is anticlockwise, the fifth transmission valley is divided into a third transmission valley towards the low frequency direction and a fourth transmission valley towards the high frequency direction;

if the free spectral width FSR1 of the first ring resonator is larger than the free spectral width FSR2 of the second ring resonator, determining the center frequency of a fifth transmission valley closest to the origin in the high frequency direction as a second resonant frequency; taking the free spectral width FSR1 of the first ring-shaped resonant cavity as a ruler and the free spectral width FSR2 of the second ring-shaped resonant cavity as a vernier scale, and obtaining a frequency difference x at a second resonant frequency according to a reading method of a vernier caliper;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is smaller than the free spectral width FSR2 of the second ring-shaped resonant cavity, the center frequency of a fifth transmission valley closest to the origin is determined in the low-frequency direction and is called as a second resonant frequency, the free spectral width FSR2 of the second ring-shaped resonant cavity is used as a ruler, the free spectral width FSR1 of the first ring-shaped resonant cavity is used as a vernier scale, and the frequency difference x is obtained at the second resonant frequency according to the vernier-caliper reading method.

7. The optical gyroscope of claim 5 based on vernier effect of optical resonator,

when the gyroscope is static, determining the center frequency of any one fifth transmission valley in the spectrum of the interference light, namely the first resonance frequency, and taking the first resonance frequency as an origin;

when the gyroscope rotates clockwise, the transmission direction of the first beam of light in the first annular resonant cavity is anticlockwise, and the transmission direction of the second beam of light in the second annular resonant cavity is clockwise, the fifth transmission valley is divided into a third transmission valley moving towards the high-frequency direction and a fourth transmission valley moving towards the low-frequency direction;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is larger than the free spectral width FSR2 of the second ring-shaped resonant cavity, determining the center frequency of a fifth transmission valley closest to the origin in the low-frequency direction to be called as second resonant frequency, taking the free spectral width FSR1 of the first ring-shaped resonant cavity as a ruler and the free spectral width FSR2 of the second ring-shaped resonant cavity as a vernier scale, and obtaining a frequency difference x at the second resonant frequency according to a vernier caliper reading method;

if the free spectral width FSR1 of the first ring resonator is smaller than the free spectral width FSR2 of the second ring resonator, the center frequency of a fifth transmission valley closest to the origin is determined in the high-frequency direction to be called a second resonant frequency, the free spectral width FSR2 of the second ring resonator is used as a ruler, the free spectral width FSR1 of the first ring resonator is used as a vernier, and the frequency difference x is obtained at the second resonant frequency according to the vernier caliper reading method.

8. The optical gyroscope of claim 5 based on vernier effect of optical resonator,

when the gyroscope is static, determining the center frequency of any one fifth transmission valley in the spectrum of the interference light, namely the first resonance frequency, and taking the first resonance frequency as an origin;

when the gyroscope rotates anticlockwise, the transmission direction of the first beam of light in the first annular resonant cavity is clockwise, and the transmission direction of the second beam of light in the second annular resonant cavity is anticlockwise, the fifth transmission valley is divided into a third transmission valley moving towards a high-frequency direction and a fourth transmission valley moving towards a low-frequency direction;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is larger than the free spectral width FSR2 of the second ring-shaped resonant cavity, determining the center frequency of a fifth transmission valley closest to the origin in the low-frequency direction to be called as second resonant frequency, taking the free spectral width FSR1 of the first ring-shaped resonant cavity as a ruler and the free spectral width FSR2 of the second ring-shaped resonant cavity as a vernier scale, and obtaining a frequency difference x at the second resonant frequency according to a vernier caliper reading method;

if the free spectral width FSR1 of the first ring resonator is smaller than the free spectral width FSR2 of the second ring resonator, the center frequency of a fifth transmission valley closest to the origin is determined in the high-frequency direction to be called a second resonant frequency, the free spectral width FSR2 of the second ring resonator is used as a ruler, the free spectral width FSR1 of the first ring resonator is used as a vernier, and the frequency difference x is obtained at the second resonant frequency according to the vernier caliper reading method.

9. The optical gyroscope of claim 5 based on vernier effect of optical resonator,

when the gyroscope is static, determining the center frequency of any one fifth transmission valley in the spectrum of the interference light, namely the first resonance frequency, and taking the first resonance frequency as an origin;

when the gyroscope rotates anticlockwise, the transmission direction of the first beam of light in the first annular resonant cavity is anticlockwise, and the transmission direction of the second beam of light in the second annular resonant cavity is clockwise, the fifth transmission valley is divided into a third transmission valley moving towards the low-frequency direction and a fourth transmission valley moving towards the high-frequency direction;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is larger than the free spectral width FSR2 of the second ring-shaped resonant cavity, determining the center frequency of a fifth transmission valley closest to the origin in the high-frequency direction to be called as second resonant frequency, taking the free spectral width FSR1 of the first ring-shaped resonant cavity as a ruler and the free spectral width FSR2 of the second ring-shaped resonant cavity as a vernier scale, and obtaining a frequency difference x at the second resonant frequency according to a vernier caliper reading method;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is smaller than the free spectral width FSR2 of the second ring-shaped resonant cavity, the center frequency of a fifth transmission valley closest to the origin is determined in the low-frequency direction and is called as a second resonant frequency, the free spectral width FSR2 of the second ring-shaped resonant cavity is used as a ruler, the free spectral width FSR1 of the first ring-shaped resonant cavity is used as a vernier scale, and the frequency difference x is obtained at the second resonant frequency according to the vernier-caliper reading method.

