Optical fiber disc for optical fiber laser

By adopting a multi-turn closed-loop coil structure and an optimized design of heat dissipation layer and coating layer in the fiber laser, the polarization instability caused by stress and temperature changes in the fiber laser is solved, and the stability of beam quality and power parameters is improved.

CN222214784UActive Publication Date: 2024-12-20WUHAN DR LASER TECH CORP LTD
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Patent Information

Application Number
CN202323508520.7
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2023-12-21
Publication Date
2024-12-20
Estimated Expiration
2033-12-21

AI Technical Summary

Technical Problem

The polarization-maintaining fibers in existing fiber lasers are instable due to stress and temperature changes, resulting in jittering of beam quality, extinction ratio and power parameters. It is difficult for the existing technology to achieve stable mass production optimization.

Method used

By adopting a multi-turn closed-loop coil structure, the optical fiber diameter of the first arc portion and the second arc portion is smaller than that of the disc fiber portion, the heat dissipation layer and the coating layer are increased, and the heat dissipation ability of the optical fiber is optimized, and the design of the bend portion is reduced. Fiber stress and heating.

Benefits of technology

Effectively reduce the stress changes of optical fibers, improve polarization stability, improve beam quality and extinction ratio, and ensure the stability of long-term high-power output.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model provides an optical fiber disc for an optical fiber laser, and the optical fiber disc comprises a plurality of circles of closed-loop coiling structures, and each circle of closed-loop coiling structure comprises a first arc part, a second arc part, a first fiber coiling part, and a second fiber coiling part. The head ends and the tail ends of the first arc part, the first fiber coiling part, the second arc part and the second fiber coiling part are sequentially connected to form the closed-loop coiling structure; the first arc part and the second arc part are sunken towards the outer side of the closed-loop coiling structure; and the optical fiber diameters at the first arc part and the second arc part are smaller than the optical fiber diameters at the first fiber coiling part and the second fiber coiling part. The internal stress of outward expansion of the optical fiber at the first arc part and the second arc part can be effectively reduced, and the heat dissipation layer at the first arc part and the second arc part is used for replacing an original coating layer, so that the heat dissipation capability of the optical fiber can be effectively improved.
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Description

Technical Field

[0001] The present application belongs to the technical field of optical fiber lasers, and in particular, relates to an optical fiber disk for an optical fiber laser. Background Art

[0002] Polarization-maintaining fiber is widely used in green light, ultraviolet light and other fiber lasers. With the continuous maturity of technology, the power of fiber lasers is getting higher and higher. At the same time, under the demand for high-precision technology manufacturing, the requirements for the beam quality and stability of fiber lasers are also getting higher and higher. Due to its unique polarization state transmission characteristics, polarization-maintaining fiber is prone to polarization instability caused by factors such as coil fiber stress or fiber temperature changes during application, especially birefringence caused by internal fiber stress changes polarization, resulting in large jitter in the final output beam quality, extinction ratio, astigmatism and power parameters.

[0003] At present, many domestic research institutes and laser manufacturing companies have tried to change the inherent parameters of optical fibers to optimize output, but there is still no report on stable mass production of polarization-maintaining special optical fibers. In the existing technology, the existing polarization-maintaining optical fiber is often optimized by designing the fiber coil curve or optical fiber coil, but the final output result still cannot meet some ultra-high index processing requirements.

[0004] For example, in the prior art, the geometric shape of the stress zone is changed, such as by designing it into a bow tie, an ellipse, etc., and the doping concentration is precisely controlled to regulate the change in the birefringence region. However, this type of polarization-maintaining special optical fiber cannot achieve stable mass production. Another example is the use of winding methods such as a figure-eight shape or fiber embedded rings, which can reduce the stress of some sections of the optical fiber to a certain extent, but the high-power amplification stress of the optical fiber is still very obvious. Utility Model Content

[0005] In view of this, the present application provides a fiber disk for fiber lasers, which analyzes the jitter sources such as stress-induced polarization and thermal-induced polarization, and optimizes the closed-loop winding structure to minimize the stress changes during the fiber power amplification process, thereby optimizing the output polarization extinction ratio, beam quality, astigmatism, stability and other parameters.

