FBG (fiber bragg grating) automatic processing and sorting system and method based on femtosecond laser

Abstract

The invention belongs to the technical field of optical fiber preparation automation, and particularly discloses an automatic processing and sorting system and method for fiber bragg gratings based on femtosecond laser. The sorting unit comprises a feeding machine used for achieving automatic fiber feeding in the machining process, a winding machine connected with the feeding machine through optical fibers and used for packaging and coiling optical fiber finished products, and an industrial mechanical arm used for sorting the packaged optical fiber finished products; the processing unit is arranged between the feeding machine and the winding machine and is used for performing grating processing on the optical fiber; the detection unit comprises a test light source, a circulator, a spectrograph and a loss module; the circulator is simultaneously connected with the test light source, the spectrograph and an optical fiber on the feeder; the loss module is arranged between the processing unit and the winding machine and is used for blocking the propagation of the test laser emitted by the test light source in the optical fiber by bending the optical fiber; the control unit is in communication connection with the machining unit, the sorting unit and the detection unit and used for achieving automatic machining and sorting of the fiber bragg gratings.

Description

Technical Field

[0001] This invention belongs to the field of automated optical fiber fabrication technology, and more specifically, relates to an automated processing and sorting system and method for fiber gratings based on femtosecond lasers. Background Technology

[0002] Fiber Bragg gratings (FBGs), passive optical devices that form periodic refractive index modulation within the fiber core, are widely used in fiber optic communication, fiber lasers, and distributed sensing systems such as structural health monitoring, temperature and strain sensing due to their advantages of high sensitivity, electromagnetic interference resistance, corrosion resistance, and reusability. Especially in long-distance, multi-point measurement scenarios, wavelength division multiplexing (WDM) and time division multiplexing (TDM) technologies allow multiple grating units to be integrated into a single fiber, enabling high-precision synchronous sensing of multiple parameters in complex environments. Currently, the mainstream manufacturing processes for long-distance distributed FBGs in China mainly include ultraviolet (UV) masking and femtosecond laser direct writing. The UV masking method involves periodic exposure of the drawn fiber using a UV laser and a phase mask, followed by coating with a protective layer to complete the grating fabrication. This method is mature and has good consistency, but the resulting refractive index modulation structure is non-permanent and susceptible to degradation due to high temperatures or long-term use, limiting its application in high-temperature or harsh environments. In comparison, femtosecond laser processing technology, with its nonlinear absorption effect brought about by ultrashort pulses, can induce stable and permanent refractive index changes inside optical fibers, thereby realizing the fabrication of high-temperature stable fiber gratings and having a broader application prospect.

[0003] To address the production needs of femtosecond laser-processed fiber gratings, existing technologies have been preliminarily explored. In the processing positioning and packaging stages, current solutions primarily rely on manual labor in conjunction with basic mechanical conveying devices. The processing position of the grating is determined by manual observation and marked, followed by manual segment-by-segment quality inspection, manual cutting, and packaging into rolls. In the processing monitoring stage, some equipment attempts to use spectral detection modules to perform offline testing of the processed fiber as a whole, judging the grating quality by comparing it with standard spectra. Regarding automation control, existing equipment can only achieve basic linkage between femtosecond laser emission and fiber transmission, and has not yet formed a complete closed-loop control process. Furthermore, to improve the targeting of monitoring, some studies have proposed adding optical detection units next to the processing device, attempting to achieve real-time observation of the processing area.

[0004] Therefore, existing technologies still have several key shortcomings that severely restrict the industrialization of femtosecond laser-processed fiber gratings. For example, in the entire processing flow, the positioning, marking, quality inspection, and packaging of gratings still heavily rely on manual operation, which is not only time-consuming and labor-intensive but also prone to human error, significantly increasing manufacturing costs and reducing overall production efficiency. Secondly, in continuous dynamic processing, there is a lack of real-time online monitoring capabilities for the latest completed grating unit, making it impossible to effectively shield the crosstalk of previously processed gratings to the current detection signal, resulting in difficulty in accurately evaluating the actual performance of individual gratings and thus affecting product consistency control. Thirdly, existing equipment generally uses offline methods to acquire reflection spectra, making it impossible to identify and classify key parameters such as the center wavelength, reflectivity, and bandwidth of each grating in real time during processing, resulting in high-quality gratings being mixed with defective products, making it difficult to achieve efficient automatic sorting. In addition, manual intervention is still required for cutting and winding after processing, further lengthening the production cycle and limiting the level of continuity and intelligence of the production line. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides an automated processing and sorting system and method for fiber gratings based on femtosecond lasers. By integrating processing units, sorting units, detection units, and control units, it significantly improves the intelligence and industrialization level of fiber grating manufacturing, thereby effectively solving the problems of relying on manual positioning, quality inspection, and packaging in existing technologies. At the same time, it overcomes the technical bottleneck of not being able to monitor and shield interference from preceding fiber gratings in real time during dynamic processing, providing reliable technical support for the large-scale, low-cost production of high-performance, high-consistency fiber gratings.