10. The optical gyroscope based on the vernier effect of the optical resonator according to any of claims 5 to 9, wherein the processing system (9) further comprises a sampling circuit (9-1), a contrast analysis circuit (9-2), and an output circuit (9-3);

the electrical input end of the sampling circuit (9-1) is the electrical input end of the processing system (9), and the electrical output end of the output circuit (9-3) is the electrical output end of the processing system (9); the electric output end of the spectrometer (8) is connected with the electric input end of the sampling circuit (9-1), the electric output end of the sampling circuit (9-1) is connected with the electric input end of the contrast analysis circuit (9-2), the electric output end of the contrast analysis circuit (9-2) is connected with the electric input end of the output circuit (9-3), and the electric output end of the output circuit (9-3) outputs a gyro output signal;

the sampling circuit (9-1) receives the spectrum voltage signal output by the spectrometer (8) and sends the spectrum voltage signal to the contrast analysis circuit (9-2); when the gyroscope is static, the contrast analysis circuit (9-2) records a first resonance frequency and takes the first resonance frequency as an origin; when the gyroscope rotates, a comparative analysis circuit (9-2) records the moving direction of a second resonance frequency, a third transmission valley and a fourth transmission valley on a frequency axis, obtains a frequency difference x at the second resonance frequency according to a reading method of a vernier caliper, calculates the rotating speed according to the frequency difference x, and determines the rotating speed direction according to the moving direction of the third transmission valley or the fourth transmission valley on the frequency axis; the comparison analysis circuit (9-2) sends the information of the rotation speed and the rotation speed direction to the output circuit (9-3), and the output circuit (9-3) outputs a gyro output signal containing the rotation speed and the rotation speed direction.

Technical Field

The invention relates to the technical field of optical gyroscopes, in particular to an optical gyroscope based on optical resonant cavity vernier effect.

Background

The optical gyro and the electromechanical gyro have different working principles, mechanical noise generated by a mechanical rotor in the electromechanical gyro and electrical noise generated by a signal device are avoided, the noise of the optical gyro is usually only at a quantum effect level, relatively speaking, the measurement threshold value of the optical gyro is generally higher than that of the electromechanical gyro, but the long-term stability of the optical gyro is superior to that of the electromechanical gyro, and the optical gyro also has the advantages of quick start, long service life, low power consumption, small volume and the like. The working principle of the optical gyroscope is based on the Sagnac effect, in the transmission process of light waves, an extra phase can be generated due to the rotation relative to an inertia space, if in a closed light path with any geometrical shape, a pair of light waves emitted from a certain observation point are transmitted in opposite directions and then return to the observation point, the phases of the pair of light waves are different due to the rotation of the closed light path relative to the inertia space, and the phase difference of the pair of light waves is in direct proportion to the rotation speed of the light path.

At present, a conventional resonant optical gyroscope employs an optical resonant cavity, when the gyroscope rotates, the resonant frequency of the optical wave in the optical resonant cavity changes with the rotation speed, and for two optical waves transmitted in opposite directions in the optical resonant cavity, the transmission directions of the two optical waves are opposite, wherein the transmission direction of one optical wave is the same as the rotation speed direction, and the transmission direction of the other optical wave is opposite to the rotation speed direction, so that the resonant frequencies of the two optical waves transmitted in opposite directions are different, and the difference between the two resonant frequencies is proportional to the rotation speed, so that the rotation speed can be measured by detecting the resonant frequency difference between the two optical waves transmitted in opposite directions.

However, for a traditional resonant optical gyroscope, only one optical resonant cavity is provided, and the resonance spectrum of light waves is wide, so that the precision of the gyroscope is difficult to further improve; on the other hand, two light waves transmitted in opposite directions in the gyroscope are resonated in the same optical resonant cavity, and the resonant spectrums of the two light waves are the same and cannot be distinguished, so that the rotation speed direction is difficult to distinguish, and the rotation speed direction can be distinguished only by adding optical devices such as a phase modulator and a complex signal processing system.

Disclosure of Invention

Based on the defects, the invention provides the optical gyroscope based on the vernier effect of the optical resonant cavity, which overcomes the problems of large volume, complex structure, low precision and the like of the conventional optical gyroscope, and particularly overcomes the problem that the rotating speed direction is difficult to distinguish.

