An end face geometry parameter testing device and method of a hollow core optical fiber

Abstract

The application discloses a kind of hollow optical fiber end face geometric parameter testing device and method, the device includes: process parameter database;For storing and configuring hollow optical fiber process parameter model, and the first optical fiber end face geometric parameter is parsed to hollow optical fiber process parameter model;Test unit;For collecting the end face image of the hollow optical fiber sample to be measured;Data acquisition and processing unit;For obtaining the second optical fiber end face geometric parameter by parsing end face image, and according to the first optical fiber end face geometric parameter and the second optical fiber end face geometric parameter obtains test result.The application effectively improves the efficiency of hollow optical fiber research and development verification.

Description

Technical Field

[0001] This invention relates to the field of hollow-core anti-resonant optical fiber testing technology, specifically to a device and method for testing the geometric parameters of the end face of hollow-core optical fiber. Background Technology

[0002] Hollow-core optical fiber has developed rapidly due to its low delay, low nonlinear effect and high power carrying capacity. Hollow-core optical fiber forms a resonant cavity based on the complex internal glass geometry. In the process of developing hollow-core optical fiber, the geometric parameters need to be continuously optimized and adjusted according to the research and development indicators. The rapid and accurate testing response of the geometric shape plays a very important role in the entire research and development and production process.

[0003] The development of hollow-core optical fiber is rapid, but relevant domestic and international technical standards have not yet been established. The technical parameters (end-face geometry and technical parameters) of hollow-core optical fiber published by existing manufacturers are inconsistent. Traditional optical fiber end-face geometry parameter testing equipment is unsuitable for testing and measuring hollow-core optical fiber due to insufficient imaging performance and incompatible image algorithms. As one of the most important technical indicators of hollow-core optical fiber, end-face geometry and technical parameters require continuous optimization and adjustment during the R&D, design, and trial production stages. Rapid response and closed-loop iteration of process parameters and production test sample data are crucial for efficient R&D and production.

[0004] Currently, there are two main testing methods for hollow optical fibers: one is to acquire images using microscopes, end-face image acquisition devices, etc., and manually calculate various geometric parameters of the hollow optical fiber, such as the nested rings, ring thickness, and ring spacing; the other is to use computer image processing software to automatically calculate the geometric parameters of images for fixed features.

[0005] Both of the above methods suffer from low testing efficiency, poor test repeatability, and limited test types. Furthermore, during the development of hollow-core optical fibers, it is necessary to rapidly adjust the fiber's geometric parameters based on the simulation results of the process model. Multiple geometric parameters will dynamically change within a certain range in conjunction with the fiber process model, requiring frequent modifications to the test program. Traditional methods cannot meet these testing needs.

[0006] An existing technology discloses a method and system for testing optical fiber geometric parameters based on geometric templates. This approach still requires first acquiring images, then constructing a test template, and finally testing the sample. It mainly tests simple geometric parameters such as the core and cladding, which requires a high level of operator expertise. For complex process model optical fiber parameters (such as hollow rings, ring spacing, and ring thickness) that are subject to temporary testing and verification, the geometric template creation process is very inefficient. It cannot quickly respond to process model verification and exploration during the R&D testing phase, nor can it form a closed-loop iteration with process model simulation data. Summary of the Invention

[0007] The purpose of this invention is to provide a device and method for testing the geometric parameters of the hollow fiber end face, so as to achieve efficient verification of the hollow fiber process parameter model and improve the R&D efficiency of hollow fiber.

[0008] To solve the above technical problems, the present invention provides a device for testing the geometric parameters of the end face of hollow optical fiber, comprising:

[0009] Process parameter database; used to store and configure hollow fiber process parameter models, and to parse the hollow fiber process parameter models into first fiber end face geometric parameters;

[0010] Test unit; used to acquire end-face images of the hollow fiber sample under test;

[0011] The data acquisition and processing unit is used to analyze the end face image to obtain the geometric parameters of the second fiber end face, and to obtain the test results based on the geometric parameters of the first fiber end face and the geometric parameters of the second fiber end face.

