JP2001066142A - Resonance-type optical gyro - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accurate optical fiber gyro easily adjustable. SOLUTION: A light source 1 is a laser beam generating source and injects the generated laser beam L to a gyro chip 2. The gyro chip 2 branches the laser beam L to a laser beam LCCW and a laser beam LCW, and when injects them, performs phase modulation for the laser beam LCW and the laser beam LCCW respectively based on a modulation signal HCW and a modulation signal HCCW. A CCW light receiver 7 converts the laser beam LCCW to an electric signal DCCW, and outputs it to a CCW optical signal processing portion 9. A CW light receiver 8 converts the laser beam LCW to an electric signal DCW, and outputs it to a CW optical signal processing portion 10. The CCW optical signal processing portion 9 synchronously detects wave of the inputted electric signal DCCW, and outputs an electric signal QCCW to the CW optical signal processing portion 10. The CW optical signal processing portion 10 synchronously detects wave of the inputted electric signal DCW, and generates an electric signal QCW. The CW optical signal processing portion 10, based on the electric signal QCW and the inputted electric signal QCCW, determines a resonance frequency Δf, and calculates a rotation angular velocity Ω.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonance type optical gyro using an optical resonator for detecting a rotational angular velocity of a mounted moving object.

[0002]

2. Description of the Related Art Moving objects (such as airplanes and ships)
By obtaining the rotational angular velocity of the object, the current attitude angle and azimuth angle of the object can be captured. Therefore, airplanes, ships and submarines are equipped with inertial navigation systems and gyro-compasses, etc., to operate the vast sky and the vast sea toward the target value with your own power and without any hesitation. I have. This inertial navigation device and gyro compass
The platform system is shifting to a strap-down system with no moving parts.

For this reason, a gyroscope (hereinafter, referred to as a gyroscope) for measuring a rotational angular velocity is built in an inertial navigation device, a gyro compass, or the like, but the use of a mechanical gyro has shifted to an optical gyro. In the light gyro,
There are three types: a ring laser gyro (RLG), an interference type optical gyro, and a resonance type optical gyro. Where RLG
Although they have been put to practical use, they require a dither mechanism or a rotary table mechanism for lock-in countermeasures, and require high-precision mirrors, and thus have problems in reliability and cost.
For this reason, an interference-type or resonance-type optical gyro that has no moving part and does not require a high-precision mirror has been developed.

The basic principle of the optical gyro will be described with reference to FIG. FIG. 4 is a conceptual diagram of the optical gyro. As shown in FIG. 4, a resonant optical gyroscope (resonant optical gyroscope)
Transmits a laser beam having a traveling waveform to the optical resonator RS from the light source LS via the beam splitter BS, and rotates clockwise (CW: Clock Wise) in a loop of the optical fiber.
Direction and counterclockwise (CCW:
ter ClockWise).

At this time, if the system of the resonance type optical gyro is stationary, the laser light around both sides propagates on the same optical path, so that the resonance frequency difference between the two laser lights becomes “0”. However, when the resonance type optical gyro system is rotated at a rotational angular velocity Ω in the direction of the arrow, the optical path length of the laser light propagated to the CW and the laser light propagated to the CCW in the optical resonator RS differs due to the Sagnac effect. Then, the resonance frequencies of the two laser beams are different.

At this time, since the spectrum of the resonance frequency of the laser beam is sharp (the half width is small), even if the rotation angular velocity is slight, the measured resonance frequency difference has a large value and the detected rotation angular velocity Ω Detection accuracy increases. For this reason, the resonance type optical gyro has recently been expected as a gyroscope. In the present invention, the optical waveguide means constituting the optical resonator used in the resonance type optical gyro is an optical fiber and an optical waveguide.

A conventional resonance type optical gyro will be described with reference to FIG. FIG. 5 is a block diagram showing an example of a configuration of a conventional resonance type optical gyro. In this figure, reference numeral 1 denotes a light source unit, which is a laser light source such as a semiconductor laser. The light source unit 1 emits the generated laser light L to the intensity modulator 100. The intensity modulator 100 performs intensity modulation with the frequency generated by the oscillator 101, and emits a laser beam ML to the gyro chip 2. Intensity modulation is applied to detect the degree of Kerr effect and backscattering (optical noise).