In order to achieve the above object, the technical solution of the present invention is to provide an optical gyroscope based on vernier effect of optical resonator, which comprises a broadband light source, a beam splitter, a first coupler, a first annular waveguide, a second coupler, a second annular waveguide, a beam combiner, a spectrometer, and a processing system;

the optical output end of the broadband light source is connected with the optical input end of the beam splitter, and the first optical output end of the beam splitter is connected with the first optical input end of the first coupler; a first optical output end and a second optical input end of the first coupler are connected with the first annular waveguide, and a second optical output end of the first coupler is connected with a first optical input end of the beam combiner; the second light output end of the beam splitter is connected with the first light input end of the second coupler; a first optical output end and a second optical input end of the second coupler are connected with the second annular waveguide, and a second optical output end of the second coupler is connected with a second optical input end of the beam combiner; the optical output end of the beam combiner is connected with the optical input end of the spectrometer, the electrical output end of the spectrometer is connected with the electrical input end of the processing system, and the electrical output end of the processing system outputs a gyroscope output signal;

the first coupler and the first annular waveguide form a first annular resonant cavity; the second coupler and the second annular waveguide form a second annular resonant cavity; the output light of the broadband light source is divided into a first beam of light and a second beam of light after passing through the beam splitter, the first beam of light enters the first annular resonant cavity through the first coupler, enters the beam combiner through the first coupler and is output by the light output end of the beam combiner; the second beam of light enters the second ring-shaped resonant cavity through the second coupler and then enters the beam combiner through the second coupler, the second beam of light is output by the light output end of the beam combiner, the first beam of light and the second beam of light meet at the light output end of the beam combiner and interfere with each other, the interference light output by the beam combiner enters the spectrometer, the spectrum of the interference light is collected by the spectrometer, the spectrum of the interference light is converted into a spectrum voltage signal, the spectrum voltage signal is input into the processing system, and a gyroscope output signal output by the processing system comprises the rotation speed and the rotation direction.

Optionally, the coupling coefficient of the first coupler is different from the coupling coefficient of the second coupler.

Optionally, the refractive index of the first annular waveguide is the same as the refractive index of the second annular waveguide.

Optionally, the length of the first ring resonator is different from the length of the second ring resonator.

Optionally, the bandwidth of the broadband light source is at least 10 times the least common multiple of the free spectral width FSR1 of the first ring resonator and the free spectral width FSR2 of the second ring resonator.

Optionally, the first coupler and the second coupler are both 2 × 2 couplers; the beam splitter and the beam combiner are both 1 × 2 couplers, and the coupling ratio is 50: 50.

Optionally, the transmission spectrum of the first ring resonator is a first transmission valley of equal frequency spacing, the frequency spacing is a free spectral width FSR1 of the first ring resonator, and the minimum transmittance of the first transmission valley is the transmittance at the resonant frequency of the first ring resonator;

the transmission spectrum of the second ring resonator is a second transmission valley of equal frequency spacing, the frequency spacing being the free spectral width FSR2 of the second ring resonator, and the minimum transmittance of the second transmission valley is the transmittance at the resonant frequency of the second ring resonator; a minimum transmittance of the first transmission valley is different from a minimum transmittance of the second transmission valley;

the transmission direction of the first beam of light in the first ring-shaped resonant cavity is opposite to the transmission direction of the second beam of light in the second ring-shaped resonant cavity; when the gyroscope rotates, the first transmission valley and the second transmission valley move in opposite directions on the frequency axis.

Optionally, when a center frequency of the first transmission valley is different from a center frequency of the second transmission valley, the first transmission valley forms a third transmission valley in the spectrum of the interference light, and the second transmission valley forms a fourth transmission valley in the spectrum of the interference light; when the center frequency of the first transmission valley is the same as the center frequency of the second transmission valley, the first transmission valley and the second transmission valley together form a fifth transmission valley in the spectrum of the interference light;

a ratio of a minimum transmittance of the third transmission valley to a minimum transmittance of the fourth transmission valley is the same as a ratio of a minimum transmittance of the first transmission valley to a minimum transmittance of the second transmission valley;

if the minimum transmittance of the first transmission valley is greater than that of the second transmission valley, the minimum transmittance of the fifth transmission valley is the smallest and the minimum transmittance of the third transmission valley is the largest in the spectrum of the interference light; if the minimum transmittance of the first transmission valley is less than that of the second transmission valley, the minimum transmittance of the fifth transmission valley is the smallest and the minimum transmittance of the fourth transmission valley is the largest in the spectrum of the interference light.

