An electron probe-based method for testing the composition of an optical fiber

Abstract

The application discloses a kind of optical fiber component test methods based on electron probe, it is related to quartz material test field, the method comprises: the carbon plating treatment is carried out to the optical fiber sample to be measured;Line scanning test is carried out to the optical fiber sample to be measured after carbon plating using electron probe, and the line scanning analysis data of each measured element is obtained;Quantitative analysis test is carried out to the optical fiber sample to be measured after carbon plating using electron probe, and the quantitative analysis data of each measured element is obtained;According to the line scanning analysis data of each measured element and the quantitative analysis data of each measured element, the component distribution of the optical fiber sample to be measured is determined.The application improves the test precision of optical fiber component by combining line scanning and quantitative analysis of electron probe.

Description

Technical Field

[0001] This application relates to the field of quartz material testing, and in particular to a fiber optic component testing method based on an electron probe. Background Technology

[0002] Optical fiber materials are generally classified into two types: active and passive. Active optical fibers are typically doped with rare earth elements. Rare earth-doped gain fibers are a crucial component of fiber lasers, significantly determining their output quality. Currently, the rare earth particles used as dopants in silica optical fibers mainly include erbium (Er), neodymium (Nd), ytterbium (Yb), thulium (Tm), and holmium (Ho). Among these, Yb... 3+ Ion-doped fiber lasers have the highest optical conversion efficiency. The main research focus for ytterbium-doped double-clad fiber (YDF) is to control the cladding refractive index of the fiber core and obtain high rare-earth ion doping concentrations. Passive fibers are mainly germanium-doped fibers, primarily used for power transmission in fiber lasers and communication fibers. However, due to their small size, often only around 10 μm, they require more precise fabrication processes.

[0003] Therefore, in the process of optical fiber fabrication, it is necessary to precisely control the composition of the fiber core and optimize the fabrication process to obtain an ideal optical structure and excellent output performance. Summary of the Invention

[0004] The purpose of this application is to provide an optical fiber component testing method based on an electron probe, which can improve the accuracy of optical fiber component testing.

[0005] To achieve the above objectives, this application provides the following solution:

[0006] This application provides a fiber optic component testing method based on an electron probe, including:

[0007] The optical fiber sample to be tested was carbon-plated.

[0008] Line scan analysis data of each element was obtained by using an electron probe microanalysis device to perform line scan tests on carbon-coated optical fiber samples.

[0009] The carbon-coated optical fiber sample was quantitatively analyzed using an electron probe microanalysis method to obtain quantitative analysis data for each element.

[0010] The compositional distribution of the optical fiber sample under test was determined based on the line scan analysis data and quantitative analysis data of each element to be tested.

[0011] According to the specific embodiments provided in this application, this application has the following technical effects:

[0012] This application provides an electron probe-based method for testing the composition of optical fibers. By combining line scanning and quantitative analysis of the electron probe, line scanning and quantitative analysis are performed on the optical fiber sample to be tested. This method can accurately analyze low-content elements and determine the composition distribution of the optical fiber sample based on the line scanning analysis data and quantitative analysis data of each element to be tested, thereby improving the testing accuracy of optical fiber composition. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 A schematic flowchart of an optical fiber component testing method based on an electron probe provided in an embodiment of this application;

[0015] Figure 2 This is a schematic diagram of fiber optic cutting in one embodiment of this application;

[0016] Figure 3 This is a backscattering pattern of sample 1 in one embodiment of this application;

[0017] Figure 4 This is a COMPO diagram of sample 1 in one embodiment of this application;

[0018] Figure 5 This is an energy dispersive spectrometer (EDS) component distribution diagram of sample 1 in one embodiment of this application;

[0019] Figure 6 This is a fitted curve of electron probe line scanning and quantitative analysis of sample 1 in one embodiment of this application;

[0020] Figure 7 This is a fitted curve of electron probe line scanning and quantitative analysis of sample 2 in one embodiment of this application.

[0021] Reference numerals: 201 - Fiber optic cleaver, 202 - Cutting surface. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Traditional optical fiber structures typically include a core, cladding, and coating. Fibers are relatively small, generally available in fixed sizes such as 10 / 125 and 20 / 400, with core sizes ranging from only 10μm to 20μm. Due to the small core size, micro-area analysis methods are the optimal choice for component analysis. These include energy dispersive spectrometers (EDS) using a scanning electron microscope (SEM) or wavelength dispersive spectrometers (WDS) using an electron probe microanalysis (EPMA). Both EPMA and SEM utilize a focused electron beam to irradiate the surface of the sample. WDS or EDS detects the characteristic X-ray wavelengths and signal intensities generated by the interaction of electrons with the sample, thereby enabling qualitative or quantitative analysis of the elements contained within the micro-area.