This intensity modulation is performed by a waveform signal having a period Tp shown in FIG.
The period Tp of the waveform signal needs to be an integral multiple of the time for the laser light to make one round of the optical resonator 102 in order to maintain the resonance state of the resonance type optical gyro. If this relationship deviates, an error occurs in the resonance frequency, and the rotational angular velocity Ω cannot be obtained accurately. Here, it is assumed that the optical resonator 102 is formed of, for example, an optical fiber.

Further, the width of the intensity I0 and the width of the intensity I0 'in the cycle Tp must be "1: 1". That is, the switching between the intensity I0 and the intensity I0 'is performed at the time "Tp /
2), accurate intensity modulation cannot be performed, an error occurs in the resonance frequency of the optical resonator 102, and the rotational angular velocity Ω cannot be obtained accurately. Here, the intensity I0 indicates the intensity of the laser beam at the time of emission from the light source unit 1, that is, at the time of incidence on the intensity modulator 100.

The gyro chip 2 distributes the laser light ML incident from the intensity modulator 100 and emits the laser light ML to the optical fibers 3 and 4. Here, the laser light ML output to the optical fiber 3 is output as a counterclockwise laser light L CCW in the optical resonator 102.

The laser light ML output to the optical fiber 4 is supplied to the optical resonator 102 by a clockwise laser light L.
Output as CW. At this time, the laser light L CCW and the laser light LC W are subjected to phase modulation in the gyro chip 2 in order to separate the frequencies to prevent the effects of the back scattering and the Kerr effect.

In this phase modulation, the phase is shifted every time unit “τ” shown in FIG. 7, and the phase is shifted “2π” at time “2π / Δω”. Then, the phase change “Δ
ω ”differs in the phase modulation between the laser light LCW and the laser light LCCW. That is, since the time when the phase of the laser light LCW and the phase of the laser light LCCW are shifted by “2π” is different,
In effect, different frequency modulations have been performed.

If the phase does not shift exactly by “2π” during the time “2π / Δω”, an error occurs in the resonance frequency as in the case of the intensity modulation performed by the intensity modulator 100, and the rotational angular velocity Ω Is not determined exactly. This gyro chip 2
Is controlled by the CW optical signal processing unit 109 and the CC
The modulation is performed by each modulation signal HCW and modulation signal HCCW from the W light signal processing unit 110.

The modulated laser light L CCW enters the optical resonator 102 from the gyro chip 2 via the coupler 105 and the coupler 103, and rotates inside the optical resonator 102 counterclockwise. Similarly, the modulated laser light LCW enters the optical resonator 102 from the gyro chip 2 via the coupler 105 and the coupler 103, and rotates clockwise in the optical resonator 102.

The CCW light receiver 7 converts the laser light LCW incident via the coupler 103 and the coupler 105 into the light shown in FIG.
The electric signal DCW shown in FIG.
To the CW optical signal processing unit 109. Further, the CW light receiver 8 converts the incident laser light L CCW via the coupler 103 and the coupler 106 into an electric signal DC shown in FIG.
The signal is converted into CW, and the electric signal DCW is output to the CCW optical signal processing unit 110.

The CW optical signal processing section 109 synchronously detects the input electric signal DCW, and outputs an electric signal QCW shown in FIG. 8B to the CCW optical signal processing section 110 as a result. In addition, the CW optical signal processing unit 109 sends a control signal to the light source driving unit 11 in order to control the frequency of the laser light L emitted from the light source 1 to always match the resonance frequency fCW obtained from the electric signal QCW. Output.

The light source driving section 11 controls the frequency of the laser light L generated by the light source section 1 based on the light driving signal SC.
The CCW optical signal processing unit 110 receives the input electric signal DCC
W is synchronously detected, and as a result, an electric signal QCCW shown in FIG. 8B is generated and compared with the input electric signal QCW.

