Optical path adjustment device and method for an optical fiber laser

Abstract

The present invention provides an optical path adjustment device and method for a fiber laser. The optical path adjustment device includes a lens barrel, an orifice plate assembly, and an adjustment bracket. The orifice plate assembly includes a plurality of orifice plates, which are detachably mounted at the light inlet and outlet of the lens barrel. The orifice plates are provided with openings coaxially arranged with the lens barrel. The lens barrel is mounted on the adjustment bracket to adjust the lens barrel in the X-axis direction, Y-axis direction, the rotation direction around the X-axis, and the rotation direction around the Y-axis. The X-axis direction and the Y-axis direction are perpendicular to each other and are distributed in a plane perpendicular to the optical axis of the lens barrel. The present invention can quickly locate the offset of the laser beam passing through the optical path adjustment device relative to the opening on the orifice plate, ensuring the consistency of the optical axis of the laser beam, and has the advantages of high precision, simple operation, high debugging efficiency, and being able to adapt to optical paths of various laser spot sizes.

Description

Technical Field

[0001] The present invention relates to the technical field of lasers and their applications, and particularly to an optical path adjustment device and method for a fiber laser. Background Art

[0002] A fiber laser refers to a laser that uses rare-earth element-doped glass fiber as the gain medium. Compared with traditional solid-state lasers, fiber lasers have the advantages of small size, long life, high laser brightness, high laser conversion efficiency, good laser beam quality, etc., and are thus widely used in fields such as material processing, optical communication, spectral imaging, and medical treatment.

[0003] In recent years, with the increasing requirements for laser processing accuracy, in the fields of optical storage, spectral imaging, and medicine, the requirements for the laser spots formed by the laser beams of fiber lasers have also become higher and higher. This correspondingly requires that the laser beams must have better monochromaticity, higher coherence, and smaller divergence angles. Among them, an important evaluation criterion for laser beam quality is the laser beam quality factor M2. In the technical field of fiber lasers, the traditional method for testing the laser beam quality factor is to use two 45° mirror groups in the test optical path to adjust the optical path of the laser beam incident into the beam quality factor tester.

[0004] Since it is necessary to ensure that the laser beam is vertically incident on the light receiving surface of the CCD detector in the tester, the requirement for the directivity of the laser beam entering the tester is relatively high. In the actual testing process, mainly relying on two 45° arranged mirrors, one mirror is used to debug the horizontal direction of the optical path, and the other mirror is used to debug the vertical direction of the optical path. The adjustment operation is relatively cumbersome, and the debugging efficiency of the optical path is low. At the same time, the offset of the laser optical path is sensitive to the mirrors and is easily affected by the installation deformation of the mirrors and other micro-variations, resulting in difficulty in finely adjusting the optical path. Summary of the Invention

[0005] The present invention provides an optical path adjustment device and method for a fiber laser to solve the problem that the existing optical path adjustment device has a cumbersome operation and it is difficult to finely adjust the optical path.

[0006] The present invention provides an optical path adjustment device for a fiber laser, including: a lens barrel, an aperture plate assembly, and an adjustment bracket; the aperture plate assembly includes a plurality of aperture plates, the aperture plates are detachably installed at the light inlet and outlet of the lens barrel, and the aperture plates are provided with openings coaxially arranged with the lens barrel for the laser beam to pass through; the adjustment bracket mounts the lens barrel to adjust the lens barrel in the X-axis direction, Y-axis direction, the rotation direction around the X-axis, and the rotation direction around the Y-axis, and the X-axis direction and the Y-axis direction are perpendicular to each other and are distributed in a plane perpendicular to the optical axis of the lens barrel.

[0007] An optical path adjustment device for a fiber laser provided according to the present invention, wherein the adjustment bracket includes a fixed bracket and an adjustment plate arranged at intervals; the fixed bracket is provided with a fixed point, a first adjustment point, and a second adjustment point, a connection line between the fixed point and the first adjustment point is arranged along the X-axis direction, and a connection line between the fixed point and the second adjustment point is arranged along the Y-axis direction; the fixed bracket is fixedly connected to the first surface of the adjustment plate through the fixed point; the fixed bracket is adjustably connected to the first surface along the optical axis direction of the lens barrel through the first adjustment point and the second adjustment point respectively; a through hole is formed in the adjustment plate, the lens barrel passes through the through hole, and an outer diameter of the lens barrel is smaller than an inner diameter of the through hole, and the lens barrel is connected to a second surface of the adjustment plate facing away from the first surface; the adjustment plate is provided with a third adjustment point and a fourth adjustment point, and is adjustably connected to an outer side wall of the lens barrel along a radial direction through the third adjustment point and the fourth adjustment point respectively, a radial adjustment direction where the third adjustment point is located is along the X-axis direction, and a radial adjustment direction where the fourth adjustment point is located is along the Y-axis direction.

