Active cavity tuning method for laser gyroscope

Abstract

The invention discloses an active cavity tuning method for a laser gyroscope, comprising: placing a first gain laser tube on the left side of a cavity to be tuned and corresponding to the upper left corner thereof, placing a first reflector on the left side of the first gain laser tube, placing a second gain laser tube on the left side of the cavity to be tuned and corresponding to the lower left corner thereof, placing a second reflector on the left side of the second gain laser tube, placing a photodetector below the cavity to be tuned and corresponding to the lower right corner thereof; placing a third reflector below the cavity to be tuned and corresponding to the lower left corner thereof; placing a fourth reflector above the cavity to be tuned and corresponding to the upper left corner thereof; forming different resonant cavities by turning on the first gain laser tube and / or the second gain laser tube, and determining the positions of the first gain laser tube and the second gain laser tube, the third reflector, the fourth reflector, the first spherical mirror and the second spherical mirror in sequence, so that the cavity tuning method of the laser gyroscope can be completed efficiently and accurately.

Description

Technical Field

[0001] The invention relates to the technical field of laser gyroscope preparation, and in particular to an active cavity tuning method of a laser gyroscope. Background Art

[0002] Laser gyro is a high-precision inertial device that is widely used in both military and civilian fields. The principle of laser gyro is to use the optical path difference to measure the angular velocity of rotation, that is, the Sagnac effect. In a closed optical path, two beams of light transmitted in the clockwise and counterclockwise directions from a light source interfere with each other. By detecting the phase difference or the change of interference fringes, the angular velocity of rotation of the closed optical path can be measured. The key component of the laser gyro to produce the Sagnac effect is the ring laser resonator, and the quality of its adjustment will directly affect the overall performance of the laser gyro.

[0003] The traditional laser gyro cavity tuning method is generally carried out by aligning the light beam and the center of the optical path hole axis and measuring the cavity loss. First, with the help of the laser gyro's visual inspection system, the cavity tuner can adjust the resonant cavity while observing the relative position of the light beam and the aperture until the light beam is located at the center of the optical path hole axis, thereby achieving rough alignment. Fine alignment is achieved by measuring the cavity loss and adjusting the spherical mirror in real time. The smaller the cavity loss, the better the cavity tuning effect. There are usually two methods for measuring cavity loss: the resonance method and the time attenuation method. The resonance method is to inject a laser with a linear frequency change into the ring laser resonant cavity, use a photodetector to receive the transmitted light wave signal, and draw a light intensity spectrum line diagram. The spectrum line is in the form of Lorentz, and its half-height width is proportional to the loss of the ring laser resonant cavity. The loss can be obtained by measuring the half-height width of the spectrum line. However, this method is not suitable for measurements when the loss is lower than 500ppm, because the shape of the spectrum line deviates from the Lorentz line shape, and the half-height width at this time can no longer represent the cavity loss. The time decay method is to control the acousto-optic switch to quickly cut off the light source at the light intensity threshold, and calculate the cavity loss by measuring the time of light loss in the optical cavity. However, the ring-down time is affected by many factors, such as ambient temperature, which may cause fluctuations in the ring-down time, resulting in inaccurate measurement results and difficulty in judging the cavity adjustment effect. Traditional cavity adjustment methods and devices have been unable to guarantee the adjustment effect of laser gyroscopes, affecting the performance and production qualification rate of high-precision laser gyroscopes. Summary of the invention

[0004] In response to the problems in the background technology, the present invention proposes an efficient and accurate active cavity tuning method for a laser gyroscope, which does not require a complex visual detection and positioning system and can effectively avoid the cumbersome loss measurement process and the technical difficulties of low-loss measurement in traditional cavity tuning methods.

[0005] The present invention adopts the following technical solutions:

[0006] An active cavity tuning method for a laser gyroscope comprises the following steps:

[0007] S1: Determine the position of the first gain laser tube and the second gain laser tube

[0008] S1.1: Install a first plane mirror at the upper right corner of the cavity to be adjusted of the laser gyroscope, install a second plane mirror at the lower right corner of the cavity to be adjusted, place the first gain laser tube on the left side of the cavity to be adjusted, and correspond to the upper left corner of the cavity to be adjusted, place the first reflector on the left side of the first gain laser tube, place the second gain laser tube on the left side of the cavity to be adjusted, and correspond to the lower left corner of the cavity to be adjusted, place the second reflector on the left side of the second gain laser tube, and place the photodetector below the cavity to be adjusted, and correspond to the lower right corner of the cavity to be adjusted;

