A side-pumped pumping device and a preparation method thereof

Abstract

The application relates to the technical field of lasers, and provides a side-pumped pumping device and a preparation method thereof. The preparation method comprises the following steps: preparing a metasurface structure in a cladding layer of an optical fiber to obtain a metasurface optical fiber; encapsulating the metasurface optical fiber by using a first encapsulating material to obtain a first encapsulating structure; encapsulating a laser diode bar by using a second encapsulating material to obtain a second encapsulating structure; and arranging the second encapsulating structure on the first encapsulating structure to obtain the pumping device; wherein the laser diode bar is arranged opposite to the metasurface structure. The preparation method is simple and easy to implement, and has a high product yield. The pumping device prepared by the method has a compact structure, a small number of components, low complexity and practicability, high coupling efficiency and stability, high alignment accuracy and strong alignment tolerance, and effectively guarantees the use performance. The method does not need an additional optical system, a special optical fiber combiner and a multimode pumping optical fiber, and effectively reduces the preparation cost.

Description

Technical Field

[0001] This application relates to the field of laser technology, and in particular to a side-pumped pumping device and its fabrication method. Background Technology

[0002] Pumped lasers utilize an external pump source to excite the gain medium, causing particles to transition from the ground state to the excited state, achieving population inversion, and generating laser light through stimulated emission. They are mainly used in various fields such as fiber optic communication amplification, industrial processing, and medical equipment.

[0003] Typically, pump lasers are pumped by coupling pump light into the fiber using fiber coupling devices. Traditional methods usually involve physically removing part of the cladding material to form a coupling window on the upper side of the fiber cladding, followed by the deposition of optical materials that become part of the overall fiber structure. The coupling window essentially forms an integrated prism, guiding light into the fiber and enhancing the coupling efficiency of light entering the fiber core. This method presents several technical challenges: complex fabrication processes requiring polishing, anti-reflective coatings, and precise alignment; and the coupling efficiency is highly dependent on the incident light angle, with differences in properties between the window material and the core / cladding materials leading to increased temperature gradients and mechanical stress, reducing fiber reliability and impacting the performance of the pump laser.

[0004] Therefore, there is an urgent need for a method that can effectively reduce the fabrication complexity of pump lasers and efficiently couple light into pump fibers to ensure the performance of pump lasers. Summary of the Invention

[0005] This application provides a side-pumped pumping device and its fabrication method to solve the technical problem that the fabrication process of pumped lasers is complex and cannot guarantee their performance.

[0006] The first aspect of this application provides a method for fabricating a side-pumped pumping device, comprising: fabricating a metasurface structure in the cladding of an optical fiber to obtain a metasurface optical fiber; encapsulating the metasurface optical fiber with a first encapsulation material to obtain a first encapsulation structure; encapsulating a laser diode bar with a second encapsulation material to obtain a second encapsulation structure; and placing the second encapsulation structure in the first encapsulation structure to obtain a pumping device; wherein the laser diode bar is disposed opposite to the metasurface structure.

[0007] In some feasible implementations, the metasurface structure is arranged in an array; the array arrangement includes a first direction and a second direction, the first direction including the circumferential direction of the optical fiber and the second direction including the axial direction of the optical fiber.

[0008] In some feasible implementations, the cross-sectional shape of the metasurface structure includes one or more of the following: square, circular, triangular, elliptical, or pentagonal.

[0009] In some feasible implementations, along the second direction, the length of the metasurface structure is greater than the length of the laser diode bar.

[0010] In some feasible implementations, the metasurface structure is fabricated in the cladding of an optical fiber, including: fabricating a mask layer in the outer cladding of the optical fiber and spin-coating photoresist; exposing and developing the photoresist according to the metasurface pattern; etching the mask layer and the outer cladding according to the metasurface pattern; and removing the mask layer and the photoresist to obtain the metasurface optical fiber.

[0011] In some feasible implementations, a metasurface structure is fabricated in the cladding of an optical fiber, including: stripping the outer cladding of a target region in the optical fiber to expose the inner cladding; sequentially fabricating polysilicon, a mask layer, and spin-coating photoresist on the inner cladding; exposing and developing the photoresist according to the metasurface pattern; etching the mask layer and polysilicon according to the metasurface pattern; and removing the mask layer and photoresist to obtain the metasurface optical fiber.

[0012] In some feasible implementations, a metasurface structure is fabricated in the cladding of an optical fiber, including: stripping the outer cladding of a target region in the optical fiber to expose the inner cladding; spin-coating photoresist onto the surface of the inner cladding; etching the inner cladding according to a metasurface pattern to form multiple grooves; and removing the photoresist to obtain a metasurface optical fiber.