Optionally, the spectrometer collects the spectrum of the interference light, converts the spectrum of the interference light into a spectrum voltage signal and inputs the spectrum voltage signal into the processing system;

when the gyroscope is static, the processing system acquires a first resonant frequency and takes the first resonant frequency as an origin;

when the gyroscope rotates, according to the free spectral width FSR1 of the first ring-shaped resonant cavity, the free spectral width FSR2 of the second ring-shaped resonant cavity, the transmission direction of the first beam of light in the first ring-shaped resonant cavity and the transmission direction of the second beam of light in the second ring-shaped resonant cavity, the processing system obtains the moving direction of the second resonant frequency, the third transmission valley and the fourth transmission valley in the spectrum of the interference light, further obtains the frequency difference x at the second resonant frequency according to the reading method of the vernier caliper, and calculates the rotating speed by utilizing the proportional relation between the frequency difference x and the rotating speed; and, the rotation speed direction is determined according to the moving direction of the third transmission valley or the fourth transmission valley in the spectrum of the interference light.

Optionally, when the gyroscope is static, determining the center frequency of any one fifth transmission valley in the spectrum of the interference light, namely the first resonance frequency, and taking the first resonance frequency as an origin;

when the gyroscope rotates clockwise, the transmission direction of the first beam of light in the first annular resonant cavity is clockwise, and the transmission direction of the second beam of light in the second annular resonant cavity is anticlockwise, the fifth transmission valley is divided into a third transmission valley towards the low frequency direction and a fourth transmission valley towards the high frequency direction;

if the free spectral width FSR1 of the first ring resonator is larger than the free spectral width FSR2 of the second ring resonator, determining the center frequency of a fifth transmission valley closest to the origin in the high frequency direction as a second resonant frequency; taking the free spectral width FSR1 of the first ring-shaped resonant cavity as a ruler and the free spectral width FSR2 of the second ring-shaped resonant cavity as a vernier scale, and obtaining a frequency difference x at a second resonant frequency according to a reading method of a vernier caliper;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is smaller than the free spectral width FSR2 of the second ring-shaped resonant cavity, the center frequency of a fifth transmission valley closest to the origin is determined in the low-frequency direction and is called as a second resonant frequency, the free spectral width FSR2 of the second ring-shaped resonant cavity is used as a ruler, the free spectral width FSR1 of the first ring-shaped resonant cavity is used as a vernier scale, and the frequency difference x is obtained at the second resonant frequency according to the vernier-caliper reading method.

Optionally, when the gyroscope is static, determining the center frequency of any one fifth transmission valley in the spectrum of the interference light, namely the first resonance frequency, and taking the first resonance frequency as an origin;

when the gyroscope rotates clockwise, the transmission direction of the first beam of light in the first annular resonant cavity is anticlockwise, and the transmission direction of the second beam of light in the second annular resonant cavity is clockwise, the fifth transmission valley is divided into a third transmission valley moving towards the high-frequency direction and a fourth transmission valley moving towards the low-frequency direction;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is larger than the free spectral width FSR2 of the second ring-shaped resonant cavity, determining the center frequency of a fifth transmission valley closest to the origin in the low-frequency direction to be called as second resonant frequency, taking the free spectral width FSR1 of the first ring-shaped resonant cavity as a ruler and the free spectral width FSR2 of the second ring-shaped resonant cavity as a vernier scale, and obtaining a frequency difference x at the second resonant frequency according to a vernier caliper reading method;

if the free spectral width FSR1 of the first ring resonator is smaller than the free spectral width FSR2 of the second ring resonator, the center frequency of a fifth transmission valley closest to the origin is determined in the high-frequency direction to be called a second resonant frequency, the free spectral width FSR2 of the second ring resonator is used as a ruler, the free spectral width FSR1 of the first ring resonator is used as a vernier, and the frequency difference x is obtained at the second resonant frequency according to the vernier caliper reading method.

Optionally, when the gyroscope is static, determining the center frequency of any one fifth transmission valley in the spectrum of the interference light, namely the first resonance frequency, and taking the first resonance frequency as an origin;

when the gyroscope rotates anticlockwise, the transmission direction of the first beam of light in the first annular resonant cavity is clockwise, and the transmission direction of the second beam of light in the second annular resonant cavity is anticlockwise, the fifth transmission valley is divided into a third transmission valley moving towards a high-frequency direction and a fourth transmission valley moving towards a low-frequency direction;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is larger than the free spectral width FSR2 of the second ring-shaped resonant cavity, determining the center frequency of a fifth transmission valley closest to the origin in the low-frequency direction to be called as second resonant frequency, taking the free spectral width FSR1 of the first ring-shaped resonant cavity as a ruler and the free spectral width FSR2 of the second ring-shaped resonant cavity as a vernier scale, and obtaining a frequency difference x at the second resonant frequency according to a vernier caliper reading method;

if the free spectral width FSR1 of the first ring resonator is smaller than the free spectral width FSR2 of the second ring resonator, the center frequency of a fifth transmission valley closest to the origin is determined in the high-frequency direction to be called a second resonant frequency, the free spectral width FSR2 of the second ring resonator is used as a ruler, the free spectral width FSR1 of the first ring resonator is used as a vernier, and the frequency difference x is obtained at the second resonant frequency according to the vernier caliper reading method.