[0009] S1.2: Turn on the first gain laser tube, the second gain laser tube and the photodetector, and adjust the positions of the first gain laser tube and the second gain laser tube so that the optical power detected by the photodetector is the maximum, and fix the positions of the first gain laser tube and the second gain laser tube;

[0010] S2: Determine the position of the third reflector

[0011] S2.1: Install a third plane mirror at the upper left corner of the cavity to be adjusted of the laser gyro, and place the third reflector below the cavity to be adjusted and corresponding to the lower left corner of the cavity to be adjusted;

[0012] S2.2: turn off the first gain laser tube, turn on the second gain laser tube and the photodetector, adjust the position of the third reflector so that the light power detected by the photodetector is maximum, and fix the position of the third reflector;

[0013] S3: Determine the position of the fourth reflector

[0014] S3.1: Remove the third plane mirror from the cavity to be adjusted, install the fourth plane mirror at the lower left corner of the cavity to be adjusted of the laser gyro, and place the fourth reflector above the cavity to be adjusted and corresponding to the upper left corner of the cavity to be adjusted;

[0015] S3.2: Turn on the first gain laser tube and the photodetector, turn off the second gain laser tube, adjust the position of the fourth reflector so that the optical power detected by the photodetector is maximum, and fix the position of the fourth reflector;

[0016] S4: Determine the position of the first spherical mirror

[0017] S4.1: Remove the first plane mirror from the cavity to be adjusted, and install the first spherical mirror at the upper right corner of the cavity to be adjusted of the laser gyroscope; turn on the first gain laser tube and the photodetector, turn off the second gain laser tube, adjust the position of the first spherical mirror so that the optical power detected by the photodetector is the maximum, and fix the position of the first spherical mirror;

[0018] S5: remove the fourth plane mirror from the cavity to be adjusted, and install the second spherical mirror at the upper left corner of the cavity to be adjusted of the laser gyroscope; turn on the second gain laser tube and the photodetector, turn off the first gain laser tube, adjust the position of the second spherical mirror so that the optical power detected by the photodetector is the maximum, and fix the position of the second spherical mirror;

[0019] S6: Install the fourth plane mirror at the lower left corner of the cavity to be adjusted of the laser gyroscope to complete the cavity adjustment of the laser gyroscope.

[0020] Optionally, between steps S1.1 and S1.2, the following is further included:

[0021] S1.1.1: Place the collimated laser on the right side of the cavity to be adjusted, corresponding to the lower right corner of the cavity to be adjusted, set the second aperture between the first gain laser tube and the cavity to be adjusted, and set the third aperture between the second gain laser tube and the cavity to be adjusted, turn on the collimated laser, turn off the photodetector, adjust the position of the second gain laser tube and the second reflector, so that the center of the incident light spot and the reflected light spot passing through the third aperture coincide with the center of the third aperture; adjust the position of the first gain laser tube and the first reflector, so that the center of the incident light spot and the reflected light spot passing through the second aperture coincide with the center of the second aperture;

[0022] S1.1.2: Turn off the collimation laser and remove the second and third apertures.

[0023] Optionally, before steps S2.1 and S2.2, the method further includes:

[0024] S2.1.1: Set a third aperture between the second gain laser tube and the cavity to be adjusted, turn on the collimating laser and turn off the photodetector, and adjust the position of the third reflector so that the centers of the incident light spot and the reflected light spot passing through the third aperture coincide with the center of the third aperture;

[0025] S2.1.2: Turn off the collimation laser and remove the third aperture.

[0026] Optionally, before steps S3.1 and S3.2, the method further includes:

[0027] S3.1.1: Set a second aperture between the first gain laser tube and the cavity to be adjusted, turn on the collimating laser and turn off the photodetector, and adjust the position of the fourth reflector so that the centers of the incident light spot and the reflected light spot passing through the second aperture coincide with the center of the second aperture;

[0028] S3.1.2: Turn off the collimation laser and remove the second aperture.

[0029] Optionally, in the S1.1.1, S2.1.1 and S3.1.1, before turning on the collimating laser, the method further includes: setting a first aperture between the cavity to be adjusted and the collimating laser.

