JP2001108446A - Gyro and its operation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gyro and its operation method capable of lowering a coupling loss generated when laser light is introduced into a light detector and a noise caused by returning light to a laser from external reflection points. SOLUTION: The gyro has characteristics that a ring resonance type laser where lights circumferentially transmit detects the variation of current or impedance due to the beat caused by interference of laser light progressing mutually reversely inside the laser.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gyro and a method for operating the gyro. More specifically, the present invention relates to a gyro utilizing a ring resonator type laser.

[0002]

2. Description of the Related Art Conventionally, as a gyro used for detecting an angular velocity of a moving object, a mechanical gyro having a rotor and a vibrator and an optical gyro are known. In particular, the optical gyro is capable of instantaneous activation and has a wide dynamic range, and is thus innovating in the gyro technical field.

The optical gyro includes a ring resonance type laser gyro, an optical fiber gyro, a passive type ring resonator gyro, and the like. Of these, the ring resonance type laser gyro using a gas laser was first developed, and has already been put to practical use for aircraft and the like. Recently, a compact and high-precision ring-resonant laser gyro has also been proposed.
No. 288556 is disclosed.

[0004]

However, the conventional ring resonator type laser gyro emits clockwise laser light and counterclockwise laser light from the laser to the outside of the laser once, and detects both laser lights. And received electrical beats as signals. For this reason, coupling loss has been present when the laser light is incident on the photodetector.

[0005] Further, since noise is generated by light returning to the laser from a reflection point outside the laser, an optical isolator must be used in some cases in order to avoid the noise.

In some cases, it has been required to further reduce the size and weight of the drive system of the ring resonator type laser gyro, or to reduce the influence of the noise of the drive power supply on the gyro.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gyro having no or reduced problems such as coupling loss and return optical noise and a method of operating the gyro. Still another object of the present invention is to reduce the size and weight of the drive system of the ring resonator laser and to reduce the influence of noise on the ring resonator laser.

[0008] A gyro according to the present invention has a ring resonator type laser in which light propagates in a counter-rotating circular shape.
The ring resonator type laser uses a constant voltage source as a driving source, and detects a beat signal as a change in current flowing through the ring resonator type laser.

The current change can be detected as a voltage change applied to a resistor connected in series to the ring resonator type laser.

In a gyro operation method according to the present invention, a ring resonator type laser is driven at a constant voltage, and a change in a current flowing through the ring resonator type laser is changed by a magnitude of an angular velocity applied to the ring resonator type laser. It is characterized in that it is used as a signal for obtaining the degree.

The present invention is further characterized in that the voltage for driving the ring resonator type laser is modulated at a frequency different from the frequency band of the signal.

The present invention is also characterized in that a vibration is applied to a gyro provided with the ring resonator type laser at a frequency different from the frequency band of the signal, and the signal is detected in synchronization with the vibration. .

The gyro according to the present invention has a ring resonator type semiconductor laser in which light propagates in a counterclockwise direction, and detects a beat signal as a change in impedance of the semiconductor laser.

The gyro operation method according to the present invention is characterized in that a change in the impedance of the ring resonator type semiconductor laser is used as a signal for determining the magnitude of the angular velocity applied to the ring resonator type semiconductor laser. I do.

The above-mentioned current change or impedance change is, more specifically, a change in their frequency.

Hereinafter, the present invention will be described specifically.

In a ring resonator type laser as shown in FIG. 1, light propagates in a circular shape. Specifically, there are light (31) circling clockwise inside the laser and light (32) circling counterclockwise. If the laser is stationary, both laser beams have the same oscillation frequency. However, when the laser is rotated, there is a difference between the oscillation frequencies of the clockwise laser light and the counterclockwise laser light, and the difference Δf is given by the following equation.

Δf = (4S / λL) Ω (1) where S is a closed area surrounded by an optical path, λ is an oscillation wavelength of laser light, L is an optical path length, and Ω is an angular velocity of rotation.

