A multi-core optical fiber preform with a positionable core and a method of manufacturing the same

Abstract

The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber preform with positionable cores and a preparation method thereof, and relates to the technical field of special optical fiber preparation. The application provides a multi-core optical fiber

Description

Technical Field

[0001] This invention relates to the field of special optical fiber fabrication technology, and in particular to a multi-core optical fiber preform with a locatable core and its fabrication method. Background Technology

[0002] Traditional single-mode fiber is no longer sufficient to meet the demands of high-speed data transmission. Multi-core fiber, with multiple cores within the same cladding, directly increases the number of fiber transmission channels, thereby improving overall transmission capacity. Multiple cores sharing the same cladding reduces the number of fibers used to achieve the same effect, significantly lowering costs, saving space, and improving economic efficiency. Simultaneous transmission of multiple cores also provides backup for signal light, enhancing line reliability. Furthermore, transmitting the same power signal light requires fewer fibers, greatly reducing the complexity of manufacturing corresponding equipment and components. Doping the fiber cores with rare-earth elements provides additional amplification to the transmitted signal light.

[0003] Multi-core optical fibers have complex structures, and ensuring their stability and reliability in application places higher demands on the fiber manufacturing process. In some special applications, different fiber cores can be customized to achieve different functions, which requires marking the fiber cores for easy identification during application.

[0004] In existing technologies, the fabrication of multi-core preforms generally involves drilling holes to simultaneously drill the positions for the positioning core and the active fiber core. However, conventional drilling of high-purity quartz rods places high demands on the rods, and the distance between the holes for the positioning core and the active fiber core is limited. If the holes are too close, it will affect the shape of the fiber core, and if the holes are too large, it will be impossible to arrange the holes for the active fiber core. Therefore, the diameter of the holes for the positioning core is limited, and machining deep holes on quartz rods becomes even more difficult given that only small holes can be drilled. Summary of the Invention

[0005] This invention provides a method for preparing a multi-core optical fiber preform with a positionable fiber core, which solves the problem that it is more difficult to process deep holes on quartz rods in the prior art.

[0006] A method for preparing a multi-core optical fiber preform with a positionable fiber core according to the present invention includes:

[0007] Preparation of quartz mother rod, positioning core rod and transmission core rod;

[0008] A positioning hole is made along the axial direction on the quartz mother rod, and the positioning core rod is installed in the positioning hole;

[0009] The quartz mother rod on which the positioning core rod is installed is reduced in length to obtain a solid positioning core mother rod.

[0010] The solid positioning core mother rod is drilled to form a core rod hole, and the transmission core rod is installed in the core rod hole to obtain a multi-core optical fiber preform rod with a positionable core.

[0011] According to the method for preparing the multi-core optical fiber preform rod with a positionable core, the diameter of the positioning hole is x, the diameter of the positioning core rod is c, and 0≤x-c≤0.2 mm.

[0012] According to the method for preparing the multi-core optical fiber preform rod with a positionable core, the step of performing rod shrinking on the quartz mother rod with the positioning core rod installed thereon comprises the following steps: vacuumizing the positioning hole, heating the quartz mother rod with the positioning core rod installed thereon to a specified temperature, and making the positioning core rod shrink in the quartz mother rod.

[0013] According to the method for preparing the multi-core optical fiber preform rod with a positionable core, the specified temperature is 2000-2300 ℃.

[0014] According to the method for preparing the multi-core optical fiber preform rod with a positionable core, the solid positioning core mother rod is rounded before the core rod hole is drilled.

[0015] According to the method for preparing the multi-core optical fiber preform rod with a positionable core, the method further comprises the following steps:

[0016] A balancing rod is prepared, the material of the balancing rod is the same as that of the quartz mother rod, and the size of the balancing rod is the same as that of the positioning core rod.

[0017] At least one balancing hole is drilled on the quartz mother rod along the axial direction when the positioning hole is drilled, and the balancing rod is installed in each balancing hole, the balancing hole has the same size as the positioning hole and is symmetrically distributed with the positioning hole, and the center of the quartz mother rod is the symmetric center.

