Mode scrambler, optical fiber laser with mode scrambler and control method of optical fiber laser

Abstract

The invention provides a mode scrambler, an optical fiber laser with the mode scrambler and a control method of the optical fiber laser. Wherein the mould scrambler comprises a base plate, an X-axis extrusion plate and a Y-axis extrusion plate; wherein the substrate is used for fixing an optical fiber; protruding points, used for extruding optical fibers, on the X-axis extrusion plate and the Y-axis extrusion plate are distributed in a staggered mode in the longitudinal direction of the optical fibers and used for extruding the optical fibers in the X-axis direction and the Y-axis direction respectively. And the displacement of the X-axis extrusion plate and the displacement of the Y-axis extrusion plate are adjusted, so that the beam quality of the original output laser is adjusted, and the adjusted output laser is obtained. According to the mode scrambler, the optical fiber laser with the mode scrambler and the control method of the optical fiber laser, the same extrusion amount is applied to the optical fiber in the X-axis direction and the Y-axis direction at the same time, so that the divergence angles of lasers in the X-axis direction and the Y-axis direction are the same, large difference is avoided, and it is guaranteed that the beam quality of the finally adjusted output laser meets the requirement.

Description

This application is a divisional application of the invention patent entitled “Mode scrambler and optical fiber laser with the same and control method thereof”, filed with the China National Intellectual Property Administration on August 1, 2023, with application number 202310962019.3. Technical Field

[0001] The invention relates to the field of optical fiber lasers, in particular to a mode scrambler and an optical fiber laser having the mode scrambler and a control method thereof. Background Art

[0002] Due to the advantages of fiber lasers such as high beam quality, low cost, high conversion efficiency, good stability, small size, strong compatibility, long life and fast heat dissipation, the fiber laser industry has now entered the fast lane of development and is being applied in more and more fields.

[0003] The optical performance of fiber lasers directly determines their application effects. In the field of industrial processing, there are different requirements for the beam quality of fiber lasers depending on the type and thickness of the processed plate and the selected process.

[0004] In the previous technical solutions, once the fiber laser was produced, its beam quality was fixed and could not be changed. In recent years, some people have proposed to set a mode scrambler in the fiber laser to break the mode balance of the fiber-transmitted laser by squeezing the fiber, enhance the inter-mode coupling, control the transfer and conversion of energy, achieve the effect of adjusting the laser beam quality, and finally output the laser with ideal beam quality.

[0005] For example, the existing utility model CN ​​216817083 U discloses a mode scrambler, a base, an extrusion block and a driving structure, wherein the base has a first extrusion surface extending along a first direction, the extrusion block has a second extrusion surface, the first extrusion surface and the second extrusion surface are used to extrude the optical fiber and are concave-convex surfaces that match each other, and the driving structure is configured to be able to drive the extrusion block to move along the second direction so that the second extrusion surface is close to the first extrusion surface; the first direction is perpendicular to the second direction. The mode scrambler, by setting a driving structure to drive the extrusion block to make a linear motion along the second direction, enables the second extrusion surface to be close to the first extrusion surface, thereby extruding the optical fiber.

[0006] For another example, the existing invention CN 112542760 A discloses a fiber laser with adjustable beam quality and a method for outputting adjustable laser, comprising: a laser light source, an energy transmission fiber, a beam quality control module driving source and a beam quality control module; the beam quality control module comprises: a mode scrambler and a pusher; the mode scrambler is installed at the active end of the pusher, the laser light source is connected to the energy transmission fiber, the energy transmission fiber is installed in the mode scrambler, and the beam quality control module is electrically connected to the pusher to adjust the pusher according to the beam quality control module driving source, so that the pusher controls the mode scrambler to squeeze the energy transmission fiber.

[0007] However, from the existing technical solutions, there are the following problems:

[0008] 1. The use of unidirectional extrusion results in a large difference in the divergence angles of the laser in the X-axis direction and the Y-axis direction, and the energy distribution ellipticity and uniformity of the output laser are poor;

[0009] 2. During the long-term use of conventional double-clad optical fibers, the coating layer in contact with the second cladding is easily damaged due to the high light energy of the second cladding, resulting in the risk of optical fiber failure;

[0010] 3. If there is no filtering mechanism after the mode scrambling, the cladding light will increase and the output beam quality will be affected. Summary of the invention

[0011] The invention provides a mode scrambler and an optical fiber laser with the mode scrambler and a control method thereof. By giving the same extrusion amount to the optical fiber in the two directions of the X-axis and the Y-axis at the same time, the divergence angles of the laser in the two directions of the X-axis and the Y-axis are made the same, thereby avoiding a large difference and ensuring that the beam quality of the output laser after final adjustment meets the requirements, and the ellipticity and uniformity of the energy distribution are in a relatively ideal state. In the production of the laser, a corresponding relationship between the displacement of the X-axis and Y-axis extrusion plates and the adjusted beam quality of the output laser is established and written into a host computer. When the required beam quality value is input into the host computer, the corresponding displacement instruction is issued to the X-axis and Y-axis extrusion plates, thereby effectively realizing the online continuous adjustment of the beam quality.