When a constant current source is used as a driving power source, if light interferes in the laser, the population inversion changes accordingly, and as a result, the voltage between the electrodes of the laser changes. Since the state of this change appears as a change in the terminal voltage, the state of light interference can be extracted as a signal.

However, when a beat signal due to light interference is taken out as a change in the terminal voltage, it may be affected by the noise of the drive power supply, and it may be required to reduce the influence.

Further, the drive system including the power supply can be made more compact,
Lightening was required.

By the way, when light interferes inside the ring resonator type laser, the population inversion changes. In the case of a laser such as a gas laser or a semiconductor laser that flows an electric current, the change in the population inversion and the impedance of the laser include: 1
There is a one-to-one correspondence.

Therefore, the state of interference of light in the laser, that is, the beat signal can be regarded as a change in impedance between the laser electrodes.

When a constant voltage source is used as the driving power source, a beat signal can be obtained as a change in current flowing through the laser.

As in the present invention, the laser is provided with a terminal for detecting a change in current or impedance caused by a beat caused by interference of laser light traveling in mutually opposite directions inside the laser, whereby the laser rotates from this terminal. The beat signal corresponding to the above can be extracted. Therefore, it is possible to obtain a gyro that can omit a photodetector and an optical system for optical coupling, which are essential in the conventional optical gyro.

In the above feature, if the ring resonator type laser is configured so that the gyro has a total reflection surface for the laser beam generated from the ring resonator type laser, mirror loss is eliminated, and the laser oscillation threshold is reduced. Value can be reduced.

Further, the gyro according to the present invention is characterized in that the total reflection surface is not provided within a range in which the evanescent light generated from the ring resonator type laser exudes. In the above configuration, if a reflector is present within the exudation distance of the evanescent light, the reflector and the laser are optically coupled to each other, which not only causes a loss when viewed from the laser, but also returns light from the reflector to the laser. Exists and becomes a noise source. Conversely, if there is no reflector within the seepage distance of the evanescent light of the laser as in the present invention, the laser becomes optically independent of other reflectors, and there is no loss due to external effects of the laser. In addition, since there is no return light noise, loss due to coupling and return light noise can be remarkably improved.

Semiconductor lasers are susceptible to surge noise and the like. Therefore, if surge noise or the like enters the semiconductor laser from a terminal that detects a change in current flowing through the laser due to rotation, the semiconductor laser may be degraded or destroyed. In contrast, by providing a protection circuit for the laser between the circuit that measures the change in current flowing through the laser and the detection terminal,
Deterioration and destruction of the semiconductor laser due to surge noise or the like can be prevented. Needless to say, it is desirable to provide a protection circuit in gas lasers as needed.

In the gyro operating method according to the present invention, in the gyro having the above-described configuration, the change in the current or the impedance detected from the terminal is determined by determining the magnitude of the angular velocity applied to the ring resonator type laser. It is characterized in that it is used as a required signal. According to this configuration, it is possible to omit a photodetector and an optical system for optical coupling, which are indispensable in the conventional optical gyro, so that problems of coupling loss and return optical noise caused by these components can be eliminated. A gyro operation method that can be eliminated can be provided.

In the above operation method, it is also preferable that the voltage or current for driving the ring resonator type laser is modulated at a frequency different from the frequency band of the signal.

This is because, in the gyro having the above-described configuration, when the gyro is rotated, a difference appears between the oscillation frequencies of the clockwise laser light and the counterclockwise laser light,
The difference Δf is given by equation (1), but the difference Δ
When f is small, the oscillation frequency is pulled in due to the non-linearity of the laser medium, and a phenomenon called lock-in occurs in which Δf = 0.

However, as shown in the above configuration, the lock-in phenomenon can be avoided if the oscillation frequency difference Δf is constantly changed.

Conventionally, a method of applying dither has been used as a method of avoiding the lock-in phenomenon, which corresponds to the modulation of the angular velocity Ω in the equation (1).

For example, in a semiconductor laser, it is known that the oscillation wavelength varies depending on the magnitude of the current. This is because the refractive index of the semiconductor changes according to the current. Accordingly, by modulating the current of the semiconductor laser, λ of the equation (1) can be modulated, and as a result, a state where Δf always varies can be created.