[0018] According to the method for preparing the multi-core optical fiber preform rod with a positionable core, the transmission core rod is a rare earth doped core rod.

[0019] According to the method for preparing the multi-core optical fiber preform rod with a positionable core, the positioning core rod is a fluorine doped quartz glass rod.

[0020] The application further provides a multi-core optical fiber preform rod with a positionable core, which is prepared by using the method for preparing the multi-core optical fiber preform rod with a positionable core according to any one of the above embodiments.

[0021] The application provides a preparation method of a multi-core optical fiber preform with positionable cores. BRIEF DESCRIPTION OF DRAWINGS DETAILED DESCRIPTION OF THE INVENTION BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0023] Figure 1 FIG. 1 is a flowchart of the preparation method of the multi-core optical fiber preform with positionable cores provided by the application.

[0024] Figure 2 FIG. 2 is a structural diagram of the multi-core optical fiber preform with positionable cores provided by the application.

[0025] Figure 3 FIG. 3 is a diagram of the connection relationship between the quartz mother rod and the positioning core rod provided by the application.

[0026] Figure 4 FIG. 4 is a diagram of the connection relationship between the positioning core rod and the balancing rod on the quartz mother rod provided by the application.

[0027] Figure 5 FIG. 5 is a diagram of the structural relationship when the rod is shrunk provided by the application.

[0028] LIST OF REFERENCE NUMERALS

[0029] 1, quartz mother rod; 11, positioning hole; 12, balancing hole; 2, positioning core rod; 3, transmission core rod; 4, core rod hole; 5, balancing rod; 6, heat source. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the application more clear, the following will combine the drawings in the application to clearly and completely describe the technical solutions in the application. Obviously, the described embodiments are some embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the application.

[0031] The terms "first", "second" in the description and claims of the present application can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in an "or" relationship.

[0032] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0033] The present application will be described below in conjunction with Figures 1-5 The present application provides a preparation method of a multi-core optical fiber preform with positionable cores.

[0034] As Figure 1 , Figure 2 The present application provides a preparation method of a multi-core optical fiber preform with positionable cores, which comprises the following steps:

[0035] S1, preparing a quartz mother rod 1, a positioning core rod 2 and a transmission core rod 3.

[0036] S2, an axial positioning hole 11 is formed on the quartz mother rod 1, and the positioning core rod 2 is installed in the positioning hole 11.

[0037] S3, the quartz mother rod 1 with the positioning core rod 2 installed is subjected to rod shrinking to obtain a solid positioning core mother rod.

[0038] S4, a core rod hole 4 is formed on the solid positioning core mother rod, and the transmission core rod 3 is installed in the core rod hole 4 to obtain a multi-core optical fiber preform with positionable cores.

[0039] Specifically, a high-purity quartz rod is selected as the quartz mother rod 1 for processing, or a pure quartz glass rod and a pure quartz glass sleeve can be combined to form a quartz mother rod 1 by hot melting and shrinking. The diameter of the positioning hole 11 is x, and the diameter of the positioning core rod 2 is c, 0≤x-c≤0.2mm.

[0040] Specifically, the positioning hole 11 is formed separately from the core rod hole 4, and the positioning hole 11 is shrunk after the positioning core rod 2 is installed, so that the positioning hole 11 is attached to the positioning core rod 2. As shown in Figure 3 a1 is a diagram showing the positional relationship between the positioning hole 11 and the quartz mother rod 1 before the positioning core rod 2 is installed, and a2 is a diagram showing the structure of the solid positioning core mother rod. Because the positioning hole 11 can be shrunk in step S3, the positioning hole 11 can have a larger opening diameter when it is formed. When the core rod hole 4 is formed, the positioning core rod 2 can support the side wall between the core rod hole 4 and the positioning hole 11, thereby reducing the risk of hole wall collapse caused by the small hole spacing between the core rod hole 4 and the positioning hole 11 when the core rod hole 4 is drilled. Therefore, a smaller gap between the core rod hole 4 and the positioning hole 11 can be provided, thereby expanding the diameter of the core rod hole 4 that can be formed. Thus, more allowance can be obtained when the positioning hole 11 and the core rod hole 4 are formed.