That is, the electric signal QCW shown in FIG.
Is the frequency (resonance frequency) f CW that crosses “0 (X axis: laser light frequency)” or the electric signal Q CCW is “0
(X-axis: laser light frequency) ”and the crossing frequency (resonance frequency) f CCW to obtain the resonance frequency difference Δf. Further, the CCW optical signal processing unit 110 outputs the obtained resonance frequency difference Δf to the gyro output unit 112. The gyro output unit 112 uses the input resonance frequency difference Δf to determine the rotational angular velocity Ω by an arithmetic process based on the following (1).

Ω = (Δf · λ · p / (4A · r)) (1) where λ is the wavelength of the laser beam L generated by the light source unit 1 in a vacuum, and p is the optical resonance. A is the circumference of the optical resonator 102, A is the closed area of the optical resonator 102, and r is the radius of the optical resonator 102.

Further, the CCW optical signal processing section 110 outputs the rotational angular velocity Ω obtained by the above-described arithmetic processing to an external circuit (not shown).

Further, based on the intensity modulation by the intensity modulator 100, the CCW optical signal processing unit 110
The difference in intensity between the signal and the electric signal QCW is obtained, and the CW optical signal processing unit 1
09 and the CCW optical signal processing unit 110 respectively
The phase modulation time “τ” is adjusted by the gyro chip 2 so that the intensity difference between the CW and the modulation signal HCCW becomes “0”, and the intensity adjustment between the laser light LCW and the laser light LCCW is performed. By adjusting the time “τ”, the intensity of the laser beam is adjusted with the progress of the phase modulation.

For example, the system of the resonance type optical gyro is indicated by an arrow Z.
8, the optical path of the laser light LCW propagating through the optical resonator 102 becomes apparently longer.
The resonance frequency fCW shown in FIG. On the other hand, the optical path of the laser light L CCW propagating through the fiber ring optical resonator 106 is apparently short, and the resonance frequency f CCW shown in FIG.

Then, the CCW optical signal processing unit 110 obtains a resonance frequency difference Δf between the laser light LCW and the laser light LCCW from the resonance frequency fCW and the resonance frequency fCCW. Thereby, the CCW optical signal processing unit 110 obtains the rotational angular velocity Ω of the system of the resonance type optical fiber gyro rotating in the arrow Z direction by the arithmetic processing based on the equation (1).

For example, if the system of the resonance type optical gyro rotates in the direction opposite to the arrow Z, the optical resonator 1
The optical path of the laser light LCW propagating through the laser beam 02 becomes apparently shorter, and the resonance frequency fCW shown in FIG. On the other hand, the optical path of the laser light L CCW propagating through the optical resonator 102 becomes apparently longer, and the resonance frequency f CCW shown in FIG.

Then, the CCW optical signal processing section 110 obtains a resonance frequency difference Δf between the laser light LCW and the laser light LCCW from the resonance frequency fCW and the resonance frequency fCCW. Thus, the CCW optical signal processing unit 110 obtains the rotational angular velocity Ω of the resonance type optical gyro rotating in the direction opposite to the arrow Z by the arithmetic processing based on the equation (1).

[0026]

As described above, the resonance type optical gyro detects an optical path difference between the laser light LCW and the laser light LCCW in the optical resonator 102 as a resonance frequency difference Δf. Here, the frequency of the light source is set to one laser light,
For example, control is performed so as to maintain the resonance frequency fCW of the optical path of the laser light LCW, and the rotational angular velocity Ω is detected from the deviation of the resonance frequency fCCW of the other laser light LCCW.

Further, since the resonance type optical gyro utilizes a resonance phenomenon, it is necessary to use a light source having high coherence (high coherence). One of the problems that occurs at this time is optical noise generated in the optical unit, that is, the optical resonator 102. Among them, the optical noise due to the Kerr effect and the backscattering is caused by the clockwise laser light LCW and the counterclockwise laser light L
Since the CCW propagates through the same optical waveguide means, that is, the optical resonator 102, the laser light LCW and the laser light LCCW affect each other.

