A highly repeatable hollow fiber warpage testing system

Abstract

This invention discloses a highly repeatable hollow fiber warpage testing system, relating to the field of hollow fiber warpage testing technology. A clamping assembly is used to hold and fix the hollow fiber; a rotating assembly is used to drive the image acquisition unit to rotate; the image acquisition unit is used to acquire images of different positions on the hollow fiber; an information processing unit is used to drive the rotating assembly to rotate the image acquisition unit, control the clamping assembly to adjust the fiber segment to be observed, and control the brightness of the light source in the image acquisition unit; a hollow fiber warpage calculation unit is used to correct the coaxiality of the hollow fiber axis with the rotating assembly platform, find the maximum value of the fiber offset axis through images of different positions on the hollow fiber, extract the offset values ​​of several positions on the image with the maximum offset, fit circles to each position, and calculate the average value to obtain the warpage value. This invention uses a fixed fiber rotating camera and light source method to improve testing accuracy, and optimizes the warpage value calculation to obtain a more accurate warpage value.

Description

Technical Field

[0001] This invention relates to the field of hollow fiber warpage testing technology, and specifically to a highly repeatable hollow fiber warpage testing system. Background Technology

[0002] Hollow-core fiber (HCF) exhibits significant advantages in low latency, electromagnetic interference resistance, and nonlinear effect suppression due to its unique air-guided structure, making it particularly suitable for high-speed communication, quantum transmission, and high-power laser systems. However, the deployment and splicing of HCF typically require a fusion splicer. The warpage parameter of the fiber significantly affects the optical performance of the splice, leading to increased connection loss. To ensure that the transmission performance after fiber splicing meets communication system standards (such as ITU-T G.652 / G.657), the warpage value of the uncoated fiber must be precisely measured and controlled to optimize the splicing process and reduce loss.

[0003] While existing testing standards provide test methods and equipment configurations, they only apply to standard optical fiber testing and are not suitable for hollow-core optical fibers. Furthermore, testing typically involves rotating the fiber, which, due to the fiber's own inertia and the gap in the clamping fixture, affects the warp value, leading to inaccurate testing. Summary of the Invention

[0004] This invention provides a highly repeatable hollow optical fiber warpage testing system. It employs a method of fixing the optical fiber and rotating the camera and light source to improve testing accuracy. At the same time, it calibrates the optical fiber axis to be coaxial with the hollow rotating platform, finds the maximum value of the optical fiber offset axis, optimizes the warpage value calculation, and obtains a more accurate warpage value.

[0005] This invention provides a highly repeatable hollow fiber warpage testing system, comprising: a clamping assembly, a rotating assembly, an image acquisition unit, an information processing unit, and a hollow fiber warpage calculation unit;

[0006] The clamping assembly is used to clamp and fix the hollow optical fiber;

[0007] The rotating component is used to drive the image acquisition unit to rotate;

[0008] The image acquisition unit is used to acquire images of different positions of the hollow optical fiber;

[0009] The information processing unit is used to drive the rotating component to rotate the image acquisition unit, control the clamping component to adjust the fiber segment to be observed in the hollow fiber, and control the brightness of the light source in the image acquisition unit.

[0010] The hollow fiber warpage calculation unit is used to correct the coaxiality of the hollow fiber axis with the rotating component platform. It finds the maximum value of the fiber offset axis by using images of different positions of the hollow fiber. It extracts the offset values ​​of several positions on the image with the maximum offset, fits circles to each position, and calculates the average value to obtain the warpage value.

[0011] In some instances, the clamping assembly includes a three-jaw clamp, a fixed axis, and an electrically driven three-dimensional displacement stage;

[0012] The hollow optical fiber is fixed on the electric three-dimensional displacement stage, and the electric three-dimensional displacement stage drives the hollow optical fiber to move vertically up and down.

[0013] The clamp is finely adjusted by turning the micrometer threaded pair to adjust the gap between the three jaws in a preset step to match hollow optical fibers with different outer diameters.

[0014] The fixed axis is fixed to the electric three-dimensional displacement stage and is used to support the fixture and hollow optical fiber for XYZ three-dimensional movement.