[0041] The present application provides a method for manufacturing a multi-core optical fiber preform that can position a core. The positioning hole 11 is formed first, and the positioning core rod 2 is installed in the positioning hole 11. The positioning hole 11 is attached to the positioning core rod 2 by shrinking. Thus, the positioning hole 11 can have a larger opening diameter when it is formed, thereby reducing the difficulty of machining a deep hole in a high-purity quartz rod. Meanwhile, the diameter of the core rod hole 4 that can be formed is expanded, thereby increasing the range of diameters of the transmission core rod 3 that can be installed in the multi-core optical fiber preform that can position a core.

[0042] In some embodiments, the step of shrinking the quartz mother rod 1 on which the positioning core rod 2 is installed includes: vacuumizing the positioning hole 11, heating the quartz mother rod 1 on which the positioning core rod 2 is installed to a specified temperature, and melting and shrinking the positioning core rod 2 in the quartz mother rod 1.

[0043] Further, the specified temperature is 2000°C-2300°C.

[0044] Specifically, when shrinking, as shown in Figure 5 the one end of the positioning hole 11 is sealed, and the other end is connected to a quartz extension tube for vacuumizing. The pressure in the positioning hole 11 is controlled at -600mbar to -700mbar. Meanwhile, the quartz mother rod 1 on which the positioning core rod 2 is installed is rotated at a speed of 30rpm-40rpm. The heated heat source 6 is moved back and forth along the axial direction of the quartz mother rod 1 at a temperature of 2000°C to 2300°C, thereby melting and shrinking the quartz mother rod 1 on which the positioning core rod 2 is installed to form a solid positioning core mother rod. The heat source 6 is a hydrogen-oxygen flame, and the moving speed of the heat source 6 is 12-16mm / min, thereby making the heating more uniform and reducing the out-of-roundness of the solid positioning core mother rod after heat shrinking.

[0045] In an optional embodiment, the manufacturing method further includes: rounding the solid positioning core mother rod before the core rod hole 4 is formed.

[0046] Specifically, because the positioning hole 11 is a single hole located off-center from the quartz mother rod 1, even though the positioning core rod 2 is close to the positioning hole 11, it still introduces a certain amount of non-roundness, affecting the subsequent drilling accuracy. By polishing the outer circle of the solid positioning core rod to ensure dimensional symmetry along that diameter, fine-tuning the outer circle boundary can improve the overall roundness of the optical fiber, reducing splicing loss and improving transmission efficiency when splicing with other components.

[0047] In some alternative embodiments, the preparation method further includes: preparing a balance bar 5, the balance bar 5 being made of the same material as the quartz mother rod 1, and the balance bar 5 having the same dimensions as the positioning core rod 2. When opening the positioning hole 11, at least one balance hole 12 is opened axially on the quartz mother rod 1, and a balance bar 5 is installed in each balance hole 12. The balance holes 12 have the same dimensions as the positioning holes 11 and are symmetrically distributed with respect to the positioning holes 11, with the center of the quartz mother rod 1 serving as the center of symmetry.

