Fiber optic mode scrambler, homogenizing system and homogenizing control method

Abstract

The application discloses a kind of optical fiber mode scrambler, light uniformization system and light uniformization control method.Optical fiber mode scrambler is used to the uniformization of the light spot of optical fiber, including mode scrambling unit and drive unit;The mode scrambling unit includes inflatable support and the elastic expansion body being arranged in the inflatable support;The outer surface of the inflatable support is equipped with the limiting portion for the winding fixed optical fiber;The drive unit is used to drive the elastic expansion body to occur deformation, and then drive the inflatable support to expand along its radial direction, to make the optical fiber wound on the outer surface of the inflatable support occur deformation, realize the uniformity regulation of the light spot of optical fiber.The application solves the problems of poor adaptability, uncontrollable uniformity and easy damage of optical fiber in the prior art mode scrambling device.

Description

Technical Field

[0001] This invention relates to the field of optical fiber technology, and in particular to an optical fiber mode scrambler, a light homogenizing system, and a light homogenizing control method. Background Technology

[0002] In fields such as high-energy lasers, fiber optic sensing, laser medicine, spectral analysis, and laser processing, it is often necessary to homogenize the intensity distribution of the laser beam, that is, to eliminate non-uniform phenomena such as hot spots, dark rings, and hollow spots in the beam, forming a flat-top beam with uniform energy distribution. Traditional homogenization methods mainly rely on spatial optical elements such as microlens arrays, diffractive optical elements (DOEs), or spatial light modulators. However, these solutions generally suffer from problems such as high cost, complex optical paths, high requirements for incident beam quality, and inability to withstand high power.

[0003] As an alternative, fiber optic mode scramblers are widely researched and applied. Their basic principle is that when an optical fiber is subjected to specific bending or stress, coupling occurs between different modes within the fiber, causing the intensity distribution of the outgoing light spot to become more uniform after passing through a section of scrambled fiber, despite the input being non-uniform. Fiber optic mode scramblers offer advantages such as compact structure, good compatibility with fiber optic systems, and the ability to withstand high power.

[0004] Current fiber optic mode scrambler technologies directly compress the optical fiber using mechanical clamping devices. However, these devices cannot adjust the bending radius of the fiber, making them difficult to optimize for different fiber types (such as single-mode and multimode fibers) or different laser wavelengths, resulting in poor adaptability. Furthermore, they can easily lead to excessive micro-bending loss or even physical damage to the fiber, and manual adjustment suffers from low precision and uncontrollable uniformity. Summary of the Invention

[0005] The purpose of this invention is to provide an optical fiber mode scrambler, a light homogenizing system, and a light homogenizing control method to solve the problems of poor adaptability, uncontrollable uniformity, and easy damage to optical fibers that still exist in existing optical fiber mode scrambling technologies.

[0006] To achieve the above objectives, the present invention provides an optical fiber mode scrambler for homogenizing the emitted light spot of an optical fiber, comprising a mode scrambling unit and a driving unit; the mode scrambling unit includes an expandable support and an elastic expansion body disposed inside the expandable support; the outer surface of the expandable support is provided with a limiting part for winding and fixing the optical fiber; the driving unit is used to drive the elastic expansion body to deform, thereby causing the expandable support to expand radially, so as to deform the optical fiber wound on the outer surface of the expandable support, thereby achieving adjustment of the uniformity of the emitted light spot of the optical fiber.

[0007] According to one embodiment of the present invention, the expandable support includes an outer cylinder formed of a grid structure, the outer cylinder being capable of expanding or contracting radially under the action of an external force.

[0008] According to one embodiment of the present invention, the outer cylinder is made of metal material, and the limiting part is a limiting groove that is spirally and continuously disposed on the surface of the outer cylinder;

[0009] In the axial direction of the expandable support, the center-to-center distance between adjacent limiting grooves is greater than half the diameter of the fiber coating, and / or the limiting grooves are uniformly distributed on the surface of the outer cylinder.

[0010] According to one embodiment of the present invention, the outer cylinder is cylindrical, and the minimum cross-sectional diameter of the outer cylinder is set to be greater than twice the product of the cladding diameter of the optical fiber and a preset empirical coefficient; and / or, the axial length of the outer cylinder is set according to the length of the optical fiber and the minimum cross-sectional diameter of the outer cylinder, and its expression is: L=Lf×1.5 / (2π(Dy / 2)), where Lf is the length of the optical fiber and Dy is the minimum cross-sectional diameter of the outer cylinder.

[0011] According to one embodiment of the present invention, the expandable support further includes an elastic inner layer disposed close to the outer cylinder and the elastic expansion body, the elastic inner layer being able to expand outward synchronously with the elastic expansion body to provide uniform radial support force for the outer cylinder.

[0012] According to one embodiment of the present invention, the limiting groove is further provided with a plurality of protrusion structures for enhancing the local stress of the optical fiber, the protrusion structures being spherical protrusions, the radius of the spherical protrusions being set to 0.5-1.2 times the diameter of the coating layer of the optical fiber.

[0013] According to one embodiment of the present invention, the drive unit includes a pressure regulating component and a pipeline connecting the pressure regulating component and the elastic expansion body. The pressure regulating component fills the interior of the elastic expansion body with a medium through the pipeline to regulate the medium pressure inside the elastic expansion body, thereby regulating the radial expansion amount of the expandable support.