[0015] In some instances, the rotating assembly includes a stepper motor, a gear train, and a hollow fixed frame;

[0016] The stepper motor provides power to drive the image acquisition unit to rotate;

[0017] The gear train transmits power to the stepper motor. The hollow fixed frame fixes the gear train, the stepper motor, and the image acquisition unit, allowing the fixed shaft to pass through the middle. The hollow optical fiber is fixed to the fixed shaft and is in a stationary state.

[0018] In some instances, the information processing unit includes a stepper motor control module, a light source brightness control module, and a network information acquisition module;

[0019] The stepper motor control module is used to drive the rotating component to rotate, thereby rotating the image acquisition unit to acquire image information, and to control the electric three-dimensional displacement stage to adjust the fiber optic segment to be observed.

[0020] The light source brightness control module controls the brightness of the light source in the image acquisition unit by controlling the current output at multiple levels.

[0021] The network information acquisition module is used to receive hollow optical fiber image information acquired by the image acquisition unit.

[0022] In some instances, the hollow fiber warpage calculation unit includes: a camera calibration module;

[0023] The camera calibration module is used to initially adjust the metal calibration rod to be concentric with the hollow fixed frame after it is installed on the fixed axis, rotate the image acquisition unit to acquire images of the metal calibration rod, acquire images of the metal calibration rod every time it rotates by a first preset angle to record the axis position of the metal calibration rod, analyze the maximum offset and offset position of the metal calibration rod after one rotation, adjust the metal calibration rod to the axis of the hollow fixed frame by the electric three-dimensional displacement stage, and continue to rotate and acquire images of the metal calibration rod until the offset of the metal calibration rod is less than a preset offset threshold, and then calibrate the position of the metal calibration rod.

[0024] In some instances, the hollow fiber warpage calculation unit further includes a free overhang length determination module;

[0025] The free overhang length determination module is used to determine the position of the distinguishable fiber offset center as the position of the acquired image when the hollow fiber falls from above and the image acquisition unit rotates to acquire the hollow fiber image. If the entire fiber is not distinguishable, the fiber length needs to be increased to determine the free overhang length of the hollow fiber of this specification.

[0026] In some instances, the hollow fiber warpage calculation unit further includes: a maximum offset position determination module;

[0027] The maximum offset position determination module is used to record the position of the offset axis of the hollow fiber by the hollow fiber image acquired by the image acquisition unit every time it rotates by a second preset angle, take the target image of the maximum position of the offset axis of the hollow fiber, find the position of the maximum offset value from the target image, and rotate back and forth by a second preset angle at the maximum offset position to find the true maximum offset position.

[0028] In some instances, the hollow fiber warpage calculation unit further includes: a fiber warpage value calculation submodule;

[0029] The fiber warpage calculation submodule is used to take several measurement points on the hollow fiber on the image corresponding to the true maximum offset position. Each measurement point corresponds to a cross section at a different length position of the hollow fiber. The offset value of the offset axis of each point is extracted, and the average value of the radius of the fitted circle is obtained as the hollow fiber warpage value after fitting a circle.

[0030] In some instances, the measurement points are spaced at equal intervals.

[0031] In some instances, the gap adjustment step accuracy of the three-jaw clamp is 1µm, which can match hollow optical fibers with different outer diameters.

[0032] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0033] This invention employs a method of fixing the optical fiber and rotating the camera and light source to improve testing accuracy. At the same time, it calibrates the optical fiber axis to be coaxial with the hollow rotating platform, finds the maximum value of the optical fiber offset axis, optimizes the warp value calculation, and obtains a more accurate warp value. Attached Figure Description

[0034] 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 accompanying 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.