[0013] In some feasible implementations, the fabrication of metasurface structures in the cladding of optical fibers after forming multiple grooves also includes: fabricating polycrystalline silicon within the grooves.

[0014] The method for fabricating a side-pumped pumping device provided in the first aspect of this application involves fabricating a metasurface structure in the cladding of an optical fiber and encapsulating it with a laser diode bar to obtain the pumping device. This fabrication method is simple and easy to implement, with a high yield. The resulting pumping device has a compact structure, few components, low complexity, and practicality. It exhibits high and stable coupling efficiency, high alignment accuracy, and eliminates the need for an additional optical system for collimating and focusing the pump radiation. It also eliminates the need for special fiber combiners and multimode pump fibers, effectively reducing fabrication costs.

[0015] The second aspect of this application provides a side-pumped pumping device, comprising: a first encapsulation structure, wherein the first encapsulation structure is obtained by encapsulating a metasurface optical fiber with a first encapsulation material, and the metasurface optical fiber is obtained by preparing a metasurface structure in the cladding of the optical fiber; and a second encapsulation structure, wherein the second encapsulation structure is obtained by encapsulating a laser diode bar with a second encapsulation material; wherein the second encapsulation structure is disposed in the first encapsulation structure, and the laser diode bar is disposed opposite to the metasurface structure in the metasurface optical fiber.

[0016] In some feasible implementations, there are multiple second encapsulation structures, and each second encapsulation structure is set up in a one-to-one correspondence with the first encapsulation structure.

[0017] The side-pumping pumping device provided in the second aspect of this application is prepared by the preparation method of the side-pumping pumping device provided in the first aspect, and its beneficial technical effects can be found in the first aspect. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart of a method for preparing a side-pumped pumping device according to an embodiment of this application;

[0020] Figure 2 This is a flowchart of the first method for preparing metasurface structures provided in the embodiments of this application;

[0021] Figure 3 yes Figure 2 One of the corresponding process flow diagrams;

[0022] Figure 4 yes Figure 2 The second corresponding process flow diagram;

[0023] Figure 5 This is a flowchart of the second method for preparing metasurface structures provided in the embodiments of this application;

[0024] Figure 6 yes Figure 5 One of the corresponding process flow diagrams;

[0025] Figure 7 yes Figure 5 The second corresponding process flow diagram;

[0026] Figure 8 This is a flowchart of the third method for preparing metasurface structures provided in the embodiments of this application;

[0027] Figure 9 yes Figure 8 Corresponding process flow diagram;

[0028] Figure 10 This is another process flow diagram provided in the embodiments of this application;

[0029] Figure 11 This is a schematic diagram of a partial arrangement of metasurface structures provided in an embodiment of this application;

[0030] Figure 12 This is a schematic diagram of a first packaging structure and a second packaging structure provided in an embodiment of this application;

[0031] Figure 13 This is a schematic diagram of the structure of a side-pumped pumping device provided in an embodiment of this application;

[0032] Figure 14 This is a schematic diagram of the light emission path of a side-pumped pumping device provided in an embodiment of this application;

[0033] Figure 15 This is a schematic diagram of the light emission path of another side-pumped pumping device provided in the embodiments of this application;

[0034] Figure 16 This is a schematic diagram of the light emission path of another side-pumped pumping device provided in an embodiment of this application;

[0035] Figure 17 yes Figure 16 A schematic diagram of the local arrangement of the corresponding metasurface structure;

[0036] Figure 18 This is a schematic diagram of the light emission path of another side-pumped pumping device provided in the embodiments of this application.

[0037] Illustration markings:

[0038] 100. Pumping device;

[0039] 10. Optical fiber; 101. Outer cladding; 102. Inner cladding; 102a. Groove; f1. Metasurface structure; g1. Target region; 10a. Metasurface optical fiber;

[0040] e1, mask layer; e2, photoresist; e3, polysilicon;

[0041] 20. First packaging material; 20a. First packaging structure;

[0042] 30. Second packaging material; 40. Laser diode bar; 40a. Second packaging structure. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the protection scope of this application.

[0044] In the following description, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0045] Furthermore, in this application, directional terms such as "upper," "lower," "inner," and "outer" are defined relative to the indicated placement of the components in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the placement of the components in the accompanying drawings.

[0046] Figure 1 This is a schematic diagram of the preparation method of a side-pumped pumping device provided in an embodiment of this application.

[0047] See Figure 1 As shown, the method for preparing the side-pumped pumping device provided in this application embodiment can be achieved by the following steps S1 to S4.

[0048] Step S1: Prepare a metasurface structure in the cladding of the optical fiber to obtain a metasurface optical fiber.

