Laser gyroscope resonant cavity structure for improving temperature stability and laser gyroscope

Abstract

The invention relates to a laser gyroscope resonant cavity structure capable of improving temperature stability and a laser gyroscope, and belongs to the technical field of laser gyroscopes. The resonant cavity structure comprises a gas storage hole, a discharge area capillary tube and a non-discharge area capillary tube; the plurality of gas storage holes are arranged in a resonant cavity of the resonant cavity structure at intervals, the adjacent gas storage holes are communicated through the discharge area capillary tube and / or the non-discharge area capillary tube to form a closed light path, and the discharge area capillary tube is connected with a discharge hole arranged in the resonant cavity; and the diameter of the non-discharge area capillary tube is greater than that of the discharge area capillary tube. Flow of gain gas in the laser gyroscope resonant cavity capillary tube and the temperature gradient of the laser gyroscope resonant cavity are reduced, and the influence of temperature field change on zero offset of the laser gyroscope is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of laser gyroscopes, and in particular to a laser gyroscope resonant cavity structure and a laser gyroscope capable of improving temperature stability. Background Art

[0002] As an angular motion sensitive device, the ring laser gyroscope is the core device of the inertial navigation system and is widely used in aviation, navigation, aerospace, guidance and other fields. The output of the laser gyroscope is angular velocity. Due to factors such as processing technology, the output angular velocity of the laser gyroscope often has a certain deviation from the input angular velocity, which is generally called zero bias, and this zero bias changes with the temperature field.

[0003] Since inertial navigation systems are often used in a wide temperature range and the temperature changes in the operating environment are often extremely complex, it is required that the laser gyro zero bias does not change significantly and irregularly with temperature changes. Irregular and large fluctuations in zero bias will cause large errors in the laser gyro output, resulting in increased navigation errors of the entire inertial navigation system and reduced navigation accuracy.

[0004] The design and manufacture of laser gyroscopes involves multiple fields such as optics, mechanics, electronics, algorithms and materials, and is a complex system engineering. Each subsystem of the laser gyroscope will change within the temperature range of -40°C to 70°C, resulting in unstable temperature performance of the laser gyroscope. Moreover, during the mass production of laser gyroscopes, the stability and fluctuation of the process will lead to differences in the temperature characteristics of the laser gyroscope.

[0005] One of the important reasons why the laser gyroscope's zero bias changes with temperature is that the flow of the gain gas in the laser gyroscope has large and unstable changes under different temperature field environments, and the asymmetric expansion of the Langmuir flow and the gain gas causes temperature errors, which affects the frequency difference between the forward and reverse beams in the laser gyroscope, and further causes changes in the zero bias. Summary of the invention

[0006] In order to reduce the influence of temperature on the zero bias of a laser gyroscope, the present invention provides a laser gyroscope resonant cavity structure and a laser gyroscope with improved temperature stability, which can reduce the flow of gain gas in the capillary of the laser gyroscope resonant cavity and reduce the influence of temperature field changes on the zero bias of the laser gyroscope.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A laser gyro resonant cavity structure for improving temperature stability, the resonant cavity structure comprising a gas storage hole, a discharge region capillary, and a non-discharge region capillary;

[0009] A plurality of the gas storage holes are arranged at intervals in the resonant cavity of the resonant cavity structure, and adjacent gas storage holes are connected through the discharge area capillary and / or the non-discharge area capillary to form a closed optical path, and the discharge area capillary is connected to the discharge hole arranged in the resonant cavity; and the diameter of the non-discharge area capillary is larger than the diameter of the discharge area capillary.

[0010] Furthermore, the diameter ratio of the capillary in the discharge region to the capillary in the non-discharge region is 1:2 to 1:4.

[0011] Furthermore, the inner tube wall roughness Ra value of the capillary tube in the discharge region and the capillary tube in the non-discharge region is not less than 0.5 μm.

[0012] Furthermore, a graphene patch is attached to the surface of the resonant cavity structure.

[0013] Furthermore, the Langmuir flow of the gain gas in the resonant cavity structure is inversely proportional to the equivalent relative molecular mass M of the gain gas.

[0014] Furthermore, the gain gas is a helium-neon mixed gas, and the ratio of helium to neon gas is 14:1 to 29:1.

[0015] Furthermore, the resonant cavity structure is composed of an expansion coefficient of (0±0.05)×10 -6 / ℃ made of microcrystalline glass.

