Adjusting device and method for aligning the optical axes of a laser and a telescope system

Abstract

The present application relates to a kind of registration laser and telescope system optical axis adjusting device and method, wherein method utilizes the detection function of collimator to laser optical axis, by recording the optical axis change of laser before and after telescope, the angle difference between incident laser and telescope main shaft is obtained by theoretical calculation, optical axis is adjusted under the monitoring of collimator, after adjustment, laser beam is emitted along the main shaft of telescope system, and the registration between laser and telescope system optical axis is completed.Compared with prior art, the advantages of the present application are that the mirror is directly adjusted to change laser optical axis to realize the registration of telescope main shaft, avoid adjusting easily deformed telescope, thereby improving the reliability of system, while simplifying the process of installation and adjustment, and the operation process is more convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optoelectronic technology, in particular to an adjusting device and method for aligning the optical axes of a laser and a telescope system. BACKGROUND

[0002] With the birth of the first laser in the world in 1960, laser technology and application have developed rapidly. As an artificial light source, due to the characteristics of high brightness, strong directivity, good monochromaticity and strong coherence, laser technology has combined with multiple disciplines to form multiple application technology fields, such as laser remote sensing, laser radar, quantum optics, laser controlled nuclear fusion, laser weapons, etc. The application of laser technology involves almost all active optoelectronic systems, greatly promoting the development of traditional industries and emerging industries.

[0003] Laser technology is also widely used in the field of laser remote sensing, such as spaceborne laser ranging, long-distance laser communication, long-distance quantum communication, etc. Due to the long transmission distance of laser, in order to detect or receive modulated light signals at a farther distance, a large-aperture telescope system is usually used to collimate the laser beam for emission, so as to compress the laser emission divergence angle, and ultimately achieve the goals of improving the angular resolution of the system, reducing the optical loss of the system, and improving the communication or detection distance.

[0004] In the active optoelectronic system of laser remote sensing, a transceiver optical path integration design is usually adopted. The laser emission system is composed of a laser and a collimator, and the receiving lens, optical receiver and data processing unit form a receiving system. In the actual design of the active optoelectronic system, an expanded-beam telescope system is usually used to compress the divergence angle of the laser. In order to achieve better laser collimation effect, the optical axes before and after the laser collimation module and the telescope system need to be aligned so that the laser is emitted from the central field of view. In the actual assembly and adjustment process, after the laser optical axis is determined, the direction of the telescope is usually adjusted by grinding the gasket of the telescope to align the optical axes between the telescope and the laser. When adjusting with this method, the telescope needs to be disassembled and assembled back and forth. Since the telescope system is the key of the entire collimation system, and due to the flatness of the gasket, the telescope system is prone to deformation under stress, thereby causing the deformation of the outgoing beam of the system, and the deformation is not easy to detect. SUMMARY

[0005] The purpose of the present application is to overcome the defects of the prior art and provide an adjusting device and method for aligning the optical axes of a laser and a telescope system. The present application records the changes of the optical axes before and after the laser passes through the telescope, calculates the azimuth and elevation angles of the incident laser that need to be adjusted, directly adjusts the direction of the laser, and thus aligns the optical axes of the laser and the telescope system. The present application avoids disassembling and assembling the telescope system back and forth, reduces the probability of deformation of the telescope, and adjusts the smaller mirror to align the optical axes of the telescope and the laser, which is convenient to adjust.

[0006] The object of the present application can be achieved by the following technical solutions.

[0007] An adjusting device for aligning the optical axes of a laser and a telescope system, comprising a laser collimation module, a mirror, a telescope system, a collimator and a beam analyzer;

[0008] The laser collimation module is used to generate a collimated laser beam and to make the collimated laser beam incident on the mirror;

[0009] The mirror is used to turn the light path of the collimated laser beam and to make the turned collimated laser beam incident on the telescope system or the collimator;

[0010] The telescope system is used to expand the turned collimated laser beam and to make the expanded collimated laser beam incident on the collimator;

[0011] The collimator is used to detect the angle change of the incident beam;

[0012] The beam analyzer is used to read the spot coordinates of the beam imaging.