[0024] Traditional EDS analysis is mainly applied to large metallic compound materials, with relatively large electron beam currents (5μm-10μm) and very limited accuracy, which cannot meet the current process requirements of optical fibers. Furthermore, traditional SEM-EDS backscattered images cannot pinpoint the exact location of the fiber core, making precise core testing impossible and limiting elemental analysis capabilities. For inorganic silicate materials like optical fibers, the overall SiO2 mass percentage is 80%-100%, while the mass percentage of various dopants is only 4%-5%, resulting in significant differences in compositional concentration and increased testing difficulty. Therefore, SEM-EDS cannot reflect the linear compositional fluctuations of dopants, making it difficult to meet the requirements of optical fiber fabrication / testing processes.

[0025] EPMA can be used for observing the surface morphology of samples and for micro-area composition analysis, and it has wide applications in qualitative analysis, quantitative analysis, and line scanning of materials. Because of its sufficiently large and stable electron beam current, EPMA spectrometers have a high peak-to-background ratio and a wide range of elemental measurements, including ultralight elements. Compared to traditional SEM-EDS analysis, it can obtain highly sensitive, high-resolution backscattered electron images, revealing micron-level micro-phase distribution phenomena, which is highly beneficial for precise localization and accurate analysis of the analytical region.

[0026] Line scan analysis using EPMA primarily involves bombarding the sample with an extremely fine electron beam (<2μm). During the test, the intensity of the electron beam is compared with the characteristic X-ray signal generated by the material. This method is mainly used for qualitative analysis and cannot accurately determine the specific content of each element in the sample, nor can it accurately control the doping content in the preparation process. Meanwhile, quantitative analysis using EPMA determines the specific content of elements by bombarding the sample surface with an electron beam of a specific size. To ensure accuracy, a relatively large electron beam spot (1μm-2μm) is required. However, the fiber core is only 10μm-20μm, meaning that sample testing can only generate a very limited amount of path information, and the testing accuracy does not meet the requirements of the process.

[0027] This application leverages the high-resolution advantage unique to EPMA, combining qualitative line scanning and quantitative analysis to accurately analyze the doping composition of optical fibers, providing strong support for improving optical fiber fabrication processes and material ratios.

[0028] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] In one exemplary embodiment, such as Figure 1 As shown, an optical fiber component testing method based on an electron probe is provided, including the following steps 101 to 105.

[0030] Step 101: Remove the coating layer from the fiber optic sample to be tested and cut the fiber optic sample longitudinally; use conductive adhesive to vertically fix the longitudinally cut fiber optic sample to be tested on the sample stage, so that the cut surface of the fiber optic sample to be tested is facing upward and flush with the sample stage, and the cut surface of the fiber optic sample to be tested is higher than the set height of the conductive adhesive.

[0031] Among them, the optical fiber sample to be tested is an active optical fiber or a passive optical fiber.

[0032] Specifically, remove the coating layer from the fiber optic sample to be tested, and wipe the surface clean with alcohol to prevent contamination from oil, dust, and water. For example... Figure 2 As shown, the fiber optic sample to be tested is longitudinally cut using a fiber optic cleaver 201 to obtain a flat cut surface 202. Then, conductive adhesive is used to vertically fix the longitudinally cut fiber optic sample to be tested onto the sample stage, so that the cut surface 202 of the fiber optic sample to be tested faces upward and is flush with the sample stage. The sample is then fixed again with conductive adhesive to ensure that the cut surface 202 of the fiber optic sample to be tested is 0.5mm higher than the conductive adhesive. This ensures that the cut surface 202 of the fiber optic sample has good conductivity after carbon plating and also prevents the electronic signals generated during the test from being blocked by the conductive adhesive.

[0033] Step 102: Carbon plating is performed on the optical fiber sample to be tested.

[0034] In a specific application example, a vacuum carbon plating machine is used to carbonize the optical fiber sample under test. During the carbon plating process, the vacuum level of the carbon plating chamber of the vacuum carbon plating machine is less than 10... -3 pa.