[0006] To achieve the above objectives, the present invention provides an automated processing and sorting system for fiber gratings based on femtosecond lasers, comprising: a processing unit, a sorting unit, a detection unit, and a control unit; wherein: The sorting unit includes: a feeder for automatically feeding fibers during processing, a winding machine connected to the feeder via optical fiber and used to package finished optical fibers into rolls, and an industrial robotic arm for sorting packaged finished optical fibers. The processing unit is located between the feeder and the winding machine and is used to perform grating processing on the optical fiber. It includes: a femtosecond laser source for emitting femtosecond laser, a three-axis motion module for ensuring that the femtosecond laser is always focused on the center of the fiber core, and an imaging lens and imaging camera for acquiring clear optical fiber images. The detection unit includes: a test light source, a circulator, a spectrometer, and a loss module; the circulator is simultaneously connected to the test light source, the spectrometer, and the optical fiber on the feeder; the loss module is located between the processing unit and the winding machine, and it blocks the propagation of the test laser emitted by the test light source in the optical fiber by bending the optical fiber; The sorting unit further includes: a length encoder, an inkjet printer, and a cutting machine; the length encoder, the inkjet printer, and the cutting machine are sequentially arranged between the loss module and the winding machine; The control unit is communicatively connected to the processing unit, the sorting unit, and the detection unit to realize automated processing and sorting of fiber optic gratings.

[0007] Furthermore, the sorting unit also includes a tension sensor; the tension sensor is located between the processing unit and the loss module, and is used to work in conjunction with the feeder to monitor and dynamically adjust the tension state of the optical fiber during processing and transmission in real time.

[0008] Furthermore, the sorting unit also includes sorting baskets, at least two of which are located on one side of the industrial robotic arm.

[0009] Furthermore, the processing unit includes: a laser beam expander, a laser power regulator, a reflector, a dichroic mirror, a microscope objective, a white light source, and an optical fiber holder; The laser emitted by the femtosecond laser source passes sequentially through the laser beam expander, the laser power regulator, the reflector, the dichroic mirror, and the microscope objective in the optical path, and then irradiates the optical fiber on the optical fiber holder. The white light source is located on the fiber optic holder and below the fiber optic cable. The light emitted by the white light source is reflected by the dichroic mirror to the imaging lens and focused into the imaging camera.

[0010] Furthermore, the three-axis motion module includes an X-axis motion submodule, a Y-axis motion submodule, and a Z-axis motion submodule; The X-axis motion submodule is movably connected to the Y-axis motion submodule and is used to adjust the horizontal position of the fiber optic clamp. The Z-axis motion submodule is fixedly equipped with the dichroic mirror, the microscope objective, the imaging lens, and the imaging camera, which are used to dynamically adjust the distance between the microscope objective and the optical fiber.

[0011] A second aspect of this invention provides an automated processing and sorting method for fiber gratings based on femtosecond lasers, implemented using the automated processing and sorting system described above, comprising the following steps: S1: The optical fiber is sequentially threaded through the fiber holder, tension sensor, loss module, length encoder, inkjet printer, cutter and winding machine via the feeder to complete the first fiber threading before grating processing, and one end of the optical fiber is connected to the circulator. S2: The horizontal position of the optical fiber and the vertical position of the processing unit components are adjusted by the three-axis motion module so that the fiber core of the area to be processed can be clearly displayed in the imaging camera; S3: The three-axis motion module, the feeder and the winding machine work together to adjust the speed of the optical fiber movement. At the same time, the femtosecond laser source switch is controlled to hit the laser onto the area of ​​the optical fiber to be processed, thus completing the processing of a section of fiber grating. S4: The fiber passing through it is shielded by the loss module. At the same time, the test light source is turned on to detect the parameters of the fiber grating processed in step S3. Then, the spectrometer sends the relevant data to the control unit and determines whether the current fiber grating is qualified. S5: After the parameter detection is completed, the feeder and the winding machine work together to feed the optical fiber and pack it into a roll. At the same time, the cutting machine cuts the finished optical fiber on the winding machine. S6: Based on the inspection results of the finished optical fiber products, the industrial robotic arm places the finished optical fiber products on the winding machine into the corresponding sorting baskets; S7: Repeat steps S2 to S6 to complete the processing of the current batch of optical fibers.