[0012] According to the above scheme, the types of geometric parameters of the first fiber end face or the second fiber end face include outer cladding diameter, inner cladding diameter, number of nested ring groups, number of nested ring group levels, proportional relationship of each level of the nested ring group, nested ring group spacing, number of nested ring support blocks, and proportional relationship between nested ring support blocks and nested ring levels.

[0013] According to the above scheme, the test unit includes a light source, a test platform, and a camera; the light source is used to illuminate the hollow fiber sample, the test platform is used to adjust the pose of the hollow fiber sample, and the camera is used to acquire the end face image of the hollow fiber sample.

[0014] According to the above scheme, the test unit operates according to the preset closed-loop control logic, so that the clarity of the end face image meets the preset requirements.

[0015] According to the above scheme, the light source has adjustable light source direction, light emission pattern, and wavelength.

[0016] According to the above scheme, the light source direction includes coaxial light source, diffused backlight source, and direct light source at opposite ends; the light emission form includes point light source and surface light source; and the wavelength includes visible light band, infrared light band, and ultraviolet light band.

[0017] According to the above scheme, the testing unit and the process parameter database are all connected to the data acquisition and processing unit through a communication link; the communication link includes wired network and / or wireless network.

[0018] This invention also provides a method for testing the geometric parameters of the end face of a hollow optical fiber, comprising:

[0019] S1. The hollow fiber process parameter model is analyzed into the geometric parameters of the first fiber end face.

[0020] S2. Acquire an image of the end face of the hollow fiber sample to be tested;

[0021] S3. Analyze the end face image to obtain the geometric parameters of the second fiber end face, and obtain the test results based on the geometric parameters of the first fiber end face and the second fiber end face.

[0022] According to the above scheme, the steps include: S4, adjusting the hollow fiber process parameter model based on the test results, and repeating S1~S3 until the test results meet the preset requirements.

[0023] The present invention also provides a hollow optical fiber, which is obtained based on the hollow optical fiber end-face geometric parameter testing method described above.

[0024] The present invention also provides a hollow optical fiber cable, which is composed of the hollow optical fiber described above.

[0025] Beneficial effects

[0026] This invention establishes a process parameter database that can directly store and configure hollow-core fiber process parameter models. Simultaneously, it accurately resolves these models into the geometric parameters of the first fiber end face, eliminating the need for manual test template construction or frequent adjustments to test logic. This effectively adapts to the dynamic changes in process parameter models during hollow-core fiber R&D, solving the problem of traditional testing methods' inability to quickly respond to process model adjustments. The testing unit is specifically designed to acquire end-face images of the hollow-core fiber sample under test, providing an accurate image foundation for subsequent parameter analysis. Combined with the data acquisition and processing unit's end-face image analysis function, it can efficiently obtain the geometric parameters of the second fiber end face, avoiding the cumbersome operations associated with traditional manual calculations or fixed feature image algorithms. The data acquisition and processing unit obtains test results by comparing the geometric parameters of the first and second fiber end faces, establishing a direct correlation between the process parameter model and the actual sample test data. This allows for rapid comparison between theoretical parameters in the R&D design stage and actual parameters of the production sample, achieving efficient verification of the hollow fiber process parameter model. This significantly reduces the cycle of process model optimization and iteration, thereby significantly improving the R&D efficiency of hollow fiber. At the same time, it ensures that the test results can be directly fed back to the process design, connecting the R&D and testing stages and solving the pain points of low efficiency, poor repeatability, and difficulty in matching complex process model verification in traditional testing. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a hollow fiber end-face geometric parameter testing device according to an embodiment of the present invention;

[0028] Figure 2 This is a flowchart of a method for testing the geometric parameters of the end face of a hollow optical fiber according to an embodiment of the present invention;

[0029] Figure 3This is a schematic diagram of the end face of a hollow optical fiber without a support block according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the hollow fiber end face of the support block according to an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of a test unit according to an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the end face image analysis result according to an embodiment of the present invention.

