A method for parallel processing of femtosecond laser multi-channel hollow core fiber

Abstract

The application discloses a kind of femtosecond laser multi-path hollow core optical fiber parallel processing methods, it is related to femtosecond laser precision machining technical field, comprising: according to target process preset 1030nm femtosecond laser parameter and output collimated calibration standard incident beam;It is divided into N path sub-beam by cascading beam splitter prism array and carries out energy and spot closed loop calibration;Each road sub-beam is coupled to anti-harmonic hollow core optical fiber, and shape transmission is realized by coupling posture adjustment, fiber core vacuum extraction and dispersion compensation;Again each road output laser is focused to corresponding processing station and carries out synchronous parallel processing, and processing size data is collected.According to processing size deviation, in combination with light source, beam splitting and transmission parameter determines deviation source, executes energy proportion, coupling posture, fiber core vacuum degree and single or cascading adjustment of processing track;Realize multi-path femtosecond laser high consistency shape transmission and nanosecond level synchronous processing, improve production stability and processing efficiency.

Description

Technical Field

[0001] This invention relates to the field of femtosecond laser precision machining technology, specifically a method for parallel processing of multiple hollow optical fibers using femtosecond lasers. Background Technology

[0002] Femtosecond lasers, with their ultrashort pulses and high peak power cold processing characteristics, have become a core technology in high-precision manufacturing. As industrial mass production demands increase, the efficiency bottleneck of single-channel processing becomes prominent, making multi-channel parallel processing a core development direction for the industry. Current mainstream femtosecond laser multi-channel processing solutions are all hardware-based, exhibiting significant technical deficiencies and protection gaps at the methodological and procedural levels, as detailed below: 1. Spatial Beam Multiprocessing Method: This method uses diffractive optical elements (DOE) and spatial light modulators (SLMs) to achieve spatial beam splitting, and then transmits the beam directly to a single workstation for multi-beam processing via a spatial optical path. This method only supports compact, fixed layouts and lacks flexible transmission and distributed multi-workstation adaptation processes, making it impossible to achieve flexible processing across workshops or production lines. Furthermore, it lacks pulse conformal and nonlinearity suppression processes in the transmission stage, making long-distance transmission of high-power femtosecond lasers prone to pulse distortion and energy attenuation, resulting in poor processing consistency and difficulty meeting mass production requirements.

[0003] 2. Solid Fiber Multipath Processing Method: A single femtosecond laser is coupled to a solid silica fiber for transmission, and then multipath processing is achieved through back-end beam splitting. This method lacks multipath transmission dispersion compensation and energy calibration processes. Pulse broadening and distortion caused by the strong nonlinear effects of solid fiber cannot be compensated for through the process. The interpath processing deviation is usually >5%, resulting in a low yield. Furthermore, it lacks fiber damage protection processes under high-power conditions, leading to short device lifespan and making it unsuitable for mass production processing with 1030nm high-power femtosecond lasers.

[0004] 3. Single-channel hollow fiber processing method: Existing single-channel femtosecond laser hollow fiber transmission processing methods only include single-channel transmission and basic processing procedures. They have not formed a complete method system for multi-channel splitting-coupling collaborative calibration, multi-channel synchronous control, inter-channel parameter consistency adjustment, and full-process closed-loop feedback, which cannot support the industrial application of multi-channel parallel processing. Furthermore, they have not customized fiber parameter adaptation and nonlinear suppression standardization processes for 1030nm industrial femtosecond lasers, making it difficult to guarantee processing stability and consistency.

[0005] Existing technologies have clear boundaries and gaps: First, existing multi-path processing methods are all designed around hardware structures and have not formed a standardized method covering the entire process from beam splitting calibration to conformal transmission, synchronous processing, and closed-loop control. This makes it impossible to form a low-level protection for the core processing logic, and it is easy to break through the patent protection boundary due to the differentiated design of the hardware structure. Second, existing methods have not established a collaborative control system for processing quality feedback and beam splitting and transmission links. They have not formed a standardized process for independent energy control of multiple beam splitter prism arrays, nonlinear suppression of air pumping in hollow fiber, and nanosecond-level synchronous processing at multiple stations. This makes it impossible to systematically solve the conformal and consistency problems of high-power femtosecond laser multi-path processing. Third, existing methods have not designed a distributed multi-station trajectory collaborative planning and flexible adaptation process, making them incompatible with mass production scenarios across production lines and different processes, and difficult to match the flexible layout requirements of industrial mass production lines.