[0012] In a first aspect, the present invention provides a mode scrambler, characterized in that the mode scrambler comprises a substrate, an X-axis extrusion plate, and a Y-axis extrusion plate; wherein

[0013] The substrate is used to fix the optical fiber;

[0014] The convex points of the X-axis extrusion plate and the Y-axis extrusion plate for extruding the optical fiber are staggeredly distributed in the longitudinal direction of the optical fiber, and are used to extrude the optical fiber from the X-axis direction and the Y-axis direction respectively;

[0015] The displacement of the X-axis pressing plate and the Y-axis pressing plate is adjusted to adjust the beam quality of the original output laser and obtain the adjusted output laser.

[0016] In a second aspect, the present invention further provides a fiber laser having the mode scrambler, characterized in that the fiber laser comprises:

[0017] A laser light source for providing an original output laser;

[0018] An optical fiber, which is used to transmit the laser light in the optical fiber laser;

[0019] The mode scrambler;

[0020] A host computer, which is used to control the displacement of the X-axis extrusion plate and the Y-axis extrusion plate to adjust the beam quality of the original output laser and obtain the adjusted output laser;

[0021] A cladding light filter, which is used to filter out the cladding light in the scrambled laser to obtain an adjusted output laser;

[0022] The output head is used to output laser.

[0023] In a third aspect, the present invention further provides a mode scrambling control method, characterized in that the method comprises:

[0024] Fixing optical fiber;

[0025] Extruding the optical fiber from the X-axis direction and the Y-axis direction at staggered positions in the longitudinal direction of the optical fiber;

[0026] The squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction is adjusted to adjust the beam quality of the original output laser and obtain the adjusted output laser.

[0027] In a fourth aspect, the present invention further provides a method for controlling a fiber laser, characterized in that the method comprises:

[0028] Provides raw output laser;

[0029] transmitting laser light from the fiber laser;

[0030] The scrambling mode control method;

[0031] Filtering out the cladding light in the scrambled laser to obtain the adjusted output laser;

[0032] Output laser.

[0033] The present invention provides a mode scrambler and an optical fiber laser having the mode scrambler and a control method thereof: first, by giving the same amount of extrusion to the optical fiber in the X-axis and Y-axis directions at the same time, the divergence angles of the laser in the X-axis and Y-axis directions are made the same, thereby avoiding large differences and ensuring that the beam quality of the output laser after final adjustment meets the requirements, and the ellipticity and uniformity of the energy distribution are in a relatively ideal state; second, in the production of the laser, a corresponding relationship between the displacement of the X-axis and Y-axis extrusion plates and the adjusted beam quality of the output laser is established, and the relationship is written into the host computer. When the required beam quality value is input into the host computer, the corresponding displacement instruction will be issued to the X-axis and Y-axis extrusion plates, thereby effectively realizing the online continuous adjustment of the beam quality; third, the stray light and cladding light in the core light excited by the mode scrambler are filtered out by the fiber winding disk and the cladding light filter; fourth, as Figure 1 As shown on the right, the optical fiber is set to a triple-cladding structure. Figure 1 Compared with the conventional double-clad optical fiber shown on the left (the core and the second cladding are pure quartz layers, and the first cladding is a fluorine-doped layer), a third cladding doped with fluorine is added outside the second cladding pure quartz layer. The optical fiber with a three-cladding structure can allow the existence of cladding light with higher power. After passing through the mode scrambler, energy may be coupled to the cladding. For conventional double-clad optical fiber, the coating layer is outside the second cladding, and the power it can withstand is limited. The triple-clad optical fiber can effectively solve this problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Figure 1 It is a schematic diagram of the cross section of an optical fiber provided by the prior art and an embodiment of the present invention;

[0036] Figure 2 is a schematic structural diagram of a mode scrambler provided by an embodiment of the present invention;

[0037] Figure 3 is a schematic structural diagram of a fiber laser having the mode scrambler provided in an embodiment of the present invention;

[0038] Figure 4 is a flow chart of a scrambling mode control method provided by an embodiment of the present invention;

[0039] Figure 5 is a flow chart of a control method of an optical fiber laser having the mode scrambler provided by an embodiment of the present invention;

[0040] Figure 6aand Figure 6b It is a diagram showing the effect of the laser divergence angles on the X-axis and Y-axis after one-dimensional extrusion in the prior art and after two-dimensional extrusion provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. SUMMARY OF THE INVENTION

[0043] As mentioned above, the present invention provides a mode scrambler and an optical fiber laser having the mode scrambler and a control method thereof, which increases the inter-mode coupling by giving the same amount of extrusion to the optical fiber in both the X-axis and Y-axis directions at the same time, thereby achieving the technical effect of changing the beam quality and meeting different laser applications.

