A ten-kilowatt fiber laser

Abstract

The application discloses a ten-thousand-watt fiber laser, and relates to the technical field of fiber lasers, which comprises an optical path module, an electric control module and a composite water cooling plate. The composite water cooling plate comprises an upper cooling plate, a thermal buffer isolation plate and a lower cooling plate which are sequentially stacked. An upper layer water channel is formed between the upper cooling plate and the thermal buffer isolation plate, and a lower layer water channel is formed between the thermal buffer isolation plate and the lower cooling plate. The two layers of water channels are isolated from each other and are communicated with the same water inlet and outlet. The upper cooling plate is provided with inner and outer layer optical fiber grooves arranged in a nested mode, the lower layer water channel is provided with a serpentine main flow channel, a local heat exchange area and a long strip rhombus shunt column, and the thermal buffer isolation plate is internally provided with a closed phase change material containing cavity. The optical path module and the electric control module are integrated on both sides of the composite water cooling plate. A plurality of groups of semiconductor pumping sources are combined according to output power, so that ten-thousand-watt laser output is realized. The overall size of the whole machine is about 500mm*500mm*70mm, and the weight is less than 25kg. The whole machine can improve heat dissipation and operation reliability.

Description

Technical Field

[0001] This invention relates to the field of fiber laser heat dissipation technology, specifically to a 10,000-watt fiber laser that uses a composite water-cooled plate to cool the optical path module and the electronic control module in sections, and improves the temperature gradient and deformation risk of the plate through a thermal buffer isolation structure. Background Technology

[0002] With the increasing demand for high-power, high-beam-quality laser output in industrial processing, 10,000-watt fiber lasers are gradually being applied to applications such as thick plate cutting, welding, and surface treatment. During operation, fiber lasers generate heat in various components, including the pump source, driver module, combiner, cladding optical filter, gain fiber, and fiber splice. The pump source and driver module generate the most heat, while the gain fiber, combiner, and cladding optical filter are particularly sensitive to temperature changes. Failure to dissipate this heat effectively can lead to decreased pump efficiency, increased temperature in optical components, output power fluctuations, and beam quality degradation.

[0003] Existing 10,000-watt fiber lasers typically employ single-layer water-cooled plates, double-sided shared-channel water-cooled plates, or multiple independent water-cooled plates to cool the pump source, electronic control components, and optical components. Single-layer water-cooled plates have limited heat exchange area and flow channel space. With multiple pump sources arranged in an array, the coolant temperature gradually increases as it flows through multiple heat-generating areas, making pump sources located further downstream prone to insufficient cooling and temperature accumulation. While double-sided shared-channel water-cooled plates can utilize both surfaces simultaneously, it's difficult to tailor cooling structures to the different heat flux densities and temperature sensitivities of the optical components and pump sources.

[0004] While using multiple independent water-cooled plates can cool different heat-generating modules separately, it increases the number of water circuit connectors, water distribution structures, and mounting supports, thus increasing the overall size, weight, and assembly complexity of the laser. Furthermore, the differences in heat generation power and temperature rise rate between the optical path side and the pump source side can easily lead to a large temperature gradient along the thickness of the cooling plate during long-term operation. Inconsistent thermal expansion between different plate layers can also cause warping or deformation of the cooling plate, thereby affecting the installation stability of optical components and the overall operational reliability of the laser. Therefore, the cooling structure of existing 10,000-watt fiber lasers still requires further improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a 10,000-watt fiber laser, which improves the heat dissipation effect of the optical path module and the electronic control module by setting up mutually isolated upper and lower water channels in the composite water cooling plate and setting a heat buffer isolation plate between them, thereby reducing the temperature gradient caused by different heat loads and the risk of plate warping.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: A 10,000-watt fiber laser includes an optical path module, an electrical control module, and a composite water-cooling plate, wherein... The composite water-cooled plate includes an upper cooling plate, a heat buffer isolation plate, and a lower cooling plate stacked and connected in sequence. An upper water channel is formed between the upper cooling plate and the heat buffer isolation plate, and a lower water channel is formed between the heat buffer isolation plate and the lower cooling plate. The upper water channel and the lower water channel are isolated from each other and connected to the same inlet and outlet to form a parallel cooling branch. The optical path module is located on the outside of the upper cold plate, and the electronic control module is located on the outside of the lower cold plate and includes multiple pump sources arranged along the lower water channel; The outer surface of the upper cold plate is integrally processed with an outer fiber optic groove and an inner fiber optic groove located within the area enclosed by the outer fiber optic groove. The outer fiber optic groove is formed by multiple sequentially tangent arc segments. The curvature centers of the corresponding arc segments in adjacent coils are shifted sequentially according to the fiber optic groove spacing. The coiled optical fibers are placed in the outer fiber optic groove and the inner fiber optic groove through thermally conductive adhesive. The upper water channel extends below the two fiber optic grooves. The lower water channel includes a serpentine main channel extending according to the arrangement of the multiple pump sources and a local heat exchange zone located directly below each pump source chip. Each local heat exchange zone is provided with multiple elongated rhomboid diverter columns extending along the flow direction of the coolant, and microchannels are formed between adjacent elongated rhomboid diverter columns. The heat buffer isolation plate is provided with a closed phase change material receiving cavity, which is located between the upper water channel and the lower water channel and extends continuously along the relative areas of the two water channels. The enclosed phase change material cavity is filled with phase change material to form a thermal buffer structure between the two water channels when the upper and lower cold plates are subjected to different heat loads. The composite water-cooled plate constitutes the mounting frame for the optical path module and the electronic control module.

[0007] Optionally, the enclosed phase change material receiving cavity is continuously arranged along the relative area of ​​the upper water channel and the lower water channel, the upper cavity wall and the lower cavity wall of the enclosed phase change material receiving cavity are adjacent to the upper water channel and the lower water channel respectively, the height of the enclosed phase change material receiving cavity is 0.3mm to 0.5mm, and the phase change temperature of the phase change material is 40℃ to 60℃.