Optionally, when the gyroscope is static, determining the center frequency of any one fifth transmission valley in the spectrum of the interference light, namely the first resonance frequency, and taking the first resonance frequency as an origin;

when the gyroscope rotates anticlockwise, the transmission direction of the first beam of light in the first annular resonant cavity is anticlockwise, and the transmission direction of the second beam of light in the second annular resonant cavity is clockwise, the fifth transmission valley is divided into a third transmission valley moving towards the low-frequency direction and a fourth transmission valley moving towards the high-frequency direction;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is larger than the free spectral width FSR2 of the second ring-shaped resonant cavity, determining the center frequency of a fifth transmission valley closest to the origin in the high-frequency direction to be called as second resonant frequency, taking the free spectral width FSR1 of the first ring-shaped resonant cavity as a ruler and the free spectral width FSR2 of the second ring-shaped resonant cavity as a vernier scale, and obtaining a frequency difference x at the second resonant frequency according to a vernier caliper reading method;

if the free spectral width FSR1 of the first ring-shaped resonant cavity is smaller than the free spectral width FSR2 of the second ring-shaped resonant cavity, the center frequency of a fifth transmission valley closest to the origin is determined in the low-frequency direction and is called as a second resonant frequency, the free spectral width FSR2 of the second ring-shaped resonant cavity is used as a ruler, the free spectral width FSR1 of the first ring-shaped resonant cavity is used as a vernier scale, and the frequency difference x is obtained at the second resonant frequency according to the vernier-caliper reading method.

Optionally, the processing system further comprises a sampling circuit, a contrast analysis circuit, and an output circuit; the electrical input end of the sampling circuit is the electrical input end of the processing system, and the electrical output end of the output circuit is the electrical output end of the processing system; the electric output end of the spectrometer is connected with the electric input end of the sampling circuit, the electric output end of the sampling circuit is connected with the electric input end of the comparison and analysis circuit, the electric output end of the comparison and analysis circuit is connected with the electric input end of the output circuit, and the electric output end of the output circuit outputs a gyro output signal;

the sampling circuit receives the spectrum voltage signal output by the spectrometer and sends the spectrum voltage signal to the contrast analysis circuit; when the gyroscope is static, the contrast analysis circuit records a first resonant frequency and takes the first resonant frequency as an origin; when the gyroscope rotates, the comparative analysis circuit records the moving direction of a second resonance frequency, a third transmission valley and a fourth transmission valley on the frequency axis, obtains a frequency difference x at the second resonance frequency according to a reading method of a vernier caliper, calculates the rotating speed according to the frequency difference x, and determines the rotating speed direction according to the moving direction of the third transmission valley or the fourth transmission valley on the frequency axis; the comparison and analysis circuit sends the information of the rotation speed and the rotation speed direction to the output circuit, and the output circuit outputs a gyro output signal containing the rotation speed and the rotation speed direction.

The optical gyroscope based on the vernier effect of the optical resonant cavity comprises two independent optical resonant cavities, and the rotation speed direction are obtained simultaneously by utilizing the vernier effect generated by the interference of the output light of the two optical resonant cavities, so that the gyroscope has the advantages of small volume, simple structure and high precision, does not comprise a phase modulation device and a related electric signal generating and processing system, and can distinguish the rotation speed direction without carrying out phase modulation on optical signals.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

fig. 2 is a schematic circuit diagram of the processing system of fig. 1.

Detailed Description

The embodiment of the present invention will be described with reference to fig. 1 and 2. The optical gyroscope based on the vernier effect of the optical resonant cavity comprises a broadband light source 1, a beam splitter 2, a first coupler 3, a first annular waveguide 4, a second coupler 5, a second annular waveguide 6, a beam combiner 7, a spectrometer 8 and a processing system 9.

The optical output end of the broadband light source 1 is connected with the optical input end of the beam splitter 2, and the first optical output end of the beam splitter 2 is connected with the first optical input end of the first coupler 3; a first optical output end and a second optical input end of the first coupler 3 are connected with the first annular waveguide 4, and a second optical output end of the first coupler 3 is connected with a first optical input end of the beam combiner 7; the second optical output end of the beam splitter 2 is connected with the first optical input end of the second coupler 5; a first optical output end and a second optical input end of the second coupler 5 are connected with the second annular waveguide 6, and a second optical output end of the second coupler 5 is connected with a second optical input end of the beam combiner 7; the optical output end of the beam combiner 7 is connected with the optical input end of the spectrometer 8, the electrical output end of the spectrometer 8 is connected with the electrical input end of the processing system 9, and the electrical output end of the processing system 9 outputs a gyro output signal.

The first coupler 3 and the first annular waveguide 4 form a first annular resonant cavity; and the second coupler 5 and the second ring waveguide 6 form a second ring resonant cavity.

The coupling coefficient of the first coupler 3 is different from the coupling coefficient of the second coupler 5.

The refractive index of the first annular waveguide 4 is the same as the refractive index of the second annular waveguide 6.

The length of the first ring resonator is different from the length of the second ring resonator.

