Optical fiber, optical fiber structure and forming method therefor

Abstract

Disclosed in the present application are an optical fiber, an optical fiber structure and a forming method therefor. The optical fiber structure comprises an optical fiber body and a tuner. The optical fiber body comprises a fiber core and a cladding coating the fiber core. A grating structure is provided in the fiber core, the cladding being provided with a stripper structure corresponding to the grating structure. The tuner is arranged on the optical fiber body to correspond to the grating structure, and is used for adjusting the included angle between the plane normal of the grating structure and the optical axis of the optical fiber body.

Description

Optical fiber, optical fiber structure and its forming method

[0001] This application claims priority to Chinese patent application No. 202410507190.X, filed on April 25, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical fiber technology, and in particular to an optical fiber, an optical fiber structure, and a method for forming the same. Background Technology

[0003] When high-power fiber lasers achieve signal light power in the tens of millions or higher, the extremely high power density in the fiber core leads to stimulated Raman scattering (SRS). This nonlinear effect causes spectral broadening and generates non-signal laser spectral components, thereby suppressing the output power of the signal light and degrading its beam quality. To suppress this nonlinear effect, the current mainstream method is to use chirped gratings to filter it out. However, current chirped gratings installed in fiber lasers only offer point-to-point control over parameters such as center wavelength, filtering depth, and filtering bandwidth, making it impossible to achieve truly controllable parameters. This limits the use of Raman suppression gratings across different power ranges and restricts their performance. Technical issues

[0004] The main objective of this application is to provide an optical fiber, an optical fiber structure, and a method for forming the same, which aims to solve the problem limiting the working performance of Raman suppression gratings. Technical solutions

[0005] To achieve the above objectives, this application provides an optical fiber structure, the optical fiber structure comprising:

[0006] An optical fiber body, comprising a fiber core and a cladding covering the fiber core, wherein a grating structure is disposed within the fiber core, and a stripper structure is disposed on the cladding corresponding to the grating structure; and...

[0007] A tuner is disposed on the optical fiber body and corresponding to the grating structure, for adjusting the angle between the plane normal of the grating structure and the optical axis of the optical fiber body.

[0008] In one embodiment, the grating structure and the stripper structure form a parallel structure group;

[0009] Multiple parallel structure groups are provided, and the multiple parallel structure groups are spaced apart along the optical axis of the optical fiber body.

[0010] In one embodiment, a grating angle is formed between the optical axis of the optical fiber body and the plane normal of the grating structure, and the angle of the grating angle is different in multiple parallel structure groups.

[0011] In one embodiment, the optical fiber structure further includes a second stripper disposed on the cladding. The second stripper and a plurality of parallel structure groups are spaced apart along the optical axis of the optical fiber body. Along the optical path propagation direction within the optical fiber body, the light passes sequentially through the plurality of parallel structure groups and the second stripper.

[0012] In one embodiment, the grating structure includes a chirped tilted grating.

[0013] In one embodiment, a plurality of etching grooves are formed on the outer sidewall of the cladding, and the plurality of etching grooves form the stripper structure.

[0014] In one embodiment, the depth of the plurality of etching grooves increases sequentially along the optical path propagation direction within the optical fiber body.

[0015] In one embodiment, the tuner includes a housing encapsulated onto the optical fiber body, with a magnetic fluid filling the space between the housing and the optical fiber body.

[0016] This application also provides an optical fiber, including the optical fiber structure according to any one of the foregoing.

[0017] This application also provides a method for forming an optical fiber structure, wherein the method for forming the optical fiber structure according to any one of the above-described methods includes the following steps:

[0018] Provide an optical fiber body, and remove the coating layer at a predetermined position on the optical fiber body;

[0019] Corresponding to the preset position, the grating structure is etched on the fiber core of the optical fiber body;

[0020] The optical fiber is subjected to annealing to remove hydrogen, and the annealed optical fiber is then cleaned.

[0021] Corresponding to the grating structure, the stripper structure is etched on the cladding of the optical fiber body;

[0022] The optical fiber body is encapsulated. Beneficial effects

[0023] This application provides an optical fiber structure that integrates a grating structure and a stripper structure into a single optical fiber, with the stripper structure corresponding to the grating structure, such that the stripper structure and the grating structure are arranged in parallel. The grating structure converts the non-signal laser spectral components transmitted on the fiber core into cladding mode light. Subsequently, the stripper structure removes the cladding light. The tilt angle of the plane normal of the grating structure is adjusted by a tuner, thereby enabling the adjustment of parameters such as the center wavelength, filtering bandwidth, and filtering depth of the optical fiber structure. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the optical fiber structure provided in the embodiment of this application;

[0025] Figure 2 is a schematic diagram of the optical fiber structure in Figure 1, which includes multiple parallel structure groups.

[0026] Figure 3 is a schematic diagram of the optical fiber structure in Figure 2, including the second stripper.

[0027] Figure 4 is a schematic diagram of the optical fiber structure provided in the embodiment of this application.