[0033] In the figure: 1. Outer cladding; 2. Resonant ring; 201. Outer ring; 202. Middle ring; 203. Inner ring; 3. Support block; 4. Hollow fiber; 5. Test stage; 6. Camera; 7. Prism; 8. Lens; 9. Coaxial light source; 10. Dispersing backlight source; 11. Opposite end direct light source. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0035] See Figure 1 This embodiment provides a device for testing the geometric parameters of the end face of a hollow optical fiber, including:

[0036] Process parameter database; used to store and configure hollow fiber process parameter models, and to parse the hollow fiber process parameter models into first fiber end face geometric parameters;

[0037] Test unit; used to acquire end-face images of the hollow fiber sample 4 to be tested;

[0038] Data acquisition and processing unit; used to analyze the end-face image to obtain the geometric parameters of the second fiber end-face (see analysis results). Figure 6 The test results are obtained based on the geometric parameters of the first and second fiber end faces.

[0039] Specifically, the process parameter database is generally maintained and configured by R&D designers, and optimized and iterated based on the test results of the equipment.

[0040] Furthermore, the types of geometric parameters of the first or second fiber end face include the diameter of the outer cladding 1, the diameter of the inner cladding, the number of nested ring groups, the number of nested ring group levels, the proportional relationship of each level of the nested ring group, the spacing between nested ring groups, the number of nested ring support blocks 3, and the proportional relationship between the nested ring support blocks 3 and the nested ring levels.

[0041] For example, the theoretical parameters of a hollow-core optical fiber process parameter model to be tested are: outer cladding 1 diameter 225µm, cladding diameter 85µm, outer ring 201 diameter 30µm, middle ring 202 diameter 20µm, inner ring 203 diameter 8µm, and the number of nested ring groups is 5. The geometric parameters of the first fiber end face obtained from the analysis of this hollow-core optical fiber process parameter model are expressed in the following communication data format:

[0042]

[0043] In other embodiments of the present invention, the representation of the geometric parameters of the first fiber end face can be transformed, converting the original specific values ​​into ratios, for example: see Figure 3 A hollow fiber 4 has five sets of resonant rings 2, each set of resonant rings 2 has three nested rings. Some of the process parameters of this hollow fiber 4 are: outer cladding diameter 225 μm; inner cladding diameter 85 μm; number of nested rings 5 ​​sets, evenly distributed; number of nested ring layers 3, outer ring 201 diameter 30 μm, middle ring 202 diameter 20 μm, inner ring 203 diameter 8 μm; nested ring wall thickness 1 μm; no support block 3 structure. Converted to ratios, the geometric parameters of the first fiber end face are: D1=1; D2=0.377; N=5; θ=[0°,72°,144°,216°,288°]; n=3, Rn1=0.133, Rn2=0.088, Rn3=0.035, H=0.004; no support structure. Where D1 is the diameter of the outer cladding 1, D2 is the diameter of the inner cladding, N is the number of nested rings, θ represents the positional relationship of the nested rings (i.e., the distribution angle), n is the number of nested ring layers, Rn1, Rn2, and Rn3 are the diameters of the three nested rings respectively, and H is the wall thickness of the nested rings. For hollow fiber 4 with support block 3 (e.g. Figure 4 The hollow fiber 4 end face shown only shows one set of support blocks 3 for the resonant ring 2. The support blocks 3 are disposed between the resonant ring 2 and the outer cladding 1, and the support blocks 3 are symmetrically distributed with respect to the resonant ring 2 they support. n Indicates the sequence number of support block 3, n p P represents the number of support blocks 3 for each set of resonant rings 2. θThis represents the angle between each group of adjacent support blocks 3 and the center of the cladding. It should be understood that the specific geometric features of the support block 3, such as its layer position (the support block 3 can also be set between different nested rings inside the resonant ring 2), shape, and area, can be transformed by setting corresponding expression rules to obtain the corresponding geometric parameters. This will not be elaborated in this embodiment.

[0044] Further, see Figure 5 The testing unit includes a light source, a testing platform 5, and a camera. The light source is used to illuminate the hollow fiber 4 sample, the testing platform 5 is used to adjust the pose of the hollow fiber 4 sample, and the camera is used to acquire end face images of the hollow fiber 4 sample.

[0045] Specifically, the camera includes a camera 6 and a lens 8, which can switch according to the light source. The test stage 5 can translate along the X, Y, and Z axes and rotate around the X, Y, and Z axes. Through precise control of the pose of the hollow fiber 4 sample, automatic focusing and clear imaging of the end face of the hollow fiber 4 sample can be achieved.