[0035] Figure 1 This is a schematic diagram of the structure of the testing system provided in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the testing process provided in an embodiment of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the following description, specific embodiments of the invention will be illustrated with reference to steps and symbols performed by one or more computers, unless otherwise stated. Therefore, these steps and operations will be referred to several times as being performed by a computer, and computer execution as referred to herein includes operations by a computer processing unit representing electronic signals of data in a structured format. This operation transforms the data or maintains it at a location in the computer's memory system, which can be reconfigured or otherwise alter the operation of the computer in a manner well known to those skilled in the art. The data structure maintained by the data is the physical location of the memory, which has specific characteristics defined by the data format. However, the principles of the invention described above are not intended to be limiting, and those skilled in the art will understand that many of the following steps and operations can also be implemented in hardware.

[0039] The terms "module" or "unit" as used herein can be considered as software objects executing on the computing system. Different components, modules, engines, and services described herein can be considered as implementations on the computing system. The apparatus and methods described herein are preferably implemented in software, but can also be implemented in hardware, both of which are within the scope of this invention.

[0040] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0041] In this embodiment of the invention, a highly repeatable hollow fiber warpage testing system is provided, such as... Figure 1 As shown, it includes: a clamping assembly, a rotating assembly, an image acquisition unit, an information processing unit, and a hollow fiber warp calculation unit;

[0042] The aforementioned clamping assembly is used to clamp and fix hollow optical fibers;

[0043] The aforementioned rotating component is used to drive the aforementioned image acquisition unit to rotate;

[0044] The aforementioned image acquisition unit is used to acquire images of different locations on the hollow optical fiber;

[0045] The aforementioned information processing unit is used to drive the aforementioned rotating component to rotate the aforementioned image acquisition unit, control the aforementioned clamping component to adjust the fiber segment of the hollow fiber to be observed, and control the brightness of the light source in the aforementioned image acquisition unit.

[0046] The hollow fiber warpage calculation unit is used to correct the coaxiality of the hollow fiber axis with the rotating component platform. It finds the maximum value of the fiber offset axis by using images of different positions of the hollow fiber. It extracts the offset values ​​of several positions on the image with the maximum offset, fits circles to each position, and calculates the average value to obtain the warpage value.

[0047] In a preferred embodiment, the clamping assembly includes a three-jaw clamp, a fixed axis, and an electric three-dimensional displacement stage;

[0048] The hollow optical fiber is fixed on the aforementioned electric three-dimensional displacement stage, and the aforementioned electric three-dimensional displacement stage drives the hollow optical fiber to move vertically up and down.

[0049] The aforementioned clamp is finely adjusted by turning the micrometer threaded pair to adjust the gap between the three jaws in a preset step to match hollow optical fibers with different outer diameters;

[0050] The aforementioned fixed axis is fixed on the aforementioned electric three-dimensional displacement stage, and is used to support the aforementioned fixture and hollow optical fiber for XYZ three-dimensional movement.

[0051] In a preferred embodiment, the rotating assembly includes a stepper motor, a gear train, and a hollow fixed frame;

[0052] The aforementioned stepper motor provides power to drive the aforementioned image acquisition unit to rotate;

[0053] The aforementioned gear system transmits power to the aforementioned stepper motor. The aforementioned hollow fixed frame fixes the aforementioned gear system, the aforementioned stepper motor, and the aforementioned image acquisition unit, allowing the aforementioned fixed shaft to pass through the middle. The hollow optical fiber is fixed to the aforementioned fixed shaft and is in a stationary state.

[0054] In a preferred embodiment, the information processing unit includes a stepper motor control module, a light source brightness control module, and a network information acquisition module;

[0055] The aforementioned stepper motor control module is used to drive the aforementioned rotating component to rotate, thereby causing the aforementioned image acquisition unit to rotate and acquire image information, and to control the aforementioned electric three-dimensional displacement stage to adjust the fiber optic segment to be observed.

[0056] The aforementioned light source brightness control module controls the brightness of the light source in the aforementioned image acquisition unit by controlling the current output at multiple levels.

[0057] The aforementioned network information acquisition module is used to receive hollow fiber image information acquired by the aforementioned image acquisition unit.