[0014] According to one embodiment of the present invention, the elastic inflator is an airbag, the pressure regulating component includes an air source and a proportional valve, the proportional valve is capable of controlling the air pressure inside the airbag, and the fiber optic mode scrambler further includes a pressure sensor for monitoring the air pressure inside the airbag.

[0015] The present invention also provides a uniform light system, comprising: an optical fiber mode scrambler according to the above embodiments; an optical detection unit for detecting the uniformity parameter of the emitted light spot of the optical fiber; and a control unit, which is communicatively connected to the optical detection unit and the driving unit of the optical fiber mode scrambler respectively; the control unit is used to receive the uniformity parameter and, according to the uniformity parameter, send a control command to the driving unit to adjust the radial expansion amount of the expandable support so that the emitted light spot of the optical fiber achieves the target uniformity.

[0016] According to one embodiment of the present invention, the optical detection unit is a beam quality analyzer, and the uniformity parameter is a flatness value calculated based on the dispersion of light intensity energy distribution at multiple sampling points in the outgoing beam space of the optical fiber.

[0017] This invention also provides a uniform light control method, applying the uniform light system described in the above embodiments. The method includes the following steps: adjusting the expandable support to achieve a preset initial diameter before initial winding; providing an optical fiber and fixing it to the expandable support; controlling the driving unit to drive the elastic expansion body to deform, thereby causing the expandable support to expand radially, and changing the curvature and stress distribution of the optical fiber wound on the expandable support through the radial expansion; acquiring the uniformity parameters of the emitted light spot of the optical fiber in real time through an optical detection unit; and adjusting the radial expansion amount of the expandable support according to the uniformity parameters so that the uniformity parameters of the emitted light spot meet preset requirements.

[0018] According to one embodiment of the present invention, the step of fixing the optical fiber to the expandable bracket specifically includes: winding and fixing the optical fiber along the limiting portion of the outer surface of the expandable bracket, and fixing the first and last ends of the optical fiber by clamps or adhesive.

[0019] According to one embodiment of the present invention, the step of adjusting the radial expansion of the expandable support according to the uniformity parameter so that the uniformity parameter of the emitted light spot meets the preset requirements specifically includes: S1: setting a target uniformity according to the preset requirements; S2: calculating the difference between the uniformity parameter and the target uniformity; S3: determining whether the difference exceeds a threshold; if it exceeds, determining the medium pressure increment according to the difference, and controlling the drive unit to increase the medium pressure increment into the elastic expander; S4: repeating steps S1 to S3 until the difference does not exceed the threshold.

[0020] According to one embodiment of the present invention, the difference is positively correlated with the medium pressure increment, and the larger the difference, the larger the corresponding medium pressure increment; the step of determining the medium pressure increment based on the difference specifically includes: matching the corresponding medium pressure increment according to the difference interval in which the difference lies and a preset relationship, wherein the preset relationship includes the correspondence between a preset difference interval and the medium pressure increment; or calculating the corresponding medium pressure increment based on the difference using a preset function.

[0021] The beneficial effects of this invention are as follows: According to the fiber optic mode scrambler provided by this invention, the elastic expansion body is driven by the driving unit to undergo controllable deformation, and the radial expansion amount of the expandable support can be continuously and steplessly adjusted, thereby precisely controlling the bending curvature and stress distribution of the optical fiber and achieving high-precision quantitative adjustment of the mode scrambling degree; since the radial expansion amount of the expandable support can be flexibly adjusted within a large range, it can adapt to optical fibers with different core diameters, different numerical apertures, and different wavelengths of incident lasers, and can quickly match the optimal mode scrambling state for various application scenarios, significantly broadening its applicability; by guiding the optical fiber to be uniformly wound on the surface of the expandable support through the limiting part, local excessive bending, compression, or stress concentration of the optical fiber during deformation is avoided, effectively reducing the risk of optical fiber damage and extending its service life. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an optical fiber mode scrambler provided according to an embodiment of the present invention; Figure 2 yes Figure 1 Schematic diagram of the outer surface structure of the expandable support; Figure 3 yes Figure 1 A schematic diagram of the cross-sectional structure of the intermediate disturbance mode unit; Figure 4 This is a cross-sectional structural diagram of the mode disturbance unit in another implementation method; Figure 5 This is a structural block diagram of the light homogenizing system provided in an embodiment of the present invention; Figure 6 This is a flowchart illustrating the uniform light control method provided in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the corresponding structural schematic diagrams.

[0024] In the description of this invention, it should be understood that the terms "center", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0025] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] This invention provides an optical fiber mode scrambler, a beam homogenizing system including the optical fiber mode scrambler, and a beam homogenizing control method based on the beam homogenizing system. The embodiments are described in detail below.

[0027] like Figure 1 As shown, the present invention provides an optical fiber mode scrambler 100, which is used to homogenize the emitted light spot of an optical fiber 1. The optical fiber mode scrambler 100 includes a mode scrambling unit 10 and a driving unit. The mode scrambling unit 10 is the core mechanical part that directly acts on the optical fiber 1 and generates mode coupling, while the driving unit provides controllable power input to the mode scrambling unit 10.