[0030] That is, a coaxial optical path is first formed by using a collimated laser and an aperture to roughly adjust the positions of the first gain laser tube and the first reflector, the second gain laser tube and the second reflector, the third reflector, and the fourth reflector, respectively, thereby reducing the difficulty of subsequently adjusting the cavity by forming a resonant optical path through the gain laser tube.

[0031] Optionally, the first reflector is a plane reflector, the second reflector is a curved reflector, the third reflector is a plane reflector, and the fourth reflector is a curved reflector.

[0032] Optionally, the first reflector is a curved reflector, the second reflector is a plane reflector, the third reflector is a curved reflector, and the fourth reflector is a plane reflector.

[0033] Optionally, one of the first gain laser tube and the second gain laser tube is a gain laser tube with a Brewster window.

[0034] Optionally, the other of the first gain laser tube and the second gain laser tube is a gain laser tube with an anti-reflection film.

[0035] A dual gain tube structure is adopted, one of which adopts a Brewster window structure and the other adopts an anti-reflection film lens gain tube structure, which can effectively avoid the gain degradation problem caused by polarization matching problems.

[0036] Specifically, one of the purposes of using a Brewster window laser tube is to ensure laser polarization and improve beam quality. When non-polarized light is incident at the Brewster angle, the reflected part will completely become S-polarized light, while the transmitted part will partially become P-polarized light. The light beam passes through the Brewster window multiple times, which can greatly reduce the S component in the transmitted light beam, thereby improving the purity and quality of the P-polarized light.

[0037] Another reason why the laser gain tube adopts the anti-reflection film flat sheet packaging structure is that if two Brewster window laser tubes are used, the two laser tubes will inevitably have an angle error of rotation perpendicular to the optical axis during installation, resulting in inconsistent directions of transmitted polarized light, forming a competitive relationship and causing power reduction. Therefore, this laser tube adopts a non-Brewster window structure, but instead adopts a surface anti-reflection film flat sheet packaging, which allows low-loss passage of polarized light in all directions to ensure laser power.

[0038] Compared with the prior art, the advantages of the present invention are:

[0039] The active cavity tuning method of the laser gyroscope of the present invention forms an active cavity with two gain laser tubes and a gyroscope cavity, and then divides into two times, each time using three plane mirrors on the cavity to be adjusted (two plane mirrors on the cavity to be adjusted and a temporary adjustment plane mirror) and the corresponding gain tube to determine an optimal resonant optical path, that is, find the maximum point of the resonant light intensity of the resonant optical path, that is, the optimal position of the lens, and then replace the temporary adjustment plane mirror in the optical path with a spherical mirror, and use the same method to determine the optimal resonant position of the resonant optical path, so as to complete the cavity tuning. Since only one spherical mirror is adjusted each time, the direction of the light beam is easy to control, and the optimal light beam path is uniquely determined, avoiding the problem of uncertainty of the optimal path caused by the simultaneous adjustment of two spherical mirrors. It is a new type of cavity tuning method with high efficiency and accuracy, and effectively avoids the relative position of the light beam and the aperture and the cavity loss detection process in the traditional cavity tuning method, without the need for a complex visual detection and positioning system. The method of the present invention can well complete the cavity tuning of the laser gyroscope, which is of great significance for optimizing the performance of the laser gyroscope and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to make the present invention more easily understood, the present invention will be described in more detail by referring to the specific embodiments shown in the accompanying drawings. These drawings only depict typical embodiments of the present invention and should not be considered as limiting the scope of protection of the present invention.

[0041] Figure 1 Schematic diagram of the optical path of step 1 of the active cavity tuning method of the laser gyroscope according to an embodiment of the present invention.

[0042] Figure 2 Schematic diagram of the optical path of step 2 of the active cavity tuning method of the laser gyroscope according to an embodiment of the present invention.

[0043] Figure 3 Schematic diagram of the optical path of step three of the active cavity tuning method of the laser gyroscope according to an embodiment of the present invention.

[0044] Figure 4 Schematic diagram of the optical path of step 4 of the active cavity tuning method of the laser gyroscope according to an embodiment of the present invention.

[0045] Figure 5 Schematic diagram of the optical path of step five of the active cavity tuning method for a laser gyroscope according to an embodiment of the present invention.

[0046] Figure 6 Schematic diagram of the optical path of step six of the active cavity tuning method for a laser gyroscope according to an embodiment of the present invention.