[0049] The cladding of the optical fiber can include an inner cladding and an outer cladding. That is, step S1 can fabricate a metasurface structure in the outer cladding of the optical fiber, or it can fabricate a metasurface structure in the inner cladding of the optical fiber.

[0050] Figure 2 This is a flowchart of the first method for preparing metasurface structures provided in the embodiments of this application; Figure 3 yes Figure 2 One of the corresponding process flow diagrams; Figure 4 yes Figure 2 The second corresponding process flow diagram.

[0051] In a specific implementation, see Figure 2 , Figure 3 and Figure 4 As shown, step S1 can be achieved by the following steps S11a-S11d.

[0052] Step S11a: Prepare a mask layer e1 on the outer cladding layer 101 of the optical fiber 10 and spin-coat photoresist e2.

[0053] in, Figure 3 Image (a1) shows a cross-sectional view of optical fiber 10 along its axial direction. Figure 3Figure (b1) shows a cross-sectional view of the optical fiber 10 in the radial direction. The optical fiber 10 includes an outer cladding 101 and an inner cladding 102. The outer cladding 101 covers the outside of the inner cladding 102, and the inner cladding 102 contains a fiber core (not shown in the figure).

[0054] In step S11a, after the mask layer e1 is prepared on the outer cladding 101 of the optical fiber 10, the following can be obtained: Figure 3 The structures shown in (a2) and (b2) are shown in the middle.

[0055] In step S11a, after spin-coating photoresist e2 onto mask layer e1, the following can be obtained: Figure 3 The structures shown in (a3) ​​and (b3) are shown in the middle.

[0056] Step S11b: Expose and develop the photoresist e2 according to the metasurface pattern.

[0057] The metasurface pattern is the pattern of the metasurface structure subsequently prepared. In this way, the corresponding metasurface pattern can be prepared according to the desired metasurface structure.

[0058] It is worth noting that in the fabrication method provided in this application, the metasurface structure is not fabricated on the entire optical fiber 10, but rather within a target region of the optical fiber 10. In other words, the subsequently fabricated metasurface structure is distributed within the target region.

[0059] In step S11b, the metasurface pattern can be designed first, and then electron beam exposure technology can be used to expose and develop the photoresist e2 according to the metasurface pattern, resulting in photoresist e2 with the metasurface pattern. After step S11b is completed, the desired result is obtained. Figure 4 The structures shown in (a1) and (b1) are as follows.

[0060] Step S11c: Etch the mask layer e1 and the outer cladding layer 101 according to the metasurface pattern.

[0061] In step S11c, the mask layer e1 and the outer cladding layer 101 located inside the photoresist e2 are etched. After etching is completed, the following can be obtained: Figure 4 The structures shown in (a2) and (b2) are as follows. In this structure, the outer cladding layer 101 with a metasurface pattern formed by etching forms a metasurface structure.

[0062] Step S11d: Remove the mask layer e1 and photoresist e2 to obtain the metasurface fiber 10a.

[0063] In step S11d, after removing the mask layer e1 and the photoresist e2, the following can be obtained: Figure 4Metasurface fiber 10a is shown in (a3) ​​and (b3). In this implementation, the metasurface structure f1 is prepared by the outer cladding 101.

[0064] It should be emphasized that in this implementation, photoresist e2 can also be directly spin-coated onto the outer cladding 101 of the optical fiber 10, eliminating the step of preparing the mask layer e1. Then, the outer cladding 101 of the optical fiber 10 is etched according to the metasurface pattern, and after removing the photoresist e2, the result is as follows: Figure 4 Metasurface structure f1 is shown in (a3) ​​and (b3).

[0065] Figure 5 This is a flowchart of the second method for preparing metasurface structures provided in the embodiments of this application; Figure 6 yes Figure 5 One of the corresponding process flow diagrams; Figure 7 yes Figure 5 The second corresponding process flow diagram.

[0066] In another specific implementation, combined with Figure 5 , Figure 6 and Figure 7 As shown, step S1 can be achieved by the following steps S12a-S12e.

[0067] Step S12a: Strip the outer cladding 101 of the target region g1 in the optical fiber 10 to expose the inner cladding 102.

[0068] The outer cladding layer 101 can be peeled off using laser ablation. Specifically, a CO2 laser ablation system is employed. The peeling depth is equal to the thickness of the outer cladding layer 101, which can be understood as peeling off the outer cladding layer 101 within the target region g1 to expose the inner cladding layer 102 within g1. After peeling, the desired result is obtained as shown below. Figure 6 The structures shown in (a1) and (b1) are as follows.

