An optical fiber and a method for making an optical fiber

Abstract

This application provides an optical fiber and a method for fabricating the optical fiber. The refractive index difference between at least two points in the cross-section of the optical fiber is greater than or equal to 0.01, and at least five sets of points in the cross-section satisfy preset conditions. The k-th set of points in the at least five sets includes x. k Point and y k Point, the x k Point and y k The point is any point in the cross-section, and the preset conditions include nx. k -ny k ≥0.001 and rx k -ry k <0, where nx k For x k The refractive index of a point, ny k For y k The refractive index of a point, rx k For x k The distance from the point to the center of the cross-section, ry k For y k The distance from the point to the center of the cross-section, k, is a positive integer greater than or equal to 1. This optical fiber includes multiple sets of points with different refractive indices, giving the cross-section different refractive index distribution characteristics. This allows light to undergo total internal reflection at appropriate locations during transmission, thereby increasing the fiber's bandwidth.

Description

Technical Field

[0001] This application relates to the field of materials, and more specifically, to an optical fiber, a method for fabricating an optical fiber, a communication medium, an optical module, and an optical transmission system. Background Technology

[0002] Plastic optical fiber (POF) is an optical fiber made from highly transparent polymers. Compared to silica optical fiber, POF has advantages such as light weight and high flexibility, and has been widely used in automotive, fiber-to-the-home, and medical applications. To improve the bandwidth of POF, the core material is usually adjusted to have different refractive indices. Current technologies for manufacturing POF require the pre-fabrication of multiple materials with different refractive indices, followed by composite bonding, resulting in a complex manufacturing process. Furthermore, the different viscosities of materials with varying refractive indices make it difficult to composite these materials into an optical fiber with a uniform structural distribution, thus affecting the fiber's performance.

[0003] Improving the performance of plastic optical fibers has become an urgent problem to be solved. Summary of the Invention

[0004] This application provides an optical fiber, a method for fabricating an optical fiber, a communication medium, an optical module, and an optical transmission system. The optical fiber contains multiple sets of points with different refractive indices, so that the cross-section of the optical fiber has different refractive index distribution characteristics, thereby enabling total internal reflection of light at corresponding positions during optical fiber transmission, thereby achieving the effect of increasing the bandwidth of the optical fiber.

[0005] In a first aspect, an optical fiber is provided. The refractive index difference between at least two points in the cross-section of the optical fiber is greater than or equal to 0.01, and at least five sets of points in the cross-section satisfy a preset condition, wherein the k-th set of points among the at least five sets includes x. k Point and y k Point, the x k Point and y k The point is any point in the cross-section, and the preset conditions include nx. k -ny k ≥0.001 and rx k -ry k <0, where nx k For x k The refractive index of a point, ny k For y k The refractive index of a point, rx k For x k The distance from the point to the center of the cross-section, ry k For y kThe distance from the point to the center of the cross-section, where k is a positive integer greater than or equal to 1.

[0006] In this embodiment, the optical fiber includes points with a refractive index difference greater than or equal to 0.01. By controlling the refractive index difference at each point, optical fibers with different numerical apertures can be fabricated, thereby obtaining optical fibers that meet performance requirements. The optical fiber also includes at least five sets of points with a refractive index difference greater than 0.001, giving the fiber cross-section different refractive index distribution characteristics. This allows total internal reflection to occur at corresponding positions during light transmission in the optical fiber, thereby increasing the fiber bandwidth. Furthermore, each set of points satisfies rx k -ry k The preset condition of <0 results in a gradually changing refractive index distribution in the optical fiber.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, at least seven sets of points in the cross section satisfy the preset condition.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, the refractive index difference between at least two points in the cross section is greater than or equal to 0.013.

[0009] In this embodiment, the optical fiber includes multiple points with a refractive index difference greater than or equal to 0.013, which makes the numerical aperture of the optical fiber larger and can improve the performance of the optical fiber.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the x-th point of at least one set of points in the cross-section i Point and y i The spacing between the points is less than or equal to 50 micrometers, and the x i Point and y i The refractive index difference between the points is greater than 0.002, and i is a positive integer greater than or equal to 1.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the light transmittance of the optical fiber material is greater than 80%.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the light transmittance of the optical fiber material is greater than 90%.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the test wavelength for transmittance is 650 nanometers.

[0014] In this embodiment, the optical fiber material has high light transmittance, which reduces light loss during transmission and improves optical fiber performance.

[0015] In conjunction with the first aspect, in some implementations of the first aspect, the spacing between any two points in the cross-section is greater than or equal to 0.2 micrometers.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the distribution of refractive index of some points along the line connecting the center to the edge of the cross section is fitted to a curve, or the distribution of the refractive index difference between these points and the center point of the cross section is fitted to a curve.

[0017] In this embodiment of the application, the refractive index in the cross-section of the optical fiber has a relatively smooth, gradual distribution.

[0018] In conjunction with the first aspect, in some implementations of the first aspect, the curve is an upwardly convex curve.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, the curve is a partial curve of a quadratic equation or a partial curve of a cubic equation.

[0020] In this embodiment of the application, the refractive index distribution in the cross-section of the optical fiber is parabolic, that is, the refractive index distribution in the cross-section of the optical fiber is a relatively smooth gradient curve.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the optical fiber is a plastic optical fiber.

[0022] Optionally, the plastic optical fiber in the embodiments of this application may comprise a polymer material. Alternatively, the plastic optical fiber in the embodiments of this application may comprise quartz and a polymer material.

[0023] Secondly, a method for fabricating optical fibers is provided. The method includes: inputting M initial materials into an optical fiber fabricator, and obtaining an optical fiber from the outlet of the optical fiber fabricator, wherein at least two of the M initial materials have different refractive indices.