[0035] Since optical fibers are made of inorganic silicate materials, which are inherently non-conductive, carbon plating is necessary to achieve good testing results. Specifically, the sample stage is placed on the rotating table of a vacuum carbon plating machine, and the vacuum level in the carbon plating chamber is evacuated to 10... -3 Below pa, a carbon rod is sputtered to create a uniform carbon film of suitable thickness on the cut surface 202 of the optical fiber sample under test. The thickness of the carbon film is 20 nm.

[0036] Step 103: Line scan testing is performed on the carbon-coated optical fiber sample using an electron probe microanalysis device to obtain line scan analysis data for each analyte. The line scan analysis data includes location information and compositional information.

[0037] In a specific application example, step 103 includes steps 31 to 34.

[0038] Step 31: Determine the test conditions for the line scan test. The test conditions for the line scan test are as follows: voltage 15KV, current 50nA, line scan length 1.5 times the core length of the carbon-coated fiber sample under test, relaxation time 500ms, electron beam spot size 0.1μm, and number of dots = scan length / electron beam spot size.

[0039] Specifically, the carbon-coated fiber sample to be tested is positioned at the center of the EPMA view, magnified to a suitable size, and the COMPO view mode is selected. The brightness and contrast are adjusted until the electronic morphology of the fiber core can be clearly seen. Then, the line scan program corresponding to each element under test is selected, the test conditions are determined, and it is ensured that the two segments and the center position of the line scan are well focused.

[0040] Step 32: Select several test elements and their corresponding test channels. Specifically, select the corresponding test channel based on the characteristic lattice of each test element.

[0041] Step 33: Based on the test conditions of the line scan test, each element to be tested and the test channel corresponding to each element to be tested, perform a line scan test on the carbon-coated fiber sample to be tested, and find the peak at the focusing position outside the line scan path but inside the fiber core of the carbon-coated fiber sample to obtain the peak spectrum value of each element to be tested.

[0042] Step 34: Determine the line scan analysis data for each element based on the peak values ​​of each element to be tested.

[0043] Step 104: Quantitative analysis is performed on the carbon-coated optical fiber sample using an electron probe microanalysis device to obtain quantitative analysis data for each analyte. The quantitative analysis data includes location information and component content information.

[0044] In a specific application example, step 104 includes steps 41 to 44.

[0045] Step 41: Determine the test conditions for quantitative analysis. The test conditions for quantitative analysis are: voltage 15KV, current 10nA, scan length 1.2 times the core length of the carbon-coated optical fiber sample, electron beam spot size 2μm, and number of dots = scan length / electron beam spot size.

[0046] Specifically, the carbon-coated fiber sample to be tested is positioned at the center of the EPMA view, magnified to a suitable size, and the COMPO view mode is selected. The brightness and contrast are adjusted until the backscattered electron morphology of the fiber core can be clearly seen. Then, the quantitative analysis program corresponding to each element to be tested is selected, the test conditions are determined, and it is ensured that the focus is good at each position for quantitative analysis.

[0047] Step 42: Select several test elements and their corresponding test channels. Specifically, select the corresponding test channel based on the characteristic lattice of each test element.

[0048] Step 43: Based on the test conditions of quantitative analysis and testing, each element to be tested and the test channel corresponding to each element to be tested, perform quantitative analysis and testing on the carbon-coated optical fiber sample, and search for peaks at the focusing position outside the online scanning path and inside the fiber core of the carbon-coated optical fiber sample to obtain the peak spectrum values ​​of each element to be tested.

[0049] Step 44: Determine the quantitative analysis data for each element based on the peak values ​​of each element to be tested.

[0050] Line scan analysis data and quantitative analysis data can be directly output as TXT text via electron probe microanalysis. This application mainly focuses on the positional information and component content information in these data.

[0051] Step 105: Determine the composition distribution of the optical fiber sample to be tested based on the line scan analysis data and quantitative analysis data of each element to be tested.

[0052] In a specific application example, step 105 uses data analysis software (such as Origin) to fit the line scan analysis data and quantitative analysis data to accurately test the specific component distribution of the optical fiber sample under test. First, the line scan analysis data and quantitative analysis data in TXT format are converted to EXCEL format. The location information and component content information are then inserted into the data analysis software, and the corresponding names, units, and annotations are set. Step 105 includes steps 51 to 54.