[0008] Optionally, the upper cold plate, the heat buffer isolation plate, and the lower cold plate are processed separately, and vacuum brazing connection interfaces are formed between the upper cold plate and the heat buffer isolation plate, and between the heat buffer isolation plate and the lower cold plate, respectively. The upper water channel and the lower water channel each have a fully enclosed brazing boundary. The heat buffer isolation plate is provided with a filling port communicating with the enclosed phase change material receiving cavity, and a friction stir welded sealing part is provided at the filling port.

[0009] Optionally, the serpentine main channel connects multiple local heat exchange zones sequentially along the coolant flow direction. A small number of downstream local heat exchange zones have more branch paths than their adjacent upstream local heat exchange zones, and the flow cross-sectional area of ​​a single branch path in the downstream local heat exchange zone is smaller than that of a single branch path in the upstream local heat exchange zone.

[0010] Optionally, each of the local heat exchange zones is opposite to the installation position of the corresponding pump source chip, the length direction of the elongated rhomboid diverter column is consistent with the flow direction of the coolant in the corresponding local heat exchange zone, the length-to-width ratio of the rhomboid structure of the elongated rhomboid diverter column is 5:1, and the length direction is consistent with the flow direction of the coolant.

[0011] Optionally, the upper channel is a wide rectangular meandering serpentine channel, extending below the coiled optical fiber, grating, optical fiber splice, optical fiber texturing section, combiner, and cladding optical filter, respectively; the upper channel corresponding to the high-power devices such as the combiner and the cladding optical filter is provided with a diverter column microchannel.

[0012] Optionally, the inner fiber groove is located within the coiled area enclosed by the outer fiber groove, and the minimum distance between the inner fiber groove and the outer fiber groove is not less than the distance between two adjacent fiber grooves; the minimum radius of curvature of the outer fiber groove is 46~60mm, multiple arc segments in the same coil are sequentially tangent, the offset distance between the curvature centers of corresponding arc segments in adjacent coils is equal to the distance between adjacent fiber grooves, and the distance between adjacent fiber grooves is 1~2mm.

[0013] Optionally, the coiled optical fiber is respectively housed in the outer optical fiber groove and the inner optical fiber groove, and the thermally conductive adhesive is filled in the gap between the coiled optical fiber and the bottom and wall of the corresponding optical fiber groove.

[0014] Optionally, the width-to-narrowness ratio of the upper water channel is 4:1, the spacing between adjacent flow channel sections is 6~7mm, the total flow length of the upper water channel is 4~5m, and the upper water channel is provided with guide ribs extending in an arc shape along the coolant turning path at the turning position.

[0015] The main advantages of this invention compared to existing technologies are as follows: This invention incorporates an upper and lower water channel within a composite water-cooled plate, which are isolated from each other and supplied in parallel. This allows the optical path module and the electronic control module to be cooled separately by matching cooling channels. A thermal buffer isolation plate with a closed phase change material cavity is placed between the upper and lower cooling plates to buffer the heat transfer caused by different thermal loads on both sides. This helps to reduce the transient temperature gradient in the thickness direction of the plate and the risk of warping deformation of the composite water-cooled plate, thereby improving the structural stability and operational reliability of the 10,000-watt fiber laser.

[0016] This invention forms a serpentine main channel in the lower water channel according to the arrangement of multiple pump sources, and sets a local heat exchange area and a long diamond-shaped diverter column directly below each pump source chip, so that microchannels are formed between adjacent long diamond-shaped diverter columns. This can increase the heat exchange area of ​​the corresponding area of ​​the pump source and enhance the coolant disturbance, which is beneficial to reduce the local heat accumulation when multiple pump sources work continuously and improve the temperature uniformity of the pump source array.

[0017] This invention integrates an outer fiber groove and an inner fiber groove on the outer surface of the upper cooling plate to form a nested variable curvature fiber coil structure. The upper water channel extends through the corresponding area of ​​the fiber coil. This reduces the area occupied by the fiber coil while continuously cooling the coiled fiber. It also helps to avoid the coiled fiber being subjected to stress along a single bending direction for a long time, thus improving the beam quality and output stability during high-power output.

[0018] This invention uses a composite water-cooled plate to simultaneously support the optical path module and the electronic control module, integrating the heat dissipation structure, device mounting structure and overall load-bearing structure into one unit. This reduces the use of multiple independent water-cooled plates, water distribution connectors and additional support components, which helps to reduce the overall size and weight of the machine and simplify the assembly connection relationship. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the pump source side structure of a 10,000-watt fiber laser in one embodiment of the present invention; Figure 2 This is a schematic diagram of the optical path module side structure of a 10,000-watt fiber laser according to one embodiment of the present invention; Figure 3 This is a schematic diagram of the interlayer structure of the composite water-cooled plate in one embodiment of the present invention; Figure 4 This is a schematic diagram of the upper cooling plate and upper water channel in one embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the lower cooling plate and the lower water channel in one embodiment of the present invention; Figure 6 This is a schematic diagram showing the power of each heat source and the flow direction of the coolant on the pump source side in one embodiment of the present invention. Figure 7This is a schematic diagram showing the power of each heat source and the flow direction of the coolant on the optical path module side in one embodiment of the present invention. Figure 8 This is a temperature distribution cloud map of the pump source side in one embodiment of the present invention; Figure 9 This is a temperature distribution cloud map of the optical path module side in one embodiment of the present invention. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings. The described embodiments are used to illustrate the structural composition, connection relationship, working process and technical effects of the present invention, and are not intended to unnecessarily limit the scope of protection of the present invention.

[0021] Example 1: This example provides a 10,000-watt fiber laser, including an optical path module, an electronic control module, and a composite water-cooled plate 1. The composite water-cooled plate 1 serves as both the cooling base for the optical path module and the electronic control module, and as the mounting framework for each component, allowing the optical path components, electronic control components, and pumping components to be disposed on different surfaces of the composite water-cooled plate 1, thereby forming a compact double-sided integrated laser.