[0069] Step S12b: Polycrystalline silicon e3 and mask layer e1 are sequentially prepared on inner cladding layer 102, and photoresist e2 is spin-coated.

[0070] In step S12b, firstly, polycrystalline silicon e3 is prepared in the inner cladding 102 of the target region g1. After preparing polycrystalline silicon e3 in the inner cladding 102, the following can be obtained: Figure 6 The structures shown in (a2) and (b2) are as follows. In this implementation, the thickness of the polysilicon e3 can be the same as the thickness of the outer cladding layer 101, thereby facilitating the stability of subsequent etching.

[0071] Polycrystalline silicon e3 can be deposited using plasma-enhanced chemical vapor deposition (PECVD), epitaxy, or other techniques.

[0072] Next, a mask layer e1 is prepared on polycrystalline silicon e3.

[0073] Mask layer e1 can be a hard mask. The hard mask can be a metal or an oxide. When the hard mask is a metal, it can be one of chromium, aluminum, or titanium, and the growth technique can include sputtering (physical vapor deposition) or plasma-enhanced chemical vapor deposition. The growth technique of mask layer e1 can be adapted to the material of mask layer e1.

[0074] After the mask layer e1 is prepared, the following can be obtained: Figure 6 The structures shown in (a3) ​​and (b3) are as follows.

[0075] Finally, photoresist e2 is spin-coated onto the mask layer e1.

[0076] Photoresist e2 is a high-sensitivity photoresist for electron beam exposure, characterized by its sensitivity to electron beam energy to achieve high-precision pattern transfer. The material of photoresist e2 can be polymethyl methacrylate, etc. After spin-coating of photoresist e2, the desired result is... Figure 6 The structures shown in (a4) and (b4) are shown in the middle.

[0077] Step S12c: Expose and develop the photoresist e2 according to the metasurface pattern.

[0078] Step S12c can be referred to step S11b in the above embodiment. After step S12c is completed, the desired result can be obtained. Figure 7 The structures shown in (a1) and (b1) are as follows.

[0079] Step S12d: Etch mask layer e1 and polysilicon e3 according to the metasurface pattern.

[0080] Step S12d can be referred to step S11c in the above embodiment. After the preparation is completed in step S12d, the following can be obtained: Figure 7 The structures shown in (a2) and (b2) are as follows.

[0081] Step S12e: Remove the mask layer e1 and photoresist e2 to obtain the metasurface fiber 10a. In this implementation, the metasurface structure f1 is prepared from polycrystalline silicon e3 deposited on the cladding layer 101.

[0082] Step S12e can refer to step S11d in the above embodiment. After step S12e is completed, the desired result can be obtained. Figure 7 The structures shown in (a3) ​​and (b3) are as follows.

[0083] It needs to be emphasized that, Figure 7 Metasurface structures f1 shown in (a3) ​​and (b3) are similar to Figure 4 The difference between metasurface structures f1 in (a3) ​​and (b3) may lie in the different materials.

[0084] Figure 8 This is a flowchart of the third method for preparing metasurface structures provided in the embodiments of this application; Figure 9 yes Figure 8 The corresponding process flow diagram.

[0085] In another specific implementation, combined with Figure 8 and Figure 9 As shown, step S1 can be achieved by steps S13a to S13e.

[0086] Step S13a: Strip the outer cladding 101 of the target region g1 in the optical fiber 10 to expose the inner cladding 102.

[0087] Step S13a can be referred to step S12a in the above embodiment. After step S13a is completed, the product as shown in the figure is obtained. Figure 9 The structures shown in (a1) and (b1) are as follows.

[0088] Step S13b: Spin-coat photoresist e2 onto the surface of the inner cladding 102.

[0089] Step S13b can be referred to step S12b in the above embodiment. After the preparation is completed in step S13b, the following can be obtained: Figure 9 The structures shown in (a2) and (b2) are as follows.

[0090] Step S13c: Expose and develop the photoresist according to the metasurface pattern.

[0091] The exposure and development processes in step S13c can refer to step S12c in the above embodiment.

[0092] Step S13d: Etch the inner cladding 102 according to the metasurface pattern to form multiple grooves 102a.

[0093] The etching process in step S13d can refer to step S12d in the above embodiment. After step S13d is completed, the desired result can be obtained as shown below. Figure 9 The structures shown in (a3) ​​and (b3) are as follows.

[0094] Step S13e: Remove photoresist e2 to obtain metasurface fiber 10a.

[0095] The process for removing photoresist e2 in step S13e can refer to step S12e in the above embodiment. After step S13e is completed, the desired result can be obtained as shown below. Figure 9 The structures shown in (a4) and (b4) are shown in the middle.