The transmission direction of the light wave in the first ring resonator is opposite to the transmission direction of the light wave in the second ring resonator, for example, if the transmission direction of the light wave in the first ring resonator is counterclockwise, the transmission direction of the light wave in the second ring resonator is clockwise.

The bandwidth of the broadband light source 1 is at least 10 times of the least common multiple of the free spectral width of the first ring-shaped resonant cavity and the free spectral width of the second ring-shaped resonant cavity.

The first coupler 3 and the second coupler 5 are both 2 × 2 couplers.

The beam splitter 2 and the beam combiner 7 are both 1 × 2 couplers, and the coupling ratio is 50: 50.

The working principle of the optical gyroscope is as follows:

the output light of the broadband light source 1 is divided into two beams of light after passing through the beam splitter 2, the two beams of light are called a first beam of light and a second beam of light, the first beam of light enters the first annular resonant cavity through the first coupler 3, enters the beam combiner 7 through the first coupler 3 and is output by the light output end of the beam combiner 7; the second beam of light enters the second ring resonator through the second coupler 5, enters the beam combiner 7 through the second coupler 5, and is output by the light output end of the beam combiner 7, the first beam of light and the second beam of light meet and interfere at the light output end of the beam combiner 7, so as to generate interference light, the interference light output by the beam combiner 7 enters the spectrometer 8, the spectrometer 8 collects the spectrum of the interference light, converts the spectrum of the interference light into a spectrum voltage signal, and inputs the spectrum voltage signal into the processing system 9.

The first coupler 3 and the first annular waveguide 4 form a first annular resonant cavity; when light enters the first ring-shaped resonant cavity, if the condition that the product of the length of the first ring-shaped resonant cavity and the refractive index of the first ring-shaped waveguide 4 is integral multiple of optical wavelengths is met, the optical wavelengths are called the resonant wavelength of the first ring-shaped resonant cavity; the light frequency corresponding to the resonant wavelength of the first ring resonator is called the resonant frequency of the first ring resonator, the frequency interval of any two adjacent resonant frequencies of the first ring resonator is equal, the frequency interval is called the free spectral width FSR1 of the first ring resonator, the light with the light frequency being the resonant frequency of the first ring resonator can resonate in the first ring resonator, the transmittance of the light is the minimum at the time of resonance, and the transmittance of the light at the time of resonance is determined by the coupling coefficient of the first coupler 3.

The second coupler 5 and the second annular waveguide 6 form a second annular resonant cavity; when light enters the second ring resonator, if the product of the length of the second ring resonator and the refractive index of the second ring waveguide 6 is an integral multiple of the wavelength of the light, the wavelengths of the light are called the resonant wavelength of the second ring resonator; the light frequency corresponding to the resonance wavelength of the second ring resonator is referred to as the resonance frequency of the second ring resonator, the frequency intervals of any two adjacent resonance frequencies of the second ring resonator are equal, the frequency intervals are referred to as the free spectrum width FSR2 of the second ring resonator, the light with the light frequency of the resonance frequency of the second ring resonator can resonate in the second ring resonator, the transmittance of the light at the time of resonance is minimum, and the transmittance of the light at the time of resonance is determined by the coupling coefficient of the second coupler 5.

Since the coupling coefficient of the first coupler 3 is different from that of the second coupler 5, the transmittance at the resonance frequency of the first ring resonator is different from that of the second ring resonator.

Since the refractive index of the first ring waveguide 4 is the same as that of the second ring waveguide 6 and the length of the first ring cavity is different from that of the second ring cavity, the free spectral width FSR1 of the first ring cavity is different from the free spectral width FSR2 of the second ring cavity.

Since the bandwidth of the broadband light source 1 is at least 10 times the least common multiple of the free spectral width FSR1 of the first ring resonator and the free spectral width FSR2 of the second ring resonator, the output light of the broadband light source 1 contains a large number of resonant frequencies of the first ring resonator, as well as the resonant frequency of the second ring resonator.

After the first beam of light output by the broadband light source 1 is output through the first ring resonator, since the light frequency is the minimum light transmittance of the resonant frequency of the first ring resonator, the transmission spectrum of the first ring resonator is a first transmission valley with equal frequency interval, the frequency interval is the free spectrum width FSR1 of the first ring resonator, and the minimum transmittance of the first transmission valley is the transmittance at the resonant frequency of the first ring resonator.

After the second beam of light output by the broadband light source 1 is output through the second ring resonator, since the light transmittance is the minimum of the resonant frequency of the second ring resonator, the transmission spectrum of the second ring resonator is a second transmission valley with an equal frequency interval, the frequency interval is the free spectrum width FSR2 of the second ring resonator, and the minimum transmittance of the second transmission valley is the transmittance at the resonant frequency of the second ring resonator.

Since the coupling coefficient of the first coupler 3 is different from that of the second coupler 5, the transmittance at the resonance frequency of the first ring resonator is different from that of the second ring resonator, and therefore the minimum transmittance of the first transmission valley is also different from that of the second transmission valley.