On the other hand, in the back scattering, one laser beam LCW generates scattered light in a direction opposite to the propagation direction (clockwise) (counterclockwise) due to refraction fluctuation in the optical waveguide means. It interferes with the other laser light L CCW and becomes optical noise.

In order to reduce the influence of these optical noises, as described above, correction of the laser light intensity deteriorated by the optical noise by sampling the intensity-modulated laser light, BPS
Although a phase modulation technique by the K system is used, it is not sufficient. That is, as shown in FIG. 8A, both the laser light LCW incident on the CW light receiver 8 and the laser light LCCW incident on the CCW light receiver 7 have noise in the signal intensity for obtaining the resonance frequency. It is in a riding state.

Therefore, the CW optical signal processing unit 109 and CW
The electric signal QCW and the electric signal QCW detected respectively in the CW optical signal processing unit 110 have a resonance point error in both the resonance frequency fCW and the resonance frequency fCCW as shown in FIG. 8B. Therefore, the accuracy of the rotational angular velocity Ω obtained from the resonance frequency difference Δf between the resonance frequency fCW and the resonance frequency fCCW is extremely poor, and the error is very large with respect to the true value as shown in FIG.

FIG. 9 is a diagram showing the accuracy with respect to the true value (theoretical calculation result) of the voltage indicating the rotational angular velocity over time when the motor is rotated at a constant speed. As described above, the conventional resonance type optical gyro has a problem of optical noise due to the use of laser light rotating in the same optical waveguide means in both directions, as described above. There is a problem that cannot be sought.

Further, the conventional resonance type optical gyro uses an intensity modulation circuit, a high-precision phase modulation circuit and the like in order to reduce the influence of optical noise. There is a disadvantage that the reliability of the device decreases.

The present invention has been made under such a background, and an object of the present invention is to provide a resonance type optical gyro which is easy to adjust and has high accuracy.

[0034]

According to a first aspect of the present invention, in a resonance type optical gyro, a laser light source for generating a laser beam having a predetermined frequency in accordance with an injection amount of an injection current; A first optical resonator in which optical waveguide means having the same optical path length is formed in a ring shape, and a first optical resonator in which optical waveguide means having an optical path length having the same length as a wavelength of a predetermined resonance frequency are formed in a ring shape. 2, the first optical resonator and the second optical resonator.
A gyro chip for distributing the laser light to each of the optical resonators; converting the first laser light output from the first optical resonator into a first electric signal; A first detection unit that detects an electric signal and outputs a first detection signal as a detection result, and converts a second laser beam output from the second optical resonator into a second electric signal; A second detection means for detecting the converted second electric signal and outputting a second detection signal as a detection result, and a signal for obtaining a rotational angular velocity based on the first detection signal and the second detection signal And a processing unit.

According to a second aspect of the present invention, in the resonance type optical gyro according to the first aspect, the gyro chip causes the laser light output from the laser light source to rotate clockwise in the first optical resonator. The laser light propagates as one laser light, and the laser light output from the laser light source propagates in the second optical resonator as a second laser light in a counterclockwise direction.

According to a third aspect of the present invention, in the resonance type optical gyro according to the first or second aspect, the gyro chip has a first optical resonator which propagates in the first optical resonator.
And after phase-modulating the laser light and the second laser light propagating in the second optical resonator, respectively, and then outputting the modulated laser light to the first optical resonator and the second optical resonator. And

According to a fourth aspect of the present invention, there is provided a resonance type optical gyro according to any one of the first to third aspects,
A light source driving unit that matches a frequency of the laser light output from the light source with a resonance frequency of the first optical resonator.

[0038]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a resonance type optical fiber gyro according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a light source unit, which is a laser light source such as a Fabry-Perot type semiconductor laser. Further, the light source unit 1 emits the generated laser light L to the gyro chip 2.