[0022] In this embodiment, the optical path module and the electronic control module are integrated onto the two surfaces of the composite water-cooled plate 1, respectively. The composite water-cooled plate 1 simultaneously undertakes the functions of cooling, device mounting, and overall machine load-bearing, allowing all pump sources, drive modules, optical path devices, control devices, and external connection interfaces to be centrally arranged on the same plate-type mounting frame. In one specific embodiment, the overall dimensions of the machine can be controlled within the range of approximately 500mm × 500mm × 70mm, and the overall weight is less than 25kg. Within this integrated size range, multiple sets of high-power pump sources 2 can be configured according to the target laser output power, and each can be driven by a corresponding high-power drive module 3. The pump light generated by each set of high-power pump sources 2 is used together after optical path coupling to amplify the seed light, thereby achieving kilowatt-level laser output.

[0023] like Figure 1 As shown, a plurality of high-power pump sources 2 and a plurality of high-power drive modules 3 are provided on one side of the composite water-cooled plate 1. The plurality of high-power pump sources 2 are arranged along the length and width directions of the composite water-cooled plate 1 and are electrically connected to the corresponding high-power drive modules 3. The high-power drive modules 3 are used to provide drive current to the corresponding high-power pump sources 2 according to the control signals output by the main control board 9, so that the high-power pump sources 2 convert electrical energy into pump light. When the plurality of high-power pump sources 2 are working, they form a concentrated and continuous high heat flux density area, which is the main heat-generating component on the side of the electronic control module.

[0024] like Figure 1 and Figure 2As shown, the 10,000-watt fiber laser in this embodiment adopts a master oscillation power amplification structure. One side of the composite water-cooled plate 1 is equipped with multiple high-power pump sources 2 and multiple high-power drive modules 3. The multiple high-power pump sources 2 are combined and arranged according to the 10,000-watt laser output power requirements, and are driven by corresponding high-power drive modules 3. The other side of the composite water-cooled plate 1 is equipped with a high-power cladding optical filter 4, a beam combiner 5, an optical fiber disk 6, a low-power pump source 7, a low-power drive module 8, a main control board 9, a power supply board 10, a low-power cladding optical filter 11, a QBH output 12, and a sensor 13. The composite water-cooled plate 1 also has a positive terminal connector 14, a negative terminal connector 15, a control terminal connector 16, and a network port connector 17 to form the power supply, control, communication, and laser output interfaces for the entire unit.

[0025] The positive and negative connectors 14 and 15 are used to connect to an external power supply. The power board 10 converts the connected power supply into a stable voltage suitable for the operation of the main control board 9 and other low-voltage electrical components. The control connector 16 is used to connect to external control and safety interlock signals. The main control board 9 can control the laser to stop emitting light based on the emergency stop and other safety control signals input by the control connector 16. The Ethernet connector 17 is used to establish an Ethernet communication connection between the main control board 9 and the host computer to receive standby, power on, power off, and power control commands sent by the host computer, and to feed back the laser's operating status to the host computer. The sensor 13 is used to collect at least one of the following operating parameters during the laser's operation: temperature, current, voltage, and output power. The main control board 9 monitors the overall operating status of the laser based on the detection results of the sensor 13, and controls the corresponding pump source to stop working when overcurrent, overvoltage, abnormal temperature, or abnormal safety interlock is detected.

[0026] The fiber optic disk 6 includes an outer fiber optic slot 6.1 and an inner fiber optic slot 6.2, with coiled optical fibers housed within both slots. In this embodiment, the coiled optical fiber in the inner fiber optic slot 6.2 forms the oscillation stage gain fiber, while the coiled optical fiber in the outer fiber optic slot 6.1 forms the amplification stage gain fiber, integrating the seed light generation section and the power amplification section onto the same composite water-cooled plate 1.

[0027] After the system is powered on, the external power supply is connected to the entire unit via the positive connector 14 and the negative connector 15. The power board 10 supplies power to the main control board 9 and related electrical components. The main control board 9 completes a power-on self-test and establishes communication with the host computer via the network connector 17. At the same time, it detects the sensor 13, the water cooling status, and the safety interlock status input by the control connector 16. At this time, both the low-power pump source 7 and the high-power pump source 2 are in a stopped light-emitting state, and the entire unit enters a cold standby state.

[0028] When the host computer sends a hot standby command, the main control board 9 controls the low-power drive module 8 to operate. The low-power drive module 8 drives the low-power pump source 7 to generate pump light by adjusting the output current. The pump light enters the gain fiber of the oscillator stage and establishes laser oscillation in the resonant cavity formed by the high-reflection grating and the low-reflection grating to generate stable seed light. After being output from the oscillator stage, the seed light passes through the low-power cladding light filter 11. The low-power cladding light filter 11 filters out the residual pump light and stray light that entered the fiber cladding during the oscillation process, allowing the processed seed light to enter the subsequent power amplification optical path.

[0029] When the host computer sends a further activation command, the main control board 9 controls multiple high-power drive modules 3 to drive the corresponding high-power pump sources 2 according to the set output power. The high-power pump light generated by the multiple high-power pump sources 2 is coupled by the combiner 5 and injected into the amplification stage gain fiber. At the same time, the seed light generated by the oscillation stage enters the amplification stage gain fiber. The high-power pump light amplifies the seed light in the amplification stage gain fiber, increasing the laser output power to the kilowatt level. By adjusting the number of multiple high-power pump sources 2 and / or the output current of the corresponding high-power drive modules 3, different laser output power requirements can be adapted.

[0030] The amplified high-power laser light passes through a high-power cladding optical filter 4, which filters out unabsorbed pump light remaining in the fiber cladding during amplification, as well as stray light entering the cladding. The processed high-power laser light is then transmitted to the QBH output 12, from which the processing laser light is output to external laser processing equipment. Thus, the oscillator stage generates seed light, the amplification stage amplifies the seed light, and after processing by the high-power cladding optical filter 4, a 10,000-watt laser output is formed.