The first light and the second light meet and interfere at the light output end of the beam combiner 7 to generate interference light, a spectrum of the interference light being generated by interference between the transmission spectrum of the first ring resonator and the transmission spectrum of the second ring resonator, and therefore, the spectrum of the interference light includes both a transmission valley caused by the first transmission valley in the transmission spectrum of the first ring resonator and a transmission valley caused by the second transmission valley in the transmission spectrum of the second ring resonator, so that three transmission valleys are formed in the spectrum of the interference light, which are a third transmission valley, a fourth transmission valley, and a fifth transmission valley, respectively, when a center frequency of the first transmission valley is different from a center frequency of the second transmission valley, the first transmission valley forms a third transmission valley in the spectrum of the interference light, the second transmission valley forms a fourth transmission valley in the spectrum of the interference light, and when the center frequency of the first transmission valley is the same as the center frequency of the second transmission valley, the first and second transmission valleys together form a fifth transmission valley in the spectrum of the interference light.

Since the beam splitter 2 and the beam combiner 7 are both 1 × 2 couplers and the coupling ratio is 50:50, the ratio of the minimum transmittance of the third transmission valley to the minimum transmittance of the fourth transmission valley is the same as the ratio of the minimum transmittance of the first transmission valley to the minimum transmittance of the second transmission valley; since the minimum transmittance of the first transmission valley is different from that of the second transmission valley, the third transmission valley may be distinguished from the fourth transmission valley by the minimum transmittance of the third transmission valley and the minimum transmittance of the fourth transmission valley; since the first and second transmission valleys together form a fifth transmission valley in the spectrum of the interference light, the minimum transmittance of the fifth transmission valley is minimum compared to the third and fourth transmission valleys.

Thus, the third, fourth, and fifth transmission valleys in the spectrum of the interference light are distinguishable; if the minimum transmittance of the first transmission valley is greater than that of the second transmission valley, the minimum transmittance of the fifth transmission valley is the smallest and the minimum transmittance of the third transmission valley is the largest in the spectrum of the interference light; if the minimum transmittance of the first transmission valley is less than that of the second transmission valley, the minimum transmittance of the fifth transmission valley is the smallest and the minimum transmittance of the fourth transmission valley is the largest in the spectrum of the interference light.

The rotating speed can change the resonant frequency of the ring resonator, the variation of the resonant frequency is in direct proportion to the rotating speed, the rotating speed direction determines that the resonant frequency moves towards the high-frequency direction or the low-frequency direction, and the transmission direction of the first beam of light in the first ring resonator is opposite to the transmission direction of the second beam of light in the second ring resonator, so that the moving directions of the first transmission valley and the second transmission valley on the frequency axis are opposite when the gyroscope rotates.

When the gyro is stationary, the center frequency of any one of the fifth transmission valleys is determined in the spectrum of the interference light, and this center frequency is referred to as a first resonance frequency, and the first resonance frequency is taken as the origin.

(1) When the gyroscope rotates clockwise, if the transmission direction of the first beam of light in the first ring-shaped resonant cavity is clockwise and the transmission direction of the second beam of light in the second ring-shaped resonant cavity is counterclockwise, at this time, the fifth transmission valley is split into a third transmission valley and a fourth transmission valley, the third transmission valley moves towards the low-frequency direction, and the fourth transmission valley moves towards the high-frequency direction; if the FSR1 is larger than the FSR2, determining the center frequency of a fifth transmission valley closest to the origin in the high-frequency direction, wherein the center frequency is called as a second resonance frequency, taking the FSR1 as a ruler and the FSR2 as a vernier caliper, and obtaining a frequency difference x at the second resonance frequency according to the reading method of the vernier caliper; if FSR1 is less than FSR2, the center frequency of the fifth transmission valley closest to the origin is determined in the low frequency direction, this center frequency is called the second resonance frequency, and the frequency difference x is obtained at the second resonance frequency according to the vernier caliper reading method, using FSR2 as a scale and FSR1 as a vernier caliper.

(2) When the gyroscope rotates clockwise, if the transmission direction of the first beam of light in the first ring-shaped resonant cavity is anticlockwise and the transmission direction of the second beam of light in the second ring-shaped resonant cavity is clockwise, at the moment, the fifth transmission valley is split into a third transmission valley and a fourth transmission valley, the third transmission valley moves towards the high-frequency direction, and the fourth transmission valley moves towards the low-frequency direction; if the FSR1 is larger than the FSR2, determining the center frequency of a fifth transmission valley closest to the origin in the low-frequency direction, wherein the center frequency is called as a second resonance frequency, taking the FSR1 as a ruler and the FSR2 as a vernier caliper, and obtaining a frequency difference x at the second resonance frequency according to the reading method of the vernier caliper; if FSR1 is less than FSR2, the center frequency of the fifth transmission valley closest to the origin is determined in the high frequency direction, this center frequency is called the second resonance frequency, and the frequency difference x is obtained at the second resonance frequency according to the vernier caliper reading method, using FSR2 as a scale and FSR1 as a vernier caliper.

