A polarization maintaining optical fiber cat-eye deflection angle measurement method, device, equipment and medium

Abstract

The present application relates to a kind of polarization maintaining optical fiber cat eye deflection angle measurement method, device, equipment and medium, comprising the following steps: obtaining imaging clear polarization maintaining optical fiber end surface image;Obtain the first center of two large circle outer contour lines, and connect the straight line of two first center, form test reference line;Obtain the second center of two small circle outer contour lines, and connect the straight line of two second center, form test reference line;According to the included angle formed by test reference line and test reference line, the deflection angle of cat eye is calculated;High measurement accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optoelectronics, and more particularly to a polarization maintaining optical fiber cat eye deflection angle measurement method, device, equipment and medium. BACKGROUND

[0002] In the actual production process of conventional optical fibers, the optical fibers are often subjected to external forces and other reasons, and the thickness of the optical fibers is uneven or curved, which causes birefringence. When the optical fiber is subjected to any external interference, such as wavelength, bending degree, temperature and other influencing factors, the polarization state of light becomes chaotic when the light is transmitted in the conventional optical fiber. Therefore, polarization maintaining optical fibers appear on the market to solve the problem of change of polarization state, but it does not eliminate the birefringence in the optical fiber, but through the design of the geometric size of the optical fiber, a stronger birefringence is generated to eliminate the influence of stress on the polarization state of the incident light, as shown in Figure 1 .

[0003] The polarization maintaining optical fiber transmits polarized light, which is used in optical fiber sensors based on optical coherent detection to achieve high-precision measurement of physical quantities, and is the core raw material for producing optical fiber gyroscopes (inertial guidance systems) and optical fiber hydrophones (sonar systems). With the continuous development of optical fiber sensors, higher requirements are put forward for the stability of the performance of the optical fiber.

[0004] The good and bad of the polarization maintaining optical fiber depends on the incident state of the polarized light, and the polarization state of the polarized light is required to be coupled and aligned with the slow (fast) axis direction of the polarization maintaining optical fiber. As shown in Figure 2 , it is necessary to minimize the θ angle error and maintain a high extinction ratio for transmission. Aligning the polarization direction of the polarized light with one axis will result in a small polarization component in the other axis, thereby maintaining the polarization state of the transmitted light. The angle of the polarization maintaining optical fiber cat eye alignment is a crucial factor to ensure the extinction ratio.

[0005] The invention with the patent number CN201410817567.8 discloses a panda type polarization maintaining optical fiber end face axis determination method, which determines the center coordinates of the two cat eyes by determining the coordinates of the cladding center in the end face image of the polarization maintaining optical fiber and the positional relationship between the cladding center and the cat eye, and calculates the cat eye deflection angle of the end face of the polarization maintaining optical fiber. This method has the disadvantages of large amount of calculation and long calculation time, and cannot directly measure the deflection angle of the cat eye, which is not conducive to industrial application. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a polarization maintaining optical fiber cat eye deflection angle measurement method, device, equipment and medium to solve the above-mentioned defects of the prior art.

[0007] The technical solution adopted by the present application to solve the technical problem is: a polarization maintaining optical fiber cat eye deflection angle measurement method, comprising the following steps:

[0008] Obtaining the end face image of the polarization maintaining optical fiber with clear imaging, and the end face imaging is provided with at least two optical fibers, and each of the optical fibers is provided with two cat eyes;

[0009] Generating two large circle outer contour lines corresponding to the two optical fibers respectively, and the large circle outer contour lines coincide with the outer contour lines of the corresponding optical fibers;

[0010] Generating two small circle outer contour lines corresponding to the two cat eyes respectively, and the small circle outer contour lines coincide with the outer contour lines of the corresponding cat eyes;

[0011] Obtaining the first circle centers of the two large circle outer contour lines, and connecting the two first circle centers in a straight line to form a test reference line;

[0012] Obtaining the second circle centers of the two small circle outer contour lines, and connecting the two second circle centers in a straight line to form a test reference line;