Further, by modulating the signal at a frequency in a band different from the signal frequency, lock-in can be avoided without adversely affecting the signal.

Of course, even if the voltage is modulated via the series resistor, the current flowing through the semiconductor laser is modulated,
The same effect is obtained. Also, in the case of a gas laser, by modulating the current or voltage, the Q value of the resonator fluctuates, so that the oscillation wavelength is modulated. This is because the oscillation wavelength of a gas laser is determined by the Q value of the resonance transition of an atom, a molecule, or an ion and the Q value of a resonator, and this phenomenon is known as attraction of the oscillation wavelength.

In the operating method, vibration is applied to the gyro having the ring resonator type laser at a frequency different from the frequency band of the signal, and a signal is detected from the terminal in synchronization with the vibration. The correspondence between the direction of vibration and the magnitude of the signal detected from the terminal can be established.

For example, when vibration is applied in the clockwise direction, if the gyro is receiving clockwise rotation, the current detected at the above terminal will be large, and conversely, if the gyro has received counterclockwise rotation. In this case, the current detected at the terminal becomes smaller.

Therefore, it is possible to identify whether the optical gyro is rotating clockwise or counterclockwise.

Moreover, by modulating the signal at a frequency in a band different from the signal frequency, the direction of rotation can be detected without adversely affecting the signal.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and operation of a gyro according to the present invention and its operating method will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic plan view showing an example of a gyro provided with a ring resonator type laser in which light propagates in a circular shape according to the present invention. Is a square.

In FIG. 1, 1 is an electric terminal, 10 is a quartz tube formed by hollowing out quartz, 11 is a mirror, 21 is an anode, 22 is a cathode, 31 is a clockwise laser beam,
32 is a counterclockwise laser beam.

In the above configuration, when helium gas and neon gas are put into the quartz tube 10 and a voltage is applied between the anode 21 and the cathode 22, discharge starts and a current flows.

When the quartz tube 10 is stationary, the oscillation frequencies of the clockwise laser light and the counterclockwise laser light are exactly the same, 4.73 × 10 ¹⁴ Hz, and the oscillation wavelength λ is 63.
2.8 nm. For example, if the quartz tube 10 functioning as a resonator receives a rotation of 1 degree per second and the length of one side of the quartz tube 10 is 10 cm, the beat frequency is 496.
5 kHz. At this time, the power supply voltage is adjusted so as to be constant, and the current flowing from the electric terminal 1 to the laser is monitored. The amplitude is 10 mA and the frequency is 496.5 kHz.
Is obtained. In particular, when a battery is used as the constant voltage source, the drive system can be significantly reduced in size,
Weight reduction becomes possible.

FIG. 2 shows an example of a circuit for detecting a change in current flowing through the ring resonator type laser 100. 105
Denotes a battery (battery) 103, an electric resistance, and 106, a voltmeter.

With such a circuit configuration, the laser 100
The rotation is detected by a change in the current flowing through the motor, more specifically, a change in the frequency.

It is to be noted that, in FIG. 2, anything may be used as long as the voltage of the electric resistance 103 can be detected without using the voltmeter 106.

Of course, as shown in FIG. 3, a change in current flowing through the ring resonator type laser 100 may be directly detected by the ammeter 107.

FIG. 4 shows an example of a circuit configuration for driving the ring resonator type laser 60 at a constant voltage and detecting a beat signal accompanying rotation.

FIG. 4 shows an example of a circuit diagram for driving the ring resonator type laser 60 at a constant voltage, reading the voltage as a voltage drop of the electric resistance 63 flowing through the laser 60, and detecting rotation.

The anode of the laser 60 is connected to the output terminal of the operational amplifier 72 via the resistor 63, and the cathode of the laser 60 is grounded to the reference potential.

When a constant potential (Vin) is applied to the inverting input terminal of the operational amplifier 72 from a microcomputer or the like, a constant voltage drive configuration is applied in which the potential always applies the resistance 63 to the laser 60.

The electric resistance 63 is connected to an operational amplifier 61 for a buffer.