[0006] A fiber disk for a fiber laser comprises a plurality of closed-loop winding structures, each of which comprises a first arc portion, a second arc portion, a first fiber coil portion and a second fiber coil portion, and the first arc portion, the first fiber coil portion, the second arc portion and the second fiber coil portion are connected in sequence at their head and tail ends to form a closed-loop winding structure; wherein:

[0007] The first arc portion and the second arc portion are both recessed toward the outer side of the closed-loop coiled structure;

[0008] The optical fiber diameters at the first arc portion and the second arc portion are both smaller than the optical fiber diameters at the first fiber coil portion and the second fiber coil portion.

[0009] Preferably, the optical fibers at the first arc portion, the second arc portion, the first fiber coil portion, and the second fiber coil portion all include a core and a cladding, wherein the cladding is coated on the outside of the core, and the optical fibers at the first fiber coil portion and the second fiber coil portion also include a coating, wherein the coating is coated on the outside of the cladding of the optical fibers at the first fiber coil portion and the second fiber coil portion.

[0010] Preferably, the optical fiber at the first arc portion and the second arc portion further comprises a heat dissipation layer, and the heat dissipation layer is coated on the outer side of the cladding of the optical fiber at the first arc portion and the second arc portion;

[0011] The thickness of the heat dissipation layer is smaller than the thickness of the coating layer.

[0012] Preferably, the diameters of the first arc portion and the second arc portion are the same, and the diameters of the first fiber coil portion and the second fiber coil portion are the same; and / or,

[0013] The first arc portion and the second arc portion have the same curvature radius.

[0014] In one solution of the present application, both the first fiber coiling portion and the second fiber coiling portion are linear fiber coiling portions.

[0015] In another embodiment of the present application, the first fiber coil portion includes a first curved portion, a second curved portion, and a third curved portion connected in sequence, an end of the first curved portion away from the second curved portion is connected to an end of the first arc portion, and an end of the third curved portion away from the second curved portion is connected to an end of the second arc portion;

[0016] The second fiber coil portion includes a fourth curved portion, a fifth curved portion and a sixth curved portion connected in sequence, wherein one end of the fourth curved portion away from the fifth curved portion is connected to the other end of the first arc portion, and one end of the sixth curved portion away from the fifth curved portion is connected to the other end of the second arc portion.

[0017] Preferably, the first curved portion, the third curved portion, the fourth curved portion and the sixth curved portion are all recessed toward the inner side of the closed-loop winding structure, and the second curved portion and the fifth curved portion are all recessed toward the outer side of the closed-loop winding structure.

[0018] Preferably, the second curved portion and the fifth curved portion have the same curvature radius.

[0019] Preferably, the first curved portion, the third curved portion, the fourth curved portion and the sixth curved portion have the same curvature radius.

[0020] Preferably, the curvature radii of the first arc portion and the second arc portion are both smaller than the curvature radii of the second curved portion and the fifth curved portion.

[0021] The beneficial effects of this application are:

[0022] 1. The first arc portion and the second arc portion are most affected by the internal stress. The diameters of the first arc portion and the second arc portion are designed to be smaller than the diameters of the first fiber coil portion and the second fiber coil portion, which can effectively reduce the internal stress of the first arc portion and the second arc portion that causes the optical fiber to expand outward;

[0023] 2. The outer side of the cladding of the optical fiber at the first arc portion and the second arc portion is coated with a heat dissipation layer, which can effectively improve the heat dissipation capacity of the optical fiber. Better optical fiber heat dissipation can reduce thermally induced polarization instability caused by the heating of the optical fiber during power amplification;

[0024] 3. The second bend and the fifth bend are both recessed toward the outside of the closed-loop winding structure, and the first bend, the third bend, the fourth bend and the sixth bend are all recessed toward the inside of the closed-loop winding structure, so that the first fiber coiling portion and the second fiber coiling portion have a certain bending arc, thereby reducing the heat generated by mode leakage; the slightly curved first fiber coiling portion and the second fiber coiling portion coated with a coating layer are used as the fiber coiling operation area to avoid damage to the optical fiber during the fiber coiling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments or descriptions of the prior art will be briefly introduced below. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0027] Figure 1 A schematic structural diagram of one embodiment of a fiber disk for a fiber laser provided in the present application;

[0028] Figure 2A schematic structural diagram of another embodiment of a fiber disk for a fiber laser provided in the present application.