[0008] An optical path adjustment device for a fiber laser provided according to the present invention, a first adjustment bolt is installed at the first adjustment point, a second adjustment bolt is installed at the second adjustment point, both the first adjustment bolt and the second adjustment bolt are installed on the fixed bracket, and screw rod ends of the first adjustment bolt and the second adjustment bolt respectively extend vertically along the optical axis direction towards the first surface; a third adjustment bolt is installed at the third adjustment point, a fourth adjustment bolt is installed at the fourth adjustment point, the third adjustment bolt and the fourth adjustment bolt are installed on the adjustment plate, and screw rod ends of the third adjustment bolt and the fourth adjustment bolt both extend into the through hole and extend along the radial direction towards the outer side wall of the lens barrel.

[0009] An optical path adjustment device for a fiber laser provided according to the present invention, the fixed bracket includes a fixed part and an adjustment part, the fixed part and the adjustment part are vertically arranged, the adjustment part and the adjustment plate are arranged at intervals, and the fixed point, the first adjustment point, and the second adjustment point are arranged on the adjustment part.

[0010] An optical path adjustment device for a fiber laser provided according to the present invention, the adjustment bracket further includes a mounting plate, the mounting plate is installed on the second surface of the adjustment plate and is fixedly connected to the lens barrel.

[0011] An optical path adjustment device for an optical fiber laser provided according to the present invention, the lens barrel includes a first lens barrel and a second lens barrel, the first lens barrel is slidably inserted into the second lens barrel, the first lens barrel passes through the through hole, and the second lens barrel is fixedly connected to the mounting plate.

[0012] An optical path adjustment device for an optical fiber laser provided according to the present invention, the orifice plate assembly includes a first group of orifice plates and a second group of orifice plates; the first group of orifice plates includes a first orifice plate and a second orifice plate, the first orifice plate is used to be installed at the light incident port of the lens barrel, the second orifice plate is used to be installed at the light exit port of the lens barrel, the opening diameter of the first orifice plate is less than 2 / 3 of the diameter of the light spot of the laser beam, and the opening diameter of the second orifice plate is greater than 1.5 times the diameter of the light spot; the second group of orifice plates includes a third orifice plate and a fourth orifice plate, the third orifice plate is used to be installed at the light incident port of the lens barrel, the fourth orifice plate is used to be installed at the light exit port of the lens barrel, the opening diameter of the third orifice plate is less than 2 / 3 of the diameter of the light spot, and the opening diameter of the fourth orifice plate is greater than 2 / 3 of the diameter of the light spot.

[0013] For an optical path adjustment device for an optical fiber laser provided according to the present invention, the radius of the opening and the wavelength of the laser beam satisfy the following formula:

[0014] θ0 = 0.61λ / a;

[0015] Wherein, θ0 represents the diffraction angle corresponding to the diffraction ring with the maximum light intensity formed by the laser beam passing through the opening on the CCD target surface; λ represents the wavelength of the laser beam; a represents the radius of the opening; the CCD target surface is arranged on the side close to the light exit port of the lens barrel, and the CCD target surface is perpendicular to the optical axis direction of the lens barrel.

[0016] The present invention also provides an adjustment method for the optical path adjustment device of the optical fiber laser as described above, including: S1, arranging the optical fiber laser, the lens barrel and the CCD target surface in sequence along the transmission direction of the laser beam, and installing the lens barrel on the adjustment bracket; S2, installing the first orifice plate at the light incident port of the lens barrel and the second orifice plate at the light exit port of the lens barrel, starting the optical fiber laser, and adjusting the lens barrel in the X-axis direction and the Y-axis direction until the center of the light spot formed by the laser beam on the CCD target surface coincides with the center of the positioning mark on the CCD target surface; S3, removing the first orifice plate and the second orifice plate from the lens barrel, then installing the third orifice plate at the light incident port of the lens barrel and the fourth orifice plate at the light exit port of the lens barrel, and adjusting the rotation direction of the lens barrel around the X-axis and the rotation direction around the Y-axis until the light spot forms a diffraction ring pattern with central symmetry distribution on the CCD target surface; wherein, the aperture diameters of the openings on the first orifice plate, the second orifice plate, the third orifice plate and the fourth orifice plate are all set according to the wavelength of the laser beam.