[0013] According to the included angle formed by the test reference line and the test reference line, the deflection angle of the cat eye is calculated;

[0014] The polarization maintaining optical fiber cat eye deflection angle measurement method disclosed by the application, wherein at least three different first positioning points are recognized on the large circle outer contour line; adjacent two first positioning points are connected by a first connecting line; a first vertical bisector is arranged on each of the plurality of first connecting lines; and the intersection point of the plurality of first vertical bisectors is the first circle center;

[0015] The polarization maintaining optical fiber cat eye deflection angle measurement method disclosed by the application, wherein at least three different second positioning points are recognized on the small circle outer contour line; adjacent two second positioning points are connected by a second connecting line; a second vertical bisector is arranged on each of the plurality of second connecting lines; and the intersection point of the plurality of second vertical bisectors is the second circle center;

[0016] The polarization maintaining optical fiber cat eye deflection angle measurement method disclosed by the application, wherein the circle center of the first circle center is not coincident with the second circle center;

[0017] The polarization maintaining optical fiber cat eye deflection angle measurement method disclosed by the application, wherein the deflection angle of the cat eye can be changed according to the relative movement of the test reference line and the test reference line by rotating any of the optical fibers;

[0018] The polarization maintaining optical fiber cat eye deflection angle measurement method disclosed by the application, wherein the extension line of the test reference line is parallel to or intersects with the extension line of the test reference line;

[0019] The application further discloses a polarization maintaining optical fiber cat eye deflection angle measurement device, which comprises:

[0020] an image extraction module for imaging a clear polarization maintaining optical fiber end face image; the end face is provided with at least two optical fibers, and each of the optical fibers is provided with two cat eyes;

[0021] a contour generation module for generating two large circle outer contour lines corresponding to the two optical fibers respectively and generating two small circle outer contour lines corresponding to the two cat eyes of the optical fibers respectively; the large circle outer contour line coincides with the outer contour line of the corresponding optical fiber; and the small circle outer contour line coincides with the outer contour line of the corresponding cat eye;

[0022] a center acquisition module for acquiring first circle centers of the two large circle outer contour lines and acquiring second circle centers of the two small circle outer contour lines;

[0023] an angle measurement module for connecting the two first circle centers in a straight line to form a test reference line and connecting the two second circle centers in a straight line to form a test reference line; and calculating the deflection angle of the cat eye based on the included angle formed by the test reference line and the test reference line;

[0024] The application further discloses a polarization maintaining optical fiber cat eye deflection angle measurement device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the cat eye angle measurement method when executing the computer program.

[0025] The application further discloses a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program implements the steps of the cat eye angle measurement method of any one of claims 1 to 6 when executed by a processor.

[0026] The application has the advantages that the polarization maintaining optical fiber cat eye deflection angle measurement method, device, equipment and medium have high measurement precision, a plurality of first positioning points are automatically searched based on the outer circle edge of the optical fiber after the cross section of the polarization maintaining optical fiber is acquired by imaging software, the first circle centers are automatically generated after the large circle outer contour line is determined, the plurality of first circle centers are connected to form a straight line, i.e., the test reference line for angle determination, a plurality of second positioning points are automatically searched based on the outer circle edge of the cat eye, the second circle centers are automatically generated after the small circle outer contour line is determined, the plurality of second circle centers are connected to form a straight line, i.e., the test reference line, the software automatically measures the included angle of the two straight lines after the two straight lines are automatically recognized, and thus the cat eye deflection angle is directly measured. The test repeatability can be controlled within ±0.5°. The upper and lower limits of the cat eye angle deflection tolerance can be set in the software, and whether the tolerance is qualified is automatically determined by the software. Meanwhile, the test data is stored in the computer in the form of a CSV file, and the product measurement data can be searched at any time. The application does not need to measure the coordinates of the plurality of first circle centers and second circle centers, and the measurement efficiency is high. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the present application will be further described below with reference to the drawings and embodiments. The drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the premise that they do not deviate from the scope of the present application:

[0028] Figure 1 is a structural schematic diagram of a polarization maintaining optical fiber in the prior art;