[0044] Among them, beam quality is a concept that describes the characteristics and quality of a beam, mainly involving the focusing degree, spatial distribution, coherence and stability of the beam. Common indicators and parameters used to describe beam quality include: spot diameter, which refers to the spot diameter of the beam at the focal position of the far field center. A smaller spot diameter usually indicates better beam quality and better focusing performance; beam divergence, which describes the degree of diffusion of the beam from the light source or emission point. A smaller divergence angle indicates better beam quality and better directivity; mode symmetry, which describes the symmetry of the mode distribution of the beam in the horizontal or vertical direction. A symmetrical mode distribution usually indicates better beam quality; coherence, which describes the phase relationship of light of different wavelengths in the beam. A higher coherence usually indicates better beam quality and a narrower spectral width; wavefront distortion, which is used to describe the shape and distortion degree of the phase front of the beam. A smaller wavefront distortion indicates better beam quality and better coherence; M2 factor, which is a comprehensive parameter used to quantify beam quality. It comprehensively considers the spatial distribution, focusing performance and directivity of the beam. The value of the M2 factor is between 1 and infinity. A value closer to 1 indicates better beam quality.

[0045] The quality of the beam is crucial to many laser applications and optical system designs. It directly affects the beam's focus, transmission efficiency, positioning accuracy, and interaction with other optical components.

[0046] The present invention is different from the prior art which squeezes the optical fiber from only one direction. By giving the same squeezing amount to the optical fiber in both the X-axis and Y-axis directions at the same time, the inter-mode coupling is increased in both the X-axis and Y-axis directions, and the divergence angles of the laser are the same, thereby avoiding large differences and ensuring that the beam quality of the output laser after the final adjustment meets the requirements, and the energy distribution ellipticity and uniformity are in a relatively ideal state.

[0047] Example Modules

[0048] Figure 2 is a schematic diagram of the structure of a minimum repeating unit in the scrambler 3 provided in an embodiment of the present invention, wherein the scrambler 3 includes at least one minimum repeating unit, such as Figure 2 As shown, the mode scrambler 3 provided in this embodiment includes: a substrate 3.1, an X-axis extrusion plate 3.2, a Y-axis extrusion plate 3.3, and a host computer; wherein

[0049] The substrate 3 . 1 is used to fix the optical fiber 2 .

[0050] Based on the waveguide effect and adjusting the propagation conditions of the optical signal, the quality of the beam can be adjusted and improved by squeezing the core and cladding. Core deformation can cause mode conversion, for example, from a single-mode mode to a multimode mode or from a low-order mode to a high-order mode. This mode conversion can change the propagation characteristics and mode field diameter of the light beam, thereby affecting the quality of the light beam; core deformation can adjust the shape and spatial distribution of the light beam. For example, by squeezing the core, the light beam can be elliptical, thereby changing the spot size and shape of the light beam in the transverse and longitudinal directions; squeezing the cladding shape in the optical fiber can also adjust the propagation conditions of the light field, control the propagation mode, residence time and waveguide effect of the optical signal, and thus affect the quality of the beam. By properly controlling the bending radius and polarization state of the optical fiber, the mode coupling and conversion behavior can be adjusted.

[0051] In order to better change the mode of the original output laser transmitted by the optical fiber, break the mode balance, and enhance the inter-mode coupling effect, the raised points on the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 for extruding the optical fiber are staggered in the longitudinal direction of the optical fiber 2 (i.e., the Z-axis direction along the length of the optical fiber or the light beam), and are used to extrude the optical fiber 2 from the X-axis direction and the Y-axis direction, respectively.

[0052] The displacements of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 can be made identical in real time to obtain an ideal circular light spot.

[0053] For example, the length of the optical fiber 2 fixed by the substrate 3.1 is 1 dm, and 18 extrusion points ar with an interval of 5 mm are evenly distributed on the 1 dm long optical fiber 2, the extrusion point a is extruded by the X-axis extrusion plate 3.2, the extrusion point b is extruded by the Y-axis extrusion plate 3.3, and the extrusion point c is extruded by the X-axis extrusion plate 3.2... Figure 2As shown, the X-axis squeezing plate 3.2 and the Y-axis squeezing plate 3.3 each have 6 protruding points for squeezing the optical fiber 2, and the X-axis squeezing plate 3.2 and the Y-axis squeezing plate 3.3 are sequentially arranged in the longitudinal direction of the optical fiber 2, that is, the protruding points of the X-axis squeezing plate 3.2 and the Y-axis squeezing plate 3.3 for squeezing the optical fiber 2 are staggered in the longitudinal direction of the optical fiber 2, so that the squeezing points ar on the optical fiber 2 are sequentially squeezed by the squeezing plates in different directions, and when the mode scrambler 3 is started, the X-axis squeezing plate 3.2 and the Y-axis squeezing plate 3.3 squeeze the optical fiber 2 simultaneously and in real time with the same squeezing amount, that is, the displacement amounts of the two squeezing plates are the same in real time, and the displacement amounts of the squeezing points ar are the same in real time, so that the inter-mode coupling is increased simultaneously and to the same extent in both the X-axis and Y-axis directions, as shown in FIG. Figure 6b The two-dimensional extrusion of the present invention ensures that the divergence angles of the laser in two directions are the same, thus avoiding the following problems: Figure 6a As shown, the divergence angles of the laser in the X-axis and Y-axis directions caused by the unidirectional extrusion are quite different, so that the beam quality of the output laser after the final adjustment meets the requirements, and the ellipticity and uniformity of the energy distribution are in a relatively ideal state.