[0017] According to an adjustment method provided by the present invention, S1 further includes: setting the output power of the fiber laser so that the beam energy corresponding to the output power is within the safety threshold range of the beam quality factor tester, starting the fiber laser, recording the spot formed by the laser beam on the CCD target surface, and preliminarily positioning the spot through the positioning marks on the CCD target surface; wherein, the CCD target surface is arranged on the beam quality factor tester.

[0018] An optical path adjustment device and method for a fiber laser provided by the present invention, by setting a lens barrel, an orifice plate assembly and an adjustment bracket, based on the principle of small hole diffraction and spot imaging, with the cooperation of multiple orifice plates, the adjustment effect of the lens barrel along the X-axis direction, Y-axis direction, the rotation direction around the X-axis and the rotation direction around the Y-axis of the adjustment bracket can be used to quickly locate the offset of the laser beam passing through the optical path adjustment device relative to the opening on the orifice plate, ensuring the consistency of the optical axis of the laser beam, and having the advantages of high precision, simple operation, high debugging efficiency, and being able to adapt to the optical paths of various laser spot sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 is a three-dimensional structural schematic diagram of the optical path adjustment device of the fiber laser provided by the present invention;

[0021] Figure 2 is a front view structural schematic diagram of the optical path adjustment device of the fiber laser provided by the present invention;

[0022] Figure 3 is a three-dimensional structural schematic diagram of the adjustment bracket provided by the present invention;

[0023] Figure 4 is a front view structural schematic diagram of the adjustment bracket provided by the present invention;

[0024] Figure 5 is a flow schematic diagram of the adjustment method of the optical path adjustment device based on the fiber laser provided by the present invention;

[0025] Figure 6 is a schematic diagram of the non-uniform symmetric diffraction ring obtained on the CCD target surface through the adjustment of the first group of orifice plates in the embodiment of the present invention;

[0026] Figure 7It is a schematic diagram of the uniform and symmetric diffraction rings obtained on the CCD target surface through the adjustment of the second set of orifice plates in the embodiments of the present invention;

[0027] Reference numerals:

[0028] 1: lens barrel; 2: orifice plate assembly; 3: adjustment bracket;

[0029] 31: fixing bracket; 32: adjustment plate; 33: mounting plate;

[0030] 301: fixing point; 302: first adjustment point; 303: second adjustment point;

[0031] 304: third adjustment point; 305: fourth adjustment point. Detailed implementation manners

[0032] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts belong to the scope of protection of the present invention.

[0033] The following combines Figures 1 - 5 to describe the optical path adjustment device and method of the fiber laser of the present invention.

[0034] As Figures 1 to 4 shown, this embodiment provides an optical path adjustment device for a fiber laser, including: a lens barrel 1, an orifice plate assembly 2 and an adjustment bracket 3; the orifice plate assembly 2 includes a plurality of orifice plates, the orifice plates are detachably installed at the light inlet and outlet of the lens barrel 1, and the orifice plates are provided with openings coaxially arranged with the lens barrel 1 for laser beams to pass through. Among them, the openings are preferably circular holes; the lens barrel 1 is installed on the adjustment bracket 3 to adjust the lens barrel 1 in the X-axis direction, Y-axis direction, the rotation direction around the X-axis and the rotation direction around the Y-axis. The X-axis direction and the Y-axis direction are perpendicular to each other and are distributed in a plane perpendicular to the optical axis of the lens barrel 1.