[0029] Figure 2 is an end surface cross-sectional view of a polarization maintaining optical fiber in the prior art;

[0030] Figure 3 is a flow chart of a cat-eye deflection angle measurement method of a polarization maintaining optical fiber according to an embodiment of the present application;

[0031] Figure 4 is an end surface cross-sectional view of a polarization maintaining optical fiber according to an embodiment of the present application

[0032] Figure 5 is a gray scale image of an end surface of a polarization maintaining optical fiber according to an embodiment of the present application;

[0033] Figure 6 is a structural schematic diagram of a cat-eye deflection angle measurement device of a polarization maintaining optical fiber according to an embodiment of the present application;

[0034] Figure 7 is a structural schematic diagram of a cat-eye deflection angle measurement device of a polarization maintaining optical fiber according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] The terms "first", "second", "third", and "fourth" and the like in the description and claims of the present application and the drawings hereto are used for distinguishing between similar objects, not necessarily for describing a particular sequential or chronological order. Moreover, the terms "include", and "have", and any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a list of steps or units are not necessarily limited to the listed steps or units, but can optionally include additional steps or units not expressly listed or inherent to such process, method, product, or apparatus.

[0036] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive or alternative embodiments. It is expressly understood that the embodiments described herein are merely examples from a whole class of comparable embodiments which those skilled in the art refer to in general as being within the scope of the present application.

[0037] "Multiple" refers to two or more. "And / or", which describes the relationship between the associated objects, means that there can be three relationships, for example, A and / or B, which can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. The character " / " generally represents that the front and rear associated objects are in an "or" relationship.

[0038] Furthermore, the terms "up, down, front, back, left, right, upper end, lower end, longitudinal direction" and the like representing the orientation are all with reference to the attitude position of the device or equipment described in the present scheme in normal use.

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0040] Example One:

[0041] A polarization maintaining optical fiber cat eye deflection angle measurement method, such as Figures 3-5 Which includes the following steps:

[0042] Get the clear imaging of the polarization maintaining optical fiber end face image, and the end face imaging is provided with at least two optical fibers 1, and each optical fiber is provided with two cat eyes 2;

[0043] Among them, the cross section of the polarization maintaining optical fiber can be imaged by CCD imaging software, and enlarged to 400 times; the imaging is clear.

[0044] Generate two large circle outer contour lines 5 corresponding to two optical fibers one by one; the large circle outer contour line 5 coincides with the outer contour line of the corresponding optical fiber 1;

[0045] Generate two small circle outer contour lines 7 corresponding to two cat eyes one by one; the small circle outer contour line 7 coincides with the outer contour line of the corresponding cat eye 2;

[0046] Get the first circle center 3 of the two large circle outer contour lines, and connect the two first circle centers 3 in a straight line to form a test reference line 8;

[0047] Among them, the method for obtaining the first circle is as follows: at least three different first positioning points 4 are recognized on the large circle outer contour line 5; the adjacent two first positioning points 4 are connected by a first connecting line (not shown in the figure); a first vertical bisector (not shown in the figure) is arranged on each of the plurality of first connecting lines (not shown in the figure); the intersection of the plurality of first vertical bisectors (not shown in the figure) is the first circle center 3.

[0048] A second circle center 9 of the outer contour line of the small circle is obtained, and two second circle centers 9 are connected in a straight line to form a test reference line 10;

[0049] The method for obtaining the second circle is as follows: at least three different second positioning points 6 are recognized on the outer contour line of the small circle 7; two adjacent second positioning points 6 are connected by a second connecting line (not shown in the figure); a second vertical bisector (not shown in the figure) is arranged on each of the plurality of second connecting lines (not shown in the figure); and the intersection of the plurality of second vertical bisectors (not shown in the figure) is the second circle center 9.

[0050] According to the included angle formed by the test reference line 10 and the test reference line 8, the deflection angle of the cat eye is calculated.

[0051] The first circle center 3 and the second circle center 9 are not coincident.