[0054] The host computer is used to control the displacement of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 to adjust the beam quality of the original output laser, obtain the adjusted output laser, and realize the adjustment of the online continuous extrusion of the optical fiber.

[0055] Wherein, the displacement is 0 to 1 mm.

[0056] The beam quality is characterized by BPP (Beam Parameter Product).

[0057] BPP is the product of the lateral size (width) of a beam and its divergence angle, and is often used to quantify the focusing ability and spatial broadening characteristics of a beam.

[0058] The definition of BPP is as follows:

[0059] BPP=θ×ω

[0060] Among them, θ is the divergence angle (half angle) of the light beam, which represents the diffusion ability of the light beam in the lateral direction, and ω is the mode field radius (lateral size) of the light beam, which represents the focusing ability of the light beam in the lateral direction.

[0061] The unit of BPP is usually mm mrad. A smaller BPP value indicates better beam quality, that is, the beam has a smaller lateral size and a smaller divergence angle, indicating better beam focusing ability.

[0062] Specifically, the host computer includes a storage module, which is used to store the correspondence between the displacement of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 under specific optical fiber parameters and specific original output laser BPP and the adjusted output laser BPP, and to search for the corresponding displacement of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 based on the required adjusted output laser BPP according to the correspondence.

[0063] Among them, the original output laser and the adjusted output laser are both the last laser output by the fiber laser. The original output laser is the last laser output by the fiber laser before the mode scrambler 3 is enabled to squeeze the optical fiber, and the adjusted output laser is the last laser output by the fiber laser after the mode scrambler 3 is enabled to squeeze the optical fiber.

[0064] For example, when the user inputs the required BPP value A in the upper computer of the fiber laser, the upper computer will issue a command corresponding to a displacement of 0.2 mm to the X-axis and Y-axis extrusion plates. The X-axis and Y-axis extrusion plates simultaneously squeeze the optical fiber 2 to a displacement of 0.2 mm, and the adjusted output laser corresponding to the BPP value A can be obtained; when the user inputs the required BPP value B in the upper computer of the fiber laser, the upper computer will issue a command corresponding to a displacement of 0.5 mm to the X-axis and Y-axis extrusion plates. The X-axis and Y-axis extrusion plates simultaneously squeeze the optical fiber 2 to a displacement of 0.5 mm, and the adjusted output laser corresponding to the BPP value B can be obtained, effectively realizing the online continuous adjustment of the beam quality.

[0065] Optical fibers with different optical fiber parameters have different beam qualities. The optical fiber parameters related to the beam quality include but are not limited to:

[0066] Fiber core diameter: The fiber core diameter determines the size of the longitudinal mode and the focusing degree of the beam. A smaller fiber core diameter usually corresponds to a smaller mode field diameter and better beam quality.

[0067] Fiber Numerical Aperture: Numerical aperture describes the fiber's ability to receive incident light and its divergence angle. A higher numerical aperture usually corresponds to better beam quality and a smaller divergence angle.

[0068] Mode Field Diameter: The mode field diameter is the diameter of the mode field transmitted in the optical fiber, which is related to the core diameter and refractive index of the optical fiber. A smaller mode field diameter usually corresponds to a smaller beam diameter and better beam quality.

[0069] Fiber Attenuation: Fiber attenuation is the power loss of light during the propagation of light in the optical fiber. Lower fiber attenuation means higher transmission efficiency and longer transmission distance, which has an important impact on the maintenance of beam quality.

[0070] The ratio of the numerical aperture of the fiber to the mode field diameter (V-number): V-number is the ratio of the numerical aperture to the mode field diameter. A higher V-number generally corresponds to better beam quality and a smaller divergence angle.

[0071] The corresponding relationship (the corresponding relationship between the displacement of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 and the adjusted output laser BPP under specific fiber parameters and specific original output laser BPP) is obtained by the following method:

[0072] First, the BPP measuring device is used to measure the BPP of the original output laser, that is, the BPP of the output laser before the mode scrambler 3 squeezes the optical fiber 2 .

[0073] Secondly, in the process that the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 respectively extrude the optical fiber 2 from the X-axis direction and the Y-axis direction, the BPP measuring device is used to measure the adjusted output laser BPP, and the corresponding displacements of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 are recorded. For example, the displacements of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 when simultaneously squeezing the optical fiber 2 are controlled to be 0.1mm, 0.2mm, 0.3mm...0.8mm, 0.9mm, 1mm, respectively. Under the above 10 displacements, the corresponding adjusted output laser BPPs are measured and recorded respectively.