[0024] In this embodiment, optical fibers can be fabricated using at least two initial materials with different refractive indices and an optical fiber fabrication device, making the method for fabricating optical fibers relatively simple and efficient.

[0025] In conjunction with the second aspect, in some implementations of the second aspect, the optical fiber fabricator includes a splitter and a compositer. The splitter includes M first inlets and N first outlets, with at least two of the M first inlets connected to at least one of the N first outlets. The compositer includes P second inlets and Q second outlets, with the P second inlets and Q second outlets connected. The N first outlets are connected to the P second inlets, where M, N, and P are positive integers greater than or equal to 2, Q is a positive integer greater than or equal to 1, and P is greater than or equal to Q.

[0026] In conjunction with the second aspect, in some implementations of the second aspect, M initial materials are respectively input into the M first inlets of the splitter, and N materials are obtained from the N first outlets of the splitter, wherein at least two of the N materials contain different proportions of the initial materials.

[0027] In this embodiment, the splitter in the optical fiber fabrication device can simultaneously split and mix the M initial materials, thereby simultaneously preparing N materials to be composited into an optical fiber. That is, according to the method in this embodiment, it is unnecessary to separately prepare the N materials required for compositing into an optical fiber from the M initial materials before fabricating the optical fiber, making the optical fiber fabrication process simpler and thus improving the efficiency of optical fiber fabrication.

[0028] In conjunction with the second aspect, in some implementations of the second aspect, N kinds of materials are respectively input into the P second inlets of the compositer, and optical fibers are obtained from the Q second outlets of the compositer, where P equals N.

[0029] In this embodiment of the application, after M kinds of initial materials are put into the optical fiber fabrication device, N kinds of materials can be obtained from the splitter, and the N kinds of materials are combined in the compositer to obtain optical fiber, thereby reducing the difficulty of optical fiber fabrication.

[0030] In conjunction with the second aspect, in some implementations of the second aspect, the refractive index fluctuation rate of each of the N materials in the first outlet of the splitter or the second inlet of the resonator is less than 0.5%.

[0031] In this embodiment, the refractive index fluctuation rate of the N materials obtained in the splitter is small, meaning the refractive index of the N materials is relatively stable, thus enabling the fabrication of a structurally stable optical fiber. By controlling the refractive index of the material in each flow channel, the refractive index in the cross-section of the optical fiber exhibits a gradually changing distribution.

[0032] In conjunction with the second aspect, in some implementations of the second aspect, the distributor further includes a perforated plate structure. At least two of the M initial materials are sequentially input to at least one first outlet through at least two first inlets and the perforated plate structure, and the amounts of the at least two initial materials input to the first outlet through the perforated plate structure are different.

[0033] In this embodiment, the amount of initial material input to each first outlet can be controlled by the porous plate structure in the splitter, thereby producing N kinds of materials, and at least two of the N kinds of materials contain different proportions of the initial material.

[0034] In conjunction with the second aspect, in some implementations of the second aspect, at least one of the M first inlets is provided with a first diversion structure, and the amount of initial material diverted through the first diversion structure is different.

[0035] In this embodiment of the application, the amount of initial material to be split can be controlled by the first splitting structure, thereby preparing N kinds of materials, and at least two of the N kinds of materials contain different proportions of the initial material.

[0036] In conjunction with the second aspect, in some implementations of the second aspect, M initial materials are obtained through M extruders.

[0037] In conjunction with the second aspect, in some implementations of the second aspect, the optical fiber is the optical fiber as described in the first aspect or any possible implementation of the first aspect.

[0038] In the embodiments of this application, optical fibers as described in the first aspect or any possible implementation of the first aspect can be fabricated using at least two initial materials with different refractive indices and an optical fiber fabrication device, thereby reducing the difficulty of fabricating high-performance optical fibers.

[0039] Thirdly, a communication medium is provided. This communication medium includes an outer sheath and an optical fiber as described in the first aspect or any possible implementation thereof. Alternatively, the optical fiber in the communication medium is fabricated using a method as described in the second aspect or any possible implementation thereof.

[0040] Fourthly, an optical module is provided. The optical module includes a photoelectric converter and an optical fiber as described in the first aspect or any possible implementation thereof. Alternatively, the optical fiber in the optical module is fabricated using the method described in the second aspect or any possible implementation thereof.

[0041] Fifthly, an optical transmission system is provided. This optical transmission system includes an optical transmitter, an optical receiver, and an optical fiber as described in the first aspect or any possible implementation thereof. Alternatively, the optical fiber in this optical transmission system is fabricated using the method described in the second aspect or any possible implementation thereof. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the cross-section of an optical fiber according to an embodiment of this application.

[0043] Figure 2 This is a schematic distribution curve of the refractive index difference at some points in a cross-section according to an embodiment of this application.

[0044] Figure 3This is a schematic flowchart of a method for fabricating optical fibers according to an embodiment of this application.

[0045] Figure 4 This is a schematic structural diagram of a device for fabricating optical fibers according to an embodiment of this application.

[0046] Figure 5 This is a schematic structural diagram of a device for fabricating optical fibers according to another embodiment of this application.

[0047] Figure 6 This is a cross-sectional schematic diagram of the first inlet according to an embodiment of this application.

[0048] Figure 7 This is a schematic flowchart of a method for fabricating optical fibers according to another embodiment of this application. Detailed Implementation

[0049] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0050] Figure 1 This is a schematic diagram of the cross-section of the optical fiber provided in the embodiments of this application. Figure 1 The cross-section of the optical fiber 100 may include at least two points. The refractive index difference between the at least two points is greater than or equal to 0.01. At least five sets of points in the cross-section satisfy a preset condition, and the k-th set of points among the at least five sets includes x. k Point and y k Point, the x k Point and y k The point is any point in the cross-section, and the preset conditions include nx. k -ny k ≥0.001 and rx k -ry k <0, where nx k For x k The refractive index of a point, ny k For y k The refractive index of a point, rx k For x k The distance from the point to the center of the cross-section, ry k For y k The distance from the point to the center of the cross-section, where k is a positive integer greater than or equal to 1.