[0012] Furthermore, in step S2, before processing the fiber Bragg grating, the feeder and the winding machine work together to control the optical fiber to move forward a set length to one side of the winding machine.

[0013] Further, in step S3, before processing the fiber grating, based on the length L of the fiber grating to be processed and the current core position focused by the imaging camera, the fiber is controlled to move backward by a length L / 2 towards the feeder side, and the newly obtained core position is recorded as the starting endpoint; then, starting from the starting endpoint, the fiber is moved forward by a length L towards the winding machine side, and the newly obtained core position is recorded as the ending endpoint, thereby obtaining the movement trajectory of the fiber to be processed during grating processing. At the same time, the fiber segment from the starting endpoint to the ending endpoint is the irradiation area of ​​the femtosecond laser source.

[0014] Furthermore, in step S4, based on the fiber grating length, the feeder 11 and the winding machine 20 work together to control the fiber to advance a certain distance, which is used to control the position of the bending fiber by the loss module 17.

[0015] A third aspect of the present invention provides a computer-readable storage medium comprising a stored computer program, wherein the computer program, when executed by a processor, controls the device containing the storage medium to perform the automated processing and sorting method as described above.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The automated processing and sorting system of the present invention significantly improves the level of intelligence and industrialization of fiber Bragg grating manufacturing by integrating processing units, sorting units, detection units and control units. This effectively solves the problem of relying on manual positioning, quality inspection and packaging in the prior art. At the same time, it overcomes the technical bottleneck of not being able to monitor and shield the interference of preceding fiber Bragg gratings in real time during dynamic processing, and provides reliable technical support for the large-scale and low-cost production of high-performance and high-consistency fiber Bragg gratings.

[0017] 2. The automated processing and sorting system of the present invention, by highly integrating precision motion control with the optical system, not only achieves three-dimensional precise positioning of the fiber position during processing, but also supports closed-loop correction under real-time vision guidance, effectively overcoming processing deviations caused by mechanical vibration, thermal drift, or fiber deformation. As a result, the system can complete the continuous automated writing of complex arrangements or multi-segment gratings without human intervention, greatly improving processing efficiency, consistency, and finished product yield, and providing a key equipment foundation for the large-scale intelligent manufacturing of high-performance fiber gratings.

[0018] 3. The automated processing and sorting system of the present invention, through the organic integration of tension closed-loop control, precise length measurement, automatic information marking and intelligent cutting, can significantly reduce labor costs and the risk of misoperation, and significantly improve sorting efficiency, product consistency and quality control capabilities. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the automated processing and sorting system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the control unit in an embodiment of the present invention; Figure 3 This is a schematic diagram of the steps of the automated processing and sorting method according to an embodiment of the present invention.

[0020] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-femtosecond laser source, 2-laser beam expander, 3-laser power regulator, 4-reflector, 5-dichroic mirror, 6-microscope objective, 7-imaging lens, 8-imaging camera, 9-white light source, 10-three-axis motion module, 11-feeder, 12-fiber optic clamp, 13-test light source, 14-circulator, 15-spectrometer, 16-tension sensor, 17-loss module, 18-length encoder, 19-inkjet printer, 20-winding machine, 21-cutting machine, 22-industrial robotic arm, 23-sorting basket, 24-processor, 25-communication bus, 26-user interface, 27-network interface, 28-memory. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Example 1, please refer to Figure 1 and Figure 2 This invention provides an automated processing and sorting system for fiber optic gratings based on femtosecond lasers, comprising: a processing unit, a sorting unit, a detection unit, and a control unit; wherein: The sorting unit includes: a feeder 11 for automatically feeding fibers during processing, a winding machine 20 connected to the feeder 11 via optical fiber and used to package finished optical fibers into rolls, and an industrial robotic arm 22 for sorting packaged finished optical fibers. The processing unit is located between the feeder 11 and the winding machine 20 and is used to perform grating processing on the optical fiber. It includes: a femtosecond laser source 1 for emitting femtosecond laser, a three-axis motion module 10 for ensuring that the femtosecond laser is always focused on the center of the fiber core, an imaging lens 7 and an imaging camera 8 for acquiring clear optical fiber images. The detection unit includes: a test light source 13, a circulator 14, a spectrometer 15, and a loss module 17; the circulator 14 is connected to the test light source 13, the spectrometer 15, and the optical fiber on the feeder 11; the loss module 17 is located between the processing unit and the winding machine 20, and it blocks the propagation of the test laser emitted by the test light source 13 in the optical fiber by bending the optical fiber. The sorting unit further includes: a length encoder 18, an inkjet printer 19, and a cutting machine 21; the length encoder 18, the inkjet printer 19, and the cutting machine 21 are sequentially arranged between the loss module 17 and the winding machine 20. The control unit is communicatively connected to the processing unit, the sorting unit, and the detection unit to realize automated processing and sorting of fiber optic gratings.