[0074] Again, the fiber parameters, the original output laser BPP, the adjusted output laser BPP and the corresponding displacements of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 are input into the host computer.

[0075] Finally, a correspondence between the displacement of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 and the adjusted output laser BPP under specific optical fiber parameters and specific original output laser BPP is established, that is, under a certain optical fiber parameter and an original output laser BPP, there is a correspondence between the displacement of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 and the adjusted output laser BPP.

[0076] In addition, the scrambler 3 may also include Figure 2 Shown are an X-axis electric block 3.4 and a Y-axis electric block 3.5.

[0077] The X-axis electric block 3.4 and the Y-axis electric block 3.5 are used to provide power for the X-axis extrusion plate and the Y-axis extrusion plate respectively.

[0078] At this time, the host computer is used to control the X-axis electric block 3.4 and the Y-axis electric block, and adjust the displacement of the X-axis extrusion plate 3.2 and the Y-axis extrusion plate 3.3 to adjust the beam quality of the original output laser and obtain the adjusted output laser.

[0079] The host computer may not be included in the scrambler 3 .

[0080] Exemplary Devices

[0081] The embodiment of the present invention further provides a fiber laser having the mode scrambler 3 . Figure 3 is a schematic diagram of the structure of a fiber laser having the mode scrambler 3 provided in an embodiment of the present invention, such as Figure 3 As shown, the fiber laser provided in this embodiment includes: a laser light source 1, an optical fiber 2, a mode scrambler 3, a cladding light filter 5 and an output head 6.

[0082] The laser light source 1 is used to provide the original output laser, which can be a single-module output or a multi-mode combined beam output.

[0083] Among them, the single module output is the output beam of the laser light source through the single-mode optical fiber. The single-mode optical fiber has a smaller core diameter, allowing only one mode of optical signal to be transmitted. It has lower transmission loss and higher beam quality, and is suitable for applications that require long-distance transmission and high-precision positioning, such as lithography and laser precision processing.

[0084] Multimode combined beam output is the output beam of the laser light source through the multimode optical fiber. Multimode optical fiber has a relatively large core diameter and can support optical signals in multiple propagation modes. Due to the limitations of the optical fiber structure and refractive index distribution, the optical signal in the multimode optical fiber will experience mode mismatch and dispersion during transmission, resulting in reduced beam quality and increased transmission loss. Therefore, multimode combined beam output is generally used in short-distance communication, sensing and imaging, etc.

[0085] The optical fiber 2 is used to transmit the laser light in the optical fiber laser.

[0086] Specifically, Figure 1 The optical fiber 2 shown on the right has a three-cladding structure: the first cladding is a fluorine-doped layer, the second cladding is a pure silica layer, and the third cladding is a fluorine-doped layer. Figure 1 Compared with the conventional double-clad optical fiber shown on the left (the core and the second cladding are pure silica layers, and the first cladding is a fluorine-doped layer), a third cladding doped with fluorine is added outside the second cladding pure silica layer.

[0087] In addition to being a fluorine-doped layer, the first cladding layer may also be made of other materials with a lower refractive index, such as silicon oxide.

[0088] The optical fiber 2 with a three-cladding structure can allow the existence of cladding light with higher power. After the optical fiber 2 is squeezed by the mode scrambler 3, first, the stray light in the core light is converted from a low mode to a high mode and enters the first cladding. Secondly, since the refractive index of the first cladding material is lower than that of the second cladding material, the first cladding light is easily refracted into the second cladding. At this time, the power borne by the second cladding is relatively large, and most of the cladding light is transmitted in the second cladding. However, since there is a thin layer of low-refractive-index fluorine-doped cladding (third cladding) outside the second cladding, the second cladding light is not easy to enter the third cladding, so that heat accumulation will not be generated on the coating outside the third cladding (generally, the coating is an opaque plastic that absorbs heat), avoiding the coating from burning and causing the optical fiber to lose protection. The third cladding plays a role in isolating the high-energy second cladding light from direct contact with the coating and protecting the coating.

[0089] For conventional double-clad optical fiber, the coating layer is outside the second cladding, which can withstand limited power and has the risk of failure after long-term use.

[0090] The scrambler 3 adopts the scrambler 3 described in detail in the exemplary module above, which includes a base plate 3.1, an X-axis extrusion plate 3.2, a Y-axis extrusion plate 3.3, and a host computer, wherein the host computer may also exist independently of the scrambler 3. No further description is given here.

[0091] The cladding light filter 5 is used to filter out the cladding light in the scrambled laser to obtain the adjusted output laser.

[0092] Specifically, the coating of a section of optical fiber 2 passing through the cladding light filter 5 is stripped off, and the third cladding is completely corroded and the second cladding is partially corroded by roughening corrosion. At this time, the surface of the second cladding is in a roughened state, so that the cladding light cannot satisfy total reflection in the second cladding to achieve filtering.

[0093] The output head 6 is used to output laser light.

[0094] The output head 6 is a quartz end cap structure, which is fused with the optical fiber 2 to output laser safely and reliably.