[0051] In some embodiments, each point in the cross-section is the intersection of the light ray passing through the cross-section and the cross-section when testing the refractive index or refractive index difference. For example, as Figure 1 As shown, the cross-section may include point a and point b. The embodiments of this application do not limit the area or size of each point in the cross-section.

[0052] In some embodiments, the difference in refractive index between two points in the cross-section can be determined based on the speed of light propagation at those two points.

[0053] In some embodiments, the center of the cross-section can be its geometric center or centroid, etc. For example, if the cross-section is a regular shape with symmetry, then the center of the cross-section can be its geometric center. Regular shapes with symmetry can be, for example, parallelograms, squares, equilateral triangles, circles, etc. Figure 1 As shown, since the cross-section is circular, its center can be the center of the circle, i.e., point z. If the cross-section is an asymmetrical or irregular shape, its center can be its centroid.

[0054] In some embodiments, the optical fiber 100 may be a plastic optical fiber.

[0055] In some embodiments, the cross-section may include at least five sets of points that satisfy the preset condition. Each of the at least five sets of points may contain different points. Alternatively, any two sets of points may contain one point that is the same.

[0056] For example, suppose the cross-section includes five sets of points, namely (x1, y1), (x2, y2), (x3, y3), (x4, y4), and (x5, y5). Here, (x1, y1) is the first set of points, meaning it includes both x1 and y1. Similarly, (x5, y5) is the fifth set of points, meaning it includes both x5 and y5. The points x1, y1, x2, y2, x3, y3, x4, y4, x5, and y5 can be ten different points. Alternatively, for the first set of points (x1, y1) and the second set of points (x2, y2), x1 and x2 can be the same point, and y1 and y2 can be different points. Or, x1 and x2 can be different points, and y1 and y2 can be the same point.

[0057] In some embodiments, each of the at least five sets of points in the cross-section is located within a sector of the cross-section. The area of ​​this sector is not limited in the embodiments of this application. Particularly preferably, each of the at least five sets of points in the cross-section is located on a line connecting the center of the cross-section to its edge.

[0058] Preferably, the cross-section includes at least seven sets of points that satisfy the preset condition.

[0059] Preferably, the refractive index difference between at least two points in the cross section is greater than or equal to 0.013.

[0060] In some embodiments, the spacing between any two points in the cross-section is greater than or equal to 0.2 micrometers (μm).

[0061] In some embodiments, the distance between two points in each group of at least one set of points in the cross-section is less than or equal to 50 micrometers, and the refractive index difference between the two points in each group is greater than 0.002. That is, the x-value of the i-th point in the at least one set of points in the cross-section is... i Point and y i The spacing between the points is less than or equal to 50 micrometers, and the x i Point and y i The refractive index difference between the points is greater than 0.002, and i is a positive integer greater than or equal to 1.

[0062] Preferably, the distance between the two points in each group of at least one point in the cross-section is less than or equal to 50 micrometers, and the difference in refractive index between the two points in each group is greater than 0.004.

[0063] For example, when point x is the center of the cross-section, the refractive index difference between some points y and point x in the cross-section is shown in Table 1.

[0064] Table 1. Refractive index difference between points y and x in a cross-section.

[0065] 0 0.0000 0.0000 0 80 -0.0010 0.0010 -80 100 -0.0017 0.0017 -100 120 -0.0027 0.0027 -120 140 -0.0042 0.0042 -140 160 -0.0060 0.0060 -160 180 -0.0080 0.0080 -180 200 -0.0107 0.0107 -200 220 -0.0140 0.0140 -220 240 -0.0151 0.0151 -240

[0066] In Table 1, the distance between point y and point x is in micrometers, and the unit of rx-ry is micrometers.

[0067] As shown in Table 1, when point x is the center of the cross-section of fiber 100, the refractive index difference between point x and point y, which is 80 micrometers away from point x, is 0.001.

[0068] In some embodiments, the distribution of refractive index at certain points along a line connecting the center to the edge of the cross-section can be fitted as a curve. Alternatively, the distribution of the refractive index difference between these points and the center point of the cross-section can be fitted as a curve.

[0069] In some embodiments, the curve can be a downwardly convex curve or an upwardly convex curve. Preferably, the curve is an upwardly convex curve.

[0070] In some embodiments, the curve is a portion of a quadratic equation curve or a portion of a cubic equation curve.

[0071] In some embodiments, the curve may include two or three extreme values.

[0072] For example, when point x is the center of the cross-section, the distribution of the refractive index difference between some points y and x in the cross-section is as follows: Figure 2 As shown.

[0073] Figure 2 This is a schematic distribution curve of the refractive index difference at some points in the cross-section of the optical fiber provided in this application embodiment. Figure 2 The x-coordinate in the figure represents the distance between the y-point and the x-point in the cross-section, in micrometers. Figure 2 The vertical axis represents the difference in refractive index between the y-point and the x-point in the cross-section. Figure 2 The diagram includes curve 1 and curve 2. Curve 1 represents the refractive index difference between a portion of points y and x in the cross-section of optical fiber 100, where points y are points on the same line connecting the center to the edge of the cross-section. Curve 2 is a curve obtained by fitting curve 1.

[0074] from Figure 2 As can be seen, curve 2 is an upward-convex curve. In other words, curve 2 is a partial curve of a quadratic equation. Alternatively, curve 2 is a partial curve of a cubic equation. Furthermore, curves 1 and 2 largely coincide, meaning that the refractive index difference between some y-points and x-points in the cross-section of optical fiber 100 exhibits a relatively smooth, gradual distribution.