[0046] Furthermore, the test unit operates according to the preset closed-loop control logic to ensure that the clarity of the end face image meets the preset requirements.

[0047] Specifically, the closed-loop control logic can be deployed in the data acquisition and processing unit. When the data acquisition and processing unit analyzes the end-face image, it can identify and locate the geometric features in the end-face image by referring to the first fiber end-face geometric parameters. When analyzing the second fiber end-face geometric parameters, the outer diameter and positional relationship of the cladding are first calculated, and the position and size data between the cladding and the nested ring are calculated and accurately located according to the geometric parameters.

[0048] Furthermore, the light source has adjustable light source direction, light emission pattern, and wavelength.

[0049] Furthermore, the light source direction includes a coaxial light source 9, a diffused backlight source 10, and a direct light source at the opposite end 11; the light emission form includes a point light source and a surface light source; and the wavelength includes the visible light band, the infrared light band, and the ultraviolet light band.

[0050] Specifically, the camera 6 and the lens 8 are connected by a coaxial lens barrel. A prism 7 is installed inside the coaxial lens barrel, and an opening is provided on the side wall of the lens barrel. The light emitted from the coaxial light source 9 enters the lens barrel through the opening and is then reflected by the prism 7 and illuminates the hollow fiber 4. The scattering backlight 10 is ring-shaped and is located at one end of the lens 8. The opposite end direct light source 11 is located at one end of the hollow fiber 4.

[0051] The light source adjustment is designed to be compatible with various types of fiber optic samples. For example, for conventional single-mode / multimode fibers, the core layer can be tested using the direct-end light source 11, while the cladding can be tested using the backlight source. For large-core specialty fibers, the core and cladding can be tested simultaneously using the direct-end light source 11. The internal structure of hollow-core fibers 4 can be tested using coaxial light. It is understood that this device is not limited to testing hollow-core fibers 4.

[0052] Furthermore, the testing unit and process parameter database are all connected to the data acquisition and processing unit via communication links; the communication links include wired networks and / or wireless networks.

[0053] In this embodiment, the wired network adopts the Industrial Ethernet protocol, and the device interface type is an RJ45 Ethernet interface; the wireless network adopts a WIFI / GPIB conversion interface, executes the SCPI standardized ASCII command set, and is used for the communication and control of this device. It is understood that other communication methods can also be used. In this embodiment, a wired network or a wireless network can be used alone, or a wired network and a wireless network can be used in combination. When selecting a specific communication method, the real-time performance, transmission bandwidth, reliability, and stability of data transmission must be considered simultaneously.

[0054] See Figure 2 The present invention also provides a method for testing the geometric parameters of the end face of a hollow optical fiber, comprising:

[0055] S1. The hollow fiber process parameter model is analyzed into the geometric parameters of the first fiber end face.

[0056] S2. Acquire end-face images of the hollow fiber sample 4 to be tested;

[0057] S3. Analyze the end face image to obtain the geometric parameters of the second fiber end face, and obtain the test results based on the geometric parameters of the first fiber end face and the second fiber end face.

[0058] Further steps include: S4, adjusting the hollow fiber process parameter model based on the test results, and repeating S1~S3 until the test results meet the preset requirements.

[0059] It is understood that the test results can also be transmitted to other systems or devices (such as optical fiber R&D simulation systems, optical fiber drawing real-time online adjustment systems, etc.), and the corresponding systems or devices can provide feedback or make adjustments as needed; the test results can also be transmitted to the process parameter database for further summarization and analysis. The adjustment in step S4 is a manual operation, and in other embodiments of the present invention, it can also be adjusted through preset control logic.

[0060] This embodiment also provides a hollow optical fiber, which is obtained based on the hollow optical fiber end-face geometric parameter testing method described above.

[0061] This embodiment also provides a hollow optical fiber cable, which is composed of the hollow optical fiber 4 described above.