[0028] The mode scrambling unit 10 includes an expandable support 2 and an elastic expansion body 3 disposed inside the expandable support 2. The outer surface of the expandable support 2 is provided with a limiting part 221 for winding and fixing the optical fiber 1. The driving unit is used to drive the elastic expansion body 3 to deform, thereby causing the expandable support 2 to expand radially, so as to deform the optical fiber 1 wound on the outer surface of the expandable support 2, thereby adjusting the uniformity of the emitted light spot of the optical fiber 1.

[0029] When the expandable support 2 expands radially, the optical fiber 1, which is wound and fixed in the limiting part 221, will be stretched synchronously. The bending curvature and stress distribution of the optical fiber 1 will change accordingly, thereby continuously exciting the coupling between different modes in the optical fiber 1, so that the intensity distribution of the emitted light spot gradually becomes more uniform, and dynamic mode disturbance is realized.

[0030] The present invention drives the elastic expansion body 3 to deform by driving the driving unit, which can precisely control the radial expansion of the expandable support 2, thereby flexibly adjusting the bending curvature and stress of the optical fiber 1. It can match the optimal mode disturbance state for different optical fiber types and different incident laser parameters, and has stronger adaptability.

[0031] Compared to traditional fixed structures or mechanical compression mode scrambling solutions, this solution can precisely adjust the mode scrambling degree of optical fiber 1 by controlling the radial expansion of the expandable support 2. It can adapt to different types of optical fiber 1 and different wavelength laser requirements, and can also avoid damage caused by excessive compression of optical fiber 1, thus greatly improving the adaptability and controllability of optical fiber 1 mode scrambling.

[0032] Specifically, the expandable support 2 is configured to undergo controllable elastic expansion in its radial direction under the action of external force. To achieve this characteristic, in one embodiment, such as Figure 2 and Figure 3 As shown, the expandable support 2 includes an outer cylinder 22 formed by a grid structure 23. The interior of the outer cylinder 22 is a hollow structure for the elastic expansion body 3 to be disposed therein. The optical fiber 1 is wound and fixed to the outer surface of the outer cylinder 22.

[0033] By setting an outer cylinder 22 formed by a grid structure 23, the grid gaps 231 inside the grid structure 23 can expand with the expansion of the elastic expander 3, allowing the outer cylinder 22 to expand radially synchronously with the elastic expander 3. This enables the optical fibers 1 wound at different positions on its outer surface to achieve more consistent bending curvature changes and uniform stress distribution changes, further improving the controllable range of mode disturbance uniformity. At the same time, the grid gaps 231 also provide a good heat dissipation channel for the expansion process of the elastic expander 3.

[0034] The outer cylinder 22 is made of a metal material with a certain hardness, such as aluminum, copper alloy or shape memory alloy, which can ensure structural strength while achieving stable radial deformation. It will not undergo plastic deformation due to repeated expansion and contraction, thus ensuring the service life and adjustment accuracy of the fiber optic mode scrambler 100.

[0035] In this embodiment, the outer cylinder 22 is cylindrical, and the limiting part 221 is a limiting groove 221a that is spirally and continuously disposed on the surface of the outer cylinder 22.

[0036] The optical fiber 1 can be tightly and evenly wound around the outer surface of the expandable support 2 along the limiting groove 221a. The limiting groove 221a is used to limit and guide the optical fiber 1, preventing the optical fiber 1 from axially slipping or being squeezed against each other during the expansion process.

[0037] Preferably, the limiting grooves 221a are evenly distributed on the surface of the outer cylinder 22 to ensure that the bending curvature and stress of each ring of optical fiber 1 are uniform, making the mode scrambling adjustment process more stable and avoiding the situation where uneven deformation of local optical fiber 1 affects the emission uniformity.

[0038] In this embodiment, the limiting groove 221a is spirally and continuously arranged on the outer surface of the expandable support 2, which allows the optical fiber 1 to be distributed on the outer surface of the expandable support 2 with a stable and uniform winding spacing, so that the bending deformation of each optical fiber 1 is consistent and the uneven stress of local optical fiber 1 is avoided from affecting the mode scrambling effect.

[0039] Optical fiber 1 is generally composed of three concentric cylinders from the inside out: core, cladding, and coating. Each layer works together to achieve the transmission and protection of optical signals. This is an existing structure well known to those skilled in the art and will not be described in detail here.

[0040] In this embodiment, the winding spacing d of the optical fiber 1, that is, the center-to-center spacing between adjacent limiting grooves 221a in the axial direction of the expandable support 2, is set to be greater than half the diameter of the coating layer of the optical fiber 1, so that each loop of the optical fiber 1 can obtain independent and uniform deformation and ensure the mode scrambling effect.

[0041] In one embodiment, in order to further improve the fixation reliability and stress control of the optical fiber 1, the limiting groove 221a is also provided with a number of protrusions 222 for enhancing the local stress of the optical fiber 1.

[0042] The protrusion structure 222 can be hemispherical, conical, strip-shaped or annular, and is randomly or regularly distributed at certain intervals along the extension direction of the limiting groove 221a.

[0043] When the optical fiber 1 is embedded in the limiting groove 221a and subjected to the tensile force generated by the radial expansion of the expandable support 2, the protrusion structure 222 will generate additional local compressive stress or bending stress on the surface of the optical fiber 1, thereby achieving a better homogenization effect with a smaller radial expansion amount and further improving the mode coupling efficiency.