[0075] from Figure 2 It can also be seen that the difference between the refractive index at point y, which is closer to the center of the cross-section, and the refractive index at point x, which is farther from the center of the cross-section, is larger. In other words, the refractive index at point y, which is closer to the center of the cross-section, is larger, and the refractive index at point y, which is farther from the center of the cross-section, is smaller.

[0076] In some embodiments, the optical fiber 100 is made from M kinds of initial materials, where M is a positive integer greater than or equal to 2.

[0077] In some embodiments, the M initial materials include a first initial material. The first initial material has a light transmittance greater than 80%, preferably greater than 85%, and more preferably greater than 90%.

[0078] In some embodiments, the M types of initial materials include a second initial material. The second initial material has a light transmittance greater than 80%, preferably greater than 85%, and more preferably greater than 90%. The second initial material is an initial material that is different from the first initial material among the M types of initial materials.

[0079] In some embodiments, each of the M initial materials may be a fluorine-containing material or a fluorine-free material.

[0080] When any of the M initial materials is a fluorine-containing material, the fluorine content of that initial material is not limited. Generally, fluorine-containing materials, especially amorphous fluorine-containing materials, have low refractive indices and good light transmittance. Through proper selection, high-performance plastic optical fibers can be fabricated.

[0081] In some embodiments, the refractive index of the material can be obtained by measuring with an Abbe refractometer. This application does not limit the wavelength for measuring the refractive index; for example, it can be 656 nanometers (nm).

[0082] In some embodiments, the initial material may be a single material or a mixture of materials containing different refractive indices.

[0083] In some embodiments, the first initial material may be a high-refractive-index polymer. For example, the first initial material may be a material comprising high-refractive-index small molecules and polymethyl methacrylate (PMMA).

[0084] In some embodiments, the second initial material may be a low-refractive-index polymer. For example, the second initial material may be PMMA.

[0085] The embodiments of this application do not limit the specific value or range of the refractive index of the first initial material or the second initial material.

[0086] In some embodiments, the refractive index difference between the first initial material and the second initial material is greater than or equal to 0.01. Preferably, the refractive index difference between the first initial material and the second initial material is greater than or equal to 0.013. For example, as shown in Tables 2 and 3 below, assuming that the refractive indices of the first initial material and the second initial material are 1.507 and 1.488 respectively under the test conditions at a wavelength of 656 nm, the refractive index difference between the first initial material and the second initial material can be 0.019.

[0087] In some embodiments, the optical fiber 100 may include N types of materials, which are prepared from M initial materials, where N is a positive integer greater than or equal to 2. At least two of the N types of materials have different refractive indices.

[0088] The embodiments of this application do not limit the relationship between N and M. For example, N can be less than M, or N can be greater than or equal to M. Preferably, N is greater than M.

[0089] In some embodiments, the optical fiber 100 may include a first material, which is a first initial material.

[0090] In some embodiments, the optical fiber 100 may include a second material prepared from at least two initial materials. The second material has a light transmittance greater than 80%, preferably greater than 85%, and more preferably greater than 90%.

[0091] In some embodiments, the optical fiber 100 may include a third material, which is prepared from at least two initial materials. The light transmittance of the third material is greater than 80%, preferably greater than 85%, and more preferably greater than 90%.

[0092] In some embodiments, the optical fiber 100 may include a fourth material, which is prepared from at least two initial materials. The fourth material has a light transmittance greater than 80%, preferably greater than 85%, and more preferably greater than 90%.

[0093] In some embodiments, the optical fiber 100 may include a fifth material, which is prepared from at least two initial materials. The transmittance of the fifth material is greater than 80%, preferably greater than 85%, and more preferably greater than 90%.

[0094] In some embodiments, the optical fiber 100 may include a sixth material, which is prepared from at least two initial materials. The transmittance of the sixth material is greater than 80%, preferably greater than 85%, and more preferably greater than 90%.

[0095] In some embodiments, the optical fiber 100 may include a seventh material, which is a second initial material.

[0096] It should be understood that the first material, second material, third material, fourth material, fifth material, sixth material, and seventh material are different materials among the N materials, and at least two of the N materials contain different proportions of the initial material. The N materials may include any one or more of the first material, second material, third material, fourth material, fifth material, sixth material, and seventh material. For example, the first material, second material, third material, fourth material, fifth material, sixth material, and seventh material may each be one of the seven first outlets listed in Tables 2 and 3 below.

[0097] In some embodiments, the light transmittance of the optical fiber material is greater than 80%. Preferably, the light transmittance of the optical fiber material is greater than 85%. More preferably, the light transmittance of the optical fiber material is greater than 90%.

[0098] In some embodiments, the transmittance of the optical fiber material is determined by testing after film formation using finished optical fiber or a portion thereof. Similarly, the transmittance of any of the M initial materials or any of the N materials can be determined by testing after film formation using finished materials. This application does not limit the specific test wavelength for transmittance; preferably, a wavelength near the light source is used, for example, a test wavelength of 650 nm.

[0099] In some embodiments, each of the N materials may be a fluorine-containing material or a fluorine-free material.

[0100] When any of the N materials is a fluorine-containing material, there is no limitation on the fluorine content. Generally, fluorine-containing materials, especially non-crystalline fluorine-containing materials, have low refractive indices and good light transmittance. Through proper selection, high-performance plastic optical fibers can be fabricated.

[0101] Figure 3 This is a schematic flowchart of a method for fabricating optical fibers provided in an embodiment of this application. Figure 3 The process includes the following step S310.

[0102] S310: Input M types of initial materials into the optical fiber fabricator and obtain optical fiber from the outlet of the optical fiber fabricator.

[0103] At least two of the M initial materials have different refractive indices, where M is a positive integer greater than or equal to 2. Preferably, M = 2 or 3.