[0029] In the figure: 1-first arc portion; 2-second arc portion; 3-first coiled fiber portion; 31-first curved portion; 32-second curved portion; 33-third curved portion; 4-second coiled fiber portion; 41-fourth curved portion; 42-fifth curved portion; 43-sixth curved portion. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0031] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] The present application provides a fiber optic disc for a fiber laser, referring to Figure 1-2 , including a plurality of closed-loop winding structures, each circle of the closed-loop winding structure includes a first arc portion 1, a second arc portion 2, a first fiber coil portion 3, and a second fiber coil portion 4, and the first arc portion 1, the first fiber coil portion 3, the second arc portion 2, and the second fiber coil portion 4 are connected in sequence at their head and tail ends to form a closed-loop winding structure; wherein,

[0033] The first arc portion 1 and the second arc portion 2 are both recessed toward the outside of the closed-loop coiled structure;

[0034] The diameters of the optical fibers at the first arc portion 1 and the second arc portion 2 are both smaller than the diameters of the optical fibers at the first fiber coiling portion 3 and the second fiber coiling portion 4 .

[0035] In the present application, the first arc portion 1, the first fiber coil portion 3, the second arc portion 2, and the second fiber coil portion 4 are sequentially connected to form a closed-loop winding structure. The multi-turn closed-loop winding structure is used to deploy the gain fiber in the fiber laser.

[0036] The optical fiber diameters at the first arc portion 1 and the second arc portion 2 are smaller than the optical fiber diameters at the first fiber coiling portion 3 and the second fiber coiling portion 4, that is, the optical fiber diameters at the first arc portion 1 and the second arc portion 2, which are most affected by the internal stress in each closed-loop coiling structure, are reduced, thereby effectively reducing the internal stress of the optical fiber expanding outward at the first arc portion 1 and the second arc portion 2, optimizing the gain amplification fiber coiling stress, and significantly improving the polarization stability at the initial time of laser loading, greatly improving the polarization extinction ratio, beam quality and astigmatism, and reducing the influence of stress-induced polarization, thereby ensuring the stability of long-term high-power optical fiber output indicators.

[0037] Furthermore, the optical fibers at the first arc portion 1, the second arc portion 2, the first fiber coil portion 3 and the second fiber coil portion 4 all include a core and a cladding, the cladding is coated on the outside of the core, and the optical fibers at the first fiber coil portion 3 and the second fiber coil portion 4 also include a coating, and the coating is coated on the outside of the cladding of the optical fibers at the first fiber coil portion 3 and the second fiber coil portion 4.

[0038] The optical fiber at the first arc portion 1 and the second arc portion 2 further comprises a heat dissipation layer, and the heat dissipation layer is coated on the outer side of the cladding of the optical fiber at the first arc portion 1 and the second arc portion 2;

[0039] The thickness of the heat dissipation layer is smaller than the thickness of the coating layer.

[0040] Specifically, the optical fibers at the first fiber coiling portion 3 and the second fiber coiling portion 4 include a fiber core, a cladding, and a coating layer from the inside to the outside, and the optical fibers at the first arc portion 1 and the second arc portion 2 include a fiber core, a cladding, and a heat dissipation layer from the inside to the outside. The coating layer is composed of materials such as acrylate and silicone rubber, and the heat dissipation layer is composed of a heat dissipation glue with a low refractive index.