[0044] In addition, the protrusion structure 222 can increase the friction between the optical fiber 1 and the expandable support 2, preventing the optical fiber 1 from axially slipping during the expansion process.

[0045] Optionally, in this embodiment, the protrusion structure 222 is a spherical protrusion disposed in the limiting groove 221a, and the radius of the spherical protrusion can be set to between 0.5 and 1.2 times the diameter of the coating layer of the optical fiber 1.

[0046] In one embodiment, the structural dimensions of the outer cylinder 22 can be matched with the specifications of the optical fiber 1 used for mode scrambling.

[0047] The minimum cross-sectional diameter Dy of the outer cylinder 22 can be set based on the cladding diameter D of the optical fiber 1. In this embodiment, the minimum cross-sectional diameter Dy of the outer cylinder 22, i.e., the preset initial diameter of the expansion bracket 2, is set to be greater than twice the product of the cladding diameter D of the optical fiber 1 and the empirical coefficient K. The expression is: Dy > 2K × D. Where D is the cladding diameter of the optical fiber 1, and K is the empirical coefficient, which can be, for example, 120.

[0048] The length L of the outer cylinder 22 can be set according to the length Lf of the optical fiber 1. Specifically, the length L of the outer cylinder 22 can be set by multiplying the length Lf of the optical fiber 1 by 1.5 and then dividing by the circumference formed by the optical fiber 1 being wound around the surface of the outer cylinder 22 once. Its mathematical expression can be expressed as: L=Lf×1.5 / (2π(Dy / 2)).

[0049] like Figure 4 As shown, in another embodiment, the expandable support 2 further includes an elastic inner layer 21 disposed between the outer cylinder 22 and the elastic expansion body 3. The elastic inner layer 21 can expand outward synchronously with the elastic expansion body 3 to provide uniform radial support force to the outer cylinder 22.

[0050] The elastic inner layer 21 is made of a material with good elasticity and flexibility, such as silicone rubber or polyurethane. The function of the elastic inner layer 21 is to transmit the pressure applied by the elastic expansion body 3 and convert it into a uniform radially distributed force, preventing uneven pressure that may occur when the elastic expansion body 3 directly contacts the outer cylinder 22. Simultaneously, the elastic inner layer 21 also acts as a buffer and protector, preventing the elastic expansion body 3 from being scratched by the grid structure 23.

[0051] The elastic expansion body 3 is disposed inside the expandable support 2. Under the action of the driving unit, the elastic expansion body 3 can undergo controllable deformation, thereby squeezing the expandable support 2 outward and causing it to expand radially.

[0052] In one embodiment, the elastic expansion body 3 can be made of a highly elastic and highly sealing material, such as highly elastic rubber or TPU (thermoplastic polyurethane). The elastic expansion body 3 has an internal cavity, and the drive unit adjusts the volume of the elastic expansion body 3 by filling the interior of the elastic expansion body 3 with a medium, thereby controlling the degree of compression on the external expandable support 2 and achieving precise adjustment of the radial expansion amount of the expandable support 2.

[0053] The drive unit includes a pressure regulating component 5 and a pipeline 4 connecting the pressure regulating component 5 and the elastic expansion body 3. The pressure regulating component 5 fills the interior of the elastic expansion body 3 with a medium through the pipeline 4 to regulate the pressure of the medium inside the elastic expansion body 3, thereby controlling the volume of the elastic expansion body 3.

[0054] The filling medium can be gas or liquid. When using a gaseous medium, a high-precision air pump can be selected for the pressure regulating component 5, which offers advantages such as lower cost, good medium flowability, and fast response speed. When using a liquid medium, a high-precision hydraulic pump can be selected for the pressure regulating component 5, which offers advantages such as lower liquid compressibility and higher precision in expansion control.

[0055] In another embodiment, the elastic expander 3 can also be made of dielectric elastomer material, and its expansion degree can be adjusted by changing the driving voltage applied to the dielectric elastomer to achieve stable and controllable radial expansion.

[0056] This embodiment uses the structure of an air bladder for the elastic expansion body 3 as an example for detailed description. Other implementation methods can be implemented by analogy with the working logic of this embodiment, and will not be repeated.

[0057] In this embodiment, the elastic inflator 3 is an airbag, which is connected to the pressure regulating component 5 via a pipe 4. The pressure regulating component 5 can precisely adjust the air pressure P inside the airbag according to the control signal. When the air pressure P increases, the airbag volume expands, squeezing the inflatable support 2 outward to cause it to expand radially.

[0058] The pressure regulating component 5 adjusts the radial expansion amount ΔR of the expandable support 2 by controlling the air pressure P inside the airbag. The relationship between the air pressure P (Pa) inside the airbag and the radial expansion amount ΔR of the expandable support 2 is: ΔR = (P × Aeff) / kr. Where Aeff is the effective working area of ​​the airbag, which is approximately equal to the inner surface area of ​​the outer cylinder 22. The radial stiffness kr (unit: N / m) can be calculated using finite element method or thin shell theory.

[0059] The pressure regulating assembly 5 includes an air source and a proportional valve, which can controllably adjust the gas flow rate into the airbag, i.e., control the air pressure inside the airbag. The air source is, for example, a motor-driven air pump or cylinder.