[0023] Understandably, in the fiber Bragg grating production process, the sorting unit includes a feeder 11, a winding machine 20, and an industrial robotic arm 22, realizing fully automated operation from automatic fiber feeding and finished product winding to intelligent sorting, significantly reducing manual intervention and time costs. The processing unit is located between the feeder 11 and the winding machine 20, ensuring efficient femtosecond laser grating writing during continuous fiber feeding. The detection unit consists of a test light source 13, a circulator 14, a spectrometer 15, and a loss module 17. The circulator 14 guides the test laser emitted by the test light source 13 into the fiber under test and directs the reflected light to the spectrometer 15 for real-time spectral analysis. The loss module 17 is located between the processing unit and the winding machine 20, and through controllable bending, it blocks crosstalk of the completed grating to subsequent detection signals, thereby ensuring accurate identification of individual grating performance parameters (such as center wavelength, bandwidth, side mode suppression ratio, reflection intensity, etc.). The control unit communicates with the above units to coordinate processing, detection, and sorting actions, realizing online quality assessment and automatic classification of each fiber Bragg grating. In addition, during the fiber Bragg grating production process, the length encoder 18 can accurately record the length of the processed optical fiber, providing high-precision data support for subsequent segmentation according to the preset grating spacing or product specifications; the inkjet printer 19 automatically prints a unique identification code on the surface of the qualified optical fiber according to the control unit command, which includes key information such as the grating center wavelength, production batch, and location number, realizing traceability management throughout the product life cycle; the cutting machine 21 accurately cuts the finished optical fiber products of different grades that are automatically wound and stored on the winding machine 20 according to the length signal fed back by the length encoder 18 and the quality judgment result of the detection unit.

[0024] It should be noted that by placing the cutting machine 21 at the front end of the winding machine 20, and packaging defective or out-of-tolerance fiber segments (oversized / short), and then having the industrial robotic arm 22 perform the sorting operation, the continuity and automation level of the production line process are effectively guaranteed. This method avoids interrupting the winding operation due to the removal of abnormal segments, improving equipment operating efficiency. At the same time, by uniformly winding the fiber segments and then having the industrial robotic arm 22 classify and place them into the corresponding sorting baskets 23 according to the inspection results, the consistency of the sorting logic and the reliability of the operation are ensured. This simplifies the complexity of the control system, enhances product quality traceability, and significantly improves the stability and intelligence of the overall production system.

[0025] Specifically, the processing unit includes: a laser beam expander 2, a laser power regulator 3, a reflector 4, a dichroic mirror 5, a microscope objective 6, a white light source 9, and a fiber optic holder 12. The laser emitted by the femtosecond laser source 1 passes sequentially through the laser beam expander 2, the laser power regulator 3, the reflector 4, the dichroic mirror 5, and the microscope objective 6 in the optical path, illuminating the optical fiber on the fiber optic holder 12. The white light source 9 is located on the fiber optic holder 12 and below the optical fiber; its emitted light is reflected by the dichroic mirror 5 to the imaging lens 7 and focused into the imaging camera 8. It can be understood that through the above design, utilizing precise optical path design and multi-component collaboration, the accuracy, stability, and automation level of femtosecond laser writing into fiber Bragg gratings are significantly improved.