[0052] Specifically, the deflection angle of the cat eye can change according to the relative movement of the test reference line and the test reference line when any one of the optical fibers is rotated to change the positions of the two cat eyes in the optical fiber. For example, when the connecting line of the two circle centers of the cat eye, i.e., the test reference line and the test reference line, are perpendicular, the deflection angle of the cat eye is 90 degrees; when the test reference line and the test reference line are parallel, the deflection angle of the cat eye is 0 degrees, which all belong to the protection scope of the present application.

[0053] Specifically, the extension line of the test reference line is parallel to or intersects with the extension line of the test reference line; it is worth noting that the two cat eyes in the optical fiber can be arranged on the same side or on both sides of the optical fiber, which all belong to the protection scope of the present application.

[0054] After the cross section of the polarization maintaining optical fiber is obtained by the imaging software, a plurality of first positioning points are automatically searched based on the outer circular edge of the optical fiber, the first circle center is automatically generated after the outer contour line of the large circle is determined, a plurality of first circle centers are connected, thereby forming a straight line, i.e., the test reference line of the angle determination reference; a plurality of second positioning points are automatically searched based on the outer circular edge of the cat eye, the second circle center is automatically generated after the outer contour line of the small circle is determined, a plurality of second circle centers are connected, thereby forming a straight line, i.e., the test reference line; the angle between the two straight lines is automatically measured by the software after the two straight lines are automatically recognized, thereby the deflection angle of the cat eye is directly measured. The test repeatability can be controlled within ±0.5°; the upper and lower limits of the cat eye angle deflection tolerance can be set in the software, whether it is qualified is automatically determined by the software, and the test data is stored in the computer in the form of CSV file, which is convenient for subsequent product measurement data searching; the present application does not need to measure the coordinates of the plurality of first circle centers and second circle centers, and the measurement efficiency is fast.

[0055] Example Two:

[0056] A polarization maintaining optical fiber cat eye deflection angle measuring device, comprising a polarization maintaining optical fiber,Figure 6 As shown in the figure, comprising:

[0057] The image extraction module 11 is used for imaging the clear polarization maintaining optical fiber end face image; the end face imaging is internally provided with at least two optical fibers, and each optical fiber is internally provided with two cat eyes;

[0058] The contour generation module 12 is used for generating two large circle outer contour lines corresponding to the two optical fibers and generating two small circle outer contour lines corresponding to the two cat eyes in the optical fibers; the large circle outer contour line coincides with the outer contour line of the optical fiber corresponding thereto; and the small circle outer contour line coincides with the outer contour line of the cat eye corresponding thereto.

[0059] The center acquisition module 13 is used for acquiring the first circle center of the two large circle outer contour lines and acquiring the second circle center of the two small circle outer contour lines.

[0060] The angle measurement module 14 connects the two first circle centers in a straight line to form a test reference line, and connects the two second circle centers in a straight line to form a test reference line; based on the included angle formed by the test reference line and the test reference line, the deflection angle of the cat eye is calculated.

[0061] After the cross section of the polarization maintaining optical fiber is acquired through the imaging software, a plurality of first positioning points are automatically searched based on the outer circular edge of the optical fiber, the first circle center is automatically generated after the large circle outer contour line is determined, the plurality of first circle centers are connected, thereby forming a straight line, that is, the test reference line for angle determination; a plurality of second positioning points are automatically searched based on the outer circular edge of the cat eye, the second circle center is automatically generated after the small circle outer contour line is determined, the plurality of second circle centers are connected, thereby forming a straight line, that is, the test reference line; after the two straight lines are automatically recognized by the software, the included angle of the two straight lines is automatically measured, thereby directly measuring the deflection angle of the cat eye. The test repeatability can be controlled within ±0.5°. The upper and lower limits of the cat eye angle deflection tolerance can be set in the software, and whether it is qualified is automatically determined by the software. At the same time, the test data is stored in the computer in the form of a CSV file, which is convenient for subsequent product measurement data searching. The present application does not need to measure the coordinates of the plurality of first circle centers and second circle centers, and the measurement efficiency is fast.