[0060] Pipeline 4 can be made of polyurethane material, and its maximum operating pressure is generally greater than one MPa. It is suitable for introducing the gas discharged from the gas source into the airbag to provide the air pressure P required for the airbag to expand.

[0061] In one embodiment, the surface of the airbag is provided with micro-vents for heat dissipation. The micro-vents are small in size (e.g., on the micrometer scale), allowing a small amount of gas to leak out slowly. The leaked gas can carry away the heat generated by the expansion of the airbag, creating a micro-airflow cooling environment.

[0062] Meanwhile, in order to achieve stable air pressure control, the pressure regulating component 5 can be used to control the balance between the air intake rate and the leakage rate, so as to ensure that the air pressure inside the airbag can be stably maintained at the set value.

[0063] The elastic inner layer 21 is also breathable, which allows a small amount of gas to be discharged during the expansion of the elastic expansion body 3, so as to facilitate heat dissipation.

[0064] The fiber optic mode scrambler 100 also includes a pressure sensor for monitoring the internal air pressure of the airbag, which is used to monitor the internal air pressure of the airbag in real time, realize stable closed-loop control of air pressure, and ensure the control accuracy of radial expansion.

[0065] like Figure 5 As shown, based on the aforementioned fiber optic mode scrambler 100, the present invention further provides a light homogenizing system. In addition to the fiber optic mode scrambler 100 described in any of the above embodiments, this light homogenizing system also includes an optical detection unit and a control unit.

[0066] An optical detection unit is positioned on the output optical path of the fiber optic mode scrambler 100 to detect the uniformity parameters of the emitted light spot from the fiber 1. The optical detection unit can be, for example, a beam quality analyzer. The beam quality analyzer can capture a two-dimensional intensity distribution image of the emitted light spot and quantize the intensity value of each pixel.

[0067] The uniformity parameter is a parameter that is calculated based on the collected light intensity distribution data and is used to quantitatively characterize the uniformity of the emitted light spot of fiber 1.

[0068] In one embodiment, the uniformity parameter is the flatness value C, which is calculated based on the dispersion of light intensity energy distribution at multiple sampling points on the cross-section of the outgoing light spot of optical fiber 1.

[0069] The formula for calculating the flatness value C is: In the formula, This represents the energy value at each sampling point. This represents the average value of each sampling point, and N represents the number of sampling points.

[0070] In the formula, the energy value of each sampling point represents the light intensity energy of that sampling point, the average value of each sampling point represents the arithmetic mean of the energy of all sampling points, and the number of sampling points represents the number of samples collected on the cross-section of the light spot. Generally, the flatness value C ≤ 1. The smaller the flatness value C, the better the uniformity of the emitted light spot.

[0071] When C ≤ 0.2, the spot size is generally considered to have achieved good homogenization, which can meet the requirements of most laser processing and medical applications.

[0072] The control unit is communicatively connected to the optical detection unit and the drive unit of the fiber optic mode scrambler 100, respectively. The control unit can be a standalone embedded controller, a programmable logic controller (PLC), or integrated into a host computer (such as a personal computer or an industrial control computer).

[0073] The core function of the control unit is to receive uniformity parameters from the optical detection unit and send control commands to the drive unit based on the difference between the uniformity parameters and the preset target uniformity. By controlling the air pressure P inside the airbag, the radial expansion amount ΔR of the expandable bracket 2 is adjusted so that the emitted light spot of the optical fiber 1 reaches the target uniformity.

[0074] In one implementation, the control unit internally runs a PID (Proportional-Integral-Derivative) control algorithm. The PID controller calculates an output control quantity based on the difference between the currently measured uniformity parameter and the target uniformity. This output control quantity is converted into an opening signal for the proportional valve or a rotational speed signal for the air pump, thereby controlling the air pressure P inside the airbag. The PID algorithm has the advantages of fast response speed and small steady-state error, making it particularly suitable for uniform light processes requiring continuous and smooth adjustment.

[0075] The specific working process of the light homogenization system is as follows: The operator winds and fixes the optical fiber 1 to be homogenized onto the expandable support 2. The initial cross-sectional diameter of the outer cylinder 22 is the minimum cross-sectional diameter Dy, which is the initial bending diameter of the optical fiber 1. The target uniformity is set by the host computer, and the system is started. The control unit sends an inflation command to the drive unit, causing the airbag to gradually inflate and expand, which drives the expandable support 2 to produce radial expansion. The optical fiber 1 wound in the limiting groove 221a is gradually stretched, and the bending curvature and stress distribution of the optical fiber 1 continuously change, constantly exciting mode coupling, and the uniformity of the emitted light spot gradually improves accordingly.

[0076] During inflation, the optical detection unit continuously collects light intensity distribution data of the emitted light spot, calculates the current uniformity parameter in real time, and feeds the data back to the control unit. The control unit compares the current uniformity parameter with the preset target uniformity, and adjusts the air pressure P inside the airbag according to the difference, thereby adjusting the radial expansion of the inflatable support 2. The above process is executed in a closed loop until the difference between the measured uniformity parameter and the preset target uniformity converges to a threshold (e.g., the deviation is less than 0.2).

[0077] After that, the system enters steady-state monitoring mode. The airbag maintains the current air pressure P and remains stable. The optical detection unit continuously monitors the uniformity parameter of the emitted light spot in real time. If the uniformity of the optical fiber is affected by factors such as changes in ambient temperature or stress relaxation, the control unit will immediately adjust the air pressure P of the airbag to always maintain the uniformity of the output light spot.