[0006] In summary, existing technologies primarily focus on hardware architecture protection, lacking supporting methodological process protection and exhibiting technological gaps in end-to-end collaborative control. There is currently no complete processing method specifically designed for the mass production needs of 1030nm industrial femtosecond lasers and compatible with multi-channel hollow fiber processing systems. This invention aims to fill the technological gap in the end-to-end method for parallel processing of multi-channel hollow fiber using femtosecond lasers, while simultaneously improving the patent protection system for supporting devices. Summary of the Invention

[0007] Based on the shortcomings of the prior art described above, the purpose of this invention is to provide a femtosecond laser parallel processing method for multiple hollow-core optical fibers to solve the above-mentioned technical problems.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers, comprising: The working parameters of the 1030nm femtosecond laser are preset according to the target processing technology, and the collimated standard incident beam is output to obtain the source end parameters of the standard incident beam. A standard incident beam is input into a cascaded array of beam-splitting prisms. By adjusting the electrically rotating half-wave plate in the array of beam-splitting prisms, the standard incident beam is split into N sub-beams, where N≥2. The energy parameters and spot parameters of each sub-beam are collected in real time, and the energy ratio of each sub-beam is calibrated in a closed loop based on the collection results. N sub-beams are coupled one-to-one to N anti-resonant hollow-core optical fibers. The coupling attitude between each sub-beam and the corresponding anti-resonant hollow-core optical fiber is adjusted. The core of the anti-resonant hollow-core optical fiber is evacuated. Dispersion compensation is performed on the laser transmitted through the anti-resonant hollow-core optical fiber. The coupling efficiency, core vacuum degree and output pulse width of each anti-resonant hollow-core optical fiber are collected in real time. N lasers output from anti-resonant hollow optical fibers are focused onto N processing stations. The output timing of each laser and the processing trajectory of the corresponding processing station are controlled by a synchronous control system, so that the N lasers can process the corresponding workpiece synchronously and in parallel, and the processing dimension data of each processing station are collected in real time. Based on the machining size deviation between the machining size data and the target machining size, and in conjunction with the light source parameters, energy parameters, spot parameters, coupling efficiency, core vacuum degree, and output pulse width, the deviation source type corresponding to the machining size deviation is determined. According to the deviation source type, at least one of the following is executed: energy ratio adjustment of the corresponding path beam, coupling attitude correction, core vacuum degree control, pulse compensation amount adjustment, and machining trajectory compensation. When a single adjustment cannot bring the machining size deviation back to within the preset threshold, at least two of these adjustments are cascaded to bring the machining size deviation back to within the preset threshold, forming a closed-loop coupling control that drives the coordinated correction of splitting parameters, transmission parameters, and machining parameters based on machining quality.

[0009] The present invention further specifies that the operating parameters of the 1030nm femtosecond laser include: a center wavelength of 1030nm, a pulse width of 50fs to 1ps, a single pulse energy of 1μJ to 1mJ, a repetition frequency of 1kHz to 200kHz, an average power of 1W to 100W, and a beam quality M. 2 <1.2, linear polarization extinction ratio >100:1; the pointing deviation of the standard incident beam after collimation calibration is ≤5μrad.

[0010] The present invention is further configured to perform a safety interlock self-check on the system access control, backlight, over-temperature state, and over-power state of the femtosecond laser source before outputting the standard incident beam. When the safety interlock self-check result is abnormal, the femtosecond laser source is prohibited from emitting light.

[0011] The present invention is further configured such that the beam splitter array is composed of N-1 polarization beam splitters and N-1 motorized rotating half-wave plates cascaded together. The standard incident beam passes through each stage of motorized rotating half-wave plates and polarization beam splitters in sequence. The polarization direction of the laser incident on the corresponding polarization beam splitter is adjusted by each stage of motorized rotating half-wave plates, so that the reflected light of the corresponding polarization beam splitter becomes the output sub-beam of this stage, and the transmitted light enters the next stage beam splitting unit, finally forming 1×N sub-beam output.

[0012] The present invention is further configured such that the energy parameters are acquired by a multi-channel energy meter array and the spot parameters are acquired by a CCD beam analyzer; the spot parameters include at least one of spot shape, spot quality and pointing deviation; after closed-loop calibration of the energy ratio of each sub-beam, the total beam splitting efficiency is ≥95%, the inter-path energy consistency deviation is ≤±1%, and the polarization retention is >100:1.

[0013] The present invention is further configured such that the anti-resonant hollow-core fiber is designed for a wavelength of 1030 nm, the core diameter of the anti-resonant hollow-core fiber is 30 μm to 50 μm, the cladding is a ring array structure composed of 6 to 8 high-purity quartz glass capillaries, and the outer diameter of the fiber is 200 μm to 300 μm; at a wavelength of 1030 nm, the transmission loss of the anti-resonant hollow-core fiber is ≤0.1 dB / m, the single-path total transmission efficiency is ≥80%, and the pulse energy damage threshold is ≥3 J / cm. 2 @150kHz, 1030nm.

[0014] The present invention is further configured such that each sub-beam is focused by a mode field matching lens group to match the mode field of the sub-beam spot with the core mode field of the corresponding anti-resonant hollow fiber, and the coupling attitude is adjusted by a six-axis electric displacement stage; the six-axis electric displacement stage is adjusted according to the real-time collected coupling efficiency feedback to make the single-path coupling efficiency ≥85% and the mode field matching degree >95%.