[0016] Furthermore, the resonant cavity structure also includes an aperture; two of the gas storage holes on one side of the resonant cavity are connected by two discharge area capillaries, and the two discharge area capillaries are connected through a through hole of the aperture; one of the discharge holes is located outside the aperture and is respectively connected to the two discharge area capillaries.

[0017] Furthermore, the resonant cavity structure further comprises a getter hole; the getter hole is arranged in the resonant cavity on one side inside the resonant cavity and is connected with the capillary in the non-discharge region.

[0018] The present invention also discloses a laser gyroscope, which comprises any one of the above-mentioned laser gyroscope resonant cavity structures for improving temperature stability.

[0019] Beneficial effects of the present invention:

[0020] The invention discloses a laser gyro resonant cavity structure and a laser gyro with improved temperature stability, which reduce the error introduced by temperature by reducing the flow of gain gas in the capillary of the laser gyro resonant cavity, thereby reducing the influence of temperature on the zero bias of the laser gyro.

[0021] The present invention optimizes the structure of the capillary in the resonant cavity structure, and expands the flow area of ​​the gain gas in the capillary through the non-discharge area capillary, which can increase the gas storage capacity of the gain gas in the capillary and slow down the flow of the gain gas, thereby reducing the influence of temperature on the zero bias of the laser gyroscope and helping to extend the service life of the laser gyroscope.

[0022] The present invention increases the inner tube wall roughness of the capillary tube in the discharge area and the capillary tube in the non-discharge area, thereby increasing the flow resistance of the tube wall to the gain gas and reducing the flow speed of the gain gas.

[0023] The present invention can accelerate the heat conduction of the resonant cavity structure through the graphene patch, thereby balancing the temperature difference and ensuring the temperature balance of the resonant cavity structure.

[0024] The present invention can also reduce the gain gas flow rate by using a gain gas whose Langmuir flow is inversely proportional to the equivalent relative molecular mass M. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the laser gyro resonant cavity structure for improving temperature stability of the present invention;

[0026] Figure 2 This is a schematic diagram of the resonant cavity structure during the laser gyro test of the present invention.

[0027] Among them: 1-discharge hole, 2-aperture, 3-gas storage hole, 4-getter hole, 5-discharge area capillary, 6-non-discharge area capillary, 7-heating resistor. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples of the specification. The following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0029] The terms such as upper, lower, left, right, inside, outside, front end, rear end, head, tail, etc. in this application document are based on the positions or positions shown in the drawings. If the drawings are different, the corresponding positions may also change accordingly, so they cannot be understood as limiting the scope of protection.

[0030] In the present invention, the terms "install", "connected", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection or mutual communication, a direct connection or an indirect connection through an intermediate medium, the internal connection of two components, or the interaction relationship between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] This embodiment describes a laser gyro resonant cavity structure and a laser gyro with improved temperature stability, which is a cavity solution for reducing the flow of gain gas in the capillary of the laser gyro, can improve the temperature stability of the laser gyro, and further extend the service life of the laser gyro.

[0032] The resonant cavity structure consists of an expansion coefficient of (0±0.05)×10 -6 / ℃ made of microcrystalline glass, such as Figure 1 As shown, the resonant cavity structure includes a discharge hole 1, an aperture 2, a gas storage hole 3, a getter hole 4, a discharge region capillary 5, and a non-discharge region capillary 6.

[0033] The resonant cavity in the resonant cavity structure is an axisymmetric structure, and multiple gas storage holes 3 are arranged at intervals in the resonant cavity. This embodiment takes four gas storage holes 3 located at four vertex corners as an example for explanation. The axes of the gas storage holes 3 are usually arranged along the diagonal of the resonant cavity. The aperture of the gas storage hole 3 is much larger than the diameter of the discharge region capillary 5 and the non-discharge region capillary 6, which can increase the storage capacity of the gain gas in the resonant cavity. The gas storage hole 3 is connected with the discharge region capillary 5 and the non-discharge region capillary 6 to form a closed optical path.