[0031] During the aforementioned light extraction process, the coolant flows synchronously through the upper channel 1.31 and the lower channel 1.51 of the composite water-cooled plate 1. The upper channel 1.31 dissipates heat from the coiled optical fiber, the bundler 5, the high-power cladding optical filter 4, the low-power cladding optical filter 11, and other optical path components. The lower channel 1.51 dissipates heat from the multiple high-power pump sources 2 and their corresponding heat-generating areas. The main control board 9 continuously acquires operating parameters such as overall machine temperature, current, voltage, and output power through the sensor 13. When the detected parameters exceed the set safety range, the main control board 9 stops the output of the corresponding drive module to cut off the pump light and stop the laser output.

[0032] When the host computer sends a shutdown command, the main control board 9 first controls the high-power drive module 3 to stop outputting, causing the high-power pump source 2 to stop working and terminating the high-power laser output of the amplification stage; then it controls the low-power drive module 8 to stop outputting, causing the low-power pump source 7 to stop working, the oscillation stage to stop generating seed light, and the entire machine returns to cold standby mode. This forms the overall machine operation process of "system power-on - cold standby - hot standby - 10,000-watt level switching - operation monitoring - switching off and returning to cold standby".

[0033] The two surfaces of the composite water-cooled plate 1 bear different types of heat loads. The high-power pump source 2 and the high-power drive module 3 generate significant heat, and multiple high-power pump sources 2 form an array of heat sources. The heat generation of optical path devices such as the fiber optic disk 6, the combiner 5, the high-power cladding optical filter 4, and the low-power cladding optical filter 11 is relatively dispersed, but they are sensitive to temperature uniformity, mounting plane stability, and local temperature rise. Therefore, in this embodiment, two mutually isolated cooling water channels are set inside the composite water-cooled plate 1, and the temperature gradient in the thickness direction caused by different heat loads on both sides is reduced through a thermal buffer isolation structure.

[0034] Interlayer structure of composite water-cooled plate like Figure 3 As shown, the composite water-cooled plate 1 includes an upper cooling plate 1.3, a heat buffer isolation plate 1.4, and a lower cooling plate 1.5 stacked sequentially. The upper cooling plate 1.3, the heat buffer isolation plate 1.4, and the lower cooling plate 1.5 are processed separately and then connected together by vacuum brazing to form a plate structure capable of supporting the optical path module and the electronic control module.

[0035] An upper water channel 1.31 is formed between the upper cooling plate 1.3 and the heat buffer isolation plate 1.4, and a lower water channel 1.51 is formed between the heat buffer isolation plate 1.4 and the lower cooling plate 1.5. The upper water channel 1.31 and the lower water channel 1.51 each have independent closed boundaries, and the two are not directly connected inside the composite water-cooled plate 1, thereby reducing the risk of coolant crossflow or leakage between the two water channels.

[0036] The composite water-cooled plate 1 has an inlet 1.1 and an outlet 1.2. The inlet 1.1 is connected to the inlets of the upper water channel 1.31 and the lower water channel 1.51, respectively, and the outlet 1.2 is connected to the outlets of the upper water channel 1.31 and the lower water channel 1.51, respectively, so that the upper water channel 1.31 and the lower water channel 1.51 form parallel cooling branches. After entering through the inlet 1.1, the coolant flows into the upper water channel 1.31 and the lower water channel 1.51, respectively. The coolant in the two water channels absorbs the heat generated by the corresponding devices on the plate, and then is discharged together through the outlet 1.2.

[0037] The upper water channel 1.31 and the lower water channel 1.51 are supplied with water in parallel, allowing both channels to directly receive the low-temperature coolant input from the inlet 1.1, preventing the heated coolant discharged from one channel from re-entering the other. The flow rates of the upper water channel 1.31 and the lower water channel 1.51 can be distributed according to the heat load on both sides. In this embodiment, the flow rate ratio of the upper water channel 1.31 to the lower water channel 1.51 is 3:5, ensuring that the pump source side with higher heat generation power receives a larger coolant flow rate.

[0038] The upper cooling plate 1.3, the heat buffer isolation plate 1.4, and the lower cooling plate 1.5 are made of aluminum alloy or other metal materials with high thermal conductivity and structural strength. The circumferential boundaries of the upper water channel 1.31 and the lower water channel 1.51 are connected by vacuum brazing to form a continuous closed connection area, so that the composite water cooling plate 1 maintains its integrity when subjected to coolant pressure and loads from the devices on both sides.

[0039] Thermal buffer isolation structure like Figure 3 As shown, the heat buffer isolation plate 1.4 is located between the upper water channel 1.31 and the lower water channel 1.51. A closed phase change material receiving cavity 1.42 is formed inside the heat buffer isolation plate 1.4. The closed phase change material receiving cavity 1.42 extends continuously along the area opposite to the upper water channel 1.31 and the lower water channel 1.51, so that the phase change material is located between two independent cooling water channels.

[0040] In this embodiment, the thickness of the heat buffer isolation plate 1.4 is approximately 5 mm, and the height of the enclosed phase change material receiving cavity 1.42 is 0.3 mm to 0.5 mm. The upper cavity wall of the enclosed phase change material receiving cavity 1.42 is adjacent to the upper water channel 1.31, and the lower cavity wall is adjacent to the lower water channel 1.51, thereby enabling the enclosed phase change material receiving cavity 1.42 to buffer the heat transfer process between the upper cold plate 1.3 and the lower cold plate 1.5.

[0041] The enclosed phase change material (PCM) cavity 1.42 is filled with PCM material with a phase change temperature of 40℃ to 60℃. In this embodiment, paraffin-based PCM material is used. When the temperature reaches the phase change range, the PCM material absorbs heat through a solid-liquid phase change and releases the stored heat after the temperature drops. The PCM material is not used to completely block heat transfer between the upper cooling plate 1.3 and the lower cooling plate 1.5, but rather to reduce the difference in temperature change rates between the two sides and slow down the formation of transient temperature gradients in the thickness direction.