[0062] Example Three:

[0063] A polarization maintaining optical fiber cat eye deflection angle measurement device, as shown in the figure, comprises a memory 21, a processor 22, and a computer program 23 stored in the memory 21 and executable on the processor 22, wherein the processor 22 implements the steps of the cat eye angle measurement method according to any one of claims 1 to 6 when executing the computer program 23. Figure 7

[0064] Example Four:

[0065] ​A readable storage medium, the computer readable storage medium stores a computer program, wherein the computer program is executed by a processor to implement the steps of the cat eye angle measurement method according to any one of claims 1 to 6.

[0066] It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. A method for measuring the deflection angle of a polarization-maintaining optical fiber cat's eye, characterized in that, Includes the following steps: To obtain a clear image of the end face of a polarization-maintaining fiber, wherein at least two optical fibers are provided in the end face image, and each optical fiber is provided with two cat's eyes. Two large circle outer contour lines are generated, each corresponding to one of the two optical fibers; the large circle outer contour lines coincide with the outer contour lines of their corresponding optical fibers. Generate two small circular outer contour lines that correspond one-to-one with the two described cat eyes; the small circular outer contour lines coincide with the outer contour lines of their corresponding cat eyes. Obtain the first center of the outer contour lines of the two large circles, and connect the two first centers with a straight line to form a test baseline. Obtain the second center of the outer contour lines of the two small circles, and connect the two second center lines with a straight line to form a test reference line; The deflection angle of the cat's eye is calculated based on the angle formed by the test reference line and the test baseline.

2. The method for measuring the deflection angle of a polarization-maintaining optical fiber cat's eye according to claim 1, characterized in that, At least three different first positioning points are identified on the outer contour line of the large circle; two adjacent first positioning points are connected by a first connecting line; a first perpendicular bisector is provided on each of the multiple first connecting lines; the intersection of the multiple first perpendicular bisectors is the center of the first circle.

3. The method for measuring the deflection angle of a polarization-maintaining optical fiber cat's eye according to claim 2, characterized in that, At least three different second positioning points are identified on the outer contour line of the small circle; two adjacent second positioning points are connected by a second connecting line; a second perpendicular bisector is provided on multiple second connecting lines; the intersection of multiple second perpendicular bisectors is the center of the second circle.

4. The method for measuring the deflection angle of a polarization-maintaining optical fiber cat's eye according to claim 1, characterized in that, The center of the first circle does not coincide with the center of the second circle.

5. The method for measuring the deflection angle of a polarization-maintaining optical fiber cat's eye according to claim 1, characterized in that, The deflection angle of the cat's eye can be varied by rotating any of the optical fibers to move the test reference line relative to the test baseline.

6. The method for measuring the deflection angle of a polarization-maintaining optical fiber cat's eye according to claim 5, characterized in that, The extension of the test reference line is parallel to or intersects the extension of the test baseline.

7. A polarization-maintaining fiber optic cat's-eye deflection angle measuring device, characterized in that... ,include: An image extraction module is used to obtain a clear image of the end face of the polarization-maintaining fiber; the end face image contains at least two optical fibers, and each optical fiber contains two cat's-eye holes. The contour generation module is used to generate two large circular outer contour lines that correspond one-to-one with the two optical fibers, and to generate two small circular outer contour lines that correspond one-to-one with the two cat's eyes inside the optical fibers; the large circular outer contour lines coincide with the outer contour lines of the corresponding optical fibers; the small circular outer contour lines coincide with the outer contour lines of the corresponding cat's eyes. The center acquisition module is used to acquire the first center of the outer contour lines of the two large circles and the second center of the outer contour lines of the two small circles; The angle measurement module connects the two first center lines to form a test baseline and connects the two second center lines to form a test reference line; based on the angle formed by the test reference line and the test baseline, the deflection angle of the cat's eye is calculated.

8. A polarization-maintaining fiber optic cat's-eye deflection angle measuring device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the cat's eye angle measurement method as described in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the cat's eye angle measurement method as described in any one of claims 1 to 6.

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