[0058] In a preferred embodiment, the hollow fiber warpage calculation unit described above can be installed in an industrial control computer, and includes: a camera calibration module;

[0059] The aforementioned camera calibration module is used to initially adjust the metal calibration rod to be concentric with the hollow fixed frame after it is installed on the fixed axis. The rotating image acquisition unit acquires images of the metal calibration rod. After each first preset angle of rotation, images of the metal calibration rod are acquired to record the axis position of the metal calibration rod. After one rotation, the maximum offset and offset position of the metal calibration rod are analyzed. The metal calibration rod is adjusted to the axis of the hollow fixed frame by an electric three-dimensional displacement stage. The rotation continues to acquire images of the metal calibration rod until the offset of the metal calibration rod is less than a preset offset threshold, thus calibrating the position of the metal calibration rod.

[0060] In a preferred embodiment, the hollow fiber warpage calculation unit further includes: a free overhang length determination module;

[0061] The aforementioned free overhang length determination module is used to determine the position of the distinguishable fiber offset center as the position of the acquired image when the hollow fiber falls from above and the image acquisition unit rotates to acquire the hollow fiber image. If the entire fiber is not distinguishable, the fiber length needs to be increased to determine the free overhang length of the hollow fiber of this specification.

[0062] In a preferred embodiment, the hollow fiber warpage calculation unit further includes: a maximum offset position determination module;

[0063] The aforementioned maximum offset position determination module is used to record the position of the hollow fiber offset axis by the hollow fiber image acquired by the image acquisition unit every second preset angle, take the target image of the maximum position of the hollow fiber offset axis, find the position of the maximum offset value from the target image, and rotate back and forth at the maximum offset position by a second preset angle to find the true maximum offset position.

[0064] The size of the first preset angle and the second preset angle can be determined according to actual needs, and the embodiments of the present invention are not limited to uniqueness.

[0065] In a preferred embodiment, the hollow fiber warpage calculation unit further includes: a fiber warpage value calculation submodule;

[0066] The aforementioned fiber warpage calculation submodule is used to take several measurement points on the hollow fiber on the image corresponding to the true maximum offset position. Each measurement point corresponds to a cross-section at a different length position of the hollow fiber. The offset value of the offset axis of each point is extracted, and the average value of the radius of the fitted circle is obtained as the hollow fiber warpage value after fitting a circle.

[0067] As a preferred implementation, the measurement points are spaced equally apart.

[0068] As a preferred embodiment, the gap adjustment step accuracy of the three-jaw clamp is 1µm, which can match hollow optical fibers with different outer diameters.

[0069] The embodiments of the present invention employ a method of fixing the optical fiber and rotating the camera and light source to improve the accuracy of the test. At the same time, the optical fiber axis is aligned with the hollow rotating platform to find the maximum value of the optical fiber offset axis, and the warp value calculation is optimized to obtain a more accurate warp value.

[0070] In another embodiment of the present invention, a highly repeatable hollow fiber warpage testing system is provided, such as... Figure 1 As shown, it includes a clamping assembly, a rotating assembly, an image acquisition unit, and an information processing unit;

[0071] The clamping assembly's main function is to hold and fix the optical fiber on the motorized 3D translation stage, facilitating subsequent adjustments to the distance between the fiber and the camera for focusing. It also moves the fiber vertically up and down to select the observation position. The assembly includes a three-jaw clamp, a fixed axis, and a motorized 3D translation stage.

[0072] The clamp is finely adjusted by turning the three jaws through the micrometer threaded joint, which can be adjusted in 1µm steps. It can match hollow optical fibers with different outer diameters, clamp the optical fiber tightly, and minimize the impact of the rotation gap on the warp test. It can test the warp value of various optical fibers with different core diameters. The three jaws can be metal, and the inner surface of the three jaws is coated with soft silicone.

[0073] The fixed axis is fixed on the electric three-dimensional displacement stage, supporting the three-jaw clamp and optical fiber, and can move in the XYZ three dimensions.

[0074] The rotating assembly comprises a stepper motor, a gear train, and a hollow fixed frame. The stepper motor provides power, driving the image acquisition unit to rotate precisely. The stepper motor is a semi-closed-loop control motor with an internal encoder; the rotational position is fed back to the driver, which adjusts and monitors the actual rotation angle in real time to ensure accuracy. The gear train precisely transmits the motor's power, offering higher efficiency and precision compared to other transmission methods. The hollow fixed frame acts as a fixed carrier, securing the gear train, motor, and image acquisition unit. A fixed shaft passes through the center, and the optical fiber is fixed to the fixed shaft, maintaining a stationary state.