(3) When the gyroscope rotates anticlockwise, if the transmission direction of the first beam of light in the first annular resonant cavity is clockwise and the transmission direction of the second beam of light in the second annular resonant cavity is anticlockwise, at the moment, the fifth transmission valley is split into a third transmission valley and a fourth transmission valley, the third transmission valley moves towards a high-frequency direction, and the fourth transmission valley moves towards a low-frequency direction; if the FSR1 is larger than the FSR2, determining the center frequency of a fifth transmission valley closest to the origin in the low-frequency direction, wherein the center frequency is called as a second resonance frequency, taking the FSR1 as a ruler and the FSR2 as a vernier caliper, and obtaining a frequency difference x at the second resonance frequency according to the reading method of the vernier caliper; if FSR1 is less than FSR2, the center frequency of the fifth transmission valley closest to the origin is determined in the high frequency direction, this center frequency is called the second resonance frequency, and the frequency difference x is obtained at the second resonance frequency according to the vernier caliper reading method, using FSR2 as a scale and FSR1 as a vernier caliper.

(4) When the gyroscope rotates anticlockwise, if the transmission direction of the first beam of light in the first annular resonant cavity is anticlockwise and the transmission direction of the second beam of light in the second annular resonant cavity is clockwise, at the moment, the fifth transmission valley is split into a third transmission valley and a fourth transmission valley, the third transmission valley moves towards the low-frequency direction, and the fourth transmission valley moves towards the high-frequency direction; if the FSR1 is larger than the FSR2, determining the center frequency of a fifth transmission valley closest to the origin in the high-frequency direction, wherein the center frequency is called as a second resonance frequency, taking the FSR1 as a ruler and the FSR2 as a vernier caliper, and obtaining a frequency difference x at the second resonance frequency according to the reading method of the vernier caliper; if FSR1 is less than FSR2, the center frequency of the fifth transmission valley closest to the origin is determined in the low frequency direction, this center frequency is called the second resonance frequency, and the frequency difference x is obtained at the second resonance frequency according to the vernier caliper reading method, using FSR2 as a scale and FSR1 as a vernier caliper.

Since the FSR1, the FSR2, the direction of the first beam of light traveling in the first ring resonator, and the direction of the second beam of light traveling in the second ring resonator are known, and the frequency difference x is proportional to the magnitude of the rotation speed, the magnitude of the rotation speed can be calculated from the frequency difference x, and the direction of the rotation speed can be determined from the direction of the third transmission valley or the fourth transmission valley moving in the spectrum of the interfering light.

The spectrometer 8 collects the spectrum of the interference light, converts the spectrum of the interference light into a spectrum voltage signal, inputs the spectrum voltage signal into the processing system 9, the processing system 9 obtains a first resonant frequency, namely, an origin, a second resonant frequency, a moving direction of a third transmission valley and a fourth transmission valley on a frequency axis, reads a frequency difference x, obtains a rotating speed by the frequency difference x, obtains a rotating speed direction by the moving direction of the third transmission valley or the fourth transmission valley on the frequency axis, and finally, the processing system 9 outputs a gyro output signal, wherein the gyro output signal comprises the rotating speed and the rotating speed direction.

As shown in FIG. 2, the processing system 9 according to the present invention includes a sampling circuit 9-1, a contrast analyzing circuit 9-2, and an output circuit 9-3. The electrical input end of the sampling circuit 9-1 is the electrical input end of the processing system 9, and the electrical output end of the output circuit 9-3 is the electrical output end of the processing system 9; the electric output end of the spectrometer 8 is connected with the electric input end of the sampling circuit 9-1, the electric output end of the sampling circuit 9-1 is connected with the electric input end of the comparison analysis circuit 9-2, the electric output end of the comparison analysis circuit 9-2 is connected with the electric input end of the output circuit 9-3, and the electric output end of the output circuit 9-3 outputs a gyro output signal.

The working principle of the processing system 9: the spectrometer 8 collects the spectrum of the interference light, converts the spectrum of the interference light into a spectrum voltage signal, inputs the spectrum voltage signal into a sampling circuit 9-1, the sampling circuit 9-1 sends the spectrum voltage signal into a comparison analysis circuit 9-2, the comparison analysis circuit 9-2 records a first resonance frequency when a gyroscope is static, takes the first resonance frequency as an origin, then records the moving directions of a second resonance frequency, a third transmission valley and a fourth transmission valley on a frequency axis when the gyroscope rotates, obtains a frequency difference x at the second resonance frequency according to the reading method of a vernier caliper, calculates the rotating speed by the frequency difference x, determines the rotating speed direction according to the moving direction of the third transmission valley or the fourth transmission valley on the frequency axis, and finally sends the rotating speed and the rotating speed direction information into an output circuit 9-3, the output circuit 9-3 outputs a gyro output signal, which includes the magnitude and direction of the rotation speed.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.