[0015] The invention is further configured to maintain the core of the anti-resonant hollow fiber in a low vacuum environment of 1 Pa to 10 Pa by a high vacuum pump group connected to the sealed joints at both ends of the anti-resonant hollow fiber, and to monitor the core vacuum level in real time by a vacuum sensor in order to suppress at least one nonlinear effect in the femtosecond laser transmission process, including self-phase modulation, stimulated Raman scattering and air ionization; dispersion compensation is achieved by a chirped mirror pair or a grating pair, so that the fidelity of the output pulse width relative to the incident pulse width is ≥95%.

[0016] The present invention is further configured to complete the calibration of the workpiece coordinate system and the machining coordinate system of the corresponding workpiece through a vision positioning system, with a calibration accuracy better than 1μm; the machining trajectory includes at least one of a straight line trajectory, a circular arc trajectory and a three-dimensional complex trajectory; the synchronous control system includes an FPGA main controller, which synchronously controls the light output timing of the femtosecond laser, the switching of the light gates of each sub-beam and the motion trajectory of each machining station motion platform, with a synchronous triggering accuracy better than 10ns.

[0017] The invention is further configured such that the deviation sources include at least one of the following: beam splitting energy deviation, spot state deviation, coupling efficiency shift, fiber core vacuum deviation, output pulse width deviation, and processing trajectory execution deviation; an early warning is triggered when the energy deviation of a single sub-beam exceeds ±2% for 10 consecutive seconds and cannot be corrected by closed-loop calibration; the corresponding optical shutter is shut off when the energy deviation of a single sub-beam continues to exceed ±5%; an early warning is triggered when the coupling efficiency of a single path decreases by more than 5% for 10 consecutive seconds; the corresponding optical shutter is shut off when the coupling efficiency of a single path continues to decrease by more than 10%; when the core vacuum of a single path suddenly rises and exceeds 100Pa, the corresponding optical shutter and pneumatic diaphragm valve are immediately closed to isolate the faulty branch; and the light source parameters, beam splitting parameters, transmission parameters, processing size data, and anomaly handling data are recorded in real time to form a processing data archive.

[0018] This invention provides a method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers. A 1030nm femtosecond laser is pre-set with operating parameters and outputs a standard incident beam. This beam is then split into N sub-beams by a beam-splitting prism array, and the energy and spot parameters of each sub-beam are acquired and calibrated in real time using a closed-loop system. The N sub-beams are then coupled to their corresponding anti-resonant hollow-core optical fibers. Low-loss conformal transmission is achieved through coupling attitude adjustment, core vacuuming, and dispersion compensation, while coupling efficiency, core vacuum, and output pulse width are acquired in real time. Each output laser beam is then focused onto its corresponding processing station, and a synchronous control system enables simultaneous parallel processing of multiple beams and acquires processing dimension data. Finally, based on the processing dimension deviation, the source of the deviation is determined by combining the light source parameters, beam splitting parameters, and transmission parameters. At least one of the following is executed: energy ratio adjustment, coupling attitude correction, core vacuum control, and processing trajectory compensation. When a single adjustment is insufficient, cascaded adjustments are performed, thus forming a closed-loop coupled control system where processing quality drives the coordinated correction of splitting, transmission, and processing parameters. The beneficial effects include: 1. Achieve high-power femtosecond laser multi-path conformal transmission and improve processing consistency: High-consistency processing originates from closed-loop coupling. Through the full-link cascade feedback control of beam splitting energy deviation → coupling efficiency → output pulse width → processing size, each step constitutes an inseparable synergistic causal chain. The inter-path energy consistency deviation is ≤±1%, the pulse width fidelity is ≥95%, and the multi-station processing size deviation is <±1μm. The consistency level is far superior to simple splicing after independent control of each link.

[0019] 2. Nanosecond-level synchronous parallel processing improves processing efficiency and equipment utilization: Through multi-station trajectory collaborative planning and nanosecond-level synchronous trigger control, 2 to 16 or more stations can be processed synchronously in parallel, and the processing efficiency is several times higher than that of single-channel processing; it supports distributed flexible layout, and a single femtosecond laser can serve multiple processing stations at the same time. Compared with the single-station processing mode, the overall equipment utilization rate (OEE) is significantly improved, and the equipment investment cost per unit capacity is greatly reduced.

[0020] 3. Closed-loop control throughout the entire process to improve mass production stability: Through real-time acquisition and dynamic closed-loop control of parameters throughout the entire process, the system automatically compensates for processing deviations caused by factors such as temperature drift, vibration, and power fluctuations. The system response time is <100ms, and the coupling efficiency fluctuation is <2% after 72 hours of continuous operation, meeting the needs of 24 / 7 industrial mass production and reducing equipment operation and maintenance costs.