[0096] It needs to be emphasized that, Figure 9 Metasurface structures f1 shown in (a4) and (b4) are similar to Figure 4 The difference between metasurface structures f1 shown in (a3) ​​and (b3) may lie in the different materials and fabrication locations.

[0097] Figure 10 This is another process flow diagram provided in the embodiments of this application.

[0098] In another specific implementation, see Figure 10 As shown, step S13d1 may be included after step S13d.

[0099] Step S13d1: Polycrystalline silicon e3 is prepared in the groove 102a.

[0100] In this implementation, after forming the groove 102a, polycrystalline silicon e3 can be deposited within the groove 102a, and the metasurface structure f1 is prepared from the polycrystalline silicon e3 deposited in the groove 102a. The surface of the polycrystalline silicon e3 can overlap with the surface of the inner cladding layer 102. After step S13c1 is completed, the metasurface structure f1 is obtained as shown. Figure 10 The structures shown in (a) and (b) are shown in the middle.

[0101] It is worth noting that the metasurface structure f1 in this application is prepared by etching or deposition processes. There is no air gap between the metasurface structure f1 and the inner cladding 102, and no refractive index matching gel is required. Therefore, the coupling efficiency is improved, and the overall structure has good integration. The optical fiber 10 provided in the embodiments of this application may include multimode single-layer optical fiber, or other optical fibers, such as double-clad optical fiber, air-clad optical fiber, etc.

[0102] Figure 11 This is a partial layout diagram of the metasurface structure provided in the embodiments of this application. Figure 11 Figures (a) to (d) show schematic diagrams of the local arrangement of different metasurface structures f1.

[0103] See Figure 11 As shown in (a), the target region g1 is rectangular, the cross-sectional shape of the metasurface structure f1 is square, and multiple metasurface structures f1 are arranged in an array.

[0104] See Figure 11As shown in (b), the target region g1 is rectangular, the cross-sectional shape of the metasurface structure f1 is triangular, and multiple metasurface structures f1 are arranged in an array. Furthermore, in this implementation, the array arrangement is similar to... Figure 11 The difference is between (a) and (b).

[0105] See Figure 11 As shown in (c), the target region g1 is rectangular, the cross-sectional shape of the metasurface structure f1 is circular, and multiple metasurface structures f1 are arranged in an array.

[0106] See Figure 11 As shown in (d), the target region g1 is circular, the cross-sectional shape of the metasurface structure f1 is circular, and multiple metasurface structures f1 are arranged in a circular array.

[0107] continue Figure 11 As shown in (a) to (c), the array of metasurface structures f1 is arranged in a first direction A and a second direction B. The first direction A is the circumferential direction of the optical fiber 10, and the second direction B is the axial direction of the optical fiber 10. Since the optical fiber 10 itself is relatively thin, the number of metasurface structures f1 can be increased by lengthening the dimension of the target region g1.

[0108] It should be emphasized that the shapes of the metasurface structure f1 and the target region g1 described above are illustrative examples. The metasurface structure f1 can also be elliptical or pentagonal, or other shapes, and the target region g1 can also be triangular or elliptical. Furthermore, in other implementations, the metasurface structures f1 can be arranged in combination. Of course, in other feasible implementations, multiple metasurface structures f1 can also be arranged in a non-array configuration.

[0109] Figure 12 This is a schematic diagram of the first and second packaging structures provided in the embodiments of this application.

[0110] Step S2: Encapsulate the metasurface optical fiber 10a with the first encapsulation material 20 to obtain the first encapsulation structure 20a.

[0111] After step S2 is completed, the result will be as follows: Figure 12 The first encapsulation structure 20a shown in (a) and (b) has a length of the first encapsulation material 20 greater than or equal to the length of the target region g1 along the second direction B, and the metasurface optical fiber 10a is encapsulated in the first encapsulation material 20, thus ensuring the encapsulation effect.

[0112] Step S3: The laser diode bar 40 is packaged using the second packaging material 30 to obtain the second packaging structure 40a.

[0113] After step S3 is completed, the following can be obtained: Figure 12The second packaging structure 40a is shown in (a) and (b). In this structure, the laser diode bar 40 is encapsulated within the second packaging material 30.

[0114] Step S4: The second packaging structure 40a is disposed in the first packaging structure 20a to obtain the pumping device; wherein the laser diode bar 40 is disposed opposite to the metasurface structure f1.

[0115] Figure 13 This is a schematic diagram of the structure of a side-pumped pumping device provided in an embodiment of this application. Wherein, Figure 13 Image (a) shows a cross-sectional view of the pumping device 100 along the axial direction of the optical fiber 10. Figure 13 (b) is a cross-sectional view of the pumping device 100 along the radial direction of the optical fiber 10.