The operational amplifier 61 outputs a signal Vout. Since this signal has a beat frequency proportional to the angular velocity, the signal is converted into a voltage by a known frequency-voltage conversion circuit (FV conversion circuit) or the like, and rotation is detected. Of course, the rotation detection may be performed by directly inputting the signal of the electric resistance and the equipotential portion to the FV conversion circuit.

Next, FIG. 19 shows a case where the reference of the signal potential is set to ground by using the subtraction circuit 75 in addition to the same constant voltage drive configuration as that of FIG.

A constant potential V ₁ is applied to the inverting input terminal of the operational amplifier 72 from a microcomputer or the like. 60 is a ring resonator type laser, 61 is a voltage follower, 63 and 76-7
Reference numeral 9 denotes an electric resistance, which makes the resistance values of 76 and 77 and 78 and 79 equal.

The potentials V ₁ and V ₂ at both ends of the electric resistor 63 are connected to an inverting input terminal and a non-inverting input terminal of the amplifier 80 through a voltage follower and resistors 76 and 78 circuits. This makes it possible to detect a change in the voltage V ₂ −V ₁ (= V ₀ ) applied to the electric resistance 63 with the reference potential as the ground. That is, a change in the current flowing through the ring resonator type laser 60 can be detected.

The rotation of the obtained signal is detected through an FV conversion circuit or the like.

FIG. 4 shows an example of a frequency-voltage conversion circuit (FV conversion circuit), but is not limited to this. This circuit consists of transistors, diodes,
The output voltage V _C2 is composed of a capacitor and a resistor, and is represented by equation (2).

[0061]

[Outside 1] Here, E _i is the peak-to-peak value of the input voltage, and f is the beat frequency. C ₂ >> C ₁ , R ₀ C ₂ f <
By designing the circuit parameters to be 1, V _C2 = E _i C ₁ R ₀ f (3) as shown in equation (3), and a voltage output proportional to the beat frequency is obtained. Becomes possible.

The example in which the change in the terminal current is directly or indirectly detected has been described above. However, the change in the discharge impedance may be directly detected using an impedance meter. When measuring the change in impedance, unlike the case where the terminal voltage or the current flowing through the element is measured, the influence of the noise of the driving power supply is reduced, so that a gyro with higher sensitivity can be provided. FIG. 6 shows a specific circuit configuration. 101 is a power supply and 108 is an impedance meter.

In this embodiment, the case where a quartz tube is used as shown in FIG. 1 has been described, but a polymer material such as fluorine polyimide or epoxy may be used.

In the gyro having the above structure, an example using helium gas and neon gas has been described. However, any gas such as an argon ion laser, a carbon dioxide gas laser, and an excimer laser may be used as long as the gas oscillates.

FIG. 7 is a schematic plan view showing another example of a gyro provided with a ring-resonant type laser in which light propagates in a circular shape according to the present invention. .

Also in the configuration, the rotation can be detected. As long as the right-handed laser light and the left-handed laser light pass through the same path, the shape of the circular path through which the light propagates is not limited to the above-described square or triangle.

(Second Embodiment) FIG. 8 is a schematic perspective view showing another example of a gyro provided with a ring-resonant semiconductor laser in which light propagates in a circular shape according to the present invention. The case where a columnar semiconductor laser is used as the laser is shown. 8, 1 is an electric terminal, 21 is an anode, 22 is a cathode, 40 is a columnar semiconductor laser,
Reference numeral 41 denotes an active layer constituting the semiconductor laser, and reference numeral 50 denotes a substrate on which the semiconductor laser is mounted. The semiconductor laser is
It is manufactured by performing etching with a reactive ion beam or the like using chlorine gas or bromine gas.

In the above configuration, a current is injected from the anode 21 into the semiconductor laser. Active layer 41 is 1.55 μm
m of InGaAsP, and 1.3 μm above and below
An InGaAsP light guide layer having a composition, and an InP clad layer are formed so as to sandwich these. Since a semiconductor and air have different refractive indexes, reflection occurs at the interface.