[0078] like Figure 6 As shown, the present invention also provides a method for controlling uniform light distribution, which applies the above-described uniform light distribution system. The method includes the following steps: Fix optical fiber 1 to expandable bracket 2.

[0079] The drive unit is controlled to drive the elastic expansion body 3 to deform, so that the expandable support 2 expands radially. The radial expansion of the expandable support 2 changes the bending curvature and stress distribution of the optical fiber 1 wound on the expandable support 2.

[0080] The uniformity parameters of the emitted light spot from fiber 1 are collected in real time by the optical detection unit; the amount of medium filling is adjusted according to the uniformity parameters so that the uniformity parameters of the emitted light spot meet the preset requirements.

[0081] The control method provided by this invention combines real-time detection with closed-loop adjustment, achieving automated and intelligent control of the light homogenization process in fiber 1. Compared to manual adjustment, this method has advantages such as fast response, high precision, and independence from operator experience.

[0082] Specifically, "fixing the optical fiber 1 to the expandable bracket 2" includes: winding and fixing the optical fiber 1 along the limiting part 221 on the outer surface of the expandable bracket 2, and fixing the two ends of the optical fiber 1 by clamps or adhesive.

[0083] Specifically, optical fiber 1 is tightly wound along the limiting groove 221a on the outer surface of the expandable support 2, so that each turn of optical fiber 1 is embedded in the limiting groove 221a, avoiding overlapping or crossing. The end of optical fiber 1 is fixed by clamps or adhesive to prevent the optical fiber from sliding due to stress when the expandable support 2 expands, ensuring that the bending radius of optical fiber 1 follows the change of the expandable support 2.

[0084] In one embodiment, after the optical fiber 1 is wound, UV-curable adhesive or thermosetting adhesive can be applied to the beginning and end of the optical fiber 1, and then the adhesive can be cured by UV irradiation or heating, thereby firmly locking the optical fiber 1 in the limiting groove 221a.

[0085] In the initial state, the expandable support 2 is in an unexpanded or slightly expanded state. The preset initial diameter of the expandable support 2 is the minimum cross-sectional diameter Dy of the outer cylinder 22 mentioned above, which is the initial bending diameter of the optical fiber 1. This minimum cross-sectional diameter Dy can be preset according to the specifications of the optical fiber 1, leaving a certain space for expansion adjustment. The mode coupling of the optical fiber 1 is relatively weak.

[0086] The step "controlling the drive unit to drive the elastic expansion body 3 to deform so that the expandable support 2 expands radially" specifically includes the control unit sending a command to the drive unit, and the drive unit gradually filling the interior of the elastic expansion body 3 with a medium according to the command, so that the volume of the airbag elastic expansion body 3 gradually expands, squeezing the outer expandable support 2 to produce radial expansion.

[0087] In this embodiment, the control unit, such as a host computer, issues an inflation command, which inflates the airbag through the drive unit. The airbag expands, uniformly compressing the expandable support 2 from the inside. Due to the presence of the grid structure, the cross-sectional diameter of the outer cylinder 22 increases uniformly.

[0088] The radial expansion of the expandable support 2 alters the curvature and stress distribution of the optical fiber 1 wound around it. As the radius of the outer cylinder 22 increases, the optical fiber 1 wound around the outer wall of the outer cylinder 22 is stretched, resulting in bending deformation and radial stress. According to mode coupling theory, the changes in curvature and stress alter the phase matching conditions between different guided modes in the optical fiber 1, promoting energy redistribution between modes and ultimately resulting in a more uniform energy distribution of the emitted light spot, forming a uniform flat-top light spot.

[0089] In the step "Real-time acquisition of uniformity parameters of the emitted light spot from fiber 1 via optical detection unit", the optical detection unit, for example, acquires two-dimensional light intensity distribution data of the emitted light spot using a beam quality analyzer. It then acquires light intensity values ​​for sampling points within the entire light spot area or a specified uniform sampling region. Subsequently, it calculates the current uniformity parameters according to a preset calculation method and transmits the calculated uniformity parameters to the control unit in real time, completing one data acquisition feedback cycle. The acquisition frequency can be set as needed.

[0090] In this embodiment, the uniformity parameter is preferably characterized by the aforementioned flatness value C. The optical detection unit acquires the current measured flatness C_current.

[0091] The step "adjusting the medium filling amount according to the uniformity parameter so that the uniformity parameter of the emitted light spot meets the preset requirements" specifically includes the following detailed steps: S1: Set the target uniformity according to the preset requirements; S2: Calculate the difference between the uniformity parameter and the target uniformity; S3: Determine whether the difference exceeds the threshold; if it does, determine the medium pressure increment based on the difference, and control the drive unit to increase the medium pressure increment into the elastic expansion body 3. S4: Repeat steps S1 to S3 until the difference does not exceed the threshold.

[0092] Step S1 involves inputting the target uniformity based on actual needs. In this embodiment, a target flatness value C_target is used, such as 0.2, 0.15, or 0.1. For general applications, 0.2 can be selected; for high-precision applications, 0.1 or lower can be selected.