[0026] It should be noted that, please refer to Figure 1 In this embodiment, the femtosecond laser source 1 is a laser with a pulse duration on the order of femtoseconds (Light Amplification by Stimulated Emission of Radiation, LASER); the imaging camera 8 converts incident photons into a corresponding number of charges based on its internal charge-coupled device (CCD), completing photoelectric conversion, and then sequentially couples and transmits these charge packets to the output end, finally converging them into a complete image electrical signal; the test light source 13 is a broadband, incoherent "laser-like" light source based on ASE (Amplified Spontaneous Emission), and when it is necessary to test the response characteristics of devices such as fiber amplifiers and filters at different wavelengths, it can provide a wide wavelength range and high power output, thereby avoiding the tediousness of repeated scanning required by using a single wavelength laser, greatly improving the testing efficiency. In other embodiments, other types of light sources and image transmissions can also be used, as long as they can output the required laser and obtain accurate images, which is not specifically limited here.

[0027] Furthermore, the three-axis motion module 10 includes an X-axis motion submodule, a Y-axis motion submodule, and a Z-axis motion submodule. The X-axis motion submodule is movably connected to the Y-axis motion submodule and is used to adjust the horizontal position of the fiber optic holder 12. The Z-axis motion submodule is fixedly equipped with the dichroic mirror 5, the microscope objective 6, the imaging lens 7, and the imaging camera 8, and is used to dynamically adjust the distance between the microscope objective 6 and the optical fiber. It can be understood that by adjusting the height of the Z-axis motion submodule, automatic focusing on optical fibers of different diameters or coating thicknesses can be achieved, ensuring that the femtosecond laser is always focused on the fiber core center, improving the accuracy and stability of refractive index modulation. Simultaneously, the imaging lens 7 and the imaging camera 8 move synchronously with the Z-axis, ensuring that clear optical fiber images can still be obtained under different focal planes, providing reliable data support for visual feedback control.

[0028] Furthermore, the sorting unit also includes a tension sensor 16; the tension sensor 16 is located between the processing unit and the loss module 17, and is used to work in conjunction with the feeder 11 to monitor and dynamically adjust the tension state of the optical fiber during processing and transmission in real time, effectively avoiding grating period distortion or fiber core damage caused by tension fluctuations, thereby ensuring the consistency of the grating structure and the stability of optical performance.

[0029] In an optional embodiment, the sorting unit further includes sorting baskets 23, of which there are at least two, located on one side of the industrial robotic arm 22. Based on the real-time quality judgment results from the detection unit, the industrial robotic arm 22 automatically sorts and stores finished optical fibers of different grades into the corresponding sorting baskets 23, achieving efficient and accurate hierarchical management and significantly improving product sorting efficiency and quality traceability. It should be noted that... (The text abruptly ends here, likely due to an incomplete sentence or missing information.) Figure 1 In this embodiment, finished optical fiber products are classified and placed into corresponding classification baskets 23. Qualified products are placed in classification baskets 23 marked with "✔", and unqualified products are placed in classification baskets 23 marked with "✘", thereby avoiding confusion.

[0030] Further, the control unit includes: a processor 24, a communication bus 25, a user interface 26, a network interface 27, and a memory 28; wherein, the communication bus 25 is at least one, used to realize communication between these components; the user interface 26 may include a display screen and a keyboard, and optionally, the user interface 26 may also include a standard wired interface or a wireless interface. The network interface 27 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 28 may be a high-speed RAM memory or a non-volatile memory, such as at least one disk storage device. Optionally, the memory 28 may also be at least one storage device located remotely from the aforementioned processor 24. Figure 3 As shown, the memory 28, which is a computer-readable storage medium, may include an operating system, a network communication module, a user interface module, and a device control application program. The network interface 27 provides network communication functions; the user interface 26 is mainly used to provide an input interface for the user; and the processor 24 can be used to call the device control application program stored in the memory 28.

[0031] It should be understood that in some feasible implementations, the processor 24 described above may be a central processing unit (CPU), which may also be other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor. The memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store device type information.