[0053] Step 51: Based on the core size of the carbon-coated optical fiber sample and the test step size of the line scan test, the line scan analysis data of each element to be tested is normalized to obtain a preliminary line scan curve.

[0054] Specifically, the fiber core size is determined based on the test coordinate information. The median of the coordinate information is set as the center point 0. The remaining position information is distributed to the left and right of point 0 according to the test step size of the line scan test, resulting in a preliminary line scan curve. The preliminary line scan curve is a line graph.

[0055] Step 52: Based on the core size of the carbon-coated optical fiber sample and the test step size of the quantitative analysis test, the quantitative analysis data of each element to be tested are normalized to obtain a preliminary quantitative analysis curve.

[0056] Specifically, the fiber core size is determined based on the test coordinate information. The median of the coordinate information is set as the center point 0. The remaining position information is distributed to the left and right of the center point according to the test step size of the quantitative analysis test, resulting in a preliminary quantitative analysis curve. The preliminary quantitative analysis curve is a dotted line graph.

[0057] Step 53: Perform component normalization processing on the preliminary line scan curve and the preliminary quantitative analysis curve respectively, and set the extreme points of the preliminary line scan curve and the preliminary quantitative analysis curve on the same standard line to obtain the final line scan curve and the final quantitative analysis curve.

[0058] Specifically, reference points are selected at both ends of the preliminary line scan curve and the preliminary quantitative analysis curve. According to the component testing requirements, the test range must cover the entire diameter of the fiber core. Therefore, the reference point for the dopant element is the lowest content point (0%), and the reference point for the matrix Si element is the content point (100%). The reference points of the preliminary line scan curve and the preliminary quantitative analysis curve are set on the same reference line. Then, the extreme points of the fiber core of the preliminary line scan curve and the preliminary quantitative analysis curve are selected. The extreme point for the dopant element is the highest content point, and the extreme point for the matrix Si element is the lowest content point. The coordinate scale of the final line scan curve and the final quantitative analysis curve is further adjusted to ensure that the final line scan curve and the final quantitative analysis curve are of appropriate size.

[0059] Step 54: Based on the final line scan curve and the final quantitative analysis curve, determine the content of each element at each location in the optical fiber sample to be tested, so as to determine the component distribution of the optical fiber sample to be tested.

[0060] In an exemplary embodiment, the peak-finding process in steps 43 and 53 is further adjusted based on pre-determined standard sample information for each analyte. The standard sample information refers to the signal quantity of each analyte at 100% concentration.

[0061] Since optical fibers prepared by different equipment have slight differences in their internal structure and composition, the tests are inaccurate. This application improves the accuracy of the tests by conducting standard tests on optical fibers obtained by different production methods in advance.

[0062] The process for determining the standard information for each analyte includes: placing several standard samples corresponding to the analyte into the sample chamber of the EPMA, and evacuating to 10°C. -4 Below pa, turn on the tungsten filament, select the standard sample to be tested and the corresponding STD standard sample program, set the voltage to 15kV and the current to 10nA, select three well-focused positions on the standard sample, and enter the position information into the program. Select the standard sample element (such as Yb, P, Al, Si, Ge, Er, F) and its corresponding test channel, and select any well-focused position outside the path for peak finding. After peak finding, read the peak position into the program, start the test, and obtain the standard sample information of the element to be tested. Repeat the above steps to test the standard samples corresponding to different elements to be tested, obtaining several standard sample information corresponding to the elements to be tested.

[0063] Unlike traditional EDS component analysis, single qualitative analysis, or single quantitative analysis, this application uses a combination of EPMA and qualitative and quantitative methods to accurately test the component information of optical fibers. Compared with traditional detection and analysis methods, the method provided in this application has the following advantages:

[0064] (1) Compared with traditional EDS, EPMA-WDS has narrower spectral peaks and a relatively higher peak-to-background ratio, resulting in higher detector sensitivity, especially for the analysis of low-abundance elements, which is significantly superior to EDS. Furthermore, WDS has high energy resolution, eliminating interference from numerous L, M, and N series spectral lines of superheavy elements near the K-line of ultralight elements. Although calculating the overlap coefficient of spectral lines beyond the M-series is difficult, and the background in the low-energy region is also difficult to estimate, making the analysis of low-abundance and ultralight elements challenging, this application utilizes the EPMA-WDS method to accurately analyze low-abundance elements.