[0021] 4. Excellent compatibility and adaptability, reducing industrialization costs: This method is deeply compatible with supporting multi-channel processing systems, compatible with mainstream 1030nm industrial-grade femtosecond lasers, and can flexibly adjust the number of beams, energy ratio and processing technology, adapting to various processing scenarios such as cutting, drilling, surface modification, and micro / nano structure fabrication; it can be directly connected to existing femtosecond laser processing equipment and automated production lines without the need to reconstruct the core optical path and production line layout, resulting in low industrialization costs and strong feasibility.

[0022] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram illustrating the process monitoring and dynamic control of a femtosecond laser multi-channel hollow fiber parallel processing method as an exemplary embodiment of the present invention. Figure 2 This is a schematic diagram of a femtosecond laser multi-path beam splitting and energy closed-loop calibration structure according to an embodiment of the present invention; The components include: 1. Femtosecond laser source module; 2. Incident collimation unit; 3. Motorized rotating half-wave plate; 4. PBS beam splitter prism; 5. Mirror; 6. Optical wedge; 7. Energy meter; 8. Controller; and 9. Fiber optic coupling module. Detailed Implementation

[0024] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0025] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0026] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0027] A method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers, such as... Figure 1 As shown, it includes: The working parameters of the 1030nm femtosecond laser are preset according to the target processing technology, and the collimated standard incident beam is output to obtain the source end parameters of the standard incident beam. A standard incident beam is input into a cascaded array of beam-splitting prisms. By adjusting the electrically rotating half-wave plate in the array of beam-splitting prisms, the standard incident beam is split into N sub-beams, where N≥2. The energy parameters and spot parameters of each sub-beam are collected in real time, and the energy ratio of each sub-beam is calibrated in a closed loop based on the collection results. N sub-beams are coupled one-to-one to N anti-resonant hollow-core optical fibers. The coupling attitude between each sub-beam and the corresponding anti-resonant hollow-core optical fiber is adjusted. The core of the anti-resonant hollow-core optical fiber is evacuated. Dispersion compensation is performed on the laser transmitted through the anti-resonant hollow-core optical fiber. The coupling efficiency, core vacuum degree and output pulse width of each anti-resonant hollow-core optical fiber are collected in real time. N lasers output from anti-resonant hollow optical fibers are focused onto N processing stations. The output timing of each laser and the processing trajectory of the corresponding processing station are controlled by a synchronous control system, so that the N lasers can process the corresponding workpiece synchronously and in parallel, and the processing dimension data of each processing station are collected in real time. Based on the machining size deviation between the machining size data and the target machining size, and in conjunction with the light source parameters, energy parameters, spot parameters, coupling efficiency, core vacuum degree, and output pulse width, the deviation source type corresponding to the machining size deviation is determined. According to the deviation source type, at least one of the following is executed: energy ratio adjustment of the corresponding path beam, coupling attitude correction, core vacuum degree control, pulse compensation amount adjustment, and machining trajectory compensation. When a single adjustment cannot bring the machining size deviation back to within the preset threshold, at least two of these adjustments are cascaded to bring the machining size deviation back to within the preset threshold, forming a closed-loop coupling control that drives the coordinated correction of splitting parameters, transmission parameters, and machining parameters based on machining quality.

[0028] Specifically, the target processing technology can be one of the following: wafer stealth dicing, micro-hole fabrication on ceramic substrates, precision cutting of brittle materials, micro-texturing of metal surfaces, or fabrication of micro / nano structures. The synchronous control system calls the corresponding process recipe according to the target processing technology. The process recipe includes at least the femtosecond laser operating parameters, the number of beam splitters N, the target energy ratio of each sub-beam, the anti-resonant hollow fiber transmission parameters, the number of processing stations, the processing trajectory, the target processing size, and the allowable dimensional deviation threshold. The target processing size can include at least one of the following: kerf width, cutting depth, hole diameter, hole depth, processing groove width, and the periodic size of the surface microstructure.

[0029] Before outputting the standard incident beam, the femtosecond laser source completes a safety interlock self-check. This safety interlock self-check includes detecting the system access control status, reflected light status, over-temperature status, and over-power status. If the system access control is not closed, the reflected light exceeds the set value, the laser temperature exceeds the set range, or the output power is abnormal, the synchronous control system prohibits the femtosecond laser source from emitting light and generates a safety alarm message. If the safety interlock self-check result is normal, the femtosecond laser source is allowed to output laser light according to the target processing technology.

[0030] The operating parameters of the 1030nm femtosecond laser include: center wavelength of 1030nm, pulse width of 50fs to 1ps, single pulse energy of 1μJ to 1mJ, repetition rate of 1kHz to 200kHz, average power of 1W to 100W, and beam quality M. 2<1.2, linear polarization extinction ratio >100:1. The laser output from the femtosecond laser source is collimated and calibrated by the incident collimation unit to ensure that the pointing deviation of the collimated standard incident beam is ≤5μrad. The source end parameters include output power, pulse width, and beam quality, which serve as reference parameters for subsequent beam splitting energy calibration, transmission conformal judgment, and traceability of processing dimensional deviations.