[0093] Step S2 calculates the difference between the uniformity parameter and the target uniformity, that is, the difference between the current measured flatness C_current and the target flatness C_target is ΔC = C_current - C_target.

[0094] If the measured uniformity parameter is already less than the target uniformity, it means that the uniformity is good enough. At this time, the difference ΔC is negative or zero, and the system can stop adjusting and maintain the current state.

[0095] Step S3 determines whether the difference exceeds a threshold. In this embodiment, specifically, it determines whether the absolute value of the difference ΔC exceeds a threshold ΔS (the threshold ΔS is set to, for example, 0.2). If |ΔC| ≤ the threshold, it is considered that the requirement has been met, and the current pressure remains unchanged. If ΔC > ΔS, it indicates that the disturbance mode intensity needs to be increased, therefore the airbag pressure needs to be increased.

[0096] When the difference ΔC exceeds the threshold ΔS, the medium pressure increment ΔP is determined based on the difference ΔC, and the drive unit is controlled to increase the medium pressure increment ΔP into the elastic expansion body 3.

[0097] The difference ΔC is positively correlated with the medium pressure increment ΔP. The larger the difference ΔC is, the larger the corresponding medium pressure increment ΔP is. Thus, a larger radial expansion ΔR can be obtained through a larger medium pressure increment ΔP, which further improves the mode disturbance intensity and thus improves the uniformity of the emitted light spot more quickly.

[0098] The step "determine the medium pressure increment based on the difference" specifically includes: matching the corresponding medium pressure increment according to the difference range where the difference lies and a preset relationship. The preset relationship includes the correspondence between a preset difference range and the medium pressure increment.

[0099] The specific method for determining the preset relationship can be through experimental calibration. After calibration, the corresponding relationship is stored in the storage module of the control unit. When calling, it can be obtained by directly looking up the table. The operation is simple and the response speed is fast.

[0100] Alternatively, in another embodiment, the corresponding medium pressure increment can be calculated using a preset function based on the difference.

[0101] The functional relationship between the difference ΔC and the medium pressure increment ΔP is obtained by pre-fitting, and the corresponding medium pressure increment ΔP is directly calculated through the function.

[0102] To accelerate the adjustment process and avoid excessively long adjustment times due to small adjustment steps, a rapid approximation method can be employed in a preferred embodiment. When the difference ΔC is large, the system uses a large medium pressure increment ΔP, which allows for rapid approximation of the target through a single large-step adjustment, followed by fine-tuning.

[0103] The specific control method is to map ΔC to a larger ΔP in a preset relationship. Alternatively, the system can directly subtract the threshold from the current measured flatness and multiply it by a preset coefficient T to obtain the next pressure increment, i.e., ΔP = T × (ΔC - ΔS).

[0104] The control unit converts the calculated medium pressure increment ΔP into the change in the opening of the proportional valve or the change in the speed of the air pump, and the drive unit accordingly adds the medium pressure increment ΔP into the elastic expansion body 3.

[0105] During the pressure regulation process, the pressure sensor provides real-time feedback of the air pressure value, forming an internal closed loop to ensure that the actual pressure accurately reaches the target value.

[0106] After one adjustment is completed, the system repeats steps S1 to S3 until the difference ΔC does not exceed the threshold ΔS, that is, the current measured uniformity parameter meets the preset requirements, the adjustment process ends, and the system enters the steady-state maintenance stage.

[0107] The control method provided by this invention realizes the automated closed-loop adjustment of the uniformity of the emitted light spot, which can accurately obtain the target uniformity according to actual needs without repeated manual adjustments. This not only improves the consistency of the light uniformity effect, but also adapts to the light uniformity requirements of different fiber specifications and different application scenarios.

[0108] In summary, according to the fiber optic mode scrambler 100, the beam homogenizing system, and the control method provided by the present invention, the fiber optic mode scrambler 100, by setting an expandable support 2 and an elastic expansion body 3 in a cooperative structure, and by driving the elastic expansion body 3 to deform through a driving unit, can continuously and steplessly change the radial expansion amount of the expandable support 2, thereby flexibly adjusting the bending radius and stress distribution of the fiber 1 wound on it. This allows the fiber optic mode scrambler 100 to be adapted to various types of optical fibers 1 and lasers of different wavelengths, greatly improving the versatility and ease of use of the device.

[0109] In the embodiments provided by the present invention, it should be understood that the above-described implementation of the structure is merely illustrative. For example, the division of the modules is merely a logical functional division. In actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0110] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. The present invention has been described in detail with reference to the foregoing embodiments. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fiber mode scrambler for homogenizing the emitted light spot of an optical fiber (1), characterized in that, Includes a mode scrambling unit and a drive unit; The mode scrambling unit includes an expandable support (2) and an elastic expansion body (3) disposed inside the expandable support (2); the outer surface of the expandable support (2) is provided with a limiting part (221) for winding and fixing the optical fiber (1); the expandable support (2) includes an outer cylinder (22) formed by a grid structure (23), and the outer cylinder (22) can expand or contract radially under the action of external force; The driving unit includes a pressure regulating component (5) and a pipeline (4) connecting the pressure regulating component (5) and the elastic expansion body (3). The pressure regulating component (5) fills the elastic expansion body (3) with a medium through the pipeline (4) to regulate the medium pressure inside the elastic expansion body (3), thereby regulating the radial expansion of the expandable support (2) so that the optical fiber (1) wrapped around the outer surface of the expandable support (2) deforms, thereby adjusting the uniformity of the emitted light spot of the optical fiber (1).