[0104] In some embodiments, the M initial materials include the first initial material and / or the second initial material described above.

[0105] In some embodiments, the optical fiber obtained from the outlet of the optical fiber fabricator and... Figure 1 It is similar to fiber optic cable 100.

[0106] Alternatively, the fiber fabricator can be as follows: Figure 4 The device 400 is shown in the figure.

[0107] Figure 4 This is a schematic structural diagram of a device for fabricating optical fibers provided in an embodiment of this application. Figure 4 The device 400 includes a cavity structure 410. The cavity structure 410 has M inlets and Q outlets, where Q is a positive integer greater than or equal to 1. At least two of the M inlets are connected to the Q outlets. The M inlets are used to input M initial materials, and the Q outlets are used to obtain optical fibers.

[0108] Preferably, Q = 1.

[0109] This application does not specifically limit the shape or material of the cavity structure 410. For example, the cavity structure 410 can be a regular cuboid, cylinder, prism, etc., or the cavity structure 410 can have an irregular shape, or the cavity structure 410 can be spliced ​​together from substructures with regular shapes and / or substructures with irregular shapes.

[0110] In some embodiments, optical fibers can be obtained directly from the outlet of the optical fiber fabricator. Alternatively, an optical fiber preform, such as an optical fiber preform rod, can be obtained from the outlet of the optical fiber fabricator. This optical fiber preform can be formed into an optical fiber after operations such as stretching and winding.

[0111] Alternatively, the fiber fabricator can be as follows: Figure 5 The device 500 is shown in the figure. It should be understood that device 500 is one design of the embodiments of this application. Various functional parts can be added to the device as needed. The position of the added parts is not limited. They can be before the shunt 510, between the shunt 510 and the recombination unit 520, or after the recombination unit 520. Multiple functional parts can also be added.

[0112] Figure 5 This is a schematic structural diagram of the device 500 for fabricating optical fibers provided in the embodiments of this application. Figure 5 Device 500 includes a shunt 510 and a combiner 520. The shunt 510 includes M first inlets and N first outlets, with at least two of the M first inlets connected to at least one of the N first outlets. The combiner 520 includes P second inlets and Q second outlets, which are connected. The N first outlets of the shunt 510 are connected to the P second inlets of the combiner 520. N and P are positive integers greater than or equal to 2, and P is greater than or equal to Q.

[0113] Optionally, the M first inlets of the splitter 510 can be the M inlets of the fiber optic fabricator 500, or each first inlet of the splitter 510 can be connected to one inlet of the fiber optic fabricator 500. The Q second outlets of the compositer 520 can be the Q outlets of the fiber optic fabricator 500, or each second outlet of the compositer 520 can be connected to one outlet of the fiber optic fabricator 500. The N first outlets of the splitter 510 are connected to the P second inlets of the compositer 520.

[0114] Preferably, N is a positive integer greater than or equal to 5.

[0115] The embodiments of this application do not limit the relationship between P and N. For example, P can be less than N, or P can be greater than or equal to N. Preferably, P equals N.

[0116] In some embodiments, after M initial materials are respectively input into the M first inlets of the distributor 510, N types of materials can be obtained from the N first outlets of the distributor 510. At least two of the N types of materials contain different proportions of the initial materials.

[0117] The embodiments of this application do not limit the relationship between N and M. For example, N can be less than M, or N can be greater than or equal to M. Preferably, N is greater than M.

[0118] In some embodiments, after obtaining N types of materials from the N first outlets of the splitter 510, the N types of materials can be respectively input into the P second inlets of the compositer 520, and optical fibers can be obtained from the Q second outlets of the compositer 520.

[0119] In some embodiments, optical fibers can be obtained directly from the second outlet of the compositer 520. Alternatively, an optical fiber preform, such as an optical fiber preform rod, can be obtained from the second outlet of the compositer 520. This optical fiber preform can be formed into an optical fiber after operations such as stretching and winding.

[0120] Optionally, the diverter 510 may include a perforated plate structure. At least two of the M initial materials are sequentially input into at least one first outlet of the diverter 510 through at least two first inlets and the perforated plate structure. The amounts of the at least two initial materials input into the first outlet through the perforated plate structure are different.

[0121] In some embodiments, the porous plate structure includes a substrate having at least one through-hole. When the porous plate structure includes multiple through-holes, the multiple through-holes may be identical, or at least two of the multiple through-holes may be different. The difference between the at least two through-holes refers to the fact that the at least two through-holes may have different shapes and / or sizes.

[0122] For example, suppose a porous plate structure includes two types of through-holes, namely a first type and a second type, and these two types of through-holes are different. A first initial material can be input to a first outlet through the first type of through-hole in the porous plate structure, and a second initial material can be input to the first outlet through the second type of through-hole in the porous plate structure. Since the first type of through-hole and the second type of through-hole are different, the amounts of the first initial material and the second initial material input to the first outlet are different. That is, by allowing different initial materials to pass through different through-holes in the porous plate structure, the amount of initial material passing through each through-hole can be adjusted, thereby controlling the amount of initial material passing through the porous plate structure, and thus controlling the proportion of initial material contained in the material output from the first outlet. For example, as shown in Tables 2 and 3 below, after two initial materials are input into the splitter and split through the porous plate structure, seven materials can be obtained from the seven first outlets of the splitter. At least two of these seven materials contain different proportions of initial material, and therefore at least two of these seven materials have different refractive indices.

[0123] It should be understood that the number of perforated plate structures included in the diverter 510 is not limited in the embodiments of this application. That is, the diverter 510 may include one or more perforated plate structures.