[0031] like Figure 2 As shown, a cascaded beam-splitting prism array is used to input a standard incident beam. The beam-splitting prism array consists of N-1 cascaded polarizing beam splitters and N-1 cascaded electrically driven rotating half-wave plates. The standard incident beam passes sequentially through each stage of the electrically driven rotating half-wave plate and polarizing beam splitter. The synchronous control system, based on the preset number of beam splitting paths N and the target energy ratio of each sub-beam, controls each stage of the electrically driven rotating half-wave plate to rotate to the corresponding angle. This adjusts the polarization direction of the laser incident on the corresponding polarizing beam splitter, ensuring that the reflected light from the corresponding polarizing beam splitter becomes the output sub-beam of that stage. The transmitted light continues to enter the next stage beam splitting unit, ultimately forming 1×N sub-beam outputs. Here, N≥2, and the target energy ratio of each sub-beam can be an equal energy ratio or a non-equal energy ratio depending on the process requirements of different processing stations.

[0032] During beam splitting, energy parameters of each sub-beam are acquired in real time using a multi-channel energy meter array, and spot parameters of each sub-beam are acquired in real time using a CCD beam analyzer. The energy parameters include at least one of single-pulse energy, average power, and energy percentage for each sub-beam; the spot parameters include at least one of spot morphology, spot quality, and pointing deviation. The synchronous control system adjusts the rotation angle of the corresponding stage of the electrically driven rotating half-wave plate in a closed loop based on the deviation between the acquired results and the target energy percentage, ensuring that the energy percentage of each sub-beam returns to the target range. After closed-loop calibration, the overall beam splitting efficiency is ≥95%, the inter-beam energy consistency deviation is ≤±1%, and the polarization retention is >100:1. To facilitate subsequent fiber coupling, the layout of the beam splitting prism array is adjusted, and / or a beam spacing adjustment unit is installed at the beam splitting output end to match the output spacing and angle of the split sub-beams with the input spacing and input angle of the anti-resonant hollow fiber array.

[0033] After each sub-beam completes energy closed-loop calibration, it is coupled one-to-one to N anti-resonant hollow-core optical fibers. The focusing state of each sub-beam is adjusted by a mode-field matching lens group to match the mode field of the focused spot of the sub-beam with the core mode field of the corresponding anti-resonant hollow-core optical fiber. Simultaneously, the position and orientation of the input end of the corresponding anti-resonant hollow-core optical fiber are adjusted by a six-axis motorized displacement stage, where the six axes include three-dimensional translation and three rotational directions. The synchronous control system adjusts the six-axis motorized displacement stage based on real-time acquired coupling efficiency feedback to ensure a single-path coupling efficiency ≥85% and a mode-field matching degree >95%. When coupling efficiency decreases due to temperature drift, vibration, or assembly misalignment, the synchronous control system prioritizes fine-tuning the six-axis motorized displacement stage of the corresponding path to restore the coupling orientation between the corresponding sub-beam and the corresponding anti-resonant hollow-core optical fiber.

[0034] Antiresonant hollow-core fiber is designed for a wavelength of 1030 nm. The core diameter is 30 μm–50 μm, and the cladding is a ring array structure composed of 6–8 high-purity silica glass capillaries. The outer diameter of the fiber is 200 μm–300 μm. At a wavelength of 1030 nm, the transmission loss of the antiresonant hollow-core fiber is ≤0.1 dB / m, the single-path total transmission efficiency is ≥80%, and the pulse energy damage threshold is ≥3 J / cm². 2 @150kHz, 1030nm. The aforementioned anti-resonant hollow-core fiber is used to reduce the material nonlinearity effects of high-power femtosecond lasers during long-distance flexible transmission and to provide a flexible transmission channel for distributed arrangements of multiple processing stations.

[0035] To suppress the nonlinear effects generated during femtosecond laser propagation within the core of hollow optical fibers, a high-vacuum pump assembly connected to the sealed connectors at both ends of the anti-resonant hollow optical fiber is used to evacuate the fiber core, maintaining a low vacuum environment of 1 Pa to 10 Pa inside the core. A vacuum sensor monitors the core vacuum level in real time and transmits this information to the synchronous control system. By reducing the gas molecule density within the core, at least one nonlinear effect among self-phase modulation, stimulated Raman scattering, and air ionization during femtosecond laser transmission is suppressed. The laser beam transmitted through the anti-resonant hollow optical fiber undergoes dispersion compensation at the output end using chirped mirror pairs or grating pairs, ensuring that the output pulse width fidelity relative to the incident pulse width is ≥95%. The synchronous control system acquires the coupling efficiency, core vacuum level, and output pulse width of each anti-resonant hollow optical fiber in real time, using these transmission parameters as the data basis for tracing dimensional deviations in subsequent processing.