[0075] The image acquisition unit includes a camera, a depth-of-field lens, and a light source. It enables the camera to focus images and observe different positions on the optical fiber.

[0076] The information processing unit integrates various functional modules into a single control board, with a microcontroller as the control center. It includes a stepper motor control module, a light source brightness control module, and a network information acquisition module. The stepper motor control module uses a control chip to drive a rotating component for precise rotation, which in turn drives the image acquisition unit to rotate and acquire image information. The driver sends pulses to the stepper motor, causing it to rotate. The encoder records the actual rotation angle of the motor and compares it with the driver's commands. If the motor rotates too little, the driver sends pulses to compensate; if it rotates too much, it reverses, achieving a closed-loop response for stepper motor motion control and position, enabling precise control and feedback of angle and position. It can also control the motor of the 3D displacement stage to move the optical fiber vertically to adjust the desired optical fiber segment and focus on that segment. The light source brightness control module controls the brightness of the light source through multi-level current output control, with an initial current accuracy of up to 0.5%, ensuring the stability of the light source output. The network information acquisition module ensures communication with the industrial control computer, enabling information exchange between the control board and the industrial control computer (including controlling motor speed, rotation angle, image information, and light source brightness control). The camera captures image information and transmits it to the industrial control computer. The industrial control computer then sends the motor control signal to the motor control chip, and the light source brightness control signal is transmitted to the motor control chip.

[0077] like Figure 2 The test process shown includes:

[0078] 1) Install the metal calibration rod (the metal calibration rod serves to calibrate and correct the equipment; it is screwed onto the fixed shaft via threads and rotated to calibrate concentricity). Initially, manually adjust the metal calibration rod to be concentric with the hollow fixed frame. Rotate the image acquisition unit to acquire images of the metal calibration rod. Every 10 degrees of rotation (not limited to 10 degrees, which can be determined according to actual needs), acquire images of the metal calibration rod and record the position of the metal calibration rod's axis. After one rotation, analyze the maximum offset of the metal calibration rod (i.e., the offset from the central axis) and its offset position. Adjust the metal calibration rod to the axis of the hollow fixed frame using an electric three-dimensional displacement stage, and continue to rotate and acquire images until the offset of the metal calibration rod is very small. At this point, the camera calibrates the position of the metal calibration rod.

[0079] 2) Cut a fixed length of optical fiber, rotate the three-jaw clamp, and clamp the optical fiber.

[0080] 3) The camera's autofocus makes the observed image clear.

[0081] 4) Determine a suitable observation position. The motor drives the image acquisition unit to rotate around the optical fiber, which then descends from top to bottom to acquire images until the center of the fiber offset can be distinguished. This position is used as the image acquisition location. If the entire fiber cannot be distinguished, the fiber length needs to be increased. If the fiber is too long, it needs to be cut and repositioned to determine the appropriate free hang length for this uniform specification of optical fiber. Subsequent tests with the same type of optical fiber do not need to repeat these steps; the length is set to a fixed value.

[0082] 5) Rotate the camera and light source to obtain the optical fiber offset axis position. Acquire an image every 18° rotation, and after two rotations, record the position of the hollow fiber offset axis. Take the image at the position of maximum offset. When the maximum offset position is found, use an algorithm to rotate 18° forward and backward from this position to find the true maximum offset position. This embodiment of the invention acquires more images, resulting in more accurate judgment. Then, take three points equidistantly along the vertical direction of the optical fiber in the image corresponding to the true maximum offset position. Analyze the distances of the three points from the offset axis, successively fit warp circles, and finally calculate the average radius of the three fitted circles.