[0042] When the heat load generated by the high-power pump source 2 and the high-power drive module 3 is higher than the heat load on the optical path module side, the temperature rise rate of the lower cooling plate 1.5 may be higher than that of the upper cooling plate 1.3. The phase change material located between the two absorbs part of the transient heat transferred from the lower cooling plate 1.5 to the upper cooling plate 1.3, making the temperature rise process of the lower cooling plate 1.5 more gradual. Conversely, when a transient temperature rise occurs in a local device on the optical path module side, the phase change material can also buffer the heat transferred from the upper cooling plate 1.3 to the lower cooling plate 1.5. This reduces the differential thermal expansion caused by the different heat loads of the upper cooling plate 1.3 and the lower cooling plate 1.5, reducing the risk of out-of-plane warping deformation of the composite water-cooled plate 1.

[0043] The heat buffer isolation plate 1.4 is provided with a filling port that communicates with the closed phase change material receiving cavity 1.42. After the upper cooling plate 1.3, the heat buffer isolation plate 1.4, and the lower cooling plate 1.5 are vacuum brazed to form the composite water-cooled plate 1, a predetermined amount of phase change material is filled into the closed phase change material receiving cavity 1.42 through the filling port. After filling, the closed phase change material receiving cavity 1.42 is subjected to negative pressure treatment to reduce residual gas in the cavity, and then the filling port is sealed by friction stir welding to form a sealing part that can limit the leakage of phase change material.

[0044] Fiber optic disk and coiled fiber structure like Figure 2 As shown, the fiber optic disk 6 is disposed on the outer surface of the upper cooling plate 1.3. The fiber optic disk 6 includes an outer layer amplifier stage gain fiber slot 6.1 and an inner layer oscillator gain fiber slot 6.2. Both the outer layer fiber slot 6.1 and the inner layer fiber slot 6.2 are directly machined on the outer surface of the upper cooling plate 1.3 to reduce the contact interface between the independent fiber optic disk component and the upper cooling plate 1.3.

[0045] The inner fiber optic slot 6.2 is located within the coiled area enclosed by the outer fiber optic slot 6.1, forming a nested arrangement. The minimum spacing between the inner fiber optic slot 6.2 and the outer fiber optic slot 6.1 is not less than the spacing between two adjacent fiber optic slots, ensuring sufficient structural material is retained between them and reducing the possibility of a decrease in the local stiffness of the upper cold plate 1.3 due to the slots being too close together.

[0046] The outer fiber slot 6.1 is composed of multiple continuous tangent circular arc segments, each with a different center of curvature. The centers of curvature of the corresponding circular arc segments in adjacent coils are shifted sequentially according to the spacing between adjacent fiber slots, so that the outer fiber slot 6.1 forms a curvature structure that changes periodically along the coiling path.

[0047] In this embodiment, the minimum radius of curvature of the outer fiber slot 6.1 is 60 mm, and the spacing between adjacent fiber slots is 1.1 mm. Adjacent arc segments within the same coil in the outer fiber slot 6.1 are tangent to each other, and the offset distance between the curvature centers of corresponding arc segments in adjacent coils is 1.1 mm. This structure ensures that the coiled fiber does not continuously maintain a single bending direction as it extends along the fiber disk 6, and forms a periodic curvature change while meeting the minimum bending radius requirement for the coiled fiber.

[0048] The coiled optical fibers are respectively housed in the outer optical fiber slot 6.1 and the inner optical fiber slot 6.2. Thermally conductive adhesive is filled between the coiled optical fiber and the bottom and wall of the outer optical fiber slot 6.1 or the inner optical fiber slot 6.2. The thermally conductive adhesive is used to fill the assembly gap between the coiled optical fiber and the slot body, so that the heat generated by the coiled optical fiber can be transferred to the upper cold plate 1.3 through the thermally conductive adhesive.

[0049] Nested arrangement reduces the planar area occupied by the two sets of coiled optical fibers on the upper cold plate 1.3, which is beneficial for the compact arrangement of the combiner 5, high-power cladding optical filter 4, low-power cladding optical filter 11, and other optical path devices on the same plate. The periodic curvature change of the outer fiber slot 6.1 can also change the bending state of the coiled optical fiber, which is beneficial for increasing the bending loss of higher-order modes and improving the mode instability threshold.

[0050] Under the same fiber specifications, output power and cooling conditions, compared with the traditional racetrack-shaped fiber disk, the surface temperature and temperature difference of the coiled fiber are basically the same when using the above-mentioned nested variable curvature fiber disk 6, while the beam quality and output stability are improved, and the mode instability threshold can be increased by about 10% to 30%.

[0051] Upper waterway structure like Figure 4 As shown, the upper cooling channel 1.31 is formed between the upper cooling plate 1.3 and the heat buffer isolation plate 1.4, and extends along the surface of the upper cooling plate 1.3. The upper cooling channel 1.31 is mainly used to cool optical path devices such as coiled optical fibers, gratings, optical fiber splices, optical fiber texturing sections, bundle combiners 5, high-power cladding optical filters 4 and low-power cladding optical filters 11.

[0052] The upper water channel 1.31 adopts a wide rectangular meandering serpentine structure. The main flow channel of the upper water channel 1.31 passes under the outer fiber optic groove 6.1 and the inner fiber optic groove 6.2 in sequence, so that the heat generated by the coiled optical fiber is transferred to the coolant in the upper water channel 1.31 through the thermally conductive adhesive and the upper cooling plate 1.3.

[0053] In this embodiment, the upper channel 1.31 has a width of 12 mm and a depth of 3 mm, with a spacing of 6 mm between adjacent channel sections and a total flow length of approximately 4.3 m. The wider rectangular channel is used to increase the heat exchange coverage area of ​​the upper channel 1.31 in the area corresponding to the fiber optic disk 6 and to reduce the resistance concentration caused by excessively small local flow cross-sections.