Assuming that the refractive index of the semiconductor is 3.5, total reflection occurs when the angle between the laser beam and the normal to the interface is 16.6 degrees or more. In the mode that receives total reflection, the oscillation threshold value can be reduced by the amount corresponding to the absence of the mirror loss as compared with the other modes, so that oscillation starts at a low injection current level.

Further, since the gain is concentrated in this oscillation mode, the oscillation in other modes is suppressed. Semiconductor laser 4
0 has a radius of 10 μm, and the active layer has a thickness of 0.1 μm.
At 1 μm, the oscillation threshold current is 0.8 mA. At a driving voltage of 0.8 V, if the camera receives camera shake or a rotation of 30 degrees per second, which is about the vibration of an automobile, a signal having an amplitude of 0.1 mA and a frequency of 23.6 Hz is obtained from the electrode terminal 1.

Further, by providing a protection circuit at the detection terminal of the semiconductor laser, deterioration or destruction of the semiconductor laser can be prevented. FIG. 9 shows an example in which a voltage follower is connected as a protection circuit. 110 is a voltage follower, and 102 is a current change detection circuit. actually,
The change in the voltage drop of the electric resistance 103 will be seen.

When a constant voltage source is used as a power source as in the present invention, the angular velocity of rotation can be measured as a change in current flowing through a ring resonator type laser. As shown in FIGS. 12 and 13 described above, the use of a battery as a constant voltage source leads to a reduction in the size and weight of a drive system. In FIG. 12, an electric resistance is connected in series with the semiconductor laser 100,
The current flowing through the semiconductor laser is measured as a change in voltage across the electric resistance. On the other hand, in FIG. 13, an ammeter is connected in series with the semiconductor laser, and the current flowing directly to the semiconductor laser is measured. Of course, the rotation may be detected by the circuit configuration shown in FIG. 4 as in the first embodiment.

Further, regardless of the type of the power supply, a change in the impedance of the semiconductor laser can be directly measured by an impedance meter. In this case, unlike the case where the terminal voltage or the current flowing through the element is measured, the influence of the noise of the driving power supply is reduced. This example is shown in FIG.

When total reflection occurs, there is evanescent light traveling along the interface. When the oscillation wavelength is 1.55 μm, the exudation distance of the evanescent light is 0.074 μm. The intensity of the evanescent light attenuates exponentially (the seepage distance is a distance at which the electric field amplitude attenuates to 1 / e).

Therefore, if the distance from the laser element outside the laser element and which can be a reflector is 10 μm, the effect of the return light can be ignored. That is, the above-described configuration example is an example in which the reflector does not exist within 10 μm from the interface of the column of the semiconductor laser 40, and is not affected by the return light noise.

Further, the applied voltage was set to an amplitude of 0.1 V and a frequency of 2
By performing modulation at kHz, the beat frequency becomes 1H
A gyro that does not cause a lock-in phenomenon even during rotation according to a small frequency that cuts z can be configured. If modulation is performed at a frequency in a band different from the signal frequency, there is no adverse effect on beat signal detection.

Here, InG is used as a semiconductor material.
aAsP type was used, but GaAs type, ZnSe type
Any material system such as a system, an InGaN system, and an AlGaN system may be used.

Hereinafter, a configuration example of the semiconductor laser 40 will be described.

FIG. 10 is a schematic perspective view showing another example of a gyro provided with a ring-resonant type laser in which light propagates in a circular shape according to the present invention. It has a columnar shape.

According to this configuration, the number of oscillation modes is reduced because the number of propagation modes is smaller than that in the case of FIG.
N is improved. Of course, the shape may be a triangular prism as shown in FIG.

According to this configuration, the number of oscillation modes is further reduced, and the S / N is improved as compared with the case of FIG.

Although the case where the semiconductor laser 40 is cylindrical, quadrangular, or triangular is shown, the shape is not limited as long as it forms a ring-resonant laser.
For example, the shape may be a disk shape instead of a column shape.

FIG. 12 is a schematic perspective view showing another example of a gyro provided with a ring resonator type laser in which light propagates in a circular shape according to the present invention. It is cylindrical instead of cylindrical.