[0041] Different types of optical fibers have different thicknesses of cladding and coating. For example, 25 / 250 or 30 / 250 optical fibers have a cladding thickness of 250 λ m and a coating thickness of 400 λ m. For example, 15 / 130 and 10 / 130 optical fibers have a cladding thickness of 130 λ m and a coating thickness of 245 μm. The present application does not specifically limit the type of optical fiber, that is, the present application can be applied to all types of optical fibers. The specific cladding thickness and coating thickness are not limited either, and are determined according to the specific type of optical fiber.

[0042] There is no specific restriction on the thickness of the heat dissipation layer coated outside the cladding of the optical fiber at the first arc portion 1 and the second arc portion 2, as long as the cladding can be completely coated and the thickness of the heat dissipation layer is less than the thickness of the coating layer. It can be understood that the core diameter and cladding thickness of the optical fiber at the first arc portion 1, the second arc portion 2, the first fiber coiling portion 3 and the second fiber coiling portion 4 are the same. When the thickness of the heat dissipation layer is less than the thickness of the coating layer, the diameters of the first arc portion 1 and the second arc portion 2 are smaller than the diameters of the first fiber coiling portion 3 and the second fiber coiling portion 4.

[0043] In this embodiment, a heat dissipation layer composed of a low-refractive-index heat dissipation adhesive is coated on the outer side of the cladding of the optical fiber at the first arc portion 1 and the second arc portion 2. On the one hand, it can protect the cladding at the first arc portion 1 and the second arc portion 2, and on the other hand, it can effectively improve the heat dissipation capacity of the optical fiber. Better optical fiber heat dissipation can reduce the thermally induced polarization instability caused by the heating of the optical fiber during power amplification, and is suitable for higher power amplification.

[0044] The force on the optical fiber coil at the first arc portion 1 and the second arc portion 2 is reduced, so that a smaller diameter coil can be easily completed, the degradation of the power amplification mode is reduced, and the multi-mode optical fiber is supported to achieve few-mode or single-mode output.

[0045] In this embodiment, the diameters of the first arc portion 1 and the second arc portion 2 are the same, and the diameters of the first fiber coil portion 3 and the second fiber coil portion 4 are the same; and / or,

[0046] The first arc portion 1 and the second arc portion 2 have the same curvature radius.

[0047] That is, the thickness of the heat dissipation layer coated on the outer side of the cladding at the first arc portion 1 and the second arc portion 2 is the same, and the thickness of the coating layer coated on the outer side of the cladding at the first fiber coil portion 3 and the second fiber coil portion 4 is the same.

[0048] It can be understood that the first arc portion 1 and the second arc portion 2 have the same curvature radius, which means that the curvature radius of the first arc portion 1 and the second arc portion 2 in each closed-loop winding structure is the same, so that the first arc portion 1 and the second arc portion 2 have the same shape and are symmetrically arranged with each other.

[0049] like Figure 1 As shown, the first fiber coiling portion 3 and the second fiber coiling portion 4 are both straight fiber coiling portions, that is, one end of the first arc portion 1 is connected to one end of the second arc portion 2 through a horizontally arranged straight first fiber coiling portion 3, and the other end of the first arc portion 1 is connected to the other end of the second arc portion 2 through a horizontally arranged straight second fiber coiling portion 3.

[0050] like Figure 2As shown, the first fiber coil portion 3 includes a first curved portion 31, a second curved portion 32 and a third curved portion 33 connected in sequence, an end of the first curved portion 31 away from the second curved portion 32 is connected to an end of the first arc portion 1, and an end of the third curved portion 33 away from the second curved portion 32 is connected to an end of the second arc portion 2;

[0051] The second fiber coil portion 4 includes a fourth curved portion 41, a fifth curved portion 42 and a sixth curved portion 43, wherein one end of the fourth curved portion 41 away from the fifth curved portion 42 is connected to the other end of the first arc portion 1, and one end of the sixth curved portion 43 away from the fifth curved portion 42 is connected to the other end of the second arc portion 2.