[0054] The upper water channel 1.31 is equipped with an arc-shaped guide rib 1.33 at the turning position. The arc-shaped guide rib 1.33 extends in an arc shape along the turning path of the coolant to guide the coolant to change its flow direction smoothly and reduce the possibility of large-scale stagnation or local backflow of coolant in the right-angle turning area.

[0055] The heat flux density in the regions corresponding to the combiner 5, the high-power cladding optical filter 4, and the low-power cladding optical filter 11 is higher than that in most of the coiled area of ​​the optical fiber. To improve the heat transfer capacity in these regions, the upper channel 1.31 is provided with a flow-splitting microchannel 1.32 in at least one corresponding region. The flow-splitting microchannel 1.32 divides the original flow channel into multiple smaller flow paths through multiple flow-splitting columns, thereby increasing the contact area between the coolant and the upper cooling plate 1.3 and enhancing the turbulence of the coolant in local areas.

[0056] In this embodiment, the shunt column microchannel 1.32 is disposed within the upper channel 1.31 corresponding to the beam combiner 5 and the high-power cladding optical filter 4. For the low-power cladding optical filter 11 or other optical path devices with high local heat flux density, the shunt column microchannel 1.32 can also be formed in its corresponding region.

[0057] Lower water channel and local heat exchange structure of pump source like Figure 5 As shown, the lower water channel 1.51 is formed between the heat buffer isolation plate 1.4 and the lower cooling plate 1.5, and extends according to the arrangement of multiple high-power pump sources 2. The lower water channel 1.51 includes a serpentine main channel 1.52 and multiple local heat exchange zones 1.53.

[0058] The serpentine main channel 1.52 passes sequentially below the multiple high-power pump sources 2 along the arrangement direction of the pump sources 2. As the coolant flows in the serpentine main channel 1.52, it sequentially enters multiple local heat exchange zones 1.53. Each local heat exchange zone 1.53 is located directly below the corresponding high-power pump source 2 chip, allowing the heat generated by the high-power pump sources 2 to be directly transferred to the coolant in the corresponding local heat exchange zone 1.53 via the lower cold plate 1.5.

[0059] Each local heat exchange zone 1.53 is equipped with multiple elongated rhomboid diverter columns 1.54. The length direction of the elongated rhomboid diverter columns 1.54 is consistent with the flow direction of the coolant in the corresponding local heat exchange zone 1.53. The upstream and downstream ends of the elongated rhomboid diverter columns 1.54 form gradually changing contours, allowing the coolant to be diverted along both sides of the elongated rhomboid diverter columns 1.54 and then re-merge behind them.

[0060] Microchannels 1.55 are formed between adjacent elongated rhomboid diverter columns 1.54. Multiple microchannels 1.55 can distribute the coolant entering the local heat exchange zone 1.53 to different positions within the projection range of the pump source chip and increase the effective contact area between the coolant and the lower cooling plate 1.5.

[0061] In this embodiment, the elongated rhomboid diversion column 1.54 has a length of 20mm, a width of 4mm, and a height of 5mm, with the height matching the depth of the lower water channel 1.51. The elongated rhomboid diversion column 1.54 also serves as a local support structure between the lower cooling plate 1.5 and the thermal buffer isolation plate 1.4, improving the structural stability of the pump source installation area under clamping force and water pressure.

[0062] As the coolant flows sequentially through multiple high-power pump sources 2 in the serpentine main channel 1.52, its temperature gradually increases along the flow direction. To mitigate the decrease in cooling capacity of the downstream high-power pump sources 2, this embodiment differentiates the branch structures of different local heat exchange zones 1.53.

[0063] The downstream local heat exchange zone 1.53, at least partially located downstream, has more branch channels than its adjacent upstream local heat exchange zone 1.53, and the flow cross-sectional area of ​​a single branch channel in the downstream local heat exchange zone 1.53 is smaller than that of a single branch channel in the upstream local heat exchange zone 1.53. By coordinating and adjusting the number of branch channels, the cross-sectional area of ​​a single branch channel, and the arrangement density of the elongated diamond-shaped branch columns 1.54, the heat exchange area and coolant disturbance of the downstream local heat exchange zone 1.53 are increased, within the limits of the overall flow rate and inlet / outlet pressure difference, to compensate for the decrease in heat exchange temperature difference caused by the coolant temperature rise along the flow path.

[0064] The number of branch paths and the flow cross-sectional area of ​​the downstream local heat exchange zone 1.53 are determined based on the location of the corresponding high-power pump source 2, the heat generation power, and the number of preceding pump sources through which the coolant flows, rather than simply reducing the channel width as the only way to increase the local flow velocity. This allows for improved temperature uniformity among multiple high-power pump sources 2 while controlling the total pressure drop in the lower channel 1.51.

[0065] The manufacturing and assembly process of this embodiment The composite water-cooled plate 1 can be manufactured according to the following process.

[0066] First, the upper cold plate 1.3, the heat buffer isolation plate 1.4, and the lower cold plate 1.5 are machined respectively. On the side of the upper cold plate 1.3 facing the heat buffer isolation plate 1.4, an upper water channel 1.31, a diversion column microchannel 1.32, and an arc-shaped guide rib 1.33 are machined. On the outer surface of the upper cold plate 1.3, an outer fiber optic groove 6.1 and an inner fiber optic groove 6.2 are machined.

[0067] A closed phase change material receiving cavity 1.42 is formed inside the heat buffer isolation plate 1.4, and a filling port communicating with the closed phase change material receiving cavity 1.42 is reserved. Then, phase change material is filled into the closed phase change material receiving cavity 1.42 through the filling port, and after the negative pressure is drawn, the filling port is sealed by friction stir welding.

[0068] The lower cooling plate 1.5 is processed on the side facing the heat buffer isolation plate 1.4 to form the lower water channel 1.51, the serpentine main channel 1.52, the local heat exchange zone 1.53, the long diamond-shaped diverter column 1.54 and the microchannel 1.55.