[0013] Further, the laser collimation module comprises a laser communication system or a laser emitting device.

[0014] Further, the telescope system selects one of a transmission telescope and a reflection telescope.

[0015] Further, the surface accuracy RMS value of the mirror is better than .

[0016] Further, the surface accuracy RMS value of the telescope system is better than .

[0017] An adjusting method for aligning the optical axes of a laser and a telescope system, which is implemented based on the adjusting device for aligning the optical axes of a laser and a telescope system as described above, and comprises the following steps:

[0018] S1, laser collimation module optical axis coordinate calibration: the laser collimation module emits a collimated laser beam, the collimated laser beam is incident on the collimator after passing through the mirror, and the laser collimation module spot coordinates are read and recorded by the beam analyzer;

[0019] S2, telescope system optical axis coordinate calibration: the laser collimation module emits a collimated laser beam, the collimated laser beam is incident on the collimator after passing through the mirror, and the telescope system spot coordinates are read and recorded by the beam analyzer;

[0020] S3, calculating the adjustment amount of the mirror based on the laser collimation module light spot coordinates and the telescope system light spot coordinates;

[0021] S4, adjusting the mirror based on the adjustment amount of the mirror to complete the optical axis registration adjustment between the laser and the telescope system.

[0022] Further, in steps S1 and S2, the positional relationship of the laser collimation module and the mirror needs to be adjusted, so that the converging light spot of the collimated laser beam is imaged at the center position of the beam analyzer image plane.

[0023] Further, the calculation of the adjustment amount of the mirror includes:

[0024] calculating the distance in the x direction that the mirror needs to be adjusted ;

[0025] calculating the distance in the y direction that the mirror needs to be adjusted .

[0026] Further, the laser collimation module light spot coordinates are denoted as (x1, y1), the telescope system light spot coordinates are denoted as (x2, y2), and the calculation formula of the distance in the x direction that the mirror needs to be adjusted is:

[0027]

[0028] The calculation formula of the distance in the y direction that the mirror needs to be adjusted is:

[0029]

[0030] In the formula, the beam expansion ratio of the telescope system.

[0031] Further, step S4 specifically adjusts the azimuth and elevation angle of the mirror, so that the outgoing collimated laser beam of the laser collimation module passes through the mirror, the telescope system and the collimator in turn, and the light spot movement amount of the converging light spot imaged on the beam analyzer is and , to complete the optical axis registration adjustment between the laser and the telescope system.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] ​​​​1. The application records the change of the optical axis of the laser before and after passing through the telescope system, obtains the azimuth and elevation angle of the incident laser that needs to be adjusted through theoretical calculation, directly adjusts the mirror to change the direction of the laser, and thus realizes the registration of the laser and the optical axis of the telescope system. The method of directly adjusting the laser optical axis to register the main axis of the telescope is adopted, the telescope that is easy to deform during disassembly and adjustment is avoided, and thus the reliability of the system assembly and adjustment is improved.

[0034] 2. The application adjusts the smaller mirror to realize the registration of the optical axis of the telescope and the optical axis of the laser. Compared with the prior art that registers the optical axis between the telescope and the laser by grinding the gasket of the telescope, the application is more convenient to adjust and simplifies the assembly and adjustment process. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The figure is a schematic diagram of the optical path of the registration of the laser and the optical axis of the telescope system in the embodiment of the application.

[0036] Figure 2 The figure is a schematic diagram of the principle of the optical axis registration method in the embodiment of the application.

[0037] Figure 3 The figure is a schematic diagram of the coordinate adjustment at the focal plane of the collimator in the embodiment of the application. DETAILED DESCRIPTION