[0047] Figure 7 Schematic diagram of the optical path of step seven of the active cavity tuning method for a laser gyroscope according to an embodiment of the present invention.

[0048] Figure 8 FIG. 1 is a schematic diagram of an optical path of step eight of the active cavity tuning method for a laser gyroscope according to an embodiment of the present invention.

[0049] Fig. 9 Schematic diagram of step nine of the active cavity tuning method for a laser gyroscope according to an embodiment of the present invention.

[0050] Fig.10 The invention is used to complete the laser gyroscope with active cavity modulation.

[0051] Reference numerals:

[0052] 10. Cavity to be adjusted; 11. First plane mirror; 12. Second plane mirror; 20. First gain laser tube; 30. Second gain laser tube; 40. First reflecting mirror; 41. Second reflecting mirror; 42. Fourth reflecting mirror; 43. Third reflecting mirror; 13. Third plane mirror; 14. Fourth plane mirror; 16. First spherical mirror; 17. Second spherical mirror; 70. Photoelectric detector; 80. Collimating laser; 81. First aperture; 82. Second aperture; 83. Third aperture. DETAILED DESCRIPTION

[0053] The following describes the implementation modes of the present invention with reference to the accompanying drawings so that those skilled in the art can better understand the present invention and implement it. However, the enumerated embodiments are not intended to limit the present invention. In the absence of conflict, the following embodiments and the technical features in the embodiments may be combined with each other, wherein the same components are represented by the same figure marks.

[0054] like Figure 1-Figure 9 As shown, the active cavity tuning method of the laser gyro of this embodiment includes the following steps:

[0055] Preparation before tuning:

[0056] A first plane mirror 11 is installed at the upper right corner of the cavity 10 to be adjusted of the laser gyroscope, a second plane mirror 12 is installed at the lower right corner of the cavity to be adjusted, a first gain laser tube 20 is placed on the left side of the cavity to be adjusted, and corresponds to the upper left corner of the cavity to be adjusted, a first reflector 40 is placed on the left side of the first gain laser tube 20, a second gain laser tube 30 is placed on the left side of the cavity to be adjusted, and corresponds to the lower left corner of the cavity to be adjusted, a second reflector 41 is placed on the left side of the second gain laser tube 30, and a photodetector 70 is placed below the cavity to be adjusted, and corresponds to the lower right corner of the cavity to be adjusted;

[0057] The collimating laser 80 is placed on the right side of the cavity to be adjusted, and corresponds to the lower right corner of the cavity to be adjusted 10. A second aperture 82 is set between the first gain laser tube 20 and the cavity to be adjusted 10, a third aperture 83 is set between the second gain laser tube 30 and the cavity to be adjusted 10, and a first aperture 81 is set between the cavity to be adjusted 10 and the collimating laser 80.

[0058] The third reflector 43 is placed below the cavity to be adjusted and corresponds to the lower left corner of the cavity to be adjusted;

[0059] The fourth reflector 42 is placed above the cavity to be adjusted and corresponds to the upper left corner of the cavity to be adjusted.

[0060] The tuning process is divided into the following steps:

[0061] Step 1: Coarse adjustment of the positions of the first gain laser tube 20 and the second gain laser tube 30

[0062] like Figure 1 As shown, turn on the collimating laser 80, turn off the photodetector 70, adjust the positions of the second gain laser tube 30 and the second reflector 41, so that the centers of the incident light spot and the reflected light spot passing through the third aperture 83 coincide with the center of the third aperture 83; adjust the positions of the first gain laser tube 20 and the first reflector 40, so that the centers of the incident light spot and the reflected light spot passing through the second aperture 82 coincide with the center of the second aperture 82; turn off the collimating laser 80, and remove the second aperture 82 and the third aperture 83.