[0069] After processing, the connecting surfaces of the upper cold plate 1.3, the heat buffer isolation plate 1.4, and the lower cold plate 1.5 are cleaned and positioned so that the upper water channel 1.31 is located between the upper cold plate 1.3 and the heat buffer isolation plate 1.4, and the lower water channel 1.51 is located between the heat buffer isolation plate 1.4 and the lower cold plate 1.5. Then, the three are connected into one piece by vacuum brazing.

[0070] Subsequently, phase change material is filled into the sealed phase change material receiving cavity 1.42 through the filling port, and the filling port is sealed by friction stir welding after negative pressure is drawn. After vacuum brazing is completed, the upper water channel 1.31 and the lower water channel 1.51 are respectively tested for sealing performance to confirm the closed boundary and mutual isolation of the two water channels.

[0071] After the composite water-cooled plate 1 is manufactured, the high-power pump source 2 and the high-power drive module 3 are installed on the outside of the lower cooling plate 1.5, so that the chips of each high-power pump source 2 correspond to a local heat exchange area 1.53. The high-power cladding optical filter 4, the bundler 5, the fiber optic disk 6, the low-power pump source 7, the low-power drive module 8, the main control board 9, the power supply board 10, and the low-power cladding optical filter 11 are installed on the outside of the upper cooling plate 1.3.

[0072] The coiled optical fiber is laid in the outer fiber optic slot 6.1 and the inner fiber optic slot 6.2, and thermally conductive adhesive is filled between the coiled optical fiber and the bottom and walls of the corresponding fiber optic slot. After the components are installed, electrical and optical connections are made so that the main control board 9, power supply board 10, high-power drive module 3, low-power drive module 8, high-power pump source 2, low-power pump source 7, and optical path module constitute a complete 10,000-watt fiber laser.

[0073] The laser in this embodiment operates as follows: After the laser is started, the power supply board 10 supplies power to the main control board 9, the high-power drive module 3, and the low-power drive module 8. The main control board 9 controls the high-power drive module 3 and the low-power drive module 8 respectively according to the output power command. The high-power drive module 3 drives the high-power pump source 2 to work, and the low-power drive module 8 drives the low-power pump source 7 to work.

[0074] Pump light generated by high-power pump source 2 and low-power pump source 7 is coupled by beam combiner 5 and enters the coiled optical fiber, forming laser output in the coiled optical fiber. High-power cladding light filter 4 and low-power cladding light filter 11 respectively filter out residual cladding light at corresponding positions.

[0075] The cooling system simultaneously inputs coolant into the inlet 1.1. The coolant is divided into an upper cooling branch and a lower cooling branch within the composite water-cooled plate 1. The upper cooling branch enters the upper water channel 1.31, passing sequentially through the fiber optic disk 6, the combiner 5, the high-power cladding optical filter 4, and the corresponding areas of other optical path devices, absorbing the heat transferred by the upper cooling plate 1.3.

[0076] The lower cooling tributary enters the lower water channel 1.51 and sequentially enters multiple local heat exchange zones 1.53 along the serpentine main channel 1.52. Within the local heat exchange zone 1.53, the coolant is diverted by elongated diamond-shaped diverter columns 1.54 to multiple microchannels 1.55 to absorb the heat generated by the corresponding high-power pump source chip 2.

[0077] The coolant in the upper water channel 1.31 and the lower water channel 1.51 absorbs heat and flows to the outlet 1.2, and is discharged from the composite water-cooled plate 1 through the outlet 1.2. The heat buffer isolation plate 1.4 and its enclosed phase change material receiving cavity 1.42 are located between the two water channels. When the heat load on the upper and lower plates is inconsistent, it buffers the transient heat transfer to reduce the temperature rise rate difference between the upper cooling plate 1.3 and the lower cooling plate 1.5.

[0078] The following is a simulation verification of the laser of this invention. To verify the heat dissipation performance of composite water-cooled plate 1, according to Figure 6 and Figure 7 The locations shown are respectively set for the heat source power on the pump source side and the optical path module side, and cooling water with a temperature of 25℃ and a total flow rate of 50L / min is introduced into the inlet 1.1. The cooling water is distributed between the upper water channel 1.31 and the lower water channel 1.51 at a flow rate ratio of 3:5, and the pressure difference between the inlet and outlet of the composite water-cooled plate 1 is controlled at 0.1MPa~0.2MPa.

[0079] Figure 6The diagram shows the power of each heat source on the pump source side and the flow direction of the coolant. Multiple high-power pump sources 2 are arranged along the lower water channel 1.51, and the serpentine main channel 1.52 passes sequentially through the local heat exchange zones 1.53 below each high-power pump source 2. By setting elongated diamond-shaped diverter columns 1.54 and microchannels 1.55 in each local heat exchange zone 1.53, a large heat exchange area is obtained in the projected area of ​​the pump source chip.

[0080] Figure 7 The power of each heat source and the flow direction of the coolant on the optical path module side are shown. The upper water channel 1.31 passes through the corresponding areas of the fiber disk 6, the bundler 5, the high-power cladding optical filter 4, the low-power cladding optical filter 11, the low-power pump source 7, and the low-power drive module 8, and enhances heat transfer in the local high-heat areas through the shunt column microchannel 1.32.

[0081] like Figure 8 As shown, under the above boundary conditions, the temperature distribution on the pump source side is relatively uniform, and the highest temperature of the high-power pump source 2 chip does not exceed about 46°C. No obvious continuous high-temperature area is formed in the rear section of the serpentine main channel 1.52, indicating that each local heat exchange zone 1.53 can effectively cool the pump source chip.

[0082] like Figure 9 As shown, the temperature in the area corresponding to fiber optic disc 6 is approximately 28℃ to 31℃, and the temperature difference between the various winding areas of the fiber is small. The temperatures in the areas corresponding to locally heating devices such as the combiner 5, cladding optical filter, and low-power pump source 7 are higher than those in the area of ​​the wound fiber, but they do not cause significant concentrated thermal interference to fiber optic disc 6.