[0038] The application will be described in detail below in combination with the drawings and specific embodiments. The embodiments are implemented on the premise of the technical scheme of the application, detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0039] The application relates to an adjusting device and method for registering the optical axis of a laser and a telescope system, in particular to the registration and adjustment of the optical axis of a laser and a telescope system in an active optoelectronic system, wherein the method is suitable for an active optoelectronic system that uses a beam expander telescope to collimate a laser. The method uses the detection function of a collimator on the optical axis of the laser, records the change of the optical axis of the laser before and after passing through the telescope, theoretically calculates the angle difference between the incident laser and the main axis of the telescope, adjusts the optical axis under the monitoring of the collimator, and makes the laser beam exit along the main axis of the telescope system after adjustment, thereby completing the registration between the laser and the optical axis of the telescope system. The method is suitable for the registration between the telescope and the optical axis of the laser in the active optoelectronic system, and is also suitable for the case that the telescope is easy to deform or the adjustment amount is too large. The method has the advantages that the laser optical axis is directly adjusted to register the main axis of the telescope, the telescope that is easy to deform during disassembly and adjustment is avoided, the reliability of the system is improved, the assembly and adjustment process is simplified, the operation process is more convenient, and the method can be applied to the fields of laser ranging, laser communication, quantum communication and the like that need to collimate and emit a laser.

[0040] For example, Figure 1As shown, it is an adjusting device for registering the optical axes of laser and telescope system according to the application, which comprises a laser collimation module 1, a mirror 2, a telescope system 3, a collimator 4 and a beam analyzer 5.

[0041] The laser collimation module 1 is used to generate a collimated laser beam and to make the collimated laser beam incident into the mirror 2.

[0042] The mirror 2 is used to turn the light path of the collimated laser beam and to make the turned collimated laser beam incident into the telescope system 3 or the collimator 4.

[0043] The telescope system 3 is used to expand the turned collimated laser beam and to make the expanded collimated laser beam incident into the collimator 4.

[0044] The collimator 4 is used to detect the angle change of the incident beam.

[0045] The beam analyzer 5 is used to read the spot coordinates of the beam imaging.

[0046] In this embodiment, the laser collimation module 1 is a simplification of various spatial optical systems, including but not limited to the laser emission module of the laser communication system and the laser radar system.

[0047] The mirror 2 is used as the relay and direction adjusting device of the laser collimation module 1 and the telescope system 3, and its surface accuracy RMS value is better than .

[0048] The telescope system 3 is an expansion system, and a transmissive telescope or a reflective telescope can be selected, and its surface accuracy RMS value is better than .

[0049] When the device is used to register the optical axes of laser and telescope system, the steps include: the laser collimation module 1 emits a collimated laser beam, which is first incident into the collimator 4 after passing through the mirror 2, and then forms an image on the beam analyzer 5 after passing through the collimator 4, and the beam analyzer 5 can read the spot coordinates at this time; then the telescope system 3 is fixed in the system light path, the laser collimation module 1 emits a collimated beam, which is incident into the telescope system 3 after passing through the mirror 2, and then forms an image on the beam analyzer 5 after expanding through the telescope system 3 and then entering the collimator 4, and the beam analyzer 5 can read the spot coordinates at this time; the adjustment amount of the mirror 2 can be calculated through the imaging positions of the two spots before and after, and the adjustment position can be monitored through the beam analyzer 5, and the registration of the optical axes of laser and telescope system is completed after adjustment.

[0050] Specifically, the method comprises the following steps:

[0051] S1, laser collimation module optical axis coordinate calibration: the laser collimation module emits a collimated laser beam, the collimated laser beam is incident into the collimator after the mirror, and the laser spot coordinates of the laser collimation module are read and recorded by the beam analyzer;

[0052] S2, telescope system optical axis coordinate calibration: the laser collimation module emits a collimated laser beam, the collimated laser beam is incident into the telescope system and the collimator in turn after the mirror, and the telescope system spot coordinates are read and recorded by the beam analyzer;

[0053] S3, based on the laser collimation module spot coordinates and the telescope system spot coordinates, the adjustment amount of the mirror is calculated;

[0054] S4, based on the adjustment amount of the mirror, the mirror is adjusted to complete the optical axis registration and adjustment between the laser and the telescope system.

[0055] In steps S1 and S2, the positional relationship of the laser collimation module and the mirror needs to be adjusted, so that the convergent light spot of the collimated laser beam is imaged at the center position of the beam analyzer image plane.