[0032] In an optional embodiment, the control unit is communicatively connected to the femtosecond laser source 1, the laser beam expander 2, the laser power regulator 3, the imaging camera 8, the three-axis motion module 10, the feeder 11, the fiber optic holder 12, the test light source 13, the spectrometer 15, the tension sensor 16, the length encoder 18, the inkjet printer 19, the winding machine 20, the cutting machine 21, and the industrial robotic arm 22, to achieve highly integrated and closed-loop control of the entire process from grating writing and online detection to post-processing sorting. Understandably, through this unified control architecture, the system can dynamically coordinate various functional modules based on preset process parameters or real-time feedback data. For example, the three-axis motion module 10 is adjusted based on the visual information from the imaging camera 8 to achieve precise focusing, while the tension sensor 16, feeder 11, and winding machine 20 work together to maintain constant tension. During processing, the femtosecond laser source 1, laser beam expander 2, and laser power regulator 3 are simultaneously triggered to ensure energy stability. After processing, the test light source 13 and spectrometer 15 work together to collect the reflection spectrum, and the control unit determines the grating quality accordingly, instructing the inkjet printer 19 to selectively mark qualified products. Subsequently, the length encoder 18 provides a length reference, driving the cutting machine 21 to precisely cut the fiber, the winding machine 20 to complete the winding, and finally, the industrial robotic arm 22 classifies and places the finished products into the corresponding sorting bins 23 based on the inkjet information. In summary, this highly coordinated control system not only completely eliminates manual intervention and significantly improves production efficiency and product consistency, but also enhances process traceability and system robustness, providing solid technical support for the large-scale, intelligent, and high-quality manufacturing of femtosecond laser direct-write fiber gratings.

[0033] Example 2, please refer to Figure 3 This invention provides an automated processing and sorting method for fiber gratings based on femtosecond lasers, comprising the following steps: S1: The optical fiber is sequentially threaded through the fiber holder 12, tension sensor 16, loss module 17, length encoder 18, inkjet printer 19, cutter 21 and winding machine 20 via the feeder 11 to complete the first fiber threading before grating processing, and one end of the optical fiber is connected to the circulator 14. S2: The horizontal position of the optical fiber and the vertical position of the processing unit components are adjusted by the three-axis motion module 10 so that the fiber core of the area to be processed can be clearly displayed in the imaging camera 8. S3: The three-axis motion module 10, the feeder 11 and the winding machine 20 work together to adjust the speed of the optical fiber movement. At the same time, the femtosecond laser source 1 is switched to hit the laser on the area to be processed in the optical fiber, thus completing the processing of a section of fiber grating. S4: The fiber passing through the loss module 17 is shielded. At the same time, the test light source 13 is turned on to detect the parameters of the fiber grating processed in step S3. Then, the spectrometer 15 sends the relevant data to the control unit and determines whether the current fiber grating is qualified. S5: After the parameter detection is completed, the feeder 11 and the winding machine 20 work together to feed and package the optical fiber into a roll. At the same time, the cutting machine 21 cuts the finished optical fiber on the winding machine 20. S6: Based on the test results of the finished optical fiber, the industrial robotic arm 22 places the finished optical fiber on the winding machine 20 into the corresponding sorting basket 23; S7: Repeat steps S2 to S6 to complete the processing of the current batch of optical fibers.

[0034] In an optional embodiment, in step S2, before processing the fiber Bragg grating, the feeder 11 and the winding machine 20 collaboratively control the fiber to move forward a set length towards the winding machine 20. This is used to provide stable initial conditions for subsequent grating writing through precise length pre-feeding, and effectively avoid periodic errors or writing failures caused by fiber position deviation. At the same time, the synchronous tension control of the feeder 11 and the winding machine 20 helps to maintain the straightness and constant tension of the fiber in the processing area, preventing micro-bending or slack from adversely affecting the grating performance. In addition, this pre-positioning mechanism lays the foundation for the orderly arrangement of multi-segment gratings and the subsequent length calibration of the length encoder 18, significantly improving processing consistency, system repeatability, and overall automation level.

[0035] In an optional embodiment, in step S3, before processing the fiber grating, based on the length L of the fiber grating to be processed and the current core position focused by the imaging camera 8, the fiber is controlled to move backward by a length L / 2 towards the feeder side, and the newly obtained core position is recorded as the starting endpoint; then, starting from the starting endpoint, the fiber is moved forward by a length L towards the winding machine 20, and the newly obtained core position is recorded as the ending endpoint, thereby obtaining the movement trajectory of the fiber to be processed during grating processing. At the same time, the fiber segment from the starting endpoint to the ending endpoint is the irradiation area of ​​the femtosecond laser source 1. Understandably, the above design fully utilizes the real-time visual feedback provided by the imaging camera 8, combined with high-resolution motion control, to achieve closed-loop calibration of the grating position. This effectively avoids problems such as grating misalignment, overlap, or missing gratings caused by initial positioning deviations, mechanical transmission errors, or micro-displacement of the fiber. Simultaneously, the clearly defined start and end boundaries provide precise basis for the triggering timing of the femtosecond laser source 1, the scanning path of the three-axis motion module 10, and the length verification of the length encoder 18, ensuring that each grating is written strictly according to the design parameters. Furthermore, this trajectory definition mechanism supports the flexible arrangement of multi-segment, non-uniform, or variable-period gratings, greatly enhancing the system's process adaptability and intelligence level. In summary, this positioning and trajectory generation method not only ensures the geometric consistency and optical performance stability of individual gratings but also lays a key technological foundation for the fully automated manufacturing of high-density, high-precision fiber grating strings.