The gyro chip 2 receives the incident laser light L
Laser light L CCW propagating in the optical resonator R1 and the optical resonator R
2 and the laser light LCW propagating in the
CW is emitted to the optical fiber 5 and laser light LCW is emitted to the optical fiber 6. When emitting the laser light LCW and the laser light LCCW, the gyro chip 2 receives the modulation signal HCW from the CW light modulation signal processing unit 10 and the CCW light modulation signal processing unit 9.
The phase modulation is performed on the laser light LCW and the laser light LCCW by the modulation signal HCCW from

The phase modulation of the resonant optical gyro in this embodiment is the same as the phase modulation processing shown in the conventional example. The phase modulation performed here is performed by changing the frequencies of the laser light L CCW and the laser light LC W in the CCW optical signal processing unit 9 and the CW optical signal processing unit 10 in order to obtain the resonance frequencies of the fiber rings 20 and 21. Scanning has been done.

The optical fiber 5 propagates the laser light L CCW via the fiber coupler 30 to the optical fiber ring 20 in the optical resonator R1. Then, the incident laser light L CCW
Propagates counterclockwise in the fiber ring 20. Similarly, the optical fiber 6 propagates the laser light LCW to the optical fiber loop 21 in the optical resonator R2 via the fiber coupler 31. Then, the incident laser light LCW
Propagates clockwise in the fiber ring 21.

The CCW light receiver 7 converts the incident laser light LCCW into an electric signal DCW shown in FIG. 2A and outputs this electric signal DCW to the CCW light signal processor 9. Similarly, the CW light receiver 8 converts the incident laser light LCW into an electric signal DCW shown in FIG.
The CW is output to the CW optical signal processing unit 10. Here, the electric signal DCW and the electric signal DCW show the shape of the electric signal QCW and the electric signal QCW using the same FIG. 2A, but the resonance frequency depends on the rotation state of the resonance type optical gyro. Have different values from each other.

The CCW optical signal processing section 9 performs synchronous detection of the input electric signal DCW, and as a result of this detection, FIG.
The electric signal QCCW shown in FIG. In the waveform of the electric signal QCW, a portion where a "0" cross (a point intersecting with the X axis indicating the optical frequency), that is, the frequency having the maximum value in the differential coefficient of the frequency is the resonance frequency fCCW of the fiber ring 20 of the optical resonator R1
It is.

The CW optical signal processing section 10 performs synchronous detection of the input electric signal DCW, and obtains the detection result as shown in FIG.
The electric signal QCW shown in FIG. In the waveform of the electric signal QCW, a portion where a “0” cross (a point intersecting with the X axis indicating the optical frequency), that is, a frequency at which the differential coefficient of the light intensity becomes “0” is a resonance of the fiber ring 21 of the optical resonator R2. The frequency is fCW.

Here, the electric signal QCW and the electric signal QCW show the shapes of the electric signal QCW and the electric signal QCW using the same FIG. 2B, but the rotational state of the resonance type optical gyro is shown. Accordingly, the resonance frequency fCCW and the resonance frequency fCW have different values from each other.

The CW optical signal processing section 10 calculates the resonance frequency ΔC from the electric signal QCW and the inputted electric signal QCW.
Find f. That is, the electric signal QCW shown in FIG.
Is the frequency (resonance frequency) fCW that crosses "0 (X-axis: laser light frequency)" and the electric signal QCCW is "0 (X-axis: laser light frequency)."
(Resonant frequency) that crosses the laser light frequency
The resonance frequency difference Δf is obtained from fCCW.

Further, the CW optical signal processing section 10 calculates the rotational angular velocity Ω from the resonance frequency Δf by the equation (1) shown in the conventional example. Further, the CW optical signal processing unit 1
0 outputs the calculated data of the rotational angular velocity Ω to the gyro output unit 12. The gyro output unit 12 converts the input data of the rotational angular velocity Ω into voltage data shown in FIG. 3, and outputs this voltage data to an external circuit.

Further, the CW optical signal processing section 10 outputs the electric signal Q
The intensity difference between the CCW and the electric signal QCW is obtained, and the CW optical signal processing unit 10 and the CCW optical signal processing unit 9 respectively output the modulated signal HCW
In the gyro chip 2, the above-mentioned phase modulation time “τ” is adjusted so that the intensity difference becomes “0” by the laser beam LCW and the laser beam LCCW.
Adjust strength with W. By adjusting the time “τ”, the intensity of the laser beam is adjusted with the progress of the phase modulation.