[0056] In this embodiment, the laser collimation module spot coordinates are denoted as (x1, y1), the telescope system spot coordinates are denoted as (x2, y2), and the mirror needs to be adjusted in the x direction by a distance The calculation formula of the distance

[0057]

[0058] The calculation formula of the distance

[0059]

[0060] In the formula, The beam expansion ratio of the telescope system.

[0061] Step S4 is to adjust the azimuth and pitch angle of the mirror, so that the emitted collimated laser beam of the laser collimation module passes through the mirror, the telescope system and the collimator in turn, and the convergent light spot is imaged on the beam analyzer, and the spot movement amount is and , to complete the optical axis registration and adjustment between the laser and the telescope system.

[0062] The basic principle of optical axis adjustment in the application is as follows:

[0063] As shown in Figure 2 , the principle of the telescope system compressing the divergence angle is as follows: the focal plane positions of the primary and secondary mirrors of the telescope system coincide, and when the divergence angle is ​​​When a laser beam is incident on the telescope system, it first passes through a focal length of... The secondary mirror converges the laser beam, with the converged spot positioned on the axis. Typically, the laser divergence angle is relatively small, resulting in a converged imaging spot size of [missing information]. The converging light spot reaches a focal length of [missing information] after transmission. Since the converging light spot is also located at the focal plane of the primary mirror, the light spot is collimated and emitted after passing through the primary mirror. The divergence angle of the collimated light is... ,in If denoted as the system's magnification factor, then the divergence angle of the emitted light from the system decreases. times.

[0064] The actual situation encountered in this invention is that a laser beam travels at a paraxial angle. When light is incident obliquely onto the telescope system at a relatively small angle, the center of the light spot will converge away from the principal axis after passing through the secondary mirror. The laser beam continues its transmission and reaches the primary mirror of the telescope system. Since the focal planes of the primary and secondary mirrors coincide, the outgoing light is collimated by the primary mirror. The angle between the collimated outgoing beam and the principal axis is... ,Right now The change in the optical axis of a laser beam before and after passing through a telescope can be measured using a collimator. Its optical axis change satisfy:

[0065]

[0066] The angle of laser deviation from the principal axis satisfy:

[0067]

[0068] Multiplying this angular relationship by the focal length of the collimator can be converted into a displacement change at the focal plane of the collimator, thus obtaining the calculated value. and The expression.

[0069] As a preferred embodiment, the main components used in this embodiment are described as follows:

[0070] 1) Laser collimation module 1: includes a customized optical path board, with an output wavelength of 850nm, a beam output aperture of 20mm, and an output light divergence angle of less than 100µA.

[0071] 2) Reflector 2: A custom-made 45-degree oval reflector with a minor axis diameter of 40mm, a surface PV value better than 1 / 4λ, and an RMS value better than 1 / 20λ@632.8nm; the optical surface is coated with a reflective film, and the average reflectivity in the 600 to 1000nm band is better than 97%.

[0072] 3) Telescope system 3: Customized telescope, RMS value better than 1 / 15λ@632.8nm, beam expander ratio is 5 times.

[0073] 4) Collimator 4: Focal length 1.2m, aperture 300mm, RMS value better than 1 / 15λ@632.8nm, coaxial parabolic surface.

[0074] 5) Beam profiler 5: Model BGS-USB3-SP920s, wavelength range 190-1100nm, pixel size 4.4um, resolution 1624x1224.

[0075] The schematic diagram of the experimental device in this embodiment is shown in Figure 1 The specific steps of using the device to realize the registration of the optical axis of the laser and the telescope system are as follows:

[0076] 1) Optical axis coordinate calibration of the laser collimation module: build the optical path, do not add the telescope system 3 at the beginning, the laser collimation module 1 emits a collimated light beam, which is directly incident into the collimator 4 after the reflection mirror 2, adjust the positional relationship of the laser collimation module 1 and the reflection mirror 2, so that the converging image is near the center position of the image plane of the beam profiler 5, the beam profiler 5 can read out the spot coordinates at this time, and record the coordinate value (x1, y1) as . .

[0077] 2) Optical axis coordinate calibration of the telescope system: build the optical path as shown in the attached Figure 1 , install the telescope system 3, the laser collimation module 1 emits a collimated light beam, which is incident into the telescope system 3 after the reflection mirror 2, and then into the collimator 4, move the telescope system 3 so that the light beam forms an image on the image plane of the beam profiler 5 after converging, the beam profiler 5 can read out the spot coordinates at this time, and record the coordinate value (x2, y2) as . .