[0083] In this embodiment of the invention, the algorithm can rotate the maximum offset position by 18° forward and backward in the following way:

[0084] If you rotate 18° at a time, you might miss the maximum offset position. You can take an image every 3° forward from the maximum offset position, for a total of 6 rotations; and take an image every 3° backward, for a total of 6 rotations. Refine the rotation angle to get closer to the position with the maximum offset. Of course, the rotation angle is not limited to 3°, and the rotation angle for each rotation is not limited to 18°.

[0085] 6) Calculate the fiber warpage value.

[0086] Compared with the prior art, the embodiments of the present invention, through the above technical solutions, have the following beneficial effects:

[0087] 1) Existing testing methods acquire images by rotating the optical fiber and fixing the camera light source: The present invention acquires images by fixing the optical fiber and rotating the image acquisition unit, thus avoiding the influence of the optical fiber's own inertia and the gap between the optical fiber and the fixture on the warping value.

[0088] 2) Existing testing methods do not mention the specific clamping structure: The embodiments of this invention design a three-jaw clamp. The clamp is finely adjusted by turning the screw thread of the clamp, which can match hollow optical fibers with different outer diameters, clamp the optical fibers tightly, and minimize the influence of the rotation gap on the warp test. It can test the warp value of various optical fibers with different core diameters.

[0089] 3) Existing testing methods require uncoated optical fibers to pass through the rotating assembly, and the standard requires them to pass through the sleeve, which makes the optical fibers prone to breakage: Uncoated hollow optical fibers have low plasticity and are more prone to breakage than conventional optical fibers during loading. In this embodiment of the invention, the optical fibers are directly clamped by a three-jaw clamp, avoiding the insertion of uncoated optical fibers into small holes during operation and thus preventing fiber breakage.

[0090] 4) Existing testing standards stipulate that free end overhang lengths of 10-20mm are not applicable to hollow-core optical fibers: In this embodiment of the invention, the rotating component adds a three-axis motorized displacement stage, which can raise and lower the optical fiber. The camera can observe the offset of the optical fiber at different positions, balancing the influence of camera resolution and the fiber's own gravity to determine the most suitable free overhang length for the hollow-core optical fiber. It is not limited by existing standards and can be matched with various types of optical fibers. The free length is matched only once for the same specification of hollow-core optical fiber.

[0091] 5) Currently, when searching for the maximum offset of an optical fiber, the optical fiber is rotated at a fixed angle, and the position of the optical fiber offset axis is collected at different angles after rotating one revolution. In this embodiment of the invention, the optical fiber is rotated 18° each time, and two revolutions are performed to record the position of the offset axis. When the position of the maximum offset value is found, the optical fiber is rotated 18° before and after the position of the maximum offset value to find the true maximum offset position. This embodiment of the invention collects more images and makes the judgment more accurate.

[0092] 6) Standard fitting evaluation, extracting the warp value of the maximum offset at only one point: In this embodiment of the invention, the maximum offset fitting circle at different points is extracted from the image of the maximum offset, and then the average value is calculated to more accurately calculate the warp value.

[0093] 7) Other optimizations: The embodiment of the present invention uses a depth-of-field lens barrel, and the depth-of-field distance covers the offset when the optical fiber rotates. After the focus is set, the focus does not need to be adjusted in real time when the image acquisition system rotates, thus speeding up the calculation speed.

[0094] The above provides a detailed description of a highly repeatable hollow fiber warping test system provided by the embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A highly repeatable hollow fiber warpage testing system, characterized in that, include: Clamping assembly, rotation assembly, image acquisition unit, information processing unit, and hollow fiber warp calculation unit; The clamping assembly is used to clamp and fix the hollow optical fiber; The rotating component is used to drive the image acquisition unit to rotate; The image acquisition unit is used to acquire images of different positions of the hollow optical fiber; The information processing unit is used to drive the rotating component to rotate the image acquisition unit, control the clamping component to adjust the fiber segment to be observed in the hollow fiber, and control the brightness of the light source in the image acquisition unit. The hollow fiber warpage calculation unit is used to correct the coaxiality of the hollow fiber axis with the rotating component platform. It finds the maximum value of the fiber offset axis by using images of different positions of the hollow fiber, extracts the offset values ​​of several positions on the image with the maximum offset, fits circles to each position, and calculates the average value to obtain the warpage value.