[0063] Specifically, after adjusting the collimation of the collimating laser 80 in this step, the collimated light emitted from the collimating laser passes through the second plane mirror 12 and the second gain laser tube 30, is reflected by the curved second reflector 41, is reflected by the second plane mirror 12 and the first plane mirror 11, enters the first gain laser tube 20, and is reflected by the flat first reflector 40. The third aperture 83 is used to observe whether the incident and reflected light spots of the optical path 81-10-83-30-41-30-83 coincide with each other. If not, the positions of the second gain laser tube 30 and the second reflector 41 are roughly adjusted so that the incident light spot and the reflected light spot passing through the third aperture 83 coincide with each other, thereby realizing the coaxiality of the optical path, that is, the second gain laser tube 30 is substantially coaxial with the lower section of the cavity 10 to be adjusted. Then observe through the second aperture 82 whether the incident and reflected light spots of the optical path 81-10-83-30-41-30-83-12-11-10-82-20-40-20-82 coincide with each other. If not, coarsely adjust the positions of the first gain laser tube 20 and the first reflector 40 so that the incident light spot and the reflected light spot through the second aperture 82 coincide with each other, thereby realizing the above-mentioned coaxial optical path, that is, the first gain laser tube 20 is basically coaxial with the upper section of the cavity 10 to be adjusted.

[0064] Step 2: Fine-tuning the positions of the first gain laser tube 20 and the second gain laser tube 30

[0065] like Figure 2 As shown, the first gain laser tube 20, the second gain laser tube 30 and the photodetector 70 are turned on, and the positions of the first gain laser tube 20 and the second gain laser tube 30 are adjusted so that the optical power detected by the photodetector 70 is maximum, and the positions of the first gain laser tube 20 and the second gain laser tube 30 are fixed.

[0066] Specifically, in this step, the first gain laser tube 20 and the second gain laser tube 30 are turned on, and the lasers emitted by the first gain laser tube 20 and the second gain laser tube 30 and the resonant gain functions of the two are used to form a resonant optical path 41-30-10-20-40. The transmitted light emitted from the second plane mirror 12 is collected by the photodetector 70, and the first gain laser tube 20 and the second gain laser tube 30, as well as the first reflector 40 and the second reflector 41 are fine-tuned to maximize the optical power detected by the photodetector 70, that is, to maximize the optical power of the resonant cavity 41-30-10-20-40, that is, the optical path is precisely coaxial and the power is optimal, thereby achieving precise coaxiality between the second gain laser tube 30 and the lower section of the cavity 10 to be adjusted, and precise coaxiality between the first gain laser tube 20 and the upper section of the cavity 10 to be adjusted.

[0067] Step 3: Coarse adjustment of the position of the third reflector 43

[0068] like Figure 3 As shown, a third plane mirror 13 is installed at the upper left corner of the cavity 10 to be adjusted of the laser gyroscope;

[0069] A third aperture 83 is set between the second gain laser tube 30 and the cavity 10 to be adjusted, the collimating laser 80 is turned on and the photodetector 70 is turned off, and the position of the third reflector 43 is adjusted so that the centers of the incident light spot and the reflected light spot passing through the third aperture 83 coincide with the center of the third aperture 83; the collimating laser 80 is turned off, and the third aperture 83 is removed.

[0070] Specifically, this step utilizes the collimated light emitted by the collimated laser to form an optical path 81-12-10-83-30-41-30-83-12-11-13-43-13-11-12-83, and observes whether the incident and reflected light spots of the above optical path overlap through the third aperture 83. If they do not overlap, the position of the third reflector 43 is roughly adjusted to make the incident light spot and the reflected light spot passing through the third aperture 83 overlap and are both in the center of the aperture, so that the laser incident on the mirror surface of the third reflector 43 is roughly perpendicular to its mirror surface, and the coaxial adjustment is completed.

[0071] Step 4: Fine-tune the position of the third reflector 43

[0072] like Figure 4 As shown, the first gain laser tube 20 is turned off, the second gain laser tube 30 and the photodetector 70 are turned on, the position of the third reflector 43 is adjusted so that the optical power detected by the photodetector 70 is maximum, and the position of the third reflector 43 is fixed.

[0073] Specifically, this step utilizes the laser emitted by the second gain laser tube 30 and its resonant gain function to form an active cavity 41-30-10-43, and finely adjusts the position of the third reflector 43 so that the optical power of the resonant cavity 41-30-10-43 is maximized (i.e., the optical power detected by the photodetector 70 is maximized), thereby achieving that the laser incident on the mirror surface of the third reflector 43 is precisely perpendicular to its mirror surface.