[0095] In addition, the fiber laser may further include a fiber winding disk 4, which is located after the mode scrambler and before the cladding light filter. By designing the winding diameter and the number of layers, the optical fiber is wound so that the stray light in the core light of the laser after the mode scrambling and the first cladding light thereof enter the second cladding. For example, a fiber winding disk 4 with a larger diameter is selected first, and then a fiber winding disk with a smaller diameter is selected. A cladding light filter 5 may be added between fiber winding disks 4 with different diameters to filter the cladding light in stages, so as to reduce the heat accumulation of the cladding light filter 5.

[0096] Specifically, the fiber winding disk 4 is a groove-type winding structure. By creating grooves on the fiber winding disk, the optical fiber can be compactly and efficiently wound along the path of the groove. The advantage of the groove-type winding structure is that it can minimize the bending radius of the optical fiber, reduce bending loss, and maintain the optical performance of the optical fiber. By precisely controlling the geometric shape and size of the groove, compact winding of the optical fiber can be achieved to avoid crossing and overlapping.

[0097] Exemplary Module Control Methods

[0098] Accordingly, an embodiment of the present invention further provides a mode scrambling control method. Figure 4 : is a flow chart of a scrambling mode control method provided by an embodiment of the present invention, and the embodiment comprises the following steps:

[0099] S401: Fixing optical fiber;

[0100] S402: Extruding the optical fiber from the X-axis direction and the Y-axis direction at staggered positions in the longitudinal direction of the optical fiber respectively;

[0101] S403: adjusting the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction to adjust the beam quality of the original output laser and obtain the adjusted output laser.

[0102] The squeezing amounts of the optical fiber in the X-axis direction and the Y-axis direction are the same in real time.

[0103] The beam quality is characterized by BPP (Beam Parameter Product). The method further comprises:

[0104] Controlling the displacement of the X-axis extrusion plate and the Y-axis extrusion plate to adjust the beam quality of the original output laser and obtain the adjusted output laser;

[0105] The correspondence between the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction under specific optical fiber parameters and specific original output laser BPP and the adjusted output laser BPP is stored, and the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction corresponding to the adjusted output laser BPP can be obtained by looking up the correspondence.

[0106] The corresponding relationship is obtained by the following method:

[0107] Measure the original output laser BPP using a BPP measurement device;

[0108] In the process of squeezing the optical fiber from the X-axis direction and the Y-axis direction respectively, using the BPP measuring device to measure the adjusted output laser BPP, and recording the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction respectively;

[0109] Inputting the optical fiber parameters, the original output laser BPP, the adjusted output laser BPP, and the corresponding squeezing amounts of the optical fiber in the X-axis direction and the Y-axis direction into the host computer;

[0110] A corresponding relationship between the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction and the adjusted output laser BPP under specific optical fiber parameters and specific original output laser BPP is established.

[0111] The optical fiber parameters include optical fiber core diameter, optical fiber attenuation, optical fiber numerical aperture, mode field diameter, and the ratio of optical fiber numerical aperture to mode field diameter.

[0112] The displacement is 0 to 1 mm.

[0113] Exemplary Device Control Methods

[0114] Correspondingly, an embodiment of the present invention further provides a method for controlling a fiber laser. Figure 5 : is a flow chart of a control method of a fiber laser having the mode scrambler provided by an embodiment of the present invention, and the embodiment comprises the following steps:

[0115] S501: providing original output laser;

[0116] S502: Transmitting laser light from the fiber laser;

[0117] S503: The scrambling mode control method adopts the method described in detail in the exemplary module control method above;

[0118] S504: filtering out the cladding light in the scrambled laser to obtain an adjusted output laser;

[0119] S505: Output laser.

[0120] The method between S503 and S504 may further include: coiling the optical fiber so that stray light in the core light of the scrambled laser and its first cladding light enter the second cladding.

[0121] It should be noted that although the mode scrambler and several devices, units, or modules of the fiber laser having the mode scrambler are mentioned in the above detailed description, this division is only exemplary and not mandatory. In fact, according to an embodiment of the present invention, the features and functions of two or more modules described above can be embodied in one module. Conversely, the features and functions of one module described above can be further divided to be embodied by multiple modules.