[0035] Specifically, in this embodiment, by setting the lens barrel 1, the orifice plate assembly 2 and the adjustment bracket 3, based on the principle of small hole diffraction and spot imaging, with the cooperation of a plurality of orifice plates, the offset of the laser beam passing through the adjustment device relative to the opening on the orifice plate can be quickly located based on the adjustment of the lens barrel 1 in the X-axis direction, Y-axis direction, the rotation direction around the X-axis and the rotation direction around the Y-axis by the adjustment bracket 3, ensuring the consistency of the optical axis of the laser beam. It has the advantages of high precision, simple operation, high debugging efficiency, and being able to adapt to the optical paths of various laser spot sizes, and is easy to be integrated with the interfaces of other laser testing devices.

[0036] It should be noted here that in the M2 measurement system of the fiber laser beam quality, the optical axis of the optical system in the beam quality factor tester must be kept coincident with the optical axis of the laser transmission system. The system has a relatively high requirement for the accuracy of the optical axis consistency. The consistency of the optical axis will directly reflect the results such as the beam quality, spot shape, and spot size received on the CCD target surface of the beam quality factor tester. Since there are both offsets in the X-axis and Y-axis directions in the emission plane of the laser beam, and there are also pitching (rotation) relative to the X-axis direction and rotational offsets relative to the Y-axis direction, thus based on the adjustment of the lens barrel 1 by the adjustment bracket 3 in this embodiment, the adjustment of the offset of the laser beam relative to the opening on the orifice plate can be achieved. Then, according to the principle of small hole diffraction and spot imaging, the optical axis of the laser beam output by the fiber laser can be adjusted to ensure the consistency of the optical axis of the laser beam output by the fiber laser and the optical axis of the optical system in the beam quality factor tester.

[0037] The adjustment bracket 3 shown in this embodiment can be set to be composed of an XY translation stage well-known in the art and rotating mechanisms respectively rotating along the X-axis and Y-axis, or can also be set to be a combined structure composed of a fixing frame 31 and an adjustment plate 32 shown in the following embodiments, and no specific limitation is made here.

[0038] Meanwhile, the orifice plate assembly 2 shown in this embodiment includes a first group of orifice plates and a second group of orifice plates. The first group of orifice plates includes a first orifice plate and a second orifice plate. The first orifice plate is used to be installed at the light inlet of the lens barrel 1, and the second orifice plate is used to be installed at the light outlet of the lens barrel 1. Specifically, the opening diameter of the first orifice plate can be set to be less than 2 / 3 of the diameter of the laser beam spot, and the opening diameter of the second orifice plate can be set to be greater than 1.5 times the diameter of the spot. Meanwhile, the second group of orifice plates includes a third orifice plate and a fourth orifice plate. Specifically, the third orifice plate can be set to be installed at the light inlet of the lens barrel 1, and the fourth orifice plate is installed at the light outlet of the lens barrel 1. The opening diameter of the third orifice plate is less than 2 / 3 of the diameter of the laser beam spot, and the opening diameter of the fourth orifice plate is greater than 2 / 3 of the diameter of the spot.

[0039] As Figure 2 And Figure 3 shown, the adjustment bracket 3 shown in this embodiment includes a fixing frame 31 and an adjustment plate 32 arranged at intervals.

[0040] Further, on the fixing bracket 31 shown in this embodiment, there are a fixing point 301, a first adjustment point 302, and a second adjustment point 303. The connection line between the fixing point 301 and the first adjustment point 302 is arranged along the X-axis direction, and the connection line between the fixing point 301 and the second adjustment point 303 is arranged along the Y-axis direction; the fixing bracket 31 is fixedly connected to the first surface of the adjustment plate 32 through the fixing point 301; the fixing bracket 31 is adjustably connected to the first surface along the optical axis direction of the lens barrel 1 through the first adjustment point 302 and the second adjustment point 303 respectively.

[0041] Among them, a first adjustment bolt is installed at the first adjustment point 302 shown in this embodiment, and a second adjustment bolt is installed at the second adjustment point 303. Both the first adjustment bolt and the second adjustment bolt are installed on the fixing bracket 31, and the screw ends of the first adjustment bolt and the second adjustment bolt extend perpendicularly along the optical axis direction towards the first surface of the adjustment plate 32. In this way, by adjusting the feeding amount of the first adjustment bolt, the rotational offset amount of the laser beam relative to the Y-axis can be finely adjusted. By adjusting the feeding amount of the second adjustment bolt, the pitching offset amount of the laser beam relative to the X-axis can be finely adjusted.