[0062] The application areas of this invention include:

[0063] 1) Hollow-core fiber testing; used for production testing and measurement of the geometric parameters of the end face of hollow-core anti-resonant optical fibers;

[0064] 2) Fiber Optic Process Research: Used for research, comparison, and rapid iteration between fiber optic design process parameters and actual production sample parameters during the fiber optic R&D and design phase;

[0065] 3) Optical fiber production and manufacturing: When dynamically adjusting optical fiber process parameters during the hollow optical fiber drawing process, it can quickly detect the geometric structure parameters of the optical fiber, provide real-time feedback on the execution status of the optical fiber drawing process, and ensure the timeliness of the optical fiber drawing process adjustment.

[0066] Potential application areas may include:

[0067] 1) Geometric parameter detection of the end face geometry of optical fiber related materials such as optical fiber preforms and optical fiber rod intermediates;

[0068] 2) Optical cable production: Used for rapid detection of optical fiber end-face geometric parameters during the optical cable production process;

[0069] 3) Materials field: Used for rapid detection of end-face geometric parameters of new transparent media such as quartz tube materials and plastic tube materials.

[0070] The beneficial effects of this invention include: using the hollow fiber process parameter model, the model data of the hollow fiber process parameter model is converted into optical fiber end face geometric parameters for testing, so as to adapt to the rapid response between process parameter research and development and testing, and can quickly respond to the adaptation of test device parameters caused by process parameter adjustment. It is simple to operate and can connect the research and development process design and production product testing links to achieve rapid research and development and production iteration.

[0071] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0072] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is 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 scope of protection of the present invention.

Claims

1. A device for testing the geometric parameters of the end face of a hollow optical fiber, characterized in that, include: Process parameter database; Used to store and configure hollow fiber process parameter models, and to resolve hollow fiber process parameter models into first fiber end face geometric parameters; Test unit; Used to acquire end-face images of the hollow fiber sample to be tested; The data acquisition and processing unit is used to analyze the end face image to obtain the geometric parameters of the second fiber end face, and to obtain the test results based on the geometric parameters of the first and second fiber end faces, and to adjust the hollow fiber process parameter model based on the test results.

2. The device for testing the geometric parameters of the hollow fiber end face according to claim 1, characterized in that, The types of geometric parameters of the first or second fiber end face include outer cladding diameter, inner cladding diameter, number of nested ring groups, number of nested ring group levels, proportional relationship of each level in the nested ring group, nested ring group spacing, number of nested ring support blocks, and proportional relationship between nested ring support blocks and nested ring levels.

3. The device for testing the geometric parameters of the hollow fiber end face according to claim 1, characterized in that, The testing unit includes a light source, a testing platform, and a camera; the light source is used to illuminate the hollow fiber sample, the testing platform is used to adjust the pose of the hollow fiber sample, and the camera is used to acquire end-face images of the hollow fiber sample.

4. The device for testing the geometric parameters of the hollow fiber end face according to claim 1 or 3, characterized in that, The test unit operates according to the preset closed-loop control logic to ensure that the clarity of the end face image meets the preset requirements.

5. The device for testing the geometric parameters of the hollow fiber end face according to claim 3, characterized in that, The light source has adjustable light source direction, light emission pattern, and wavelength.

6. The device for testing the geometric parameters of the hollow fiber end face according to claim 5, characterized in that, The light source direction includes coaxial light source, diffused backlight source, and direct light source at opposite ends; the light emission form includes point light source and surface light source; the wavelength includes visible light band, infrared light band, and ultraviolet light band.

7. The device for testing the geometric parameters of the hollow fiber end face according to claim 1, characterized in that, The testing unit and process parameter database are all connected to the data acquisition and processing unit via communication links; the communication links include wired networks and / or wireless networks.

8. A method for testing the geometric parameters of the end face of a hollow optical fiber, characterized in that, include: S1. The hollow fiber process parameter model is analyzed into the geometric parameters of the first fiber end face. S2. Acquire an image of the end face of the hollow fiber sample to be tested; S3. Analyze the end face image to obtain the geometric parameters of the second fiber end face, and obtain the test results based on the geometric parameters of the first fiber end face and the second fiber end face. S4. Adjust the hollow fiber process parameter model according to the test results, and repeat S1~S3 until the test results meet the preset requirements.

Images