According to this configuration, since the laser beam circulates along the interface of the semiconductor, the semiconductor laser 40
The central part of the element composed of can be omitted as shown in FIG. Therefore, by making the shape of a cylinder as shown in FIG. 12, a gain can be given only to the circulating light, and the volume of the active layer is reduced, so that the driving power is further reduced. Needless to say, a quadrangular or triangular cylindrical structure as shown in FIGS.

FIG. 13 is a schematic perspective view showing another example of a gyro having a ring resonator type laser in which light propagates in a circular shape according to the present invention, and is a columnar semiconductor laser used as a laser. 13 shows a case where the resistance is increased by ion implantation at the central portion (the cross hatched portion in FIG. 13). For example, protons are used as ions, and the dose is 5
× 10 ¹⁴ cm ⁻² and an acceleration voltage of 100 keV. Although laser light is distributed also in the proton injection region, it is preferable to perform annealing at 200 to 400 ° C. for several minutes in order to reduce absorption loss of light in this region.

According to this configuration, a gain can be mainly given to the circulating light, and further, since the volume of the active layer is substantially reduced, the driving power is further reduced. The ion implantation region is not limited to the illustrated portion, and the projection range may be set to the active layer portion. As shown in FIGS. 15 and 17, the shape of the laser may be quadrangular prism or triangular prism.

FIG. 18 is a schematic perspective view showing another example of a gyro provided with a ring-resonant laser in which light propagates in a circular shape according to the present invention, and shows a substrate on which a semiconductor laser used as a laser is formed. 50 includes a piezoelectric element 51.

According to the above configuration, by applying a voltage of, for example, a frequency of 20 kHz to the piezoelectric element 51, the semiconductor laser 40 constituting the gyro can be given clockwise and counterclockwise rotation. Terminal 1 to piezoelectric element 51
By detecting a signal synchronized with the voltage applied to the clock signal, clockwise rotation and counterclockwise rotation can be distinguished. For example, when vibration is given in the clockwise rotation direction, if the semiconductor laser 40 is receiving clockwise rotation, the change in current detected at the terminal is large, and if the semiconductor laser 40 is receiving counterclockwise rotation, The change in current detected at the terminal is small. Moreover, by modulating the signal at a frequency in a band different from the signal frequency, the direction of rotation can be detected without adversely affecting the signal. Of course, without relying on the piezoelectric element,
Anything can be used as long as the desired vibration can be given.

[0089]

As described above, according to the gyro according to the present invention, in a ring resonator type laser in which light propagates in a circular shape, the gyro is generated by the interference of laser light traveling in opposite directions inside the laser. By detecting a change in current or impedance caused by the beat, a beat signal corresponding to the rotation can be extracted.
Therefore, it is possible to provide a gyro that can omit a photodetector and an optical system for optical coupling, which are essential in the conventional optical gyro. Further, by considering the beat signal as a change in impedance, the influence of noise of the driving power supply can be reduced, and a gyro with higher sensitivity can be manufactured. In addition, by using a constant voltage source (battery, battery) as the driving source, the size and weight of the gyro can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an example of a gyro according to the present invention.

FIG. 2 is an example of a circuit diagram for detecting a change in beat according to the present invention.

FIG. 3 is an example of a circuit diagram for detecting a change in beat according to the present invention.

FIG. 4 is an example of a circuit diagram for detecting a change in beat according to the present invention.

FIG. 5 is an example of a circuit diagram for detecting a change in beat according to the present invention.

FIG. 6 is an example of a circuit diagram for detecting a change in beat according to the present invention.

FIG. 7 is a schematic plan view showing another example of the gyro according to the present invention.

FIG. 8 is a schematic perspective view showing an example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 9 is a diagram showing an example of a circuit for detecting a change in beat according to the present invention.

FIG. 10 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 11 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 12 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 13 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 14 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 15 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 16 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 17 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 18 is a schematic perspective view showing another example of a gyro provided with a semiconductor laser according to the present invention.