[0048] Specifically, this embodiment also provides another solution to the out-of-roundness of the solid positioning core rod caused by rod shrinkage. For example... Figure 4 As shown, b1 is a schematic diagram of the positional relationship between the balance hole 12 and the positioning hole 11 when the balance bar 5 and the positioning core rod 2 are not installed, and b2 is a schematic diagram of the solid positioning core rod when the balance bar 5 and the positioning core rod 2 are installed. By opening a balance hole 12 with the same size as the positioning hole 11 on the quartz core rod 1, the balance hole 12 and the positioning hole 11 are centrally symmetrically distributed, with the center of the quartz core rod 1 as the center of symmetry. Of course, multiple balance holes 12 can also be opened, and the balance holes 12 and the positioning holes 11 are rotationally symmetrically distributed, with the center of the quartz core rod 1 as the center of symmetry. While the positioning core rod 2 is installed in the positioning hole 11, the balance bar 5 is installed in the balance hole 12 one by one. The positioning hole 11 and the balance hole 12 are melted together during the rod shrinkage, so that the dimensional shrinkage caused by the melting and shrinkage is evenly distributed on the outer circle of the quartz core rod 1, thereby reducing the out-of-roundness of the core rod caused by the rod shrinkage. Then, according to the angle between the positioning core and the other core hole 4, the remaining core hole 4 is opened, and the transmission core 3 is assembled. No grinding operation is required.

[0049] In some alternative embodiments, the transmission core rod 3 is a rare earth-doped core rod.

[0050] Specifically, the transmission core rod 3 is configured as a rare-earth-doped core rod, which is prepared using an MCVD device. The rare-earth elements doped in the transmission core rod 3 include one or a combination of erbium and ytterbium. The doping of rare-earth elements such as erbium and ytterbium can provide additional amplification under the action of pump light.

[0051] Specifically, when the transmission core rod 3 is prepared by MCVD, the sunken cladding layer is constructed on the outer wall of the transmission core rod 3, and the refractive index of the sunken cladding layer is lower than the refractive index of the transmission core rod 3 and the quartz mother rod 1, so as to prevent the interference between different cores when the signal light is transmitted and affect the stability of the transmission mode.

[0052] In some optional embodiments, the positioning core rod 2 is a fluorine-doped quartz glass rod. The numerical aperture of the fluorine layer of the positioning core rod 2 is 0.06-0.18.

[0053] Specifically, a fluorine-doped core rod is prepared by MCVD or PCVD, the numerical aperture (NA) of the fluorine layer is 0.06-0.18, the refractive index of the positioning core rod 2 is different from the refractive index of the quartz mother rod 1, the outer glass layer is polished to be less than 0.2 mm of the diameter of the positioning hole 11, and then the positioning core rod 2 is placed into the quartz rod with the hole after cleaning.

[0054] In some optional embodiments, the step of drilling the core rod hole 4 on the solid positioning core mother rod comprises: marking and positioning the center position of the core rod hole 4 on the solid positioning core mother rod based on the relative position of the positioning core rod 2 on the quartz mother rod 1, and drilling the core rod hole 4 on the solid positioning core mother rod in the axial direction according to the center position obtained by the marking and positioning.

[0055] Specifically, the center of the quartz mother rod 1 is taken as the origin, and the direction of the line connecting the center of the quartz mother rod 1 and the center of the positioning core is taken as the positive direction of the Y axis to construct a coordinate system on the end surface of the quartz mother rod 1, so that the coordinates of the centers of the core rod holes 4 can be marked and positioned on the end surface of the quartz mother rod 1, and the core rod hole 4 is drilled on the solid positioning core mother rod in the axial direction according to the center position obtained by the marking and positioning.

[0056] Specifically, the core rod hole 4 is drilled in at least two and symmetrically distributed, the transmission core rod 3 is installed one by one corresponding to the core rod hole 4, and α<180° / N, wherein α is the included angle between the line connecting the center of the positioning core and the center of the quartz mother rod 1 and the line connecting the center of the nearest positioning core rod and the center of the quartz mother rod 1, the nearest positioning core rod is the transmission core rod 3 closest to the positioning core, and N is the number of core rod holes 4 drilled. Preferably, α<160° / N.