[0034] The specific configuration of the closed optical path includes but is not limited to the following structures: the two gas storage holes 3 on the front side of the resonant cavity are connected through the non-discharge area capillary 6, the getter hole 4 is installed in the resonant cavity along the front and rear axis of the resonant cavity and communicates with the non-discharge area capillary 6, and the getter in the getter hole 4 absorbs impurities to purify the gain gas in the resonant cavity, which is beneficial to improve the life of the laser gyroscope. The two gas storage holes 3 on the rear side of the resonant cavity are connected through two discharge area capillaries 5, and the two discharge area capillaries 5 are connected through the through hole of the aperture 2, the center of the through hole is on the front and rear axis of the resonant cavity, and the size of the through hole opening is adjustable. The through hole of the aperture 2, the gas storage hole 3, the discharge area capillary 5, and the non-discharge area capillary 6 together form a gain gas loop. The aperture 2 is used to filter out stray light in the gain gas loop to ensure that the laser beam passes through the gain gas loop and avoid stray light affecting the accuracy of the laser gyroscope. The discharge hole 1 outside the aperture 2 is connected to the two discharge area capillaries 5 respectively, as the cathode of the laser circuit. The two gas storage holes 3 on the left and right sides of the resonant cavity are respectively connected through capillaries composed of a discharge area capillary 5 and a non-discharge area capillary 6, and the non-discharge area capillary 6 and the discharge area capillary 5 are arranged front and back. The two discharge holes 1 on the left and right sides of the resonant cavity along the left and right axes of the resonant cavity are respectively arranged in the resonant cavity and are respectively connected to the discharge area capillary 5, serving as the anode of the laser circuit.

[0035] The discharge region capillary 5 is a gain region, and the non-discharge region capillary 6 is a non-gain region. This embodiment optimizes the diameter ratio of the discharge region capillary 5 to the non-discharge region capillary 6, so that the diameter of the non-discharge region capillary 6 is larger than the diameter of the discharge region capillary 5, which can increase the storage capacity of the gain gas in the resonant cavity and change the gas flow rate in the gain region, thereby reducing the temperature error. Preferably, the diameter ratio of the discharge region capillary 5 to the non-discharge region capillary 6 is 1:2 to 1:4.

[0036] In this embodiment, the inner tube wall of the discharge region capillary 5 and the non-discharge region capillary 6 has a certain degree of roughness, and the greater the roughness, the greater the flow resistance to the gain gas, reducing the flow speed of the gain gas. Preferably, the roughness Ra of the inner tube wall of the capillary is not less than 0.5 μm, and a protrusion structure can be further provided on the inner tube wall to increase the roughness of the inner tube wall of the capillary and increase the airflow resistance.

[0037] In order to solve the problem of unequal temperatures of the two arms of the resonant cavity, this embodiment pastes a graphene patch on the surface of the resonant cavity structure to accelerate the heat conduction of the resonant cavity structure, balance the temperature difference, and ensure the temperature balance of the resonant cavity structure.

[0038] The Langmuir flow of the gain gas in the resonant cavity structure of this embodiment is inversely proportional to the equivalent relative molecular mass M of the gain gas. Increasing the relative molecular mass of the gain gas reduces the gain gas flow rate. Taking helium-neon gas as the gain gas, the Langmuir flow test of different proportions of helium-neon gas is performed as an example, as shown in Table 1 below, to illustrate the gain gas of this embodiment.

[0039] Table 1 Langmuir flow tests at different ratios

[0040] He-Ne filling ratio Langmuir Flow Bias 14:1 14° / h 19:1 10° / h 29:1 6° / h 39:1 5° / h 49:1 4° / h

[0041] The resonant cavity structure of this embodiment is used in a laser gyro, which can greatly reduce the zero bias fluctuation under a variable temperature environment. The temperature difference sensitivity test can be performed on it through the test equipment to detect the impact on the zero bias. The test equipment usually includes an optical platform, a laser gyro test bench, a host computer, a counterweight, a temperature control power supply, a heating resistor (Pt1000)7, and a temperature recorder. The test method is as follows:

[0042] 1. Before the test, the closed optical path in the resonant cavity structure is filled with a predetermined proportion of helium-neon gas, the discharge hole 1 above the aperture 2 is connected to the cathode of the laser circuit power supply, and the two discharge holes 1 on the left and right are connected to the anode of the laser circuit power supply respectively; at the same time, Figure 2 As shown, at the junction of the anode discharge hole 1 and the discharge region capillary 5 of the left or right arm of the resonant cavity structure (i.e. Figure 2 A heating resistor 7 is pasted above the X point and the C point shown;

[0043] 2. Place the resonant cavity structure on the laser gyro test bench, and connect the heating resistor 7 to the temperature control power supply through a wire; turn on the laser circuit, generate laser in the closed optical path, and excite the helium-neon gas, the helium-neon gas generates fluctuations, and the laser circulates in the closed optical path; turn on the temperature control power supply, control the heating resistor 7 to heat, until the single arm of the resonant cavity structure is heated to a predetermined temperature (so that the temperature difference between the two arms of the resonant cavity reaches a preset temperature difference, such as the 10°C temperature difference used in the test in Table 2), and record the temperature data of the two arms of the resonant cavity structure and the zero bias data test through a temperature recorder, and stop after the zero bias curve is stable.