[0052] In this embodiment, one end of the first arc portion 1 is connected to one end of the second arc portion 2 through the first bend 31, the second bend 32 and the third bend 33 in sequence, and the other end of the first arc portion 1 is connected to the other end of the second arc portion 2 through the fourth bend 41, the fifth bend 42 and the sixth bend 43 in sequence.

[0053] Continue to refer Figure 2 , the first curved portion 31, the third curved portion 33, the fourth curved portion 41 and the sixth curved portion 43 are all recessed toward the inner side of the closed-loop winding structure, and the second curved portion 32 and the fifth curved portion 42 are all recessed toward the outer side of the closed-loop winding structure. That is, the recessed directions of two adjacent curved portions are opposite.

[0054] It can be understood that the outer side of the cladding at the first bend 31, the second bend 32, the third bend 33, the fourth bend 41, the fifth bend 42 and the sixth bend 43 are all covered with a coating layer, and the thickness of the coating layer is the same, that is, the diameters of the optical fibers at the first bend 31, the second bend 32, the third bend 33, the fourth bend 41, the fifth bend 42 and the sixth bend 43 are the same.

[0055] In this embodiment, the optical fiber at the first arc portion 1 and the second arc portion 2 has no coating layer, which makes the optical fiber at this location easily damaged. During the fiber coiling process, the first fiber coiling portion 3 and the second fiber coiling portion 4 are used as the fiber coiling operation area. The first fiber coiling portion 3 and the second fiber coiling portion 4 are both composed of three curved portions, that is, the first fiber coiling portion 3 and the second fiber coiling portion 4 have a certain curvature, and the first fiber coiling portion 3 and the second fiber coiling portion 4 have a coating layer, so that the optical fiber damage during the fiber coiling process can be avoided, and the fiber coiling method with or without a coating layer can greatly release the internal stress of the gain optical fiber.

[0056] In this embodiment, the first fiber coiling portion 3 and the second fiber coiling portion 4 are designed to have a certain curvature, which can reduce the heat generated by mode leakage. The second curved portion 32 and the fifth curved portion 42 are both recessed toward the outside of the closed-loop winding structure, which can make the optical fiber more naturally reduce the external control force.

[0057] Furthermore, the curvature radii of the second curved portion 32 and the fifth curved portion 42 are equal; the curvature radii of the first curved portion 31, the third curved portion 33, the fourth curved portion 41 and the sixth curved portion 43 are equal. That is, the first fiber coil portion 3 and the second fiber coil portion 4 have the same structure, and the second curved portion 32 and the fifth curved portion 42 are connected to the first arc portion 1 and the second arc portion 2 respectively by two curved portions with the same structure.

[0058] In this embodiment, the curvature radii of the first arc portion 1 and the second arc portion 2 are both smaller than the curvature radii of the second curved portion 32 and the fifth curved portion 42 .

[0059] In this way, the second curved portion 32 and the fifth curved portion 42 can have a larger curvature, and extrusion caused by bending can be avoided as much as possible.

[0060] The curvature radius of the first arc portion 1 and the second arc portion 2 is determined according to the type of fiber core. Generally, the smaller the fiber coil, the better the mode control. For example, in this embodiment, the curvature radius range of the first arc portion 1 and the second arc portion 2 of the innermost circle of the closed-loop winding structure can be designed to be 4-7 cm, and the curvature radius range of the first arc portion 1 and the second arc portion 2 of the outermost circle of the closed-loop winding structure can be designed to be 7-10 cm. The curvature radius of the second bend 32 and the fifth bend 42 of each circle of the closed-loop winding structure is at least greater than 7 cm. The specific value is not limited, as long as the curvature radius of the second bend 32 and the fifth bend 42 of each circle of the closed-loop winding structure is greater than the curvature radius of the first arc portion 1 and the second arc portion 2, and the bending curvature of the second bend 32 and the fifth bend 42 can be made larger, so as to avoid bending and extrusion.

[0061] In this specification, each embodiment is described in a progressive, parallel, or progressive and parallel manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0062] It should be noted that in the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are 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, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. When a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time.

[0063] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the article or device including the above elements.