Further, the CCW optical signal processing section 9 determines that the frequency of the laser light L emitted from the light source section 1 is always the resonance frequency f CCW obtained from the synchronously detected electric signal Q CCW.
, The laser light L emitted from the light source unit 1
To control the frequency. That is, the CCW optical signal processing unit 9
Outputs a control signal for controlling the frequency of the laser light L emitted from the light source unit 1 to the light source driving unit 11.

The light source driving section 11 includes the CCW optical signal processing section 9
And outputs a light drive signal SC for controlling the frequency of the emitted laser light L to the light source unit 1 based on the control signal from the controller. The light source unit 1 controls the frequency of the emitted laser light L according to the input optical drive signal SC. Thereby, the light source unit 1
Is controlled so that the frequency of the laser light L emitted from the laser light LCCW always coincides with the resonance frequency of the laser light LCCW detected by the CCW optical signal processing unit 9.

Next, an operation example of the above-described embodiment will be described with reference to FIGS. The light source unit 1 emits a laser beam L having a predetermined frequency to the gyro chip 2. Then, the gyro chip 2 distributes the input laser light L into a laser light LCW and a laser light LCCW.

The gyro chip 2 outputs the modulated signal H
A predetermined phase modulation is performed on the laser light LCW based on the CW, and the modulated laser light LCW is emitted to the fiber ring 20 via the optical fiber 5 and the coupler 30. Similarly, the gyro chip 2 performs a predetermined phase modulation on the laser light LCCW based on the modulation signal HCCW, and emits the modulated laser light LCCW to the fiber ring 21 via the optical fiber 6 and the coupler 31.

At this time, if the resonance type optical gyro system is not rotating, the Sagnac effect does not occur, and the optical path length of the fiber ring 20 in the optical resonator R1 and the optical path length of the fiber ring 21 in the optical resonator R2. Are the same without change. Therefore, the frequency difference Δf between the resonance frequency f CCW obtained by synchronous detection in the CCW optical signal processing unit 9 and the resonance frequency f CW obtained by synchronous detection in the CW optical signal processing unit 10 is “0”.

Then, the CW optical signal processing section 10 outputs "0"
The rotational angular velocity Ω is obtained by the above-described equation (1) based on the data of the frequency difference Δf. Here, the rotational angular velocity Ω is obtained as “0” because the frequency difference Δf is “0”. As a result, the CW optical signal processing unit 10 outputs the obtained data of the rotational angular velocity Ω “0” to the gyro output unit 12.

As a result, the gyro output unit 12 outputs voltage data corresponding to the input data of the rotational angular velocity Ω “0” to the external circuit in the state shown in FIG.

Next, for example, if the resonance type optical gyro system is rotated at a constant angular velocity in the direction of arrow Z,
The Sagnac effect occurs, the optical path length of the laser light LCW propagating through the fiber ring 21 of the optical resonator R2 becomes apparently longer, and the resonance frequency fCW shown in FIG. On the other hand, the optical path length of the laser light L CCW propagating through the fiber ring 20 of the optical resonator R1 is apparently short, and the resonance frequency f CCW shown in FIG.

Then, the CW optical signal processing section 10 obtains a resonance frequency difference Δf between the laser light LCW and the laser light LCCW from the resonance frequency fCW and the resonance frequency fCCW. This allows
The CW optical signal processing unit 10 obtains the rotation angular velocity Ω of the system of the resonance type optical fiber gyro rotating in the direction of the arrow Z by the arithmetic processing based on the above equation (1). At this time, C
The CW optical signal processing unit 9 controls the control signal to adjust the frequency of the laser light L emitted from the light source unit 1 to the resonance frequency fCCW obtained based on the electric signal QCCW obtained by synchronously detecting the input electric signal DCCW. Is output to the optical drive unit 11.