[0065] (2) The elemental analysis principle of EPMA-WDS in this application is to set the spectrometer at the characteristic X-ray wavelength of a certain element, and use an electron beam scanning accessory or sample stage to scan the specified area, and record the intensity of the X-rays point by point to obtain the distribution of the element in the specified area. WDS can distinguish the characteristic X-ray energies between elements with low content or small concentration differences, so it can well show the distribution differences of elements.

[0066] (3) This application utilizes the COMPO image of an electron probe to clearly display the morphology of the fiber core, enabling better positioning of the fiber core and accurate analysis of elemental composition. When performing tests using EDS, manual sampling and multiple tests are required, resulting in very coarse compositional information. In contrast, EPMA can automatically generate test paths based on the sample's position information and automatically perform tests according to the range of samples that need to be tested, providing convenient and accurate information on the compositional distribution on the sample surface.

[0067] To verify the accuracy of the fiber composition testing in this application, the EPMA and EDS composition analysis data of silica optical fibers are analyzed and compared below. Two test samples were prepared: Sample 1 and Sample 2. The application method was demonstrated in the application environments of active and passive optical fibers, respectively. The core diameter of Sample 1 was 16 μm and the cladding diameter was 125 μm; the core diameter of Sample 2 was 20 μm and the cladding diameter was 400 μm. The comparative analysis process is as follows.

[0068] (1) Prepare the sample to be tested.

[0069] Remove the coating from sample 1, clean the surface with alcohol, and longitudinally cleave the fiber using a fiber optic cleaver 201 to obtain a flat cut surface 202. Then, use conductive adhesive to vertically fix the non-cut end of sample 1 onto the sample stage, with the cut surface 202 facing upwards and parallel to the sample stage. Place the sample stage inside the vacuum carbon plating machine, and evacuate the carbon plating chamber to a vacuum level of 10. -3 Carbon rods are sputtered at a pressure below 8 Pa to create a uniform carbon film of suitable thickness on the cut surface 202 of the optical fiber. The vacuum level is 8 × 10⁻⁶. -3 The sputtering current was 22A, the sputtering time was 40s, and the carbon film thickness was 20nm.

[0070] (2) Create standard sample information.

[0071] Component analysis was performed using EPMA. Standard samples corresponding to the elements to be analyzed were placed in the sample chamber. In this embodiment, the elements to be analyzed and the standard samples are shown in Table 1. The chamber was evacuated to 10°C. -4Below pa, turn on the tungsten filament, select the standard sample to be tested and the corresponding STD standard sample program, set the voltage to 15kV and the current to 10nA, select three well-focused positions on the standard sample, and enter the position information into the program. Select the elements to be tested, Yb, P, Al, Si, Ge, Er, and F respectively, select the corresponding test channel according to the characteristic crystal of each element, and select any well-focused position outside the path for peak finding. After peak finding, read the peak position into the program, and start testing each element to be tested in sequence.

[0072] Table 1. Information on Standard Samples

[0073] element Al P Si Yb Er Ge F Standard <![CDATA[Al2O3]]> <![CDATA[YbPO4]]> <![CDATA[SiO2]]> <![CDATA[YbPO4]]> <![CDATA[ErPO4]]> <![CDATA[Bi4Ge3O 12 ]]> <![CDATA[Al2SiO4(F,OH)2]]> crystal TAP PETJ TAP LIFH LDE1 TAP TAP

[0074] (3) Component analysis was performed using SEM-EDS.

[0075] The sample to be tested is placed in the sample chamber of the scanning electron microscope, magnified to a suitable size, and backscatter mode is selected. The detection results are as follows: Figure 3 As shown, EDS cannot accurately locate the fiber core. The experiment can only use geometric positioning to select a 100μm square block in the middle of the fiber for rough testing. The voltage is set to 15KV, the electron beam spot is set to 3μm, and the corresponding elements are selected for analysis and testing. Figure 4 The COMPO image detection results also reflect the inaccuracy of EDS testing, as the fluctuations and changes of various components inside the fiber core cannot be reflected, failing to meet the requirements for process preparation and testing.

[0076] (4) Use EPMA for component analysis.