[0057] In a specific embodiment, as shown in the figure, the number of core rod holes 4 is 4, symmetrically distributed, the radius of the quartz mother rod 1 is R, the diameter of the core rod hole 4 is d, the minimum edge hole spacing between the outer circle of the quartz mother rod 1 and the core rod hole 4 is b, and α < 40°. Taking the center of the quartz mother rod 1 as the origin (0, 0), the coordinates of the closest point A of the core rod 2 to the outer circle of the quartz mother rod 1 are (0, R), and the coordinates of point B are (Rsinα, Rcosα). The core rod hole 4 closest to the positioning core is defined as No. 1, and the core rod holes are defined clockwise as No. 2, No. 3, and No. 4 in sequence. The center of No. 1 is ( (R-b-d / 2) sinα, (R-b-d / 2) cosα), the center of No. 3 is (- (R-b-d / 2) sinα, - (R-b-d / 2) cosα), the center of No. 2 is ( (R-b-d / 2) cosα, - (R-b-d / 2) sinα), and the center of No. 4 is (- (R-b-d / 2) cosα, (R-b-d / 2) sinα). The core rod hole 4 is opened on the quartz mother rod 1 according to the coordinates of No. 1, No. 2, No. 3, and No. 4.

[0058] The application also provides a multi-core optical fiber preform with positionable cores, which is prepared by the method for preparing a multi-core optical fiber preform with positionable cores according to any one of the above embodiments. The multi-core optical fiber preform with positionable cores prepared by the method for preparing a multi-core optical fiber preform with positionable cores according to any one of the above embodiments can be prepared into a multi-core optical fiber with positionable cores after drawing and coating.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of producing a positionable multicore optical fiber preform, characterized by, The preparation method comprises the following steps: preparing a quartz mother rod, a positioning core rod and a transmission core rod; drilling a positioning hole on the quartz mother rod in an axial direction, and installing the positioning core rod in the positioning hole; shrinking the quartz mother rod with the positioning core rod installed therein to obtain a solid positioning core mother rod; drilling a core rod hole on the solid positioning core mother rod, and installing the transmission core rod in the core rod hole to obtain a multi-core optical fiber preform with a positionable core.

2. The method of claim 1, wherein the method further comprises: The diameter of the positioning hole is x, and the diameter of the positioning core rod is c, and 0≤x-c≤0.2 mm.

3. The method of claim 1, wherein the method further comprises: The step of shrinking the quartz mother rod with the positioning core rod installed therein comprises the following steps: vacuumizing the positioning hole, heating the quartz mother rod with the positioning core rod installed therein to a specified temperature, and making the positioning core rod shrink in the quartz mother rod.

4. The preparation method of the multi-core optical fiber preform with a positionable core according to claim 3, wherein the specified temperature is 2000-2300 ℃.

5. The method of claim 1, wherein the method further comprises: The preparation method further comprises the following step: rounding the solid positioning core mother rod before drilling the core rod hole.

6. The method of claim 1, wherein the method further comprises: The preparation method further comprises the following steps: preparing a balancing rod, wherein the material of the balancing rod is the same as that of the quartz mother rod, and the size of the balancing rod is the same as that of the positioning core rod; drilling at least one balancing hole on the quartz mother rod in an axial direction when drilling the positioning hole, and installing the balancing rod in each balancing hole, wherein the balancing hole has the same size as the positioning hole and is symmetrically distributed with the positioning hole, and the center of the quartz mother rod is the center of symmetry.

7. The method of claim 1-6, wherein the method is characterized by, The transmission core rod is a rare earth doped core rod.

8. The method of claim 1-6, wherein the method is characterized by, The positioning core rod is a fluorine doped quartz glass rod.

9. A method of making a positionable core optical fiber preform according to any of claims 1-6, wherein, The step of drilling the core rod hole on the solid positioning core mother rod comprises the following steps: marking and positioning the center of the core rod hole on the solid positioning core mother rod based on the relative position of the positioning core rod on the quartz mother rod, and drilling the core rod hole on the solid positioning core mother rod in an axial direction according to the center position obtained by marking and positioning.

10. A positionable core multi-core optical fiber preform, characterized by, The multi-core optical fiber preform with a positionable core is prepared by the preparation method of the multi-core optical fiber preform with a positionable core according to any one of claims 1-9.

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