Then, the light source driving section 11 outputs the light driving signal S
C is output to the light source unit 1. Accordingly, the light source unit 1 always emits the laser light L having the same frequency as the resonance frequency fc of the fiber ring 20, that is, the resonance frequency fCCW. For this reason, the resonance frequency fCCW of the fiber ring 20 is used as a reference.
The direction of rotation is determined by whether the resonance frequency fcW is large or small, that is, whether the frequency difference Δf is positive or negative in polarity.

Next, assuming that the system of the resonance type optical gyro rotates at a constant angular velocity in a direction opposite to the arrow Z,
The optical path length of the laser light LCW propagating through the fiber ring 21 of the optical resonator R2 is apparently shortened, and FIG.
The resonance frequency fCW shown in FIG. On the other hand, the optical resonator R1
The optical path length of the laser light L CCW propagating through the fiber ring 20 becomes apparently longer, and the resonance frequency f CCW shown in FIG.

Then, the CW optical signal processing section 10 obtains a resonance frequency difference Δf between the laser light LCW and the laser light LCCW from the resonance frequency fCW and the resonance frequency fCCW. This allows
The CW optical signal processing unit 10 obtains the rotation angular velocity Ω of the system of the resonance type optical gyro rotating in the direction opposite to the arrow Z by the arithmetic processing based on the equation (1). At this time, the CCW optical signal processing unit 9 generates a resonance frequency f CCW obtained based on an electric signal Q CCW obtained by synchronously detecting the input electric signal DC CW.
Then, a control signal is output to the light source driving unit 11 in order to match the frequency of the laser light L emitted from the light source unit 1.

Then, the optical drive section 11 outputs the optical drive signal SC
Is output to the light source unit 1. Accordingly, the light source unit 1 always emits the laser light L having the same frequency as the resonance frequency fc of the fiber ring 20, that is, the resonance frequency fCCW. Therefore, the resonance frequency fCCW of the fiber ring 20 is used as a reference, and the rotation direction is determined based on whether the resonance frequency fCW is large or small with respect to the resonance frequency fCCW, that is, whether the frequency difference Δf is positive or negative in polarity. Is done. The polarity of the frequency difference Δf obtained at this time is obtained with a polarity opposite to that when the system of the resonance type optical gyro is rotated in the above-described arrow Z direction.

As described above, the resonance type optical gyro according to the embodiment of the present invention has different optical resonators R1 and R2 for the propagation of the clockwise laser light LCW and the counterclockwise laser light LCCW. Since the resonator R2 is provided, optical noise such as the optical Kerr effect and backscattering that occurs when the conventional clockwise and counterclockwise laser light propagates through the common optical resonator is shown in FIG. Since a stable output is obtained as shown in FIG. 3 without riding on the gyro output, it is possible to eliminate the cause of the occurrence of the error component, and to obtain an accurate rotation angular velocity Ω data.

As mentioned above, one embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and a design change or the like may be made without departing from the gist of the present invention. The present invention is also included in the present invention. For example, in the embodiment shown in FIG. 1, optical fibers are used as light propagation means such as the fiber ring 20 of the optical resonator R1, the fiber ring 21 of the resonator R2, the optical fiber 5, the optical fiber 6, and the like. It is also possible to use an optical transport path as the propagation means.

[0064]

According to the present invention, a laser light source for generating a laser beam having a predetermined frequency in accordance with an injection amount of an injection current;
A first optical resonator in which optical waveguide means having the same optical path length as the wavelength of the predetermined resonance frequency is formed in a ring shape; and an optical waveguide means having the same optical path length as the wavelength of the predetermined resonance frequency. A second optical resonator formed in a ring shape; a gyro chip for distributing the laser light to each of the first optical resonator and the second optical resonator; and a gyro chip output from the first optical resonator. First detecting means for converting the first laser light into a first electric signal, detecting the converted first electric signal, and outputting a first detection signal as a detection result; A second laser light output from the optical resonator of the second is converted into a second electric signal, the converted second electric signal is detected, and a second detection signal is output as a detection result. Detection means, and a signal processing unit for obtaining a rotational angular velocity based on the first detection signal and the second detection signal , The first optical resonator in which the first laser light propagates clockwise is different from the second optical resonator in which the second laser light propagates counterclockwise. Optical noise such as the optical Kerr effect and backscattering, which occur when the laser light in the clockwise and counterclockwise directions propagates through the common optical resonator, do not occur, and stable laser light propagation is performed. The cause of occurrence can be eliminated, and there is an effect that highly accurate rotation angular velocity data can be obtained.