[0036] In an optional embodiment, in step S3, the fiber moving speed is obtained based on the grating period of the fiber grating to be processed and the laser repetition frequency of the femtosecond laser source 1, and the moving speed value is the product of the grating period and the laser repetition frequency.

[0037] In an optional embodiment, in step S4, according to the fiber Bragg grating length, the feeder 11 and the winding machine 20 collaboratively control the fiber to advance a certain distance to control the position of the bending fiber by the loss module 17. It is understood that there is a certain distance between the processing position and the loss module 17, typically 0.8-1m. When the total length of the fiber Bragg grating is small, there may be a preceding grating between the processing position and the loss module 17. For example, if the distance between the processing position and the loss module 17 is 0.8m, and the finished length of the fiber Bragg grating is 0.5m (fiber Bragg grating 5mm, fiber Bragg grating center distance 250mm from each end of the fiber), in this case, if the fiber is not controlled to advance a certain distance, the signal from the preceding fiber Bragg grating will not be shielded when testing the current fiber Bragg grating. The reflection spectrum collected by the spectrometer 15 will contain multiple superimposed signals, severely affecting the accurate identification of key parameters such as the center wavelength and reflectivity of the current grating.

[0038] It should be noted that in step S4, when the loss module 17 shields the optical fiber passing through it, it means shielding the optical fiber path after the loss module 17, not just the preceding grating, so that performance testing can be performed in subsequent steps.

[0039] In an optional embodiment, in step S5, if the parameters of the fiber Bragg grating are qualified, the inkjet printer 19 marks the surface of the fiber; if the parameters of the fiber Bragg grating are not qualified, the inkjet printer 19 does not perform inkjet printing on that section of fiber, thereby realizing a direct distinction between qualified and defective products, facilitating accurate sorting and quality traceability by the subsequent industrial robotic arm 22, and improving sorting efficiency and product consistency.

[0040] Example 3: This application also provides a computer-readable storage medium storing a computer program that is executed by a processor to implement the various steps in the automated processing and sorting method of fiber optic grating based on femtosecond lasers in the above embodiments. For details, please refer to the implementation methods provided for the above steps, which will not be repeated here.

[0041] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0042] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0043] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0044] In this invention, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit it; those skilled in the art will readily understand that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An automated processing and sorting system for fiber gratings based on femtosecond lasers, characterized in that, include: Processing unit, sorting unit, detection unit, and control unit; wherein: The sorting unit includes: a feeder (11) for automatically feeding fibers during processing, a winding machine (20) connected to the feeder (11) via optical fiber and used to package finished optical fibers into rolls, and an industrial robotic arm (22) for sorting packaged finished optical fibers. The processing unit is located between the feeder (11) and the winding machine (20) and is used to perform grating processing on the optical fiber. It includes: a femtosecond laser source (1) for emitting femtosecond laser, a three-axis motion module (10) for ensuring that the femtosecond laser is always focused on the center of the fiber core, an imaging lens (7) and an imaging camera (8) for acquiring clear optical fiber images. The detection unit includes: a test light source (13), a circulator (14), a spectrometer (15), and a loss module (17); the circulator (14) is connected to the test light source (13), the spectrometer (15), and the optical fiber of the feeder (11); the loss module (17) is located between the processing unit and the winding machine (20), and it blocks the propagation of the test laser emitted by the test light source (13) in the optical fiber by bending the optical fiber; The sorting unit further includes: a length encoder (18), an inkjet printer (19), and a cutting machine (21); the length encoder (18), the inkjet printer (19), and the cutting machine (21) are sequentially arranged between the loss module (17) and the winding machine (20); The control unit is communicatively connected to the processing unit, the sorting unit, and the detection unit to realize automated processing and sorting of fiber optic gratings.

2. The automated processing and sorting system according to claim 1, characterized in that, The sorting unit further includes a tension sensor (16); the tension sensor (16) is located between the processing unit and the loss module (17) and is used to work in conjunction with the feeder (11) to monitor and dynamically adjust the tension state of the optical fiber during processing and transmission in real time.