[0124] In some embodiments, the porous plate structure may be disposed in the communicating cavity, that is, the distributor 510 may include the communicating cavity. The communicating cavity may be connected to at least two of the M first inlets, and may also be connected to at least one of the N first outlets. The initial material input into the communicating cavity passes through the porous plate structure and is output to the first outlet connected to the communicating cavity.

[0125] In some embodiments, a non-planar structure may also be provided in the communicating cavity. This non-planar structure is disposed between the porous plate structure and one inlet of the communicating cavity, each inlet of the communicating cavity communicating with at least one first inlet. Alternatively, the non-planar structure is disposed near one inlet of the communicating cavity. The initial material flow velocity differs before and after passing through the non-planar structure.

[0126] Optionally, at least one of the M first inlets is provided with a first diversion structure. The amount of initial material diverted through this first diversion structure varies. That is, by allowing the initial material to pass through the first diversion structure and then be input into the first outlet, the amount of initial material input to the first outlet can be adjusted, thereby controlling the proportion of initial material contained in the material output from the first outlet. For example, as shown in Tables 2 and 3 below, after two types of initial materials are input into the diverter and diverted through the first diversion structure, seven types of materials can be obtained from the seven first outlets of the diverter. At least two of these seven materials contain different proportions of initial material, and therefore at least two of these seven materials have different refractive indices.

[0127] In some embodiments, the first diversion structure may include at least two different through holes, and a first inlet with the first diversion structure is connected to at least one first outlet through the at least two different through holes. The through holes may be different in cross-sectional dimensions, including information such as length, width, radius, diameter, and area. Alternatively, the first diversion structure may include at least two different flow channels, and a first inlet with the first diversion structure is connected to at least one first outlet through the at least two different flow channels. The flow channels may be different in length and / or cross-sectional dimensions, while the flow channels may be identical in both length and cross-sectional dimensions.

[0128] In some embodiments, the first inlet can communicate with at least one first outlet through at least one through hole, and the inner surface of the first inlet where the at least one through hole is located is a first inner surface. The first diversion structure can be fitted to the first inner surface.

[0129] For example, when the first inlet is a flow channel structure or a cavity structure, the distance between the first surface of the first diversion structure and the first through hole is different from the distance between the first through hole and the bottom surface of the first inlet. The first surface of the first diversion structure is the surface of the first diversion structure adjacent to the first through hole, and the first through hole is any one of the at least one through hole of the first inlet. The first diversion structure is used to control the amount of initial material passing through each through hole of the first inlet.

[0130] The embodiments of this application do not limit the specific form of the first shunt structure. For example, the first shunt structure may have a regular shape or an irregular shape. For example, the first shunt structure may be as follows: Figure 6 The first shunt structure 620 is shown in the diagram. It should be understood that... Figure 6 This is one possible form of the first diversion structure. Depending on actual needs, the first diversion structure can also take the form of a stepped structure, a curved surface structure, or many other forms.

[0131] Figure 6This is a cross-sectional schematic diagram of the first entry point provided in an embodiment of this application. Figure 6 The first inlet 600 includes a through-hole 610, a first diversion structure 620, through-holes 601, 602, 603, 604, and 605. Through-hole 610 is used to input initial material. Through-holes 601 to 605 can each communicate with at least one first outlet. The amount of initial material input through through-hole 610 and then through the first diversion structure 620 into through-holes 601 to 605 differs. The embodiments of this application do not limit the cross-sectional dimensions of through-holes 601 to 605; for example, through-holes 601 to 605 can be the same through-hole, or at least two of the through-holes 601 to 605 can be different through-holes.

[0132] Optionally, the orifice diameters at both ends of each of the N first outlets may be the same, and the orifice diameter near the first inlet of the first outlet with the same orifice diameter at both ends may be the same as the orifice diameter away from the first inlet. Alternatively, the N first outlets may include at least one first outlet with different orifice diameters at both ends, and the orifice diameter near the first inlet of the first outlet with different orifice diameters at both ends may be different from the orifice diameter away from the first inlet. The material flow velocity is different before and after passing through the first outlet with different orifice diameters at both ends.

[0133] Optionally, the compositer 520 may include a first flow channel. This first flow channel connects P second inlets and Q second outlets. N materials input from the P second inlets can be composited within this first flow channel, and Q optical fibers or Q optical fiber preforms can be obtained from the Q second outlets.

[0134] Optionally, the compositer 520 may include a mandrel. The mandrel is disposed between P second inlets and Q second outlets. N materials input from the P second inlets can be composited on the surface of the mandrel, and Q optical fibers or Q optical fiber preforms are obtained from the Q second outlets.

[0135] In some embodiments, the mandrel may be disposed in the first flow channel, or a portion of the mandrel may be located in the first flow channel.

[0136] Optionally, at least one of the P second inlets of the compositer 520 may include a first opening, a second flow channel, and a second opening connected in sequence. After material is input through the first opening, it flows through the second flow channel and the second opening to the second outlet. The specific form of the second flow channel is not limited in this embodiment. For example, the second flow channel may be a straight flow channel, a non-straight flow channel, a straight groove, or a non-straight groove. When the second flow channel is a non-straight flow channel or a groove, the material input from the first opening will not flow directly into the first flow channel or directly cover the mandrel. Simultaneously, the flow distance of the material in the second inlet can be better controlled, and the melt flow rate can be controlled, resulting in a more uniform structural distribution of the material in each layer of the fabricated optical fiber. In some embodiments, the second flow channel may be a closed structure or a non-closed structure.

[0137] Optionally, M initial materials can be obtained using M extruders. Each of the M extruders can be connected to one inlet of the optical fiber fabrication unit.

[0138] Optionally, the refractive index fluctuation rate of each of the N materials in the first outlet of the splitter or the second inlet of the resonator is less than 0.5%.