[0077] First, perform a line scan qualitative test using EPMA. Place the sample to be tested into the sample chamber of the EPMA, adjust the sample to the center position, magnify to a suitable size, select COMPO image mode, and the detection results are as follows. Figure 5 As shown. Due to the contrast effect of each element, the morphology of the fiber core can be clearly seen, facilitating positioning, reducing the test range, and increasing test accuracy. Select the line scan program, set the voltage to 15KV, adjust the current to 50nA, determine the line scan length as 30μm based on the fiber core size, set the relaxation time to 500ms, select an electron beam spot size of 0.1μm, and set the number of dots to 300. Confirm the program. Then use EPMA for quantitative analysis. Select the quantitative analysis program, set the voltage to 15KV, adjust the current to 10nA, determine the quantitative analysis length as 30μm based on the fiber core size, select an electron beam spot size of 2μm, and set the number of dots to 15. Confirm the program and start the analysis test.

[0078] (5) Use data analysis software to fit and analyze the data.

[0079] Convert the quantitative analysis data and line scan analysis data of each element to be tested obtained in steps (3) and (4) from TXT format to EXCEL format, insert the location information and component content information of each element to be tested into the data analysis software, and set the corresponding name, unit and annotation.

[0080] The line scan analysis data and quantitative analysis data are subjected to position normalization and component normalization respectively to generate line scan curves and quantitative analysis curves. Appropriate coordinate scales are set to adjust the line scan curves and quantitative analysis curves to a suitable size for data analysis.

[0081] The line scan and quantitative analysis curves clearly show that in EDS testing, the approximate location of the fiber core can only be identified by the aggregation of elements, but the exact location of the core cannot be pinpointed. This expands the testing range and reduces component sensitivity. Furthermore, due to the large electron beam spot size and limited resolution in EDS testing, it cannot effectively display the concentration difference distribution of components.

[0082] This application utilizes a combination of line scanning and quantitative methods to accurately analyze the specific component distribution of the optical fiber core, with results as follows: Figure 6 As shown, the compositional distribution of the active optical fiber in Sample 1 is clearly visible. Sample 1 contains elements such as Al, Ge, P, Si, Er, and Yb. By combining line scanning and quantitative analysis, it can be seen that because Al and Ge elements are distributed in rings, and the Al and Ge rings are relatively narrow (only 4 μm thick), quantitative analysis can only cover a maximum of 2 test points. However, line scanning can cover 40 test points, clearly reflecting the concentration changes of the elements. Combined with the values ​​from quantitative analysis, the values ​​of each micro-test point can be obtained, further demonstrating the concentration distribution of elements in the fiber core. Simultaneously, the distribution of rare earth elements Er and Yb also shows that even with doping levels of only 0 mass%-0.26 mass%, compositional fluctuations are clearly reflected, demonstrating the precise testing performance of EPMA and the reliability of the combined EPMA line scanning and quantitative analysis method.

[0083] Sample 2 was tested and analyzed using the same method described above, and the test results are as follows: Figure 7As shown, fluorine (F), being a light element, is difficult to accurately measure using conventional EDS testing. However, the fiber composition testing method provided in this application clearly displays the specific content. Even though the highest F content is only 0.3 mass%, combining line scanning with quantitative analysis allows for a clear analysis of the F distribution within the material. Similarly, gemine (Ge) exhibits a ring-like distribution within the material, with a ring width of 5 μm. Quantitative analysis can only analyze two values, but combined with line scanning, a 2 μm plateau is observed at the highest Ge content. Furthermore, the Al element analysis demonstrates the stability of this application, showing no significant testing error.

[0084] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0085] In this application, all actions to acquire signals, information, or data are carried out in compliance with the relevant data protection laws and policies of the country where the location is situated, and with the authorization granted by the owner of the relevant device.