[0116] See Figure 13 As shown in (a) and (b), a first encapsulation structure 20a is placed on a second encapsulation structure 40a to obtain a pumping device 100. The first encapsulation structure 20a and the second encapsulation structure 40a can be fused together; that is, the opposing surfaces of the first encapsulation structure 20a and / or the second encapsulation structure 40a are fused together after high-temperature melting. Alternatively, the first encapsulation structure 20a and the second encapsulation structure 40a can be encapsulated together using an encapsulation material. The first encapsulation material 20, the second encapsulation material 30, and the encapsulation material used to encapsulate the first encapsulation structure 20a and the second encapsulation structure 40a can be the same to simplify the encapsulation operation. It is important to emphasize that the metasurface structure f1 faces the laser diode bar 40, thus enabling the propagation of the desired optical path.

[0117] The method for fabricating the pumping device provided in this application involves fabricating a metasurface structure f1 in the cladding of optical fiber 10, and then encapsulating it with a laser diode bar 40 to obtain the pumping device 100. This fabrication method is simple, easy to implement, and has a high yield. The resulting pumping device 100 has a compact structure, few components, low complexity, and practicality. It can achieve high stable coupling efficiency, high alignment accuracy, and strong alignment tolerance. It does not require an additional optical system for collimating and focusing the pump radiation, nor does it require a special fiber combiner or multimode pump fiber 10, effectively reducing the fabrication cost.

[0118] It should be emphasized that the pumping device 100 prepared in the embodiments of this application can be used as a pump laser or as an amplifier.

[0119] To facilitate a better understanding of the pumping device 100 prepared according to the embodiments of this application, the working process of the pumping device 100 is briefly described below.

[0120] Figure 14This is a schematic diagram of the light emission path of a side-pumped pumping device provided in an embodiment of this application.

[0121] Figure 14 Image (a) shows a cross-sectional view of the pumping device 100 along the axial direction of the optical fiber 10. Figure 14 Image (b) shows a cross-sectional view of the pumping device 100 along the radial direction of the optical fiber 10. The cross-section is designed to facilitate understanding of the light emission path. Figure 14 As shown in (a) and (b), the laser diode bar 40 is spaced apart from the optical fiber 10, and the first encapsulation material 20 and the second encapsulation material 30 are not shown.

[0122] The laser diode bar 40 emits a light beam. After the light beam illuminates the metasurface structure f1, the path of the light beam is changed by the metasurface structure f1. The light beam is focused on the contact surface between the bottom of the metasurface structure f1 and the inner cladding 102 in a plane perpendicular to the axis of the optical fiber 10.

[0123] See Figure 14 In (a), the beam can form a group of beams propagating toward the side of the fiber 10, and this group of beams contains multiple beams in the same direction. See also Figure 14 As shown in (b), in the metasurface structure f1, the optical path of the metasurface structure f1 located at the center is along the radial direction of the optical fiber 10, and the metasurface structures f1 located on both sides of it are symmetrically arranged about the radial direction of the optical fiber 10.

[0124] The deflection angle of the light beam at the interface between the inner cladding 102 and the outer cladding 101 (the bottom surface of the metasurface structure f1) is α. α is greater than the total internal reflection angle at the interface between the inner cladding 102 and the outer cladding 101 in the optical fiber 10. The specific angle α can be obtained by adjusting various parameters of the metasurface structure f1. This effectively maximizes transmission efficiency, ensures the stability of long-distance communication, suppresses interference and noise, and supports high-speed and high-capacity communication.

[0125] It is important to emphasize that the metasurface structure f1 provided in this embodiment should be matched with the laser diode bar 40 and the optical fiber 10. The metasurface structure f1 ensures that radiation of a specific wavelength is selected from the luminous flux of the laser diode bar 40, which can be effectively transmitted in the inner cladding 102 of the optical fiber 10, and the metasurface structure f1 should satisfy the condition that the optical fiber 10 emitted from the laser diode bar 40 is collimated before entering the inner cladding 102. For the axial directions of the optical fiber 10, the metasurface structure f1 ensures that the incident deflection angle of the beam emitted from the laser diode bar 40 is α.

[0126] It is worth noting that, along the second direction, the length of the metasurface structure f1 is greater than the length of the laser diode bar 40. Thus, the dimensions of the metasurface structure f1 distributed along the axial direction of the optical fiber 10 must be sufficient to receive the entire beam emitted by the laser diode bar 40.

[0127] Figure 15 This is a schematic diagram of the light emission path of another side-pumped pumping device provided in the embodiments of this application.