Further, according to the present invention, the gyro chip propagates the laser light output from the laser light source in the first optical resonator in the clockwise direction as the first laser light. A first optical resonator in which the first laser light propagates clockwise in order to cause the laser light output from to propagate in the second optical resonator as a second laser light in the counterclockwise direction; Since the second laser light is different from the second optical resonator in which the second laser light propagates counterclockwise,
Conventional clockwise and counterclockwise laser light propagates through a common optical resonator, optical Kerr effect and optical noise such as backscatter do not occur with each other, and stable laser light propagation is performed. The cause of the occurrence of the error component can be eliminated, and there is an effect that highly accurate rotation angular velocity data can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a resonant optical gyro according to an embodiment of the present invention.

FIG. 2 shows a CW optical signal processing unit 10 (CCW
It is a figure explaining operation | movement of the optical signal processing part 9).

FIG. 3 is a diagram showing voltage data output from a gyro output unit 12 in FIG. 1;

FIG. 4 is a conceptual diagram illustrating the concept of a resonance type optical gyro.

FIG. 5 is a block diagram illustrating the concept of a resonance type optical gyro according to a conventional example.

FIG. 6 is a timing chart illustrating an operation of intensity modulation in a resonance type optical gyro according to a conventional example.

FIG. 7 is a timing chart illustrating an operation in a phase modulation process in the resonance type optical gyro.

FIG. 8 shows a CW optical signal processing unit 109 (CC
FIG. 3 is a diagram illustrating the operation of a W optical signal processing unit 110).

9 is a diagram showing voltage data output from a gyro output unit 112 in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source unit 2 gyro chip 5, 6 optical fiber 7 CCW optical receiver 8 CW optical receiver 9 CCW optical signal processing unit 10 CW optical signal processing unit 11 light source driving unit 12 gyro output unit 20, 21 fiber ring 30, 31 coupler R1, R2 optical resonator

Claims (4)

[Claims] 1. A laser light source for generating a laser beam having a predetermined frequency corresponding to an injection amount of an injection current, and an optical waveguide having the same optical path length as a wavelength of a predetermined resonance frequency are formed in a ring shape. A second optical resonator in which an optical waveguide having the same optical path length as the wavelength of the first optical resonator and a predetermined resonance frequency is formed in a ring shape; a first optical resonator and a second optical resonator; A gyro chip for distributing the laser light to a resonator, a first laser light output from the first optical resonator to a first electric signal, and the converted first electric signal , And a first detection means for outputting a first detection signal as a detection result, and a second laser light output from the second optical resonator is converted into a second electric signal, and converted. The second electric signal is detected, and a second detected signal is output as a detection result. And detection means, the first detection signal and the resonance type optical gyro, characterized by comprising a signal processing unit for obtaining a rotational angular velocity based on the second detection signal. 2. The laser beam output from the laser light source, wherein the gyro chip propagates the laser light output from the laser light source in the first optical resonator in a clockwise direction as a first laser light. 2. The resonance type optical gyro according to claim 1, wherein the laser beam propagates in the second optical resonator as a second laser beam in a counterclockwise direction. 3. The gyro chip after phase-modulating a first laser beam propagated in the first optical resonator and a second laser beam propagated in the second optical resonator. 3. The resonance type optical gyro according to claim 1, wherein each is output to the first optical resonator and the second optical resonator. 4. The apparatus according to claim 1, further comprising: a light source driving unit configured to match a frequency of the laser light output from the light source with a resonance frequency of the first optical resonator. 2. A resonance type optical gyro according to item 1.