2. The testing system according to claim 1, characterized in that, The clamping assembly includes a three-jaw clamp, a fixed axis, and an electric three-dimensional displacement stage; The hollow optical fiber is fixed on the electric three-dimensional displacement stage, and the electric three-dimensional displacement stage drives the hollow optical fiber to move vertically up and down. The clamp is finely adjusted by turning the micrometer threaded pair to adjust the gap between the three jaws in a preset step to match hollow optical fibers with different outer diameters. The fixed axis is fixed to the electric three-dimensional displacement stage and is used to support the fixture and hollow optical fiber for XYZ three-dimensional movement.

3. The testing system according to claim 2, characterized in that, The rotating assembly includes a stepper motor, a gear system, and a hollow fixed frame; The stepper motor provides power to drive the image acquisition unit to rotate; The gear train transmits power to the stepper motor. The hollow fixed frame fixes the gear train, the stepper motor, and the image acquisition unit, allowing the fixed shaft to pass through the middle. The hollow optical fiber is fixed to the fixed shaft and is in a stationary state.

4. The testing system according to claim 3, characterized in that, The information processing unit includes a stepper motor control module, a light source brightness control module, and a network information acquisition module; The stepper motor control module is used to drive the rotating component to rotate, thereby rotating the image acquisition unit to acquire image information, and to control the electric three-dimensional displacement stage to adjust the fiber optic segment to be observed. The light source brightness control module controls the brightness of the light source in the image acquisition unit by controlling the current output at multiple levels. The network information acquisition module is used to receive hollow optical fiber image information acquired by the image acquisition unit.

5. The testing system according to claim 4, characterized in that, The hollow fiber warpage calculation unit includes: a camera calibration module; The camera calibration module is used to initially adjust the metal calibration rod to be concentric with the hollow fixed frame after it is installed on the fixed axis, rotate the image acquisition unit to acquire images of the metal calibration rod, acquire images of the metal calibration rod every time it rotates by a first preset angle to record the axis position of the metal calibration rod, analyze the maximum offset and offset position of the metal calibration rod after one rotation, adjust the metal calibration rod to the axis of the hollow fixed frame by the electric three-dimensional displacement stage, and continue to rotate and acquire images of the metal calibration rod until the offset of the metal calibration rod is less than a preset offset threshold, and then calibrate the position of the metal calibration rod.

6. The testing system according to claim 5, characterized in that, The hollow fiber warpage calculation unit also includes: a free overhang length determination module; The free overhang length determination module is used to determine the position of the distinguishable fiber offset center as the position of the image acquisition by the acquired hollow fiber image when the hollow fiber falls from above and the image acquisition unit rotates to acquire the hollow fiber image. If the entire fiber is not distinguishable, the fiber length needs to be increased to determine the free overhang length of the hollow fiber.

7. The testing system according to claim 6, characterized in that, The hollow fiber warpage calculation unit also includes: a maximum offset position determination module; The maximum offset position determination module is used to record the position of the offset axis of the hollow fiber by the hollow fiber image acquired by the image acquisition unit every time it rotates by a second preset angle, take the target image of the maximum position of the offset axis of the hollow fiber, find the position of the maximum offset value from the target image, and rotate back and forth by a second preset angle at the maximum offset position to find the true maximum offset position.

8. The testing system according to claim 7, characterized in that, The hollow fiber warpage calculation unit also includes: a fiber warpage value calculation submodule; The fiber warpage calculation submodule is used to take several measurement points on the hollow fiber on the image corresponding to the true maximum offset position. Each measurement point corresponds to a cross section at a different length position of the hollow fiber. The offset value of the offset axis of each point is extracted, and the average value of the radius of the fitted circle is obtained as the hollow fiber warpage value after fitting a circle.

9. The testing system according to claim 8, characterized in that, The measurement points are spaced at equal intervals.

10. The testing system according to claim 2, characterized in that, The gap adjustment step accuracy of the three-jaw clamp is 1µm, which can match hollow optical fibers with different outer diameters.

Images