FIG. 19 is an example of a circuit diagram for detecting a change in beat according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 electric terminal 10 quartz tube 11 mirror 21 anode 22 cathode 31 clockwise laser light 32 counterclockwise laser light 40 semiconductor laser 41 active layer 50 substrate 51 piezoelectric element 100 semiconductor laser 101 power supply 102 current detection circuit 103 electric resistance 105 battery ( Battery) 107 Ammeter 108 Impedance meter 110 Voltage follower

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 23, 2000 (2000.10.
23)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008] A gyro according to the present invention has a ring resonator type laser in which light propagates in a counter-rotating circular shape,
The ring resonator type laser uses a constant voltage source as a drive source, and the drive source is modulated at a frequency different from the frequency band of the beat signal, and detects the beat signal as a change in current flowing through the ring resonator type laser. It is characterized by the following.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

In a gyro operation method according to the present invention, a ring resonator type laser is driven by a constant voltage source, and a change in current flowing through the ring resonator type laser is changed by an angular velocity applied to the ring resonator type laser. The constant voltage source is modulated at a frequency different from the frequency band of the signal.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

A gyro according to the present invention has a ring resonator type semiconductor laser in which light propagates in a counterclockwise circular shape, modulates a driving source of the semiconductor laser at a frequency different from a frequency band of a beat signal, The beat signal is detected as a change in impedance of the semiconductor laser.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

The method of operating a gyro according to the present invention uses the change in the impedance of the ring resonator type semiconductor laser as a signal for determining the magnitude of the angular velocity applied to the ring resonator type semiconductor laser. Is characterized by being modulated at a frequency different from the frequency band of the signal.

Claims (16)

[Claims] 1. A gyro having a ring resonator type laser in which light propagates in a counterclockwise direction, wherein the ring resonator type laser uses a constant voltage source as a driving source and converts a beat signal into the ring resonance type laser. A gyro characterized by detecting a change in current flowing through a rectangular laser. 2. The gyro according to claim 1, wherein the ring resonator type laser is a semiconductor laser. 3. The gyro according to claim 1, wherein a battery is used as the constant voltage source. 4. The gyro according to claim 1, wherein the current change is a frequency change of the current. 5. The gyro according to claim 1, wherein the current change is detected as a voltage change applied to a resistor connected in series with the ring resonator type laser. 6. A ring resonator type laser is driven at a constant voltage, and a change in current flowing through the ring resonator type laser is
A method for operating a gyro, wherein the method is used as a signal for obtaining the magnitude of an angular velocity applied to the ring resonator type laser. 7. The gyro operation method according to claim 6, wherein the ring resonator type laser is a semiconductor laser. 8. The gyro operation method according to claim 6, wherein a voltage for driving the ring resonator type laser is modulated at a frequency different from a frequency band of the signal. 9. The gyro according to claim 6, wherein a vibration is applied to the gyro provided with the ring resonator type laser at a frequency different from the frequency band of the signal, and the signal is detected in synchronization with the vibration. Method of operation. 10. A gyro having a ring-resonant semiconductor laser in which light propagates in a counterclockwise direction, wherein the gyro detects a beat signal as a change in impedance of the semiconductor laser. 11. The semiconductor laser according to claim 1, wherein
The gyro according to claim 10, wherein the driving source is a constant voltage source. 12. The ring resonator type semiconductor laser,
The gyro according to claim 10, further comprising a battery as a driving power source. 13. The gyro according to claim 10, wherein the change in the impedance is a change in the frequency of the impedance. 14. A method for operating a gyro, wherein a change in impedance of a ring resonator type semiconductor laser is used as a signal for determining a magnitude of an angular velocity applied to the ring resonator type semiconductor laser. 15. The gyro operation method according to claim 14, wherein a voltage or a current for driving the ring resonant semiconductor laser is modulated at a frequency different from a frequency band of the signal. 16. The gyro operation method according to claim 14, wherein a vibration is applied to the gyro provided with the ring-resonant semiconductor laser at a frequency different from the frequency band of the signal, and the signal is detected in synchronization with the vibration. .