[0036] The lasers output from each anti-resonant hollow fiber are focused onto N processing stations by a collimating and focusing unit. The collimating and focusing unit focuses the output laser into processing spots, the diameter of which can be 0.5 μm to 5 μm, and the focused spot quality factor M. 2≤1.2. Each machining station is equipped with a workpiece clamping mechanism, a vision positioning system, and a machining motion platform. The vision positioning system identifies positioning marks or contour features on the corresponding workpiece and completes the calibration of the workpiece coordinate system and the machining coordinate system, with a calibration accuracy better than 1μm. The machining trajectory is generated according to the target machining process, and the machining trajectory includes at least one of straight-line trajectory, circular arc trajectory, and three-dimensional complex trajectory.

[0037] The synchronous control system includes an FPGA main controller, which synchronously controls the emission timing of the femtosecond laser, the switching of the shutters of each sub-beam, and the motion trajectory of the motion platform at each processing station, enabling synchronous parallel processing of corresponding workpieces by N laser beams. The synchronization triggering accuracy is better than 10ns. The N processing stations can be arranged centrally or flexibly in a distributed manner, and the spacing between adjacent processing stations can be adjusted according to the production line layout. For scenarios where different stations have different processing cycles, the synchronous control system can also control some processing stations to enter synchronous processing mode, while controlling other processing stations to be in standby or waiting for clamping mode, to adapt to the flexible production needs of multiple stations.

[0038] During the processing, machining dimensional data at each machining station is acquired in real time via online measurement units. These online measurement units may include spectral confocal measurement units, visual measurement units, displacement measurement units, or other measurement units suitable for micro / nano machining dimensional detection. Machining dimensional data includes at least one of the following: kerf width, cutting depth, hole diameter, hole depth, machining groove width, or surface microstructure dimensions. The synchronous control system compares the real-time acquired machining dimensional data with the target machining dimensions to obtain the machining dimensional deviation.

[0039] When the processing dimensional deviation does not exceed the preset threshold, the synchronous control system maintains the current beam splitting parameters, transmission parameters, and processing parameters. When the processing dimensional deviation exceeds the preset threshold, the synchronous control system correlates the processing dimensional deviation with the light source parameters, energy parameters, spot parameters, coupling efficiency, core vacuum degree, and output pulse width to determine the type of deviation source corresponding to the processing dimensional deviation. The deviation source type includes at least one of the following: beam splitting energy deviation, spot state deviation, coupling efficiency offset, core vacuum degree deviation, output pulse width deviation, and processing trajectory execution deviation.

[0040] Specifically, when the dimensional deviation of a certain processing station corresponds to the deviation of the energy parameters of the corresponding sub-beam, and the coupling efficiency, core vacuum, and output pulse width of the corresponding path are all within the target range, the synchronous control system determines that the deviation is caused by beam splitting energy deviation and adjusts the rotation angle of the corresponding stage's electric rotating half-wave plate to correct the energy ratio of the sub-beam. When the dimensional deviation of a certain processing station corresponds to an abnormal spot shape or increased pointing deviation, the synchronous control system determines that the deviation is caused by spot state deviation and corrects the beam state through the beam spacing adjustment unit, beam pointing adjustment unit, or corresponding optical path adjustment mechanism at the beam splitting output end.

[0041] When a machining dimensional deviation at a certain processing station is accompanied by a decrease in the corresponding coupling efficiency, the synchronous control system determines that the deviation originates from a coupling efficiency offset. Based on the coupling efficiency feedback, it adjusts the corresponding six-axis electric displacement stage to restore the coupling attitude between the corresponding sub-beam and the corresponding anti-resonant hollow fiber to the target range. When a machining dimensional deviation at a certain processing station is accompanied by a deviation of the fiber core vacuum from the target range or a widening of the output pulse width, the synchronous control system determines that the deviation originates from a fiber core vacuum offset and / or an output pulse width offset. It then adjusts the pumping state of the high-vacuum pump group and the corresponding dispersion compensation amount to restore the nonlinear suppression effect and pulse width conformal state. When a machining dimensional deviation at a certain processing station does not correspond to laser output, beam splitting energy, coupling efficiency, fiber core vacuum, or output pulse width, but corresponds to the position deviation or trajectory execution deviation of the machining motion platform, the synchronous control system determines that the deviation originates from a machining trajectory execution deviation and compensates for the machining trajectory of the corresponding processing station.