2. The fiber optic mode scrambler according to claim 1, characterized in that, The outer cylinder (22) is made of metal material, and the limiting part (221) is a limiting groove (221a) that is spirally and continuously provided on the surface of the outer cylinder (22). In the axial direction of the expandable support (2), the center-to-center distance between adjacent limiting grooves (221a) is greater than half the diameter of the coating layer of the optical fiber (1), and / or, the limiting grooves (221a) are uniformly distributed on the surface of the outer cylinder (22).

3. The fiber optic mode scrambler according to claim 1, characterized in that, The outer cylinder (22) is cylindrical, and the minimum cross-sectional diameter of the outer cylinder (22) is set to be greater than twice the product of the cladding diameter of the optical fiber (1) and a preset empirical coefficient; And / or, the axial length of the outer cylinder (22) is set according to the length of the optical fiber (1) and the minimum cross-sectional diameter of the outer cylinder (22), and its expression is: L=Lf×1.5 / (2π(Dy / 2)), where Lf is the length of the optical fiber (1) and Dy is the minimum cross-sectional diameter of the outer cylinder (22).

4. The fiber optic mode scrambler according to claim 1, characterized in that, The expandable support (2) also includes an elastic inner layer (21) that is closely attached between the outer cylinder (22) and the elastic expansion body (3). The elastic inner layer (21) can expand outward synchronously with the elastic expansion body (3) to provide uniform radial support force for the outer cylinder (22).

5. The fiber optic mode scrambler according to claim 2, characterized in that, The limiting groove (221a) is further provided with a number of protrusion structures (222) for enhancing the local stress of the optical fiber (1). The protrusion structure (222) is a spherical protrusion, and the radius of the spherical protrusion is set to 0.5-1.2 times the diameter of the coating layer of the optical fiber (1).

6. The fiber optic mode scrambler according to claim 1, characterized in that, The elastic expansion body (3) is an airbag, the pressure regulating component (5) includes an air source and a proportional valve, the proportional valve can controllably adjust the air pressure inside the airbag, and the fiber optic mode scrambler also includes a pressure sensor for monitoring the air pressure inside the airbag.

7. A light homogenizing system, characterized in that, include: The fiber optic mode scrambler as described in any one of claims 1 to 6; An optical detection unit is used to detect the uniformity parameter of the emitted light spot of the optical fiber (1); The control unit is connected to the optical detection unit and the drive unit of the fiber optic mode scrambler, respectively. The control unit is used to receive the uniformity parameter and send a control command to the drive unit according to the uniformity parameter to adjust the radial expansion of the expandable support (2) so that the emitted light spot of the fiber (1) reaches the target uniformity.

8. The light homogenizing system according to claim 7, characterized in that, The optical detection unit is a beam quality analyzer, and the uniformity parameter is the flatness value calculated based on the dispersion of light intensity energy distribution at multiple sampling points in the spatial domain of the outgoing light spot of the optical fiber (1).

9. A method for controlling uniform light distribution, characterized in that, The method, employing the light homogenizing system as described in claim 7 or 8, comprises the following steps: Adjust the expandable support (2) to make its diameter reach the preset initial diameter before performing initial winding; Provide an optical fiber (1) and fix the optical fiber (1) to the expandable bracket (2); The drive unit is controlled to drive the elastic expansion body (3) to deform so that the expandable support (2) expands radially. The radial expansion of the expandable support (2) changes the bending curvature and stress distribution of the optical fiber (1) wrapped on the expandable support (2). The uniformity parameter of the emitted light spot of the optical fiber (1) is collected in real time by the optical detection unit; the radial expansion of the expandable support (2) is adjusted according to the uniformity parameter so that the uniformity parameter of the emitted light spot meets the preset requirements.

10. The uniform light control method according to claim 9, characterized in that, The step of fixing the optical fiber (1) to the expandable bracket (2) specifically includes: winding and fixing the optical fiber (1) along the limiting part (221) on the outer surface of the expandable bracket (2), and fixing the first and last ends of the optical fiber (1) by clamps or glue.

11. The uniform light control method according to claim 9, characterized in that, The step of adjusting the radial expansion of the expandable support (2) according to the uniformity parameter so that the uniformity parameter of the emitted light spot meets the preset requirements specifically includes: S1: Set the target uniformity according to the preset requirements; S2: Calculate the difference between the uniformity parameter and the target uniformity; S3: Determine whether the difference exceeds the threshold; if it does, determine the medium pressure increment based on the difference and control the drive unit to increase the medium pressure increment into the elastic expansion body (3); S4: Repeat steps S1 to S3 until the difference does not exceed the threshold.

12. The uniform light control method according to claim 11, characterized in that, The difference is positively correlated with the increase in medium pressure; the larger the difference, the larger the corresponding increase in medium pressure. The step of determining the medium pressure increment based on the difference specifically includes: Based on the difference range where the difference is located and the preset relationship, the corresponding medium pressure increment is obtained by matching, wherein the preset relationship includes the correspondence between the preset difference range and the medium pressure increment; Alternatively, the corresponding medium pressure increment can be calculated using a preset function based on the difference.

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