[0139] For example, suppose the refractive indices of the two initial materials input to the shunt are 1.507 and 1.488, respectively, under a test condition at a wavelength of 656 nm. With N=7, the fluctuation rate of the refractive index of the materials at the same location in the shunt at different time points within 50 minutes under the test condition of 656 nm wavelength is shown in Tables 2 and 3. The fluctuation rate is calculated as (sampled refractive index - average refractive index) * 100 / average refractive index. This average refractive index is the average of the refractive indices of 10 batches of sampled materials.

[0140] Table 2: Fluctuation Rate Data of Refractive Index of Materials

[0141]

[0142] Table 3: Refractive Index Fluctuation Data for Materials

[0143]

[0144]

[0145] As shown in Tables 2 and 3, the average refractive index of the material at the first location is approximately 1.507 within 50 minutes. At the 15-minute mark, the fluctuation rate of the refractive index at the first location is approximately (1.505 - 1.507) * 100 / 1.507 ≈ -0.1. These first, second, third, fourth, fifth, sixth, and seventh locations are situated in different first outlets of the splitter. Tables 2 and 3 show that the fluctuation rate of the refractive index of the material at different first outlets within 50 minutes is less than or equal to 0.1%.

[0146] When each first outlet is connected to a second inlet, the fluctuation rate of the refractive index of the material in the connected first outlet and second inlet is basically the same. That is, as shown in Tables 2 and 3, the fluctuation rate of the refractive index of the material in different second inlets can be less than or equal to 0.1% within 50 minutes.

[0147] As can be seen from Tables 2 and 3, according to the method in the embodiments of this application, the fluctuation rate of the refractive index of the material in each first outlet of the splitter or each second inlet of the compositer is relatively small within a certain period of time. That is, according to the method in the embodiments of this application, the refractive index of the material in each first outlet of the splitter or each second inlet of the compositer can be made relatively stable, thereby producing an optical fiber with a relatively stable structure. At the same time, according to the method in the embodiments of this application, plastic optical fibers with graded refractive indices can be produced using only two materials with different refractive indices, thereby reducing the difficulty of producing plastic optical fibers.

[0148] Figure 7 This is a schematic flowchart of a method for fabricating optical fibers provided in an embodiment of this application. Figure 7 The method includes the following steps.

[0149] S710 feeds two initial materials into two extruders.

[0150] Two initial materials with different refractive indices were dried and then fed into two separate extruders. The specific extrusion temperature of the extruders is not limited in this embodiment and can be determined based on the thermal properties of the different initial materials. Preferably, the maximum extrusion temperature for each initial material can be in the range of Tg+50°C to Tg+150°C. Here, Tg is the glass transition temperature of the initial material.

[0151] Optionally, the two initial materials may include the first initial material and / or the second initial material described above.

[0152] In some embodiments, the maximum extrusion temperature corresponding to the first initial material can be 210°C. The maximum extrusion temperature corresponding to the second initial material can be 220°C.

[0153] Alternatively, the two initial materials can be dried at 80°C for more than 4 hours before being fed into the extruder.

[0154] S720: Two initial materials are fed into the optical fiber fabricator from the extruder, and an optical fiber preform is obtained from the outlet of the optical fiber fabricator.

[0155] This fiber optic fabricator can be used with... Figure 4 400 fiber fabrication device Figure 5 The fiber optic fabricator 500 is similar and will not be described in detail here.

[0156] In some embodiments, the optical fiber fabricator includes two inlets. Two extruders are connected to the two inlets of the optical fiber fabricator, respectively, thereby feeding two initial materials into the optical fiber fabricator.

[0157] In optical fiber fabrication equipment and Figure 5 When the device 500 is similar, the embodiments of this application do not limit the number of each initial material shunted in the shunt. For example, each initial material can be shunted into more than or equal to 5 parts after entering the shunt.

[0158] In this embodiment, the composite temperature when multiple materials are combined into an optical fiber preform in the compositer is not limited. The composite temperature can be determined based on the thermal properties of each initial material. For example, when the two initial materials are a first initial material and a second initial material, the composite temperature can be between 215°C and 220°C.

[0159] In some embodiments, optical fibers can be obtained directly from the outlet of the optical fiber generator. When optical fibers can be obtained directly from the outlet of the optical fiber generator, method 700 ends, meaning steps S730 and S740 no longer need to be executed.

[0160] In some embodiments, an optical fiber preform can be obtained from the outlet of the optical fiber fabricator. When obtaining the optical fiber preform at the outlet of the optical fiber fabricator, method 700 may further include steps S730 and S740.

[0161] S730, cooling fiber optic preform.

[0162] Optionally, the optical fiber preform can be cooled by natural cooling or air cooling. Natural cooling means cooling at room temperature.

[0163] S740 stretches and winds the cooled optical fiber preform to obtain the optical fiber.

[0164] After the optical fiber preform has been sufficiently cooled, it can be stretched and wound up to obtain the optical fiber.

[0165] Optionally, the optical fiber can have different core diameters depending on the winding speed. This application embodiment does not limit the winding speed; it can be determined based on the desired core diameter of the optical fiber. This application embodiment also does not limit the core diameter of the prepared optical fiber; it can be determined based on actual usage requirements. For example, the core diameter of the optical fiber can be 0.5 mm, i.e., the radius can be 0.25 mm.

[0166] This application embodiment can provide a communication medium that may include an outer sleeve and an optical fiber as described in the above-described embodiments. Alternatively, the optical fiber in the communication medium may be composed of, for example, Figure 3 or Figure 7 The method described above is used for preparation.

[0167] Alternatively, the communication medium may be, for example, a plastic optical fiber, optical cable, patch cord, etc.

[0168] This application embodiment can provide an optical module, which may include a photoelectric converter and an optical fiber as described in the above-described embodiments. Alternatively, the optical fiber in the optical module may be composed of, for example,... Figure 3 or Figure 7 The method described above is used for preparation.