[0042] After determining the type of deviation source, the synchronous control system performs at least one of the following based on the deviation source type: energy ratio adjustment of the corresponding sub-beam, coupling attitude correction, core vacuum control, and machining trajectory compensation. If a single adjustment can bring the machining dimensional deviation back to within a preset threshold, the closed-loop control for that path is completed; if a single adjustment cannot bring the machining dimensional deviation back to within the preset threshold, a cascaded adjustment of at least two adjustment methods is performed. For example, when the machining dimensional deviation is simultaneously affected by beam splitting energy deviation and coupling efficiency shift, the synchronous control system first corrects the coupling attitude using a six-axis electric displacement stage, and then corrects the energy ratio of the corresponding sub-beam using an electric rotating half-wave plate; when the machining dimensional deviation is simultaneously affected by output pulse width broadening and machining trajectory execution deviation, the synchronous control system first adjusts the core vacuum and dispersion compensation, and then compensates the machining trajectory of the corresponding machining station. Through the above single and cascaded adjustments, the machining dimensional deviation is brought back to within the preset threshold, forming a closed-loop coupled control that drives the coordinated correction of splitting parameters, transmission parameters, and machining parameters based on machining quality.

[0043] During closed-loop control, the synchronous control system also performs anomaly handling and safety interlocking. An early warning is triggered when the energy deviation of a single sub-beam exceeds ±2% for 10 consecutive seconds and cannot be corrected through closed-loop calibration; when the energy deviation of a single sub-beam continues to exceed ±5%, the corresponding optical shutter is shut off. An early warning is triggered when the coupling efficiency of a single path decreases by more than 5% for 10 consecutive seconds; when the coupling efficiency of a single path continues to decrease by more than 10%, the corresponding optical shutter is shut off. When the vacuum level of a single fiber core suddenly rises and exceeds 100 Pa, the corresponding optical shutter and pneumatic diaphragm valve are immediately closed to isolate the faulty branch; if three or more paths experience vacuum abnormalities simultaneously, the entire laser output is shut off. For severe abnormal states such as over-temperature, over-power, fiber damage, excessive return light, and access control activation, the synchronous control system immediately triggers safety interlocks, shuts off laser output, and issues an alarm.

[0044] During processing, the synchronous control system records light source parameters, beam splitting parameters, transmission parameters, processing dimensions, and anomaly handling data in real time, forming a processing data archive. This processing data archive includes at least the processing time, process formula, number of beam splitting paths N, target energy percentage of each sub-beam, actual energy parameters of each sub-beam, spot parameters, coupling efficiency of each anti-resonant hollow fiber, core vacuum degree, output pulse width, processing trajectory of each processing station, processing dimensions, type of deviation source, adjustment actions, and safety interlock records. The processing data archive allows for traceability of the processing process and provides a basis for subsequent optimization of process parameters.

[0045] Therefore, by using a 1030nm femtosecond laser standard incident beam output, cascaded beam-splitting prism arrays for multi-path beam splitting, closed-loop calibration of energy and spot size for each sub-beam, vacuum-sealed conformal transmission via anti-resonant hollow fiber, multi-station synchronous parallel processing, and single and cascaded adjustments driven by processing dimensional deviations, a closed-loop coupled control relationship is established for the beam splitting, transmission, processing, and monitoring links. This method can reduce pulse distortion and energy drift during high-power femtosecond laser multi-path transmission, and improve the consistency, synchronization, and mass production stability of multi-path processing.

[0046] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers, characterized in that, include: The working parameters of the 1030nm femtosecond laser are preset according to the target processing technology, and the collimated standard incident beam is output to obtain the source end parameters of the standard incident beam. A standard incident beam is input into a cascaded array of beam splitters. By adjusting the electrically rotating half-wave plate in the array of beam splitters, the standard incident beam is split into N sub-beams, where N≥2. The energy parameters and spot parameters of each sub-beam are collected in real time, and the energy ratio of each sub-beam is calibrated in a closed loop based on the collection results. N sub-beams are coupled one-to-one to N anti-resonant hollow-core optical fibers. The coupling attitude between each sub-beam and the corresponding anti-resonant hollow-core optical fiber is adjusted. The core of the anti-resonant hollow-core optical fiber is evacuated. Dispersion compensation is performed on the laser transmitted through the anti-resonant hollow-core optical fiber. The coupling efficiency, core vacuum degree and output pulse width of each anti-resonant hollow-core optical fiber are collected in real time. N lasers output from anti-resonant hollow optical fibers are focused onto N processing stations. The output timing of each laser and the processing trajectory of the corresponding processing station are controlled by a synchronous control system, so that the N lasers can process the corresponding workpiece synchronously and in parallel, and the processing dimension data of each processing station are collected in real time. Based on the machining dimension deviation between the machining dimension data and the target machining dimension, and in conjunction with the light source end parameters, energy parameters, spot parameters, coupling efficiency, fiber core vacuum degree and output pulse width, the type of deviation source corresponding to the machining dimension deviation is determined; Depending on the type of deviation, at least one of the following is performed: energy ratio adjustment of the corresponding path beam, coupling attitude correction, core vacuum degree control, pulse compensation amount adjustment, and processing trajectory compensation. When a single adjustment cannot bring the processing size deviation back to within the preset threshold, at least two of these adjustments are cascaded to bring the processing size deviation back to within the preset threshold, thus forming a closed-loop coupled control that drives the coordinated correction of the splitting parameters, transmission parameters, and processing parameters based on processing quality.