[0074] Step 5: Coarse adjustment of the position of the fourth reflector 42

[0075] like Figure 5 As shown, the third plane mirror 13 is removed from the cavity 10 to be adjusted, and the fourth plane mirror 14 is installed at the lower left corner of the cavity 10 to be adjusted of the laser gyroscope;

[0076] A second aperture 82 is set between the first gain laser tube 20 and the cavity 10 to be adjusted, the collimating laser 80 is turned on and the photodetector 70 is turned off, and the position of the fourth reflector 42 is adjusted so that the centers of the incident light spot and the reflected light spot passing through the second aperture 82 coincide with the center of the second aperture 82; the collimating laser 80 is turned off, and the second aperture 82 is removed.

[0077] Specifically, this step utilizes the collimated light emitted by the collimated laser to form an optical path 12-14-42-14-12-11-82-20-40-20-82, and coarsely adjusts the position of the fourth reflector 42 so that the incident light spot and the reflected light spot passing through the second aperture 82 coincide with each other and are at the center of the second aperture 82, thereby achieving that the laser light incident on the mirror surface of the fourth reflector 42 is roughly perpendicular to its tangent of the incident point, thereby completing the coaxial coarse adjustment.

[0078] Step 6: Fine-tune the position of the fourth reflector 42

[0079] like Figure 6 As shown, the first gain laser tube 20 and the photodetector 70 are turned on, the second gain laser tube 30 is turned off, the position of the fourth reflector 42 is adjusted so that the optical power detected by the photodetector 70 is maximum, and the position of the fourth reflector 42 is fixed.

[0080] Specifically, this step utilizes the laser emitted by the first gain laser tube 20 and its resonance gain function, and the resonant cavity composed of 40-20-10-42 generates laser through resonance, and fine-tunes the position of the fourth reflector 42 so that the optical power of the resonant cavity 40-20-10-42 is maximized (that is, the optical power detected by the photodetector 70 is maximized), thereby achieving that the laser incident on the mirror surface of the fourth reflector 42 is precisely perpendicular to its mirror surface, thereby completing coaxial fine-tuning.

[0081] Step 7: Determine the position of the first spherical mirror 16

[0082] like Figure 7 As shown, the first plane mirror 11 is removed from the cavity to be adjusted, and the first spherical mirror 16 is installed at the upper right corner of the cavity to be adjusted of the laser gyroscope; the first gain laser tube 20 and the photodetector 70 are turned on, and the second gain laser tube 30 is turned off. The position of the first spherical mirror 16 is adjusted so that the light power detected by the photodetector 70 is the maximum, and the position of the first spherical mirror 16 is fixed.

[0083] Specifically, in this step, the first plane mirror 11 is replaced by the first spherical mirror 16, and the laser emitted by the first gain laser tube 20 and its resonance gain function are utilized. The resonant cavity composed of 40-20-10-42 generates laser through resonance, and the orientation of the first spherical mirror 16 is fine-tuned so that the optical power of the resonant cavity 40-20-10-42 is maximized (that is, the optical power detected by the photodetector 70 is maximized), thereby realizing the adjustment of the first spherical mirror 16.

[0084] Step 8: Determine the position of the second spherical mirror 17

[0085] like Figure 8As shown, the fourth plane mirror 14 is removed from the cavity to be adjusted, and the second spherical mirror 17 is installed at the upper left corner of the cavity to be adjusted of the laser gyroscope; the second gain laser tube 30 and the photodetector 70 are turned on, the first gain laser tube 20 is turned off, the position of the second spherical mirror 17 is adjusted so that the optical power detected by the photodetector 70 is the maximum, and the position of the second spherical mirror 17 is fixed;

[0086] Specifically, in this step, the fourth plane mirror 14 is replaced by the second spherical mirror 17, and the laser emitted by the second gain laser tube 30 and its resonance gain function are utilized. The resonant cavity composed of 41-30-10-43 generates laser through resonance, and the orientation of the second spherical mirror 17 is fine-tuned so that the optical power of the resonant cavity 41-30-10-43 is maximized (that is, the optical power detected by the photodetector 70 is maximized), thereby realizing the adjustment of the second spherical mirror 17.

[0087] Step 9: Install the fourth plane mirror 14

[0088] like Fig. 9 As shown, a fourth plane mirror 14 is installed at the lower left corner of the cavity to be adjusted of the laser gyroscope to complete the cavity adjustment of the laser gyroscope. The laser gyroscope after cavity adjustment is as shown in FIG. Fig.10 shown.

[0089] In this embodiment, the first reflector 40 is a plane reflector, the second reflector 41 is a curved reflector, the third reflector 43 is a plane reflector, and the fourth reflector 42 is a curved reflector.