[0078] 3) Calculate the adjustment amount of the reflection mirror 2: as shown in the attached Figure 3 , the beam expander ratio of the telescope system 3 is 5 times, the x coordinate values of steps 1) and 2) are extracted respectively, then the distance needed to adjust in the x direction of the image plane of the beam profiler 5 in step 1) is . The calculation formula is as follows:

[0079] um

[0080] Similarly, the distance needed to adjust in the y direction of the image plane of the beam profiler 5 in step 1) is .

[0081]

[0082] 4) Directly adjust the azimuth-elevation of the mirror 2, so that the exit collimated beam of the laser collimation module 1 passes through the mirror 2, the telescope system 3, enters the parallel light pipe 4, and then is imaged on the spot movement of the beam analyzer 5 , the rear spot of the mirror 2 moves to ( ) that is , the system adjustment is completed, and the telescope and the laser exit optical axis are registered.

[0083] The above describes the preferred embodiments of the present application in detail. It should be understood that those skilled in the art can make many modifications and changes without any creative work according to the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment on the basis of the prior art according to the concept of the present application should be within the protection scope defined by the claims.

Claims

1. A method of adjusting the registration of the optical axes of a laser and a telescope system, characterized in that, The method is realized based on an adjusting device for registering laser and optical axis of a telescope system, the device comprises a laser collimation module (1), a mirror (2), a telescope system (3), a collimator (4) and a beam analyzer (5); The laser collimation module (1) is used for generating a collimated laser beam and making the collimated laser beam incident into the mirror (2); The mirror (2) is used for turning the light path of the collimated laser beam and making the turned collimated laser beam incident into the telescope system (3) or the collimator (4); The telescope system (3) is used for expanding the turned collimated laser beam and making the expanded collimated laser beam incident into the collimator (4); The collimator (4) is used for detecting the angle change of the incident beam; The beam analyzer (5) is used for reading the spot coordinates of the beam imaging; The method comprises the following steps: S1, laser collimation module optical axis coordinate calibration: the laser collimation module emits a collimated laser beam, the collimated laser beam is incident into the collimator after passing through the mirror, and the laser collimation module spot coordinates are read and recorded by the beam analyzer; S2, telescope system optical axis coordinate calibration: the laser collimation module emits a collimated laser beam, the collimated laser beam is incident into the telescope system and the collimator in turn after passing through the mirror, and the telescope system spot coordinates are read and recorded by the beam analyzer; S3, based on the laser collimation module spot coordinates and the telescope system spot coordinates, the adjusting amount of the mirror is calculated; S4, the mirror is adjusted based on the adjusting amount of the mirror, and the registration adjustment of the optical axis between the laser and the telescope system is completed; The step S4 specifically comprises adjusting the azimuth and elevation angles of the mirror, so that the outgoing collimated laser beam of the laser collimation module sequentially passes through the mirror, the telescope system and the collimator tube, and the movement amount of the light spot on the beam analyzer is and , and the adjustment of the optical axis between the laser and the telescope system is completed. The laser collimation module spot coordinates are ( The coordinates of the light spot of the telescope system are ( ). ), In the formula, The telescope system has an expansion ratio.

2. The method of claim 1, wherein, The laser collimation module (1) comprises a laser communication system or a laser emitting device.

3. The method of claim 1, wherein the step of adjusting the optical axis of the laser and the optical axis of the telescope system is performed by adjusting the position of the laser relative to the telescope system. The telescope system (3) selects one of a transmission telescope and a reflection telescope.

4. The method of claim 1, wherein, The surface accuracy of the mirror (2) is better than .

5. The method of claim 1, wherein, The surface accuracy of the telescope system (3) is better than .

6. The method of claim 1, wherein, In steps S1 and S2, the positional relationship of the laser collimation module and the mirror needs to be adjusted, so that the converging spot of the collimated laser beam is imaged at the center position of the beam analyzer image surface.

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