[0128] In a specific implementation, see Figure 15 As shown, along the cross-section of the fiber 10 in the radial direction, the propagation direction of the beam can also be parallel to the radial direction of the fiber 10. In this way, the propagation direction of the beam path can be adjusted by adjusting the arrangement of the metasurface structure f1, thereby improving the adaptability of the pumping device 100.

[0129] Figure 16 This is a schematic diagram of the light emission path of another side-pumped pumping device provided in an embodiment of this application.

[0130] See Figure 16 As shown, the pumping device 100 in this implementation can also be divided into two groups of beams with opposite propagation directions and the same number of beams inside the optical fiber 10. The deflection angle of the beams in both groups is α.

[0131] In this implementation, the metasurface structure f1 can focus the light beam emitted by the laser diode bar 40 into the inner cladding 102.

[0132] Figure 17 yes Figure 16 A schematic diagram of the local arrangement of the corresponding metasurface structure.

[0133] In a specific implementation, see Figure 16 The local arrangement of the metasurface structure f1 shown can achieve Figure 16 The beam propagation path is shown in the diagram. The beam propagation path within the optical fiber 10 can be achieved by adjusting the local setting position and angle of the metasurface structure f1.

[0134] Specifically, the metasurface structures f1 can be arranged in a 5×7 array, with rows n1, n2, n3, n4, and n5, and columns m1, m2, m3, m4, m5, m6, and m7. In the multiple metasurface structures f1, the orientation of the metasurface structures f1 in each column is the same.

[0135] Taking column m4 as an example, multiple metasurface structures f1 in column m4 can be in a reference state, with L4 as the reference line. Multiple metasurface structures f1 in column m5 rotate relative to column m4 along direction S by a preset angle, and the angle between the reference line L5 and reference line L4 of column m5 is the preset angle. Multiple metasurface structures f1 in column m6 continue to rotate relative to column m5 along direction S by a preset angle, and the angle between the reference line L6 and reference line L5 of column m6 is the preset angle. Multiple metasurface structures f1 in column m7 continue to rotate relative to column m6 along direction S by a preset angle, and the angle between the reference line L7 and reference line L6 of column m7 is the preset angle. Multiple metasurface structures f1 in column m3 rotate relative to column m4 along direction N by a preset angle, and the angle between the reference line L3 and reference line L4 of column m3 is the preset angle. Multiple metasurface structures f1 in column m2 continue to rotate relative to column m3 along direction N by a preset angle, and the angle between the reference line L2 and reference line L3 of column m2 is the preset angle. Similarly, multiple metasurface structures f1 in column m1 continue to rotate relative to column m2 along direction N by a preset angle, and the angle between the reference line L1 and reference line L2 of column m1 is the preset angle. Here, direction N and direction S are two opposite directions.

[0136] In one specific implementation, the metasurface structure f1 in column m1 is rotated 180° relative to the metasurface structure f1 in m7, the metasurface structure f1 in m2 is rotated 180° relative to the metasurface structure f1 in m6, and the metasurface structure f1 in m3 is rotated 180° relative to the metasurface structure f1 in m5.

[0137] It should be emphasized that the above example is only for implementation purposes. Figure 16 This is one specific implementation of two sets of beams pointing in opposite directions; other implementation methods are also possible. Figure 16 In other implementations of the beam path shown, the shape, position, number, and angle of the metasurface structure f1 can be compared with... Figure 17 Different. In this way, the required optical path can be set by adjusting parameters such as the shape, position, number, and setting angle of the metasurface structure f1, thus meeting the diverse usage requirements of the pumping device 100.

[0138] Corresponding to the embodiments of the aforementioned pump device preparation method, this application also provides an embodiment of a pump device 100. This pump device 100 is prepared by the aforementioned method for preparing the pump device.

[0139] See also Figure 13 The pumping device 100 includes a first encapsulation structure 20a, which is obtained by encapsulating a metasurface optical fiber 10a with a first encapsulation material 20. The metasurface optical fiber 10a is obtained by preparing a metasurface structure f1 in the cladding of the optical fiber 10.

[0140] The metasurface fiber 10a is prepared by step S1 in the above embodiments. The first packaging structure 20a is prepared by step S2 in the above embodiments.

[0141] The second packaging structure 40a is obtained by encapsulating the laser diode bar 40 with the second packaging material 30; wherein the second packaging structure 40a is disposed in the first packaging structure 20a, and the laser diode bar 40 is disposed opposite to the metasurface structure f1 in the metasurface fiber 10a.

[0142] The second encapsulation structure 40a is prepared by step S3 in the above embodiment. The first encapsulation structure 20a is then disposed on the second encapsulation structure 40a in step S4 to obtain the pumping device 100.