[0169] This application provides an optical transmission system that may include an optical transmitter, an optical receiver, and an optical fiber as described in the above embodiments. Alternatively, the optical fiber in this optical transmission system may be composed of, for example,... Figure 3 or Figure 7 The method described above is used for preparation.

[0170] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical fiber, characterized in that, The refractive index difference between at least two points in the cross-section of the optical fiber is greater than or equal to 0.01, and at least five sets of points in the cross-section satisfy a preset condition. The k-th set of points among the at least five sets includes... Point and Point, the Point and the The point is any point in the cross-section, and the preset conditions include... and ,in, For the The refractive index of a point For the The refractive index of a point For the The distance from the point to the center of the cross-section. For the The distance from the point to the center of the cross-section, where k is a positive integer greater than or equal to 1. Point and The spacing between points is greater than or equal to 0.2 micrometers. The distribution of refractive index of some points along the line connecting the center to the edge of the cross-section is fitted to a curve, or the distribution of the refractive index difference between the some points and the center point of the cross-section is fitted to a curve. The some points include the at least five sets of points, and the curve is a gradient curve. The optical fiber is obtained through an optical fiber fabrication device. The fabrication device is used to input M initial materials, at least two of which have different refractive indices. The fabrication device includes a splitter and a recombination device. The splitter includes M first inlets and N first outlets, with at least two of the M first inlets connected to at least one of the N first outlets. The recombination device includes P second inlets and Q second outlets, with the P second inlets and Q second outlets connected, and the N first outlets connected to the P second inlets. M, N, and P are positive integers greater than or equal to 2, Q is a positive integer greater than or equal to 1, and P is greater than or equal to Q. The M first inlets of the splitter are used to input the M initial materials respectively, and the N first outlets of the splitter are used to obtain N materials. At least two of the N materials contain different proportions of the initial materials, and the refractive index fluctuation rate of each of the N materials within the first outlet of the splitter or the second inlet of the recombination device is less than 0.5%.

2. The optical fiber according to claim 1, characterized in that, At least seven sets of points in the cross-section satisfy the preset conditions.

3. The optical fiber according to claim 1 or 2, characterized in that, The refractive index difference between at least two points in the cross-section is greater than or equal to 0.

013.

4. The optical fiber according to claim 1 or 2, characterized in that, The i-th set of points in at least one set of points in the cross-section Point and the The spacing between the points is less than or equal to 50 micrometers. Point and the The refractive index difference between the points is greater than 0.002, and i is a positive integer greater than or equal to 1.

5. The optical fiber according to claim 1 or 2, characterized in that, The light transmittance of the optical fiber material is greater than 80%.

6. The optical fiber according to claim 1 or 2, characterized in that, The light transmittance of the optical fiber material is greater than 90%.

7. The optical fiber according to claim 5, characterized in that, The transmittance was measured at a wavelength of 650 nanometers.

8. The optical fiber according to claim 1 or 2, characterized in that, The curve is an upward-convex curve.

9. The optical fiber according to claim 1 or 2, characterized in that, The curve is a partial curve of a quadratic equation or a partial curve of a cubic equation.

10. The optical fiber according to claim 1 or 2, characterized in that, The optical fiber is a plastic optical fiber.

11. A method for fabricating optical fibers, characterized in that, include: M initial materials are input into an optical fiber fabrication device, and an optical fiber is obtained from the outlet of the optical fiber fabrication device. At least two of the M initial materials have different refractive indices. The optical fiber is an optical fiber as described in any one of claims 1 to 10. The optical fiber fabrication device includes a splitter and a compositer. The splitter includes M first inlets and N first outlets. At least two of the M first inlets are connected to at least one of the N first outlets. The compositer includes P second inlets and Q second outlets. The P second inlets are connected to the Q second outlets, and the N first outlets are connected to the P second inlets. M, N, and P are positive integers greater than or equal to 2, Q is a positive integer greater than or equal to 1, and P is greater than or equal to Q. The step of inputting M initial materials into the optical fiber fabrication device and obtaining optical fiber from the outlet of the optical fiber fabrication device includes: The M initial materials are respectively input into the M first inlets of the splitter, and N materials are obtained from the N first outlets of the splitter. At least two of the N materials contain different proportions of the initial materials, and the refractive index fluctuation rate of each of the N materials in the first outlet of the splitter or the second inlet of the composite is less than 0.5%.

12. The method according to claim 11, characterized in that, The method further includes: The N materials are respectively input into the P second inlets of the compositer, and the optical fiber is obtained from the Q second outlets of the compositer, where P equals N.

13. The method according to claim 11 or 12, characterized in that, The diverter also includes a perforated plate structure, wherein at least two of the M initial materials are sequentially input to the at least one first outlet through the at least two first inlets and the perforated plate structure, and the amounts of the at least two initial materials input to the first outlet through the perforated plate structure are different.

14. The method according to claim 11 or 12, characterized in that, At least one of the M first inlets is provided with a first diversion structure, and the amount of initial material diverted through the first diversion structure is different.

15. The method according to claim 11 or 12, characterized in that, The method further includes: The M initial materials are obtained through M extruders.

16. A communication medium, characterized in that, It includes an outer sheath and an optical fiber as described in any one of claims 1 to 10, or the optical fiber in the communication medium is prepared by the method as described in any one of claims 11 to 15.

17. An optical module, characterized in that, It includes a photoelectric converter and an optical fiber as described in any one of claims 1 to 10, or the optical fiber in the optical module is prepared by the method as described in any one of claims 11 to 15.

18. An optical transmission system, characterized in that, It includes an optical transmitter, an optical receiver, and an optical fiber as described in any one of claims 1 to 10, or the optical fiber in the optical transmission system is prepared by the method described in any one of claims 11 to 15.

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