[0122] Furthermore, although the operations of the mode scrambling control method and the control method of the optical fiber laser having the mode scrambler of the present invention are described in a specific order in the drawings, this does not require or imply that the operations must be performed in this specific order, or that all the operations shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0123] Although the spirit and principle of the present invention have been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the disclosed specific embodiments, and the division of various aspects does not mean that the features in these aspects cannot be combined to benefit, and such division is only for the convenience of expression. The present invention is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the attached claims. The present invention provides: 1. A mode scrambler, characterized in that the mode scrambler comprises a substrate, an X-axis extrusion plate, and a Y-axis extrusion plate; wherein The substrate is used to fix the optical fiber; The protruding points on the X-axis extrusion plate and the Y-axis extrusion plate for extruding the optical fiber are staggeredly distributed in the longitudinal direction of the optical fiber, and are used to extrude the optical fiber from the X-axis direction and the Y-axis direction respectively; The displacement of the X-axis pressing plate and the Y-axis pressing plate is adjusted to adjust the beam quality of the original output laser and obtain the adjusted output laser. 2. The mode scrambler according to item 1 is characterized in that the displacements of the X-axis extrusion plate and the Y-axis extrusion plate are the same in real time. 3. The mode scrambler according to item 1 or 2, characterized in that the beam quality is characterized by BPP (beam parameter product). 4. The mode scrambler according to any one of items 1 to 3 is characterized in that the mode scrambler also includes a host computer, which is used to control the displacement of the X-axis extrusion plate and the Y-axis extrusion plate to adjust the beam quality of the original output laser and obtain the adjusted output laser, and the host computer includes a storage module, which is used to store the corresponding relationship between the displacement of the X-axis extrusion plate and the Y-axis extrusion plate under specific fiber parameters and specific original output laser BPP and the adjusted output laser BPP, and search for the corresponding displacement of the X-axis extrusion plate and the Y-axis extrusion plate based on the required adjusted output laser BPP according to the corresponding relationship. 5. The mode scrambler according to item 4, wherein the corresponding relationship is obtained by the following method: Measure the original output laser BPP using a BPP measurement device; In the process that the X-axis squeezing plate and the Y-axis squeezing plate squeeze the optical fiber from the X-axis direction and the Y-axis direction respectively, the BPP measuring device is used to measure the adjusted output laser BPP, and the displacement of the corresponding X-axis squeezing plate and the Y-axis squeezing plate is recorded; Inputting the optical fiber parameters, the original output laser BPP, the adjusted output laser BPP, and the corresponding displacements of the X-axis extrusion plate and the Y-axis extrusion plate into the host computer; A corresponding relationship between the displacement of the X-axis extrusion plate and the Y-axis extrusion plate and the adjusted output laser BPP under specific optical fiber parameters and specific original output laser BPP is established. 6. The mode scrambler according to item 5, characterized in that the optical fiber parameters include optical fiber core diameter, optical fiber attenuation, optical fiber numerical aperture, mode field diameter, and the ratio of optical fiber numerical aperture to mode field diameter. 7. The mode scrambler according to any one of items 1 to 6, wherein the displacement is 0 to 1 mm. 8. An optical fiber laser having a mode scrambler as described in any one of items 1 to 3, characterized in that the optical fiber laser comprises: A laser light source for providing an original output laser; An optical fiber, which is used to transmit the laser light in the optical fiber laser; A mode scrambler as described in any one of items 1 to 3; A host computer, which is used to control the displacement of the X-axis extrusion plate and the Y-axis extrusion plate to adjust the beam quality of the original output laser and obtain the adjusted output laser; A cladding light filter, which is used to filter out the cladding light in the scrambled laser to obtain an adjusted output laser; The output head is used to output laser. 9. The optical fiber laser according to item 8, characterized in that the optical fiber is a triple-cladding structure; The first cladding is a fluorine-doped layer, the second cladding is a pure quartz layer, and the third cladding is a fluorine-doped layer. 10. The fiber laser according to item 8 or 9, characterized in that the fiber laser further comprises: The fiber winding disk is located after the mode scrambler and before the cladding light filter, and is used to coil the optical fiber so that the stray light in the core light of the laser light after mode scrambling and the first cladding light thereof enter the second cladding. 11. The optical fiber laser according to any one of items 8 to 10, characterized in that the fiber winding disk is a groove-type winding structure. 12. The optical fiber laser according to any one of items 8 to 11, characterized in that the output head is a quartz end cap structure. 13. The optical fiber laser according to any one of items 9 to 12 is characterized in that the cladding light filter is used to completely corrode the third cladding and partially corrode the second cladding of a section of optical fiber with the coating stripped and passing through the cladding light filter through roughening corrosion, and the surface of the second cladding is in a roughened state. 14. A scrambling mode control method, characterized in that the method comprises: Fixing optical fiber; Extruding the optical fiber from the X-axis direction and the Y-axis direction at staggered positions in the longitudinal direction of the optical fiber; The squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction is adjusted to adjust the beam quality of the original output laser and obtain the adjusted output laser. 15. The mode scrambling control method according to item 14 is characterized in that the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction are the same in real time. 16. The mode scrambling control method according to item 14 or 15 is characterized in that the beam quality is characterized by BPP (beam parameter product). 17. The mode scrambling control method according to any one of items 14 to 16, characterized in that the method further comprises: controlling the displacement of the X-axis extrusion plate and the Y-axis extrusion plate to adjust the beam quality of the original output laser to obtain an adjusted output laser; The correspondence between the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction under specific optical fiber parameters and specific original output laser BPP and the adjusted output laser BPP is stored, and the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction corresponding to the adjusted output laser BPP can be obtained by looking up the correspondence. 18. The scrambling mode control method according to item 17 is characterized in that the corresponding relationship is obtained by the following method: Measure the original output laser BPP using a BPP measurement device; In the process of squeezing the optical fiber from the X-axis direction and the Y-axis direction respectively, using the BPP measuring device to measure the adjusted output laser BPP, and recording the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction respectively; Inputting the optical fiber parameters, the original output laser BPP, the adjusted output laser BPP, and the corresponding squeezing amounts of the optical fiber in the X-axis direction and the Y-axis direction into the host computer; A corresponding relationship between the squeezing amount of the optical fiber in the X-axis direction and the Y-axis direction and the adjusted output laser BPP under specific optical fiber parameters and specific original output laser BPP is established. 19. The mode disturbance control method according to item 18 is characterized in that the optical fiber parameters include optical fiber core diameter, optical fiber attenuation, optical fiber numerical aperture, mode field diameter, and the ratio of optical fiber numerical aperture to mode field diameter. 20. The mode disturbance control method according to any one of items 14 to 19, characterized in that the displacement is 0 to 1 mm. 21. A method for controlling a fiber laser, characterized in that the method comprises: Provides raw output laser; transmitting laser light from the fiber laser; The scrambling mode control method according to any one of items 14 to 20; Filtering out the cladding light in the scrambled laser to obtain the adjusted output laser; Output laser. 22. The optical fiber laser according to item 21 is characterized in that before the step of filtering out the cladding light in the scrambled laser to obtain the adjusted output laser, it also includes: coiling the optical fiber so that the stray light in the core light of the scrambled laser and its first cladding light enter the second cladding.