[0143] Figure 18 This is a schematic diagram of the light emission path of another side-pumped pumping device provided in the embodiments of this application.

[0144] In some feasible implementation methods, combined Figure 13 and Figure 18 As shown, the number of second encapsulation structures 40a can be multiple, and each second encapsulation structure 40a corresponds one-to-one with the first encapsulation structure 20a. That is, the pumping device 100 can also include multiple pump light sources. These multiple pump light sources are arranged sequentially along the axial direction of the optical fiber 10. By adjusting the distance between the pump light sources, the coupling between pump light propagating in the optical fiber 10 can be minimized, and losses reduced. In this implementation, the pump light can be absorbed before reaching adjacent pump sources. Thus, by arranging multiple pump light sources along the axial direction of the optical fiber 10, the required pump power of the pumping device 100 can be matched, providing good scalability.

[0145] It is worth noting that in this implementation, the distance between any two adjacent pump sources can be equal or unequal.

[0146] It should be noted that, upon considering the specification and practicing the application disclosed herein, those skilled in the art will readily conceive of other embodiments of this application. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0147] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The true scope is indicated by this application.

Claims

1. A method for preparing a side-pumped pumping device, characterized in that, include: Metasurface structures are fabricated in the cladding of optical fibers to obtain metasurface optical fibers; The metasurface optical fiber is encapsulated using a first encapsulation material to obtain a first encapsulation structure; A second packaging structure is obtained by packaging the laser diode bar with a second packaging material; The second packaging structure is disposed in the first packaging structure to obtain the pumping device; wherein the laser diode bar is disposed opposite to the metasurface structure.

2. The method for preparing the side-pumped pumping device according to claim 1, characterized in that, The metasurface structure is arranged in an array; The array arrangement includes a first direction and a second direction. The first direction includes the circumferential direction of the optical fiber, and the second direction includes the axial direction of the optical fiber.

3. The method for preparing the side-pumped pumping device according to claim 1, characterized in that, The cross-sectional shape of the metasurface structure includes one or more of the following: square, circular, triangular, elliptical, or pentagonal.

4. The method for preparing the side-pumped pumping device according to claim 2, characterized in that, Along the second direction, the length of the metasurface structure is greater than the length of the laser diode bar.

5. The method for preparing the side-pumped pumping device according to claim 1, characterized in that, Fabricating metasurface structures in the cladding of optical fibers includes: A mask layer is prepared on the outer cladding of an optical fiber and then spin-coated with photoresist. The photoresist is exposed and developed according to the metasurface pattern; The mask layer and the outer cladding layer are etched according to the metasurface pattern; Remove the mask layer and the photoresist to obtain a metasurface optical fiber.

6. The method for preparing the side-pumped pumping device according to claim 1, characterized in that, Fabricating metasurface structures in the cladding of optical fibers includes: Strip the outer cladding of the target region in the optical fiber to expose the inner cladding; Polycrystalline silicon and a mask layer are sequentially fabricated on the inner cladding layer, and photoresist is then spin-coated. The photoresist is exposed and developed according to the metasurface pattern; The mask layer and the polysilicon are etched according to the metasurface pattern; Remove the mask layer and the photoresist to obtain a metasurface optical fiber.

7. The method for preparing the side-pumped pumping device according to claim 1, characterized in that, Fabricating metasurface structures in the cladding of optical fibers includes: Strip the outer cladding of the target region in the optical fiber to expose the inner cladding; Photoresist is spin-coated onto the surface of the inner cladding layer; The photoresist is exposed and developed according to the metasurface pattern; The inner cladding is etched according to the metasurface pattern to form multiple grooves; Remove the photoresist to obtain metasurface optical fiber.

8. The method for preparing the side-pumped pumping device according to claim 7, characterized in that, After forming multiple grooves, the preparation method further includes: Polycrystalline silicon is prepared within the groove.

9. A side-pumped pumping device, characterized in that, The side-pumping pumping device is prepared by the method described in any one of claims 1-8, wherein the side-pumping pumping device comprises: A first packaging structure is obtained by encapsulating a metasurface optical fiber with a first packaging material, wherein the metasurface optical fiber is obtained by preparing a metasurface structure in the cladding of an optical fiber; The second packaging structure is obtained by encapsulating a laser diode bar with a second packaging material; wherein the second packaging structure is disposed in the first packaging structure, and the laser diode bar is disposed opposite to the metasurface structure in the metasurface fiber.

10. The side-pumped pumping device according to claim 9, characterized in that, There are multiple second packaging structures, and each second packaging structure corresponds to one of the first packaging structures.

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