[0083] The above results demonstrate that the upper water channel 1.31 and the lower water channel 1.51 can respectively adapt to the different thermal loads of the optical path module and the electronic control module. The local heat exchange structure directly below the pump source chip helps improve the temperature uniformity of the pump source array. The thermal buffer isolation plate 1.4 located between the two water channels can buffer the transient heat transfer in the thickness direction. The composite water-cooled plate 1 simultaneously undertakes the functions of cooling, device mounting, and structural support, and can reduce the overall size and additional support structure while meeting the heat dissipation requirements of the 10,000-watt fiber laser.

[0084] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A 10,000-watt fiber laser, comprising an optical path module, an electrical control module, and a composite water-cooling plate, characterized in that, The composite water-cooled plate includes an upper cooling plate, a heat buffer isolation plate, and a lower cooling plate stacked and connected in sequence. An upper water channel is formed between the upper cooling plate and the heat buffer isolation plate, and a lower water channel is formed between the heat buffer isolation plate and the lower cooling plate. The upper water channel and the lower water channel are isolated from each other and connected to the same inlet and outlet to form a parallel cooling branch. The optical path module is located on the outside of the upper cold plate, and the electronic control module is located on the outside of the lower cold plate and includes multiple pump sources arranged along the lower water channel; The outer surface of the upper cold plate is integrally processed with an outer fiber optic groove and an inner fiber optic groove located within the area enclosed by the outer fiber optic groove. The outer fiber optic groove is formed by multiple sequentially tangent arc segments. The curvature centers of the corresponding arc segments in adjacent coils are shifted sequentially according to the fiber optic groove spacing. The coiled optical fibers are placed in the outer fiber optic groove and the inner fiber optic groove through thermally conductive adhesive. The upper water channel extends below the two fiber optic grooves. The lower water channel includes a serpentine main channel extending according to the arrangement of the multiple pump sources and a local heat exchange zone located directly below each pump source chip. Each local heat exchange zone is provided with multiple elongated rhomboid diverter columns extending along the flow direction of the coolant, and microchannels are formed between adjacent elongated rhomboid diverter columns. The heat buffer isolation plate is provided with a closed phase change material receiving cavity, which is located between the upper water channel and the lower water channel and extends continuously along the relative areas of the two water channels. The enclosed phase change material cavity is filled with phase change material to form a thermal buffer structure between the two water channels when the upper and lower cold plates are subjected to different heat loads. The composite water-cooled plate constitutes the mounting frame for the optical path module and the electronic control module.

2. The kilowatt-level fiber laser according to claim 1, characterized in that, The closed phase change material receiving cavity is continuously arranged along the relative area of ​​the upper water channel and the lower water channel. The upper cavity wall and the lower cavity wall of the closed phase change material receiving cavity are adjacent to the upper water channel and the lower water channel, respectively. The height of the closed phase change material receiving cavity is 0.3mm to 0.5mm, and the phase change temperature of the phase change material is 40℃ to 60℃.

3. The kilowatt-level fiber laser according to claim 1, characterized in that, The upper cold plate, the heat buffer isolation plate, and the lower cold plate are processed respectively. Vacuum brazing connection interfaces are formed between the upper cold plate and the heat buffer isolation plate, and between the heat buffer isolation plate and the lower cold plate. The upper water channel and the lower water channel have fully enclosed brazing boundaries. The heat buffer isolation plate is provided with a filling port that communicates with the closed phase change material receiving cavity. The filling port is provided with a friction stir welded sealing part.

4. The kilowatt-level fiber laser according to claim 1, characterized in that, The serpentine main channel connects multiple local heat exchange zones sequentially along the coolant flow direction. A small number of downstream local heat exchange zones have more branch paths than their adjacent upstream local heat exchange zones, and the flow cross-sectional area of ​​a single branch path in the downstream local heat exchange zone is smaller than that of a single branch path in the upstream local heat exchange zone.

5. The kilowatt-level fiber laser according to claim 4, characterized in that, Each of the aforementioned local heat exchange zones is opposite to the installation position of the corresponding pump source chip. The length direction of the elongated rhomboid diverter column is consistent with the flow direction of the coolant in the corresponding local heat exchange zone. The length-to-width ratio of the rhomboid structure of the elongated rhomboid diverter column is 5:1, and its length direction is consistent with the flow direction of the coolant.

6. The kilowatt-level fiber laser according to claim 1, characterized in that, The upper channel is a wide rectangular meandering serpentine flow channel, which extends below the coiled optical fiber, grating, optical fiber splice, optical fiber texturing section, combiner, and cladding optical filter, respectively; the upper channel corresponding to the high-power devices such as the combiner and the cladding optical filter is provided with a flow-splitting column microchannel.

7. The kilowatt-level fiber laser according to claim 1, characterized in that, The inner fiber groove is located within the coiled area enclosed by the outer fiber groove. The minimum distance between the inner fiber groove and the outer fiber groove is not less than the distance between two adjacent fiber grooves. The minimum radius of curvature of the outer fiber groove is 46~60mm. Multiple arc segments in the same coil are sequentially tangent to each other. The offset distance between the curvature centers of corresponding arc segments in adjacent coils is equal to the distance between adjacent fiber grooves. The distance between adjacent fiber grooves is 1~2mm.

8. The kilowatt-level fiber laser according to claim 1 or 7, characterized in that, The coiled optical fibers are respectively housed in the outer optical fiber groove and the inner optical fiber groove, and the thermally conductive adhesive is filled in the gap between the coiled optical fiber and the bottom and wall of the corresponding optical fiber groove.

9. The kilowatt-level fiber laser according to claim 6, characterized in that, The upper water channel has a width-to-narrowness ratio of 4:1, the spacing between adjacent flow channel sections is 6-7mm, the total flow length of the upper water channel is 4-5m, and the upper water channel is provided with guide ribs extending in an arc shape along the coolant turning path at the turning position.

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