[0042] Further, a through hole is formed on the adjustment plate 32 shown in this embodiment. The lens barrel 1 passes through the through hole, and the outer diameter of the lens barrel 1 is smaller than the aperture of the through hole. The lens barrel 1 is connected to the second surface of the adjustment plate 32 facing away from the first surface.

[0043] Further, a third adjustment point 304 and a fourth adjustment point 305 are provided on the adjustment plate 32 shown in this embodiment, and the adjustment plate 32 is adjustably connected to the outer side wall of the lens barrel 1 along the radial direction through the third adjustment point 304 and the fourth adjustment point 305 respectively. The radial adjustment direction where the third adjustment point 304 is located is along the X-axis direction, and the radial adjustment direction where the fourth adjustment point 305 is located is along the Y-axis direction.

[0044] Among them, a third adjustment bolt is installed at the third adjustment point 304 shown in this embodiment, and a fourth adjustment bolt is installed at the fourth adjustment point 305. The third adjustment bolt and the fourth adjustment bolt are installed on the adjustment plate 32, and the screw ends of the third adjustment bolt and the fourth adjustment bolt both extend into the through hole and extend radially towards the outer side wall of the lens barrel 1. In this way, by adjusting the feeding amount of the third adjustment bolt, the fine adjustment of the offset amount of the laser beam in the X-axis direction can be performed. By adjusting the feeding amount of the fourth adjustment bolt, the fine adjustment of the offset amount of the laser beam in the Y-axis direction can be performed.

[0045] It should be noted that the adjustment plate 32 shown in this embodiment can be set to a rectangular shape. The third adjustment point 304 shown in this embodiment is not limited to one, but two can be set, and they are set on opposite sides of the adjustment plate 32 along the X direction. At the same time, the fourth adjustment point 305 shown in this embodiment is not limited to one, but two can be set, and they are set on opposite sides of the adjustment plate 32 along the Y direction.

[0046] like Figure 3 As shown, the fixing frame 31 shown in this embodiment includes a fixing part and an adjusting part, the fixing part and the adjusting part are vertically arranged, the adjusting part and the adjusting plate 32 are spaced apart, and a fixing point 301, a first adjusting point 302 and a second adjusting point 303 are arranged on the adjusting part.

[0047] In actual installation, the fixing portion of the fixing frame 31 can be horizontally arranged and installed on a horizontally distributed optical platform, and strip-shaped mounting holes can be provided on the fixing portion to adjust the installation position of the fixing frame 31 .

[0048] Preferably, the adjustment bracket 3 shown in this embodiment further includes a mounting plate 33 , which is mounted on the second surface of the adjustment plate 32 and fixedly connected to the lens barrel 1 .

[0049] like Figure 1 As shown, in order to facilitate the adjustment of the axial spacing between the two orifice plates installed at both ends of the lens barrel 1, the lens barrel 1 shown in this embodiment includes a first lens barrel and a second lens barrel, the first lens barrel can be slidably inserted into the second lens barrel, the first lens barrel passes through the through hole, and the second lens barrel is fixedly connected to the mounting plate 33.

[0050] It should be noted that the orifice plate shown in this embodiment is threadedly connected to the lens barrel 1. A circular edge extending in the circumferential direction may be provided on one side surface of the orifice plate, an internal thread is provided on the circular edge, and an external thread is provided at the end of the lens barrel 1, so that the orifice plate and the lens barrel 1 can be threadedly connected through the internal thread and the external thread.

[0051] The scheme shown in this embodiment will be derived below based on the circular aperture Fraunhofer diffraction theory.

[0052] Assuming that the radius of the circular hole on the aperture plate is a, the center of the circular hole and the center of the CCD target surface are on the same optical axis, θ is the diffraction angle of the laser beam after passing through the circular hole, that is, the angle between the laser beam and the optical axis after passing through the center of the circular hole, the light intensity at point P at the diffraction angle θ received on the CCD target surface can be obtained as shown in the following formula:

[0053]

[0054] In the formula, I0=(πa 2 )|C1| 2, which represents the light intensity at the center point P0 on the optical axis; J1(Z) is the first-order Bessel function; Z = kaθ, representing the formula for the light intensity distribution of the circular hole diffraction to be obtained.