[0044] 3. Take the difference ΔBs between the maximum and minimum values ​​of the laser gyro zero bias in multiple tests and calculate the temperature difference sensitivity. The temperature difference sensitivity is: Wherein: the difference between the maximum and minimum values ​​of the laser gyro zero bias ΔBs, the temperature difference sensitivity S ΔT , the test results are shown in Table 2:

[0045] Table 2 Temperature sensitivity test results

[0046] serial number Sensitivity Conventional cavity 1 0.035° / h / ℃ Conventional cavity 2 0.040° / h / ℃ Optimized cavity 1 0.007° / h / ℃ Optimized cavity 2 0.010° / h / ℃

[0047] It can be seen from the test that, compared with the conventional resonant cavity structure with a capillary of the same diameter, the zero bias fluctuation of the resonant cavity structure of the laser gyro of this embodiment is reduced by about 2.5 times within the temperature range of -40°C to 70°C.

[0048] Note: The temperature difference sensitivity of the laser gyro resonant cavity is used to evaluate the laser gyro's resistance to temperature fluctuations in a variable temperature environment. The temperature difference sensitivity is defined as the change in the zero bias 100-second mean value when the temperature difference between the two arms of the resonant cavity increases by 1°C: Where ΔT is the temperature difference between the left and right arms of the resonant cavity.

[0049] Although the principles of the present invention are described in detail above in conjunction with the preferred embodiments of the present invention, those skilled in the art should understand that the above embodiments are merely explanations of the exemplary implementations of the present invention, and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute limitations on the scope of the present invention, and any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, fall within the protection scope of the present invention.

Claims

1. A laser gyro resonant cavity structure for improving temperature stability, characterized in that: The resonant cavity structure comprises a gas storage hole (3), a discharge region capillary (5), and a non-discharge region capillary (6); A plurality of gas storage holes (3) are arranged at intervals in the resonant cavity of the resonant cavity structure, and adjacent gas storage holes (3) are connected through the discharge region capillary (5) and / or the non-discharge region capillary (6) to form a closed optical path, and the discharge region capillary (5) is connected to the discharge hole (1) arranged in the resonant cavity; and the diameter of the non-discharge region capillary (6) is greater than the diameter of the discharge region capillary (5).

2. The laser gyro resonant cavity structure for improving temperature stability according to claim 1, wherein: The diameter ratio of the discharge region capillary (5) to the non-discharge region capillary (6) is 1:2 to 1:

4.

3. The laser gyro resonant cavity structure with improved temperature stability according to claim 1 or 2, characterized in that: The inner tube wall roughness Ra value of the discharge region capillary (5) and the non-discharge region capillary (6) is not less than 0.5 μm.

4. The laser gyro resonant cavity structure for improving temperature stability according to claim 1, characterized in that: A graphene patch is pasted on the surface of the resonant cavity structure.

5. The laser gyro resonant cavity structure for improving temperature stability according to claim 1, characterized in that: The Langmuir flow of the gain gas in the resonant cavity structure is inversely proportional to the equivalent relative molecular mass M of the gain gas.

6. The laser gyro resonant cavity structure for improving temperature stability according to claim 5, characterized in that: The gain gas is a helium-neon mixed gas, and the ratio of helium-neon gas is 14:1 to 29:

1.

7. The laser gyro resonant cavity structure for improving temperature stability according to claim 1, characterized in that: The resonant cavity structure has an expansion coefficient of (0±0.05)×10 -6 / ℃ made of microcrystalline glass.

8. The laser gyro resonant cavity structure for improving temperature stability according to claim 1, characterized in that: The resonant cavity structure also includes an aperture (2); two gas storage holes (3) on one side of the resonant cavity are connected via two discharge area capillaries (5), and the two discharge area capillaries (5) are connected via a through hole of the aperture (2); one discharge hole (1) is located outside the aperture (2) and is respectively connected to the two discharge area capillaries (5).

9. The laser gyro resonant cavity structure for improving temperature stability according to claim 1, characterized in that: The resonant cavity structure also includes a getter hole (4); the getter hole (4) is arranged in the resonant cavity on one side of the resonant cavity and is connected to the non-discharge region capillary (6).

10. A laser gyro, characterized in that: The laser gyro comprises the laser gyro resonant cavity structure for improving temperature stability according to any one of claims 1 to 9.

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