[0028] Explanation of icon numbers:

[0029] Label Name Label Name 100 Fiber Structure 2 Cladding 1 Fiber Core 21 Stripper Structure 11 Grating Structure 22 Second Stripper

[0030] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Embodiments of the present invention

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application.

[0032] This does not encompass all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without inventive effort are within the scope of protection of this application.

[0033] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0034] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0035] Please refer to Figure 1. An optical fiber structure 100 includes an optical fiber body and a tuner. The optical fiber body includes a fiber core 1 and a cladding 2 covering the fiber core 1. A grating structure 11 is disposed inside the fiber core 1, and a stripper structure 21 is disposed on the cladding 2 corresponding to the grating structure 11. The tuner is disposed on the optical fiber body and corresponding to the grating structure 11, and is used to adjust the angle between the plane normal of the grating structure 11 and the optical axis of the optical fiber body.

[0036] In the fiber structure 100 provided in this application, the grating structure 11 and the stripper structure 21 are integrated into a single fiber, and the stripper structure 21 is configured corresponding to the grating structure 11, such that the stripper structure 21 and the grating structure 11 are arranged in parallel. The grating structure 11 converts the non-signal laser spectral components transmitted on the fiber core 1 into cladding mode light. Then, the stripper structure 21 removes the cladding light. The tilt angle of the plane normal of the grating structure 11 is adjusted by the tuner, thereby adjusting parameters such as the center wavelength, filtering bandwidth, and filtering depth of the fiber structure 100.

[0037] Furthermore, referring to Figure 2, in one embodiment provided in this application, the grating structure 11 and the stripper structure 21 form a parallel structure group; multiple parallel structure groups are provided, and the multiple parallel structure groups are spaced apart along the optical axis direction of the optical fiber body. In this embodiment, the multiple parallel structure groups are sequentially connected in series to enhance the control effect of the optical fiber body 100, so that each power segment can be controlled at different positions.

[0038] Furthermore, a grating angle is formed between the optical axis of the optical fiber body and the plane normal of the grating structure 11, and the angles of the grating angles are different in the plurality of parallel structure groups. In this embodiment, the plurality of grating angles are different to obtain different spectral characteristics of the light within the optical fiber body.

[0039] Additionally, referring to Figure 3, in this embodiment, the fiber structure further includes a second stripper 22 disposed on the cladding 2. The second stripper 22 and the plurality of parallel structure groups are spaced apart along the optical axis of the fiber body. Along the optical path propagation direction within the fiber body, light sequentially passes through the plurality of parallel structure groups and the second stripper. In this embodiment, the stripping efficiency of the plurality of parallel structure groups cannot reach 100%. To minimize cladding light at the output end, fiber lasers with power ratings of 10,000 watts or higher require the additional introduction of a second stripper 22 to minimize nonlinear effects.

[0040] Specifically, in this embodiment, two parallel structure groups are provided. Along the optical path propagation direction within the optical fiber body, the second stripper 22 is located at the rear end of the second parallel structure group to minimize nonlinear effects.

[0041] It should be noted that, in this embodiment, the second stripper 22 is formed by a plurality of etching grooves.

[0042] It should be noted that the grating structure 11 can be implemented in various ways, such as a tilted grating. Specifically, in the embodiment provided in this application, the grating structure 11 includes a chirped tilted grating. In this embodiment, the chirped tilted grating can meet the usage requirements of different power ranges and improve the working performance of the Raman suppression grating.

[0043] Similarly, the stripper structure 12 can also be implemented in various ways. For example, the total internal reflection mode of the cladding outer wall can be destroyed by laser ablation. In this embodiment, multiple etching grooves are formed on the outer wall of the cladding, and these multiple etching grooves form the stripper structure 12. In this embodiment, the total internal reflection condition of the cladding mode light is broken by the multiple etching grooves, thereby increasing the roughness of the cladding surface of the optical fiber body.

[0044] Furthermore, along the optical path propagation direction within the optical fiber, the depth of the plurality of etching grooves increases sequentially. In this embodiment, since the stripper structure 12 generates heat when stripping the cladding light, it causes the chirped tilt grating to generate a temperature gradient field. This temperature gradient field can degrade the performance of the chirped tilt grating, for example, increasing the insertion loss. To reduce the impact of the temperature gradient field, the concept of range extension is used, and the stripping effect is increased by increasing the depth of the etching grooves.

[0045] On the other hand, it should be noted that the regulator can be implemented in various ways, as long as it can adjust the tilt angle of the grating plane of the grating structure 11. For example, a Bragg grating tuner can be used and directly connected to the optical fiber body to achieve the tuning of the wavelength of the grating structure 11 within the optical fiber body.

[0046] In this embodiment, the tuner includes a housing encapsulated on the optical fiber body, and a magnetic fluid is filled between the housing and the optical fiber body. In this embodiment, by controlling an external magnetic field, the angle between the optical axis of the optical fiber body and the plane normal of the optical fiber structure can be adjusted, thereby adjusting parameters such as the center wavelength, filtering bandwidth, and filtering depth of the chirped tilt grating.