[0055] It can be seen from the above formula that after the laser beam diffracts through the small hole and reaches point P on the CCD target surface, the light intensity at point P forms a light spot at the corresponding diffraction angle. However, the solution shown in this embodiment requires adjusting the optical path quality of the laser beam, that is, adjusting the diffraction angle of the laser beam after passing through the small hole.

[0056] According to the diffraction principle, θ = r / f; where r is the radius of the diffraction ring formed after the laser beam reaches the CCD target surface, and f is the equivalent focal length.

[0057] As can be seen from the above, the diffraction pattern of the laser beam on the CCD target surface is a circular ring-shaped light intensity fringe. At Z = 0, that is, at the center point P0 of the optical axis, when, the light intensity has a maximum value; when J1(Z) = 0, when, the light intensity has a minimum value.

[0058] Therefore, there is a maximum value between the light intensities of two adjacent minimum values, and the central light energy is the strongest. Assuming that the radius of the light spot with the maximum central light intensity on the CCD target surface after the laser beam diffracts through the small hole is r0, the following formula can be obtained:

[0059]

[0060]

[0061] In the above formula, θ0 represents the diffraction angle corresponding to the diffraction ring with the maximum illumination intensity formed on the CCD target surface after the laser beam passes through the circular hole; λ represents the wavelength of the laser beam; a represents the radius of the opening.

[0062] Based on the above principle, when adjusting the laser optical path with a wavelength of 1080 nm, the aperture diameters of the circular holes of the first hole plate and the second hole plate can be set to 4 mm and 9 mm respectively, and the offset of the laser beam in the X-axis direction and the Y-axis direction can be adjusted respectively through the third adjusting bolt and the fourth adjusting bolt; at the same time, the aperture diameters of the circular holes of the third hole plate and the fourth hole plate can be set to 4 mm and 5 mm respectively, and the fine adjustment of the rotation direction around the X-axis and the rotation direction around the Y-axis of the laser beam can be carried out respectively through the first adjusting bolt and the second adjusting bolt.

[0063] Such as Figure 5As shown in the figure, this embodiment also provides an adjustment method for the optical path adjustment device of the fiber laser as described above, including: S1, arranging the fiber laser, the lens barrel and the CCD target surface in sequence along the transmission direction of the laser beam, and installing the lens barrel on the adjustment bracket; S2, installing a first orifice plate at the light inlet of the lens barrel and a second orifice plate at the light outlet of the lens barrel, starting the fiber laser, and adjusting the lens barrel in the X-axis direction and the Y-axis direction until the center of the light spot formed by the laser beam on the CCD target surface coincides with the center of the positioning mark on the CCD target surface; S3, removing the first orifice plate and the second orifice plate from the lens barrel, then installing a third orifice plate at the light inlet of the lens barrel and a fourth orifice plate at the light outlet of the lens barrel, and adjusting the rotation direction of the lens barrel around the X-axis and the rotation direction around the Y-axis until the light spot forms a diffraction ring pattern with central symmetry distribution on the CCD target surface.

[0064] Specifically, taking the optical path adjustment of the laser beam with a wavelength of 1080nm as an example, this embodiment combines the first set of orifice plates and the second set of orifice plates shown in the above embodiment, and the following specific description is made.

[0065] In the first step, first fix the output head of the fiber laser in the optical path for testing the laser beam quality, set the output power of the fiber laser, calculate the appropriate laser attenuation multiple, and add an attenuation lens so that the energy of the laser beam output by the fiber laser is within the safety threshold range required by the beam quality factor tester.

[0066] In the second step, perform a preliminary adjustment of the laser optical path. Place the CCD target surface of the beam quality factor tester in the optical path, record the position of the light spot at this time, and use the positioning mark on the CCD target surface for positioning. Among them, the positioning mark is usually the "cross" line well-known in the art.