3. The automated processing and sorting system according to claim 2, characterized in that, The sorting unit also includes sorting baskets (23), of which there are at least two, which are located on one side of the industrial robotic arm (22).

4. The automated processing and sorting system according to any one of claims 1-3, characterized in that, The processing unit includes: a laser beam expander (2), a laser power regulator (3), a reflector (4), a dichroic mirror (5), a microscope objective (6), a white light source (9), and an optical fiber holder (12). The laser emitted by the femtosecond laser source (1) passes sequentially through the laser beam expander (2), the laser power regulator (3), the reflector (4), the dichroic mirror (5), and the microscope objective (6) in the optical path, and irradiates the optical fiber on the fiber holder (12). The white light source (9) is located on the fiber optic holder (12) and below the fiber optic cable. The light emitted by the white light source is reflected by the dichroic mirror (5) to the imaging lens (7) and focused into the imaging camera (8).

5. The automated processing and sorting system according to claim 4, characterized in that, The three-axis motion module (10) includes an X-axis motion submodule, a Y-axis motion submodule, and a Z-axis motion submodule; The X-axis motion submodule is movably connected to the Y-axis motion submodule and is used to adjust the horizontal position of the fiber optic clamp (12); The Z-axis motion submodule is fixedly equipped with the dichroic mirror (5), the microscope objective (6), the imaging lens (7) and the imaging camera (8), which are used to dynamically adjust the distance between the microscope objective (6) and the optical fiber.

6. An automated processing and sorting method for fiber gratings based on femtosecond lasers, implemented using the automated processing and sorting system as described in any one of claims 1-5, characterized in that... Includes the following steps: S1: The optical fiber is sequentially threaded through the fiber holder (12), tension sensor (16), loss module (17), length encoder (18), inkjet printer (19), cutter (21) and winding machine (20) via the feeder (11) to complete the first fiber threading before grating processing, and one end of the optical fiber is connected to the circulator (14). S2: Adjust the horizontal position of the optical fiber and the vertical position of the processing unit components through the three-axis motion module (10) so that the fiber core of the area to be processed can be clearly displayed in the imaging camera (8); S3: The fiber moving speed is adjusted by the three-axis motion module (10), the feeder (11) and the winding machine (20) in coordination. At the same time, the femtosecond laser source (1) is switched to hit the laser on the fiber to be processed area to complete the processing of a fiber grating. S4: The fiber passing through it is shielded by the loss module (17). At the same time, the test light source (13) is turned on to detect the parameters of the fiber grating processed in step S3. Then, the spectrometer (15) sends the relevant data to the control unit and determines whether the current fiber grating is qualified. S5: After the parameter detection is completed, the feeder (11) and the winding machine (20) work together to feed and package the optical fiber into a roll. At the same time, the cutting machine (21) cuts the finished optical fiber on the winding machine (20). S6: Based on the test results of the finished optical fiber, the industrial robotic arm (22) places the finished optical fiber on the winding machine (20) into the corresponding sorting basket (23); S7: Repeat steps S2 to S6 to complete the processing of the current batch of optical fibers.

7. The automated processing and sorting method according to claim 6, characterized in that, In step S2, before processing the fiber grating, the feeder (11) and the winding machine (20) work together to control the fiber to move forward a set length to one side of the winding machine (20).

8. The automated processing and sorting method according to claim 6, characterized in that, In step S3, before processing the fiber grating, according to the length L of the fiber grating to be processed and the current core position focused by the imaging camera (8), the fiber is controlled to move in the opposite direction to the feeder by a length of L / 2, and the newly obtained core position is recorded as the starting end point; then, with the starting end point as the starting point, the fiber is moved forward by a length L to the winding machine (20), and the newly obtained core position is recorded as the ending end point, thereby obtaining the movement trajectory of the fiber to be processed during grating processing. At the same time, the fiber segment from the starting end point to the ending end point is the irradiation area of ​​the femtosecond laser source (1).

9. The automated processing and sorting method according to claim 6, characterized in that, In step S4, according to the fiber grating length, the feeder (11) and the winding machine (20) work together to control the fiber to advance a certain distance, which is used to control the position of the loss module (17) bending the fiber.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program that, when executed by a processor, controls the device containing the storage medium to perform the automated processing and sorting method as described in any one of claims 6 to 9.

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