[0047] Please refer to Figure 4. Based on the optical fiber structure 100 described above, this application also provides an optical fiber, which includes the optical fiber structure 100 described above. That is, it also has all the technical features of the optical fiber structure 100 described above, and therefore also has the technical effects brought about by all the technical features described above, which will not be described in detail here.

[0048] Based on the above-described optical fiber structure 100, this application also provides a method for forming an optical fiber structure, the method comprising the following steps:

[0049] S10. Provide an optical fiber body and remove the coating layer at a predetermined position on the optical fiber body;

[0050] S20. Corresponding to the preset position, the grating structure is engraved on the fiber core of the optical fiber body to form the grating structure.

[0051] In this process, the angle between the optical axis and the normal to the grating plane in the fiber core is adjusted, and the grating structure is inscribed in the fiber core. Depending on the angle between the optical axis and the normal to the grating plane, different types of gratings can be inscribed, including any one of cavity mirror gratings, tilted gratings, chirped tilted gratings, or long-period gratings.

[0052] S30. Anneal the optical fiber body to remove hydrogen, and clean the annealed optical fiber body.

[0053] S40. Corresponding to the grating structure, the stripper structure is etched on the cladding of the optical fiber body to form the stripper structure;

[0054] Specifically, by etching the cladding layer, the total internal reflection condition of the cladding mode light is broken, thereby increasing the roughness of the cladding surface and breaking the total internal reflection condition of the cladding mode light, thus realizing the fabrication of the stripper structure.

[0055] It should be noted that, in this embodiment, the cladding is etched using a Q-switched laser or an etchant to form the stripper structure.

[0056] S50. The optical fiber body is encapsulated.

[0057] In the fiber structure 100 provided in this application, the grating structure 11 and the stripper structure 21 are integrated into a single fiber, and the stripper structure 21 is configured corresponding to the grating structure 11, such that the stripper structure 21 and the grating structure 11 are arranged in parallel. The grating structure 11 converts the non-signal laser spectral components transmitted on the fiber core 1 into cladding mode light. Then, the stripper structure 21 removes the cladding light. The tilt angle of the plane normal of the grating structure 11 is adjusted by the tuner, thereby adjusting parameters such as the center wavelength, filtering bandwidth, and filtering depth of the fiber structure 100.

[0058] The above are merely optional embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An optical fiber structure, wherein, The optical fiber structure includes: An optical fiber body, comprising a fiber core and a cladding covering the fiber core, wherein a grating structure is disposed within the fiber core, and a stripper structure is disposed on the cladding corresponding to the grating structure; and... A tuner is disposed on the optical fiber body and corresponding to the grating structure, for adjusting the angle between the plane normal of the grating structure and the optical axis of the optical fiber body.

2. The optical fiber structure according to claim 1, wherein, The grating structure and the stripper structure form a parallel structure group; Multiple parallel structure groups are provided, and the multiple parallel structure groups are spaced apart along the optical axis of the optical fiber body.

3. The optical fiber structure according to claim 2, wherein, The optical axis of the optical fiber body and the plane normal of the grating structure form a grating angle, and the angle of the grating angle is different in multiple parallel structure groups.

4. The optical fiber structure according to claim 2, wherein, The optical fiber structure further includes a second stripper disposed on the cladding. The second stripper and the plurality of parallel structure groups are spaced apart along the optical axis of the optical fiber body. Along the optical path propagation direction within the optical fiber body, the light passes sequentially through the plurality of parallel structure groups and the second stripper.

5. The optical fiber structure according to claim 1, wherein, The grating structure includes a chirped tilted grating.

6. The optical fiber structure according to claim 1, wherein, Multiple etching grooves are formed on the outer wall of the cladding, and the multiple etching grooves form the stripper structure.

7. The optical fiber structure according to claim 6, wherein, Along the optical path propagation direction within the optical fiber, the depth of the plurality of etching grooves increases sequentially.

8. The optical fiber structure according to claim 1, wherein, The tuner includes a housing that is encapsulated onto the optical fiber body, and a magnetic fluid is filled between the housing and the optical fiber body.

9. An optical fiber, wherein, The optical fiber includes the optical fiber structure according to any one of claims 1 to 8.

10. A method for forming an optical fiber structure, used to form the optical fiber structure according to any one of claims 1 to 9, wherein, The method for forming the optical fiber structure includes the following steps: Provide an optical fiber body, and remove the coating layer at a predetermined position on the optical fiber body; Corresponding to the preset position, the grating structure is etched on the fiber core of the optical fiber body; The optical fiber body is subjected to annealing to remove hydrogen, and the annealed optical fiber body is then cleaned. Corresponding to the grating structure, the stripper structure is etched on the cladding of the optical fiber body; The optical fiber body is encapsulated.

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