[0067] In the third step, install a first orifice plate with a diameter of 4mm at the light inlet of the lens barrel, install a second orifice plate with a diameter of 9mm at the light outlet of the lens barrel, start the fiber laser, and observe the approximate distribution position of the light spot on the beam quality factor tester. Due to the principle of small hole diffraction, the concentric rings formed have an offset relative to the X-Y direction, and the center of the ring does not coincide with the physical center of the "cross" target positioning. Observe the light spot image on the CCD target surface. At this time, by turning the third adjustment bolt and the fourth adjustment bolt, adjust in the X-axis direction and the Y-axis direction, and gradually make the center of the light spot image coincide with the center of the "cross" target, that is, complete the preliminary adjustment of the consistency of the incident laser and the optical axis of the CCD target surface. The purpose of this step is to adjust the offset of the laser beam in the horizontal and vertical directions. After this step of adjustment, a diffraction pattern at the center of the CCD target surface can be obtained. However, this diffraction pattern is a non-uniform symmetric diffraction ring, as Figure 6As shown, the reason why the diffraction pattern is non-uniformly symmetric is that there are still rotation relative to the Y-axis and offset in the pitching direction relative to the X-axis of the laser beam within the spherical emission surface.

[0068] In the fourth step, a hole plate with a diameter of 4 mm is also used at the light inlet of the lens barrel. The second hole plate is removed from the lens barrel and replaced with a fourth hole plate with a diameter of 5 mm. The purpose of this adjustment is to adjust the rotation of the laser beam relative to the Y-axis and the offset degree in the pitching direction relative to the X-axis. After replacing the fourth hole plate and starting the fiber laser again, check the diffraction ring formed on the CCD target surface. Just finely adjust the first adjustment bolt and the second adjustment bolt to adjust the divergence offset of the laser beam within the spherical surface at the laser output end until a uniformly symmetric diffraction pattern is obtained, that is, the diffraction pattern is a plurality of circular diffraction rings with central symmetry distribution, as Figure 7 shown. After completing this step, until a completely symmetric diffraction ring is clearly seen in the beam quality analyzer. At this time, the debugging of the test optical path for laser beam quality analysis is completed. The results show that this device has a high adjustment efficiency and can well present the original mode of the laser spot.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An optical path adjustment device for a fiber laser, characterized in that, Comprising: A lens barrel; An orifice plate assembly including a plurality of orifice plates, which are detachably mounted at the light incident port and the light exit port of the lens barrel. An opening coaxial with the lens barrel is provided on the orifice plate for a laser beam to pass through; An adjustment bracket on which the lens barrel is mounted to adjust the lens barrel in the X-axis direction, the Y-axis direction, the rotation direction around the X-axis, and the rotation direction around the Y-axis. The X-axis direction and the Y-axis direction are perpendicular to each other and are distributed in a plane perpendicular to the optical axis of the lens barrel; According to the principle of small hole diffraction and spot imaging, with the cooperation of the plurality of orifice plates, based on the adjustment of the lens barrel by the adjustment bracket in the X-axis direction, the Y-axis direction, the rotation direction around the X-axis, and the rotation direction around the Y-axis, the offset of the laser beam output by the fiber laser relative to the opening on the orifice plate is adjusted to ensure the consistency of the optical axis of the laser beam and the optical axis of the optical system in the beam quality factor tester.

2. The optical path adjusting device of the fiber laser according to claim 1, wherein, The adjustment bracket includes a fixed bracket and an adjustment plate arranged at intervals; The fixed bracket is provided with a fixed point, a first adjustment point, and a second adjustment point. The connection line between the fixed point and the first adjustment point is arranged along the X-axis direction, and the connection line between the fixed point and the second adjustment point is arranged along the Y-axis direction; the fixed bracket is fixedly connected to the first surface of the adjustment plate through the fixed point; the fixed bracket is adjustably connected to the first surface along the optical axis direction of the lens barrel through the first adjustment point and the second adjustment point respectively; A through hole is formed in the adjustment plate, and the lens barrel passes through the through hole. The outer diameter of the lens barrel is smaller than the aperture of the through hole, and the lens barrel is connected to the second surface of the adjustment plate facing away from the first surface; The adjustment plate is provided with a third adjustment point and a fourth adjustment point, and is adjustably connected to the outer side wall of the lens barrel along the radial direction through the third adjustment point and the fourth adjustment point respectively. The radial adjustment direction where the third adjustment point is located is along the X-axis direction, and the radial adjustment direction where the fourth adjustment point is located is along the Y-axis direction.