2. The method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, The operating parameters of the 1030nm femtosecond laser include: center wavelength of 1030nm, pulse width of 50fs to 1ps, single pulse energy of 1μJ to 1mJ, repetition rate of 1kHz to 200kHz, average power of 1W to 100W, and beam quality M. 2 <1.2, linear polarization extinction ratio >100:1; the pointing deviation of the standard incident beam after collimation calibration is ≤5μrad.

3. The method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, Before outputting the standard incident beam, a safety interlock self-check is performed on the system access control, backlight, over-temperature status, and over-power status of the femtosecond laser source. If the safety interlock self-check result is abnormal, the femtosecond laser source is prohibited from emitting light.

4. The method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, The beam splitter array consists of N-1 polarization beam splitters and N-1 motorized rotating half-wave plates cascaded together. The standard incident beam passes through each stage of motorized rotating half-wave plates and polarization beam splitters in sequence. The polarization direction of the laser incident on the corresponding polarization beam splitter is adjusted by each stage of motorized rotating half-wave plates, so that the reflected light of the corresponding polarization beam splitter becomes the output sub-beam of this stage, and the transmitted light enters the next stage beam splitting unit, finally forming 1×N sub-beam outputs.

5. The method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, Energy parameters are acquired through a multi-channel energy meter array, and spot parameters are acquired through a CCD beam analyzer. Spot parameters include at least one of spot shape, spot quality, and pointing deviation. After closed-loop calibration of the energy ratio of each sub-beam, the total beam splitting efficiency is ≥95%, the inter-path energy consistency deviation is ≤±1%, and the polarization retention is >100:

1.

6. The method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, Antiresonant hollow-core fiber is designed for a wavelength of 1030 nm. The core diameter of the antiresonant hollow-core fiber is 30 μm–50 μm, and the cladding is a ring array structure composed of 6–8 high-purity quartz glass capillaries. The outer diameter of the fiber is 200 μm–300 μm. At a wavelength of 1030 nm, the transmission loss of the antiresonant hollow-core fiber is ≤0.1 dB / m, the single-path total transmission efficiency is ≥80%, and the pulse energy damage threshold is ≥3 J / cm². 2 @150kHz, 1030nm.

7. The method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, Each sub-beam is focused by a mode field matching lens group to match the mode field of the sub-beam spot with the core mode field of the corresponding anti-resonant hollow fiber. The coupling attitude is adjusted by a six-axis electric displacement stage. The six-axis electric displacement stage is adjusted according to the real-time collected coupling efficiency feedback to make the single-path coupling efficiency ≥85% and the mode field matching degree >95%.

8. The method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, By using a high-vacuum pump group connected to the sealed joints at both ends of the anti-resonant hollow fiber, the core of the anti-resonant hollow fiber is maintained in a low vacuum environment of 1Pa to 10Pa. The core vacuum level is monitored in real time by a vacuum sensor to suppress at least one nonlinear effect in the femtosecond laser transmission process, including self-phase modulation, stimulated Raman scattering, and air ionization. Dispersion compensation is achieved through chirped mirror pairs or grating pairs, ensuring that the output pulse width has a fidelity of ≥95% relative to the incident pulse width.

9. The method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, The workpiece coordinate system and the machining coordinate system of the corresponding workpiece are calibrated by a vision positioning system with a calibration accuracy better than 1μm; the machining trajectory includes at least one of a straight line trajectory, a circular arc trajectory and a three-dimensional complex trajectory; the synchronous control system includes an FPGA main controller, which synchronously controls the emission timing of the femtosecond laser, the switching of the light gates of each sub-beam, and the motion trajectory of each machining station motion platform, with a synchronous triggering accuracy better than 10ns.

10. A method for parallel processing of multiple hollow-core optical fibers using femtosecond lasers according to claim 1, characterized in that, The types of deviation sources include at least one of the following: beam splitting energy deviation, spot state deviation, coupling efficiency shift, core vacuum deviation, output pulse width deviation, and processing trajectory execution deviation; when the energy deviation of a single sub-beam exceeds ±2% for 10 consecutive seconds and cannot be corrected by closed-loop calibration, an early warning is triggered; when the energy deviation of a single sub-beam continues to exceed ±5%, the corresponding optical shutter is shut off. An early warning is triggered when the single-path coupling efficiency decreases by more than 5% for 10 consecutive seconds; the corresponding optical gate is shut down when the single-path coupling efficiency continues to decrease by more than 10%. When the vacuum level of a single fiber core suddenly rises and exceeds 100Pa, the corresponding optical shutter and pneumatic diaphragm valve are immediately closed to isolate the faulty branch; the light source parameters, beam splitting parameters, transmission parameters, processing size data and abnormal handling data are recorded in real time to form a processing data archive.

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