[0086] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for testing the composition of optical fibers based on an electron probe, characterized in that, The electron probe-based optical fiber component testing method includes: The process of carbonizing the optical fiber sample to be tested specifically includes: placing the sample stage on the rotating table of the vacuum carbonization machine, and evacuating the carbonization chamber to a vacuum level of 10. -3 Below pa, a carbon rod is sputtered to make the surface of the cut surface of the optical fiber sample under test have a uniform carbon film with a thickness of 20nm; Line scan analysis data of each element was obtained by using an electron probe microanalysis device to perform line scan tests on carbon-coated optical fiber samples. The carbon-coated optical fiber sample was quantitatively analyzed using an electron probe microanalysis method to obtain quantitative analysis data for each element. Based on the line scan analysis data and quantitative analysis data of each analyte, the compositional distribution of the optical fiber sample under test is determined, specifically including: Based on the core size of the carbon-coated optical fiber sample and the test step size of the line scan test, the line scan analysis data of each element under test are normalized to obtain a preliminary line scan curve. Specifically, the core size is determined based on the test coordinate information, the median of the coordinate information is set as the center 0 point, and the remaining position information is distributed to the left and right of the 0 point according to the test step size of the line scan test to obtain the preliminary line scan curve. Based on the core size of the carbon-coated optical fiber sample and the test step size of the quantitative analysis test, the quantitative analysis data of each element to be tested are normalized to obtain a preliminary quantitative analysis curve. Specifically, the core size is determined based on the test coordinate information, the median of the coordinate information is set as the center 0 point, and the remaining position information is distributed to the left and right of the 0 point according to the test step size of the quantitative analysis test to obtain the preliminary quantitative analysis curve. The preliminary line scan curve and the preliminary quantitative analysis curve are subjected to component normalization processing respectively. The extreme points of the preliminary line scan curve and the preliminary quantitative analysis curve are set on the same standard line to obtain the final line scan curve and the final quantitative analysis curve. Based on the final line scan curve and the final quantitative analysis curve, the content of each element at each location in the optical fiber sample under test is determined to determine the component distribution of the optical fiber sample under test.

2. The method for testing the composition of optical fibers based on an electron probe according to claim 1, characterized in that, Before carbon plating the optical fiber sample to be tested, the optical fiber composition testing method based on electron probe further includes: Remove the coating layer from the fiber optic sample to be tested and cut the fiber optic sample longitudinally. The longitudinally cut fiber optic sample is vertically fixed on the sample stage using conductive adhesive, with the cut surface of the fiber optic sample facing upwards and flush with the sample stage, and the cut surface of the fiber optic sample being higher than the set height of the conductive adhesive.

3. The method for testing the composition of optical fibers based on an electron probe according to claim 1, characterized in that, Line scan analysis of the carbon-coated optical fiber sample was performed using an electron probe microanalysis device to obtain line scan analysis data for each analyte, specifically including: Determine the test conditions for line scan testing; Select several test elements and the corresponding test channels for each test element; Based on the test conditions of line scan test, each element to be tested and the test channel corresponding to each element to be tested, line scan test is performed on the carbon-coated fiber sample to be tested, and peaks are searched at the focusing positions outside the line scan path and inside the fiber core of the carbon-coated fiber sample to obtain the peak spectrum values ​​of each element to be tested. Based on the peak values ​​of each analyte, the line scan analysis data for each analyte are determined.

4. The method for testing the composition of optical fibers based on an electron probe according to claim 3, characterized in that, The test conditions for line scan testing are as follows: voltage is 15KV, current is 50nA, line scan length is 1.5 times the core length of the carbon-coated fiber sample, relaxation time is 500ms, and electron beam spot size is 0.1μm.

5. The method for testing the composition of optical fibers based on an electron probe according to claim 1, characterized in that, An electron probe microanalysis method was used to perform quantitative analysis on the carbon-coated optical fiber sample to obtain quantitative analysis data for each analyte, including: Determine the test conditions for quantitative analysis; Select several test elements and the corresponding test channels for each test element; Based on the test conditions of quantitative analysis and testing, each element to be tested and the test channel corresponding to each element to be tested, quantitative analysis and testing are carried out on the carbon-coated optical fiber sample. Peaks are found at the focusing positions outside the online scanning path and inside the fiber core of the carbon-coated optical fiber sample to obtain the peak spectrum values ​​of each element to be tested. Based on the peak values ​​of each analyte, the quantitative analysis data for each analyte are determined.

6. The method for testing the composition of optical fibers based on an electron probe according to claim 5, characterized in that, The test conditions for quantitative analysis were: voltage 15KV, current 10nA, scanning length 1.2 times the core length of the carbon-coated optical fiber sample, and electron beam spot size 2μm.

7. The method for testing the composition of optical fibers based on an electron probe according to claim 3 or 5, characterized in that, The electron probe-based optical fiber component testing method further includes: The peak-finding process is adjusted based on the pre-determined standard sample information for each analyte; the standard sample information is the signal quantity of each analyte at a concentration of 100%.

8. The method for testing the composition of optical fibers based on an electron probe according to claim 1, characterized in that, Both the line scan analysis data and the quantitative analysis data include location information and component content information.

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