Claims

1. A mode scrambler, characterized in that: The scrambler includes a substrate, an X-axis extrusion plate, and a Y-axis extrusion plate; wherein: The substrate is used to fix the optical fiber; The protruding points on the X-axis squeezing plate and the Y-axis squeezing plate for squeezing the optical fiber are staggered in the longitudinal direction of the optical fiber, and are respectively used to synchronously apply equal amounts of squeezing to the optical fiber from the X-axis direction and the Y-axis direction, so as to achieve uniform inter-mode coupling in the X-axis and Y-axis directions; The displacement of the X-axis pressing plate and the Y-axis pressing plate is adjusted to adjust the beam quality of the original output laser and obtain the adjusted output laser.

2. The mode scrambler according to claim 1, characterized in that The displacements of the X-axis extrusion plate and the Y-axis extrusion plate are the same in real time.

3. The mode scrambler according to claim 1 or 2, characterized in that: The beam quality is characterized by BPP (Beam Parameter Product).

4. The mode scrambler according to any one of claims 1 to 3, characterized in that: The scrambler also includes a host computer, which includes: A storage module, used to store the corresponding relationship between the displacement of the X-axis extrusion plate and the Y-axis extrusion plate under specific optical fiber parameters and the original output laser BPP and the adjusted output laser BPP; The control module is used to find and adjust the displacement of the corresponding X-axis extrusion plate and the Y-axis extrusion plate based on the output laser BPP that needs to be adjusted, so as to achieve online continuous adjustment of the beam quality.

5. The mode scrambler according to claim 4, characterized in that The corresponding relationship is obtained by the following method: Measure the original output laser BPP using a BPP measurement device; During the process of the X-axis squeezing plate and the Y-axis squeezing plate squeezing the optical fiber, the adjusted output laser BPP is measured by the BPP measuring device, and the corresponding squeezing plate displacement is recorded; The optical fiber parameters, the original output laser BPP, the adjusted output laser BPP and the corresponding displacement of the extrusion plate are input into the host computer, a corresponding relationship is established, and stored in the storage module.

6. The mode scrambler according to claim 5, characterized in that The optical fiber parameters include optical fiber core diameter, optical fiber attenuation, optical fiber numerical aperture, mode field diameter, and the ratio of optical fiber numerical aperture to mode field diameter.

7. The mode scrambler according to any one of claims 1 to 6, characterized in that: The displacement is 0 to 1 mm.

8. An optical fiber laser having a mode scrambler according to any one of claims 1 to 3, characterized in that: The fiber laser comprises: A laser light source, used for providing original output laser; An optical fiber, used for transmitting the laser; The mode scrambler according to any one of claims 1 to 3; A cladding light filter is used to filter out the cladding light in the scrambled laser to obtain an adjusted output laser; Output head, used for outputting laser; The upper computer is used to control the displacement of the extrusion plate in the scrambler.

9. The optical fiber laser according to claim 8, characterized in that: The optical fiber has a triple-cladding structure; The first cladding layer is a fluorine-doped layer; The second cladding is a pure quartz layer; The third cladding layer is a fluorine-doped layer, which is used to isolate the high-energy second cladding light from direct contact with the coating layer.

10. The optical fiber laser according to claim 8 or 9, characterized in that: The fiber laser also includes: The fiber winding disk is located after the mode scrambler and before the cladding light filter, and is used to guide the core light and the first cladding light of the laser light after the mode scrambling to the second cladding.

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