3. The optical path adjusting device of the fiber laser according to claim 2, characterized in that, A first adjustment bolt is installed at the first adjustment point, and a second adjustment bolt is installed at the second adjustment point. Both the first adjustment bolt and the second adjustment bolt are installed on the fixed bracket, and the screw ends of the first adjustment bolt and the second adjustment bolt extend vertically along the optical axis direction towards the first surface; A third adjustment bolt is installed at the third adjustment point, and a fourth adjustment bolt is installed at the fourth adjustment point. The third adjustment bolt and the fourth adjustment bolt are installed on the adjustment plate, and the screw ends of the third adjustment bolt and the fourth adjustment bolt extend into the through hole and respectively extend along the radial direction of the lens barrel towards the outer side wall of the lens barrel.

4. The optical path adjusting device of the fiber laser according to claim 2, characterized in that, The fixed bracket includes a fixed part and an adjustment part, the fixed part and the adjustment part are perpendicularly arranged, the adjustment part is arranged at an interval from the adjustment plate, and the fixed point, the first adjustment point, and the second adjustment point are arranged on the adjustment part.

5. The optical path adjusting device of the fiber laser according to claim 2, characterized in that, The adjustment bracket further includes a mounting plate, which is mounted on the second surface of the adjustment plate and fixedly connected to the lens barrel.

6. The optical path adjusting device of the fiber laser according to claim 5, characterized in that, The lens barrel includes a first lens barrel and a second lens barrel. The first lens barrel is slidably inserted into the second lens barrel. The first lens barrel passes through the through hole, and the second lens barrel is fixedly connected to the mounting plate.

7. The optical path adjusting device of the fiber laser according to claim 1, characterized in that, The orifice plate assembly includes a first group of orifice plates and a second group of orifice plates; The first group of orifice plates includes a first orifice plate and a second orifice plate. The first orifice plate is used to be mounted on the light inlet of the lens barrel, and the second orifice plate is used to be mounted on the light outlet of the lens barrel. The opening diameter of the first orifice plate is less than 2 / 3 of the diameter of the light spot of the laser beam, and the opening diameter of the second orifice plate is greater than 1.5 times the diameter of the light spot. The second group of orifice plates includes a third orifice plate and a fourth orifice plate. The third orifice plate is used to be mounted on the light inlet of the lens barrel, and the fourth orifice plate is used to be mounted on the light outlet of the lens barrel. The opening diameter of the third orifice plate is less than 2 / 3 of the diameter of the light spot, and the opening diameter of the fourth orifice plate is greater than 2 / 3 of the diameter of the light spot.

8. The optical path adjusting device of the fiber laser according to any one of claims 1 to 7, characterized in that, The radius of the opening and the wavelength of the laser beam satisfy the following formula: θ0 = 0.61λ / a; where θ0 represents the diffraction angle corresponding to the diffraction ring with the maximum illumination intensity formed by the laser beam passing through the opening on the CCD target surface; λ represents the wavelength of the laser beam; a represents the radius of the opening; the CCD target surface is arranged on the side close to the light outlet of the lens barrel and is perpendicular to the optical axis direction of the lens barrel.

9. A method for adjusting the optical path of the optical path adjusting device of the fiber laser according to any one of claims 1 to 8, characterized in that, Including: S1, arranging the fiber laser, the lens barrel and the CCD target surface in sequence along the transmission direction of the laser beam, and mounting the lens barrel on the adjustment bracket; S2, mounting the first orifice plate on the light inlet of the lens barrel and the second orifice plate on the light outlet of the lens barrel, starting the fiber laser, and adjusting the lens barrel in the X-axis direction and the Y-axis direction until the center of the light spot formed by the laser beam on the CCD target surface coincides with the center of the positioning mark on the CCD target surface; S3, disassembling the first orifice plate and the second orifice plate from the lens barrel, then mounting the third orifice plate on the light inlet of the lens barrel and the fourth orifice plate on the light outlet of the lens barrel, and adjusting the rotation direction of the lens barrel around the X-axis and the rotation direction around the Y-axis until the light spot forms a diffraction ring pattern with central symmetry distribution on the CCD target surface.

10. The adjustment method according to claim 9, characterized in that, S1 further includes: Setting the output power of the fiber laser so that the beam energy corresponding to the output power is within the safety threshold range of the beam quality factor tester, starting the fiber laser, recording the light spot formed by the laser beam on the CCD target surface, and preliminarily positioning the light spot through the positioning mark on the CCD target surface; wherein, the CCD target surface is arranged on the beam quality factor tester.

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