[0090] In other embodiments, the first reflector 40 may be a curved reflector, the second reflector 41 may be a plane reflector, the third reflector 43 may be a curved reflector, and the fourth reflector 42 may be a plane reflector.

[0091] In this embodiment, one of the first gain laser tube 20 and the second gain laser tube 30 is a gain laser tube with a Brewster window, and the other is a gain laser tube with an anti-reflection film.

[0092] The present invention introduces a gain tube with a Brewster window and a gain tube with an anti-reflection film to form a resonant cavity with a cavity to be adjusted. First, the two gain tubes are adjusted to be coaxial with the cavity channel to be adjusted through the collimation device and the resonant gain function of the gain tube itself. Next, three plane mirrors (two plane mirrors on the cavity to be adjusted and a temporary adjustment plane mirror) and corresponding gain tubes are used twice each time to determine an optimal resonant optical path, that is, to find the maximum point of the resonant light intensity of the resonant optical path, that is, the optimal position of the lens. The temporary adjustment plane mirror in the optical path is then replaced with a spherical mirror, and the same method is used to determine the optimal resonant position of the resonant optical path, thereby completing the cavity adjustment. Since only one spherical mirror is adjusted each time, the direction of the light beam is easily controlled, and the optimal light beam path is uniquely determined, avoiding the problem of uncertainty in the optimal path caused by the simultaneous adjustment of two spherical mirrors. It is a new type of cavity adjustment method with high efficiency and accuracy, and effectively avoids the relative position of the light beam and the aperture and the cavity loss detection process in the traditional cavity adjustment method, without the need for a complex visual detection and positioning system. The method of the present invention can well complete the cavity adjustment of the laser gyroscope, which is of great significance for optimizing the performance of the laser gyroscope and improving production efficiency.

[0093] The embodiments described above are only preferred specific implementations of the present invention. This specification uses the phrases "in one embodiment", "in another embodiment", "in yet another embodiment" or "in other embodiments" to refer to one or more of the same or different embodiments according to the present disclosure. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. An active cavity tuning method for a laser gyroscope, characterized in that: The following steps are involved: S1: Determine the positions of the first gain laser tube (20) and the second gain laser tube (30): S1.1: Install a first plane mirror (11) at the upper right corner of the cavity to be adjusted (10) of the laser gyroscope, install a second plane mirror (12) at the lower right corner of the cavity to be adjusted, place the first gain laser tube (20) on the left side of the cavity to be adjusted, and correspond to the upper left corner of the cavity to be adjusted, place the first reflector (40) on the left side of the first gain laser tube (20), place the second gain laser tube (30) on the left side of the cavity to be adjusted, and correspond to the lower left corner of the cavity to be adjusted, place the second reflector (41) on the left side of the second gain laser tube (30), and place the photodetector (70) below the cavity to be adjusted, and correspond to the lower right corner of the cavity to be adjusted; S1.2: turning on the first gain laser tube (20), the second gain laser tube (30) and the photodetector (70), adjusting the positions of the first gain laser tube (20) and the second gain laser tube (30) so that the optical power detected by the photodetector (70) is maximum, and fixing the positions of the first gain laser tube (20) and the second gain laser tube (30); S2: Determine the position of the third reflector (43): S2.1: installing a third plane mirror (13) at the upper left corner of the cavity (10) to be adjusted of the laser gyroscope, and placing a third reflector (43) below the cavity to be adjusted and corresponding to the lower left corner of the cavity to be adjusted; S2.2: turning off the first gain laser tube (20), turning on the second gain laser tube (30) and the photodetector (70), adjusting the position of the third reflector (43) so that the optical power detected by the photodetector (70) is maximum, and fixing the position of the third reflector (43); S3: Determine the position of the fourth reflector (42): S3.1: removing the third plane mirror (13) from the cavity to be adjusted (10), installing the fourth plane mirror (14) at the lower left corner of the cavity to be adjusted (10) of the laser gyroscope, and placing the fourth reflector (42) above the cavity to be adjusted and corresponding to the upper left corner of the cavity to be adjusted; S3.2: turning on the first gain laser tube (20) and the photodetector (70), turning off the second gain laser tube (30), adjusting the position of the fourth reflector (42) so that the optical power detected by the photodetector (70) is maximum, and fixing the position of the fourth reflector (42); S4: Determine the position of the first spherical mirror (16): S4.1: remove the first plane mirror (11) from the cavity to be adjusted, and install the first spherical mirror (16) at the upper right corner of the cavity to be adjusted of the laser gyroscope; turn on the first gain laser tube (20) and the photodetector (70), turn off the second gain laser tube (30), adjust the position of the first spherical mirror (16) so that the optical power detected by the photodetector (70) is the maximum, and fix the position of the first spherical mirror (16); S5: removing the fourth plane mirror (14) from the cavity to be adjusted, and installing the second spherical mirror (17) at the upper left corner of the cavity to be adjusted of the laser gyroscope; turning on the second gain laser tube (30) and the photodetector (70), turning off the first gain laser tube (20), adjusting the position of the second spherical mirror (17) so that the optical power detected by the photodetector (70) is the maximum, and fixing the position of the second spherical mirror (17); S6: Install a fourth plane mirror (14) at the lower left corner of the cavity to be adjusted of the laser gyroscope to complete the cavity adjustment of the laser gyroscope.