[0064] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An optical fiber disk for an optical fiber laser, characterized in that: The invention comprises a plurality of closed-loop winding structures, each of which comprises a first arc portion (1), a second arc portion (2), a first fiber coil portion (3) and a second fiber coil portion (4), and the first arc portion (1), the first fiber coil portion (3), the second arc portion (2) and the second fiber coil portion (4) are connected in sequence at their head and tail ends to form a closed-loop winding structure; wherein, The first arc portion (1) and the second arc portion (2) are both recessed toward the outer side of the closed-loop coiled structure; The diameters of the optical fibers at the first circular arc portion (1) and the second circular arc portion (2) are both smaller than the diameters of the optical fibers at the first fiber coiling portion (3) and the second fiber coiling portion (4).

2. The optical fiber disk for optical fiber laser according to claim 1, characterized in that: The optical fibers at the first circular arc portion (1), the second circular arc portion (2), the first fiber coil portion (3) and the second fiber coil portion (4) all include a core and a cladding, wherein the cladding is coated on the outside of the core. The optical fibers at the first fiber coil portion (3) and the second fiber coil portion (4) also include a coating layer, wherein the coating layer is coated on the outside of the cladding of the optical fibers at the first fiber coil portion (3) and the second fiber coil portion (4).

3. The optical fiber disk for optical fiber laser according to claim 2, characterized in that: The optical fiber at the first circular arc portion (1) and the second circular arc portion (2) further comprises a heat dissipation layer, wherein the heat dissipation layer is coated on the outer side of the cladding of the optical fiber at the first circular arc portion (1) and the second circular arc portion (2); The thickness of the heat dissipation layer is smaller than the thickness of the coating layer.

4. The optical fiber disk for optical fiber laser according to claim 1, characterized in that: The diameters of the first arc portion (1) and the second arc portion (2) are the same, and the diameters of the first fiber coil portion (3) and the second fiber coil portion (4) are the same; and / or, The first circular arc portion (1) and the second circular arc portion (2) have the same curvature radius.

5. The optical fiber disk for optical fiber laser according to any one of claims 1 to 4, characterized in that: The first fiber coiling portion (3) and the second fiber coiling portion (4) are both straight fiber coiling portions.

6. The optical fiber disk for optical fiber laser according to any one of claims 1 to 4, characterized in that: The first fiber coil portion (3) comprises a first curved portion (31), a second curved portion (32) and a third curved portion (33) which are connected in sequence, wherein one end of the first curved portion (31) away from the second curved portion (32) is connected to one end of the first circular arc portion (1), and one end of the third curved portion (33) away from the second curved portion (32) is connected to one end of the second circular arc portion (2); The second fiber coil portion (4) comprises a fourth curved portion (41), a fifth curved portion (42) and a sixth curved portion (43) which are connected in sequence, wherein one end of the fourth curved portion (41) away from the fifth curved portion (42) is connected to the other end of the first circular arc portion (1), and one end of the sixth curved portion (43) away from the fifth curved portion (42) is connected to the other end of the second circular arc portion (2).

7. The optical fiber disk for optical fiber laser according to claim 6, characterized in that: The first curved portion (31), the third curved portion (33), the fourth curved portion (41) and the sixth curved portion (43) are all recessed toward the inner side of the closed-loop winding structure, and the second curved portion (32) and the fifth curved portion (42) are all recessed toward the outer side of the closed-loop winding structure.

8. The optical fiber disk for optical fiber laser according to claim 7, characterized in that: The curvature radii of the second curved portion (32) and the fifth curved portion (42) are equal.

9. The optical fiber disk for optical fiber laser according to claim 7, characterized in that: The first curved portion (31), the third curved portion (33), the fourth curved portion (41) and the sixth curved portion (43) have the same curvature radius.

10. The optical fiber disk for optical fiber laser according to claim 7, characterized in that: The curvature radii of the first circular arc portion (1) and the second circular arc portion (2) are both smaller than the curvature radii of the second curved portion (32) and the fifth curved portion (42).