2. The active cavity tuning method of a laser gyro according to claim 1, characterized in that: Between steps S1.1 and S1.2, it also includes: S1.1.1: Place the collimating laser (80) on the right side of the cavity to be adjusted, corresponding to the lower right corner of the cavity to be adjusted (10), set a second aperture (82) between the first gain laser tube (20) and the cavity to be adjusted (10), set a third aperture (83) between the second gain laser tube (30) and the cavity to be adjusted (10), turn on the collimating laser (80), turn off the photodetector (70), adjust the positions of the second gain laser tube (30) and the second reflector (41), so that the centers of the incident light spot and the reflected light spot passing through the third aperture (83) coincide with the center of the third aperture (83); adjust the positions of the first gain laser tube (20) and the first reflector (40), so that the centers of the incident light spot and the reflected light spot passing through the second aperture (82) coincide with the center of the second aperture (82); S1.1.2: Turn off the collimating laser (80), and remove the second aperture (82) and the third aperture (83).

3. The active cavity tuning method of a laser gyro according to claim 2, characterized in that: Before steps S2.1 and S2.2, the method further includes: S2.1.1: a third aperture (83) is arranged between the second gain laser tube (30) and the cavity to be adjusted (10), the collimating laser (80) is turned on and the photodetector (70) is turned off, and the position of the third reflector (43) is adjusted so that the centers of the incident light spot and the reflected light spot passing through the third aperture (83) coincide with the center of the third aperture (83); S2.1.2: Turn off the collimating laser (80) and remove the third aperture (83).

4. The active cavity tuning method of a laser gyro according to claim 3, characterized in that: Before steps S3.1 and S3.2, the method further includes: S3.1.1: a second aperture (82) is arranged between the first gain laser tube (20) and the cavity to be adjusted (10), the collimating laser (80) is turned on, the photodetector (70) is turned off, and the position of the fourth reflector (42) is adjusted so that the centers of the incident light spot and the reflected light spot passing through the second aperture (82) coincide with the center of the second aperture (82); S3.1.2: Turn off the collimating laser (80) and remove the second aperture (82).

5. The active cavity tuning method of a laser gyro according to claim 4, characterized in that: In the above S1.1.1, S2.1.1 and S3.1.1, before turning on the collimating laser (80), the method further comprises: arranging a first aperture (81) between the cavity to be adjusted (10) and the collimating laser (80).

6. The active cavity tuning method of a laser gyro according to any one of claims 1 to 5, characterized in that: The first reflector (40) is a plane reflector, the second reflector (41) is a curved reflector, the third reflector (43) is a plane reflector, and the fourth reflector (42) is a curved reflector.

7. The active cavity tuning method of a laser gyro according to any one of claims 1 to 5, characterized in that: The first reflector (40) is a curved reflector, the second reflector (41) is a plane reflector, the third reflector (43) is a curved reflector, and the fourth reflector (42) is a plane reflector.

8. The active cavity tuning method of a laser gyro according to any one of claims 1 to 5, characterized in that: One of the first gain laser tube (20) and the second gain laser tube (30) is a gain laser tube with a Brewster window.

9. The active cavity tuning method of a laser gyro according to any one of claims 1 to 5, characterized in that: The other of the first gain laser tube (20) and the second gain laser tube (30) is a gain laser tube with an anti-reflection film.

Images