A hollow core fiber body end face sealing structure, sealing device and sealing method

Abstract

This application belongs to the field of optical fiber manufacturing, specifically disclosing a sealing structure, sealing device, and sealing method for the end face of a hollow optical fiber. The sealing structure is disposed on the end face of the hollow optical fiber body and includes a connecting layer and a sealing layer arranged sequentially. The connecting layer is a silane coupling agent molecular layer, with one side surface of the connecting layer covalently bonded to the silanol groups of the end face via siloxane bonds, and the other side surface of the connecting layer having active functional groups. The sealing layer is an organic sealant layer, which also has active functional groups, and these active functional groups form chemical bonds with the active functional groups on the other side surface of the connecting layer. Through the structural design of this application, the sealant can penetrate to a certain depth inside the hollow optical fiber body under pressure and form a flat sealing layer on the end face to be sealed, effectively improving the compactness and adhesion strength of the sealing layer on the end face of the hollow optical fiber body, thereby improving the sealing quality.

Description

Technical Field

[0001] This application belongs to the field of optical fiber manufacturing, and more specifically, relates to a sealing structure, sealing device and sealing method for the end face of a hollow optical fiber. Background Technology

[0002] Hollow-core fiber is an advanced optical waveguide technology. Its core characteristic is that optical signals are primarily transmitted within a core composed of air, rather than within a traditional solid glass material. Hollow-core fiber no longer relies on the principle of "total internal reflection," but instead uses precise microstructures in the cladding to confine light within an air channel for transmission. Typical implementations include photonic bandgap fiber utilizing the photonic bandgap effect, and anti-resonant microstructure fiber based on the principle of anti-resonant reflection. Because light travels faster and with lower loss in air, hollow-core fiber can significantly reduce signal transmission delay by approximately 30% and reduce signal attenuation. Therefore, hollow-core fiber is considered a key technology for solving bottleneck problems in future high-speed communications and high-power laser transmission.

[0003] However, the end face of hollow optical fibers is susceptible to environmental contamination. It is the primary pathway for moisture and impurities to enter the hollow core channel. Once these substances enter, they severely interfere with optical signal transmission. Moisture and impurities cause a sharp increase in signal attenuation through strong absorption and scattering, and significantly degrade transmission stability and beam quality by introducing time-varying loss and wavefront distortion. Therefore, a reliable sealing structure is needed to seal the end face of hollow optical fibers. However, due to the micrometer-level diameter of hollow optical fibers, the actual sealing process often faces numerous challenges. For example, when using sealant to seal the end face, problems such as air bubbles, incomplete coating, or failure to adhere are easily generated during the coating process, and these defects are difficult to observe with the naked eye. Furthermore, there is insufficient thermal bonding strength between the sealant and the glass material; their coefficients of thermal expansion are mismatched, and gaps can easily form due to inconsistent contraction during temperature changes, ultimately leading to end face seal failure. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a sealing structure, sealing device, and sealing method for the end face of hollow optical fibers. The aim is to solve the problems of poor sealing quality and thus affecting the sealing effect of the end face due to defects such as air bubbles, incomplete coating, and insufficient adhesion in existing methods of sealing the end face of hollow optical fibers with sealant.

[0005] This application provides a hollow fiber body end face sealing structure, which is disposed on the end face of the hollow fiber body and includes a connecting layer and a sealing layer disposed sequentially.

[0006] The connecting layer is a silane coupling agent molecular layer. One side of the connecting layer is covalently bonded to the silanol group of the end face through siloxane bonds, and the other side of the connecting layer has active functional groups.

[0007] The sealing layer is an organic sealant layer, which has active functional groups. The active functional groups of the organic sealant layer form chemical bonds with the active functional groups on the other side surface of the connecting layer.

[0008] As a further preferred embodiment, the hollow fiber body is hollow inside, and the sealing layer extends into the hollow fiber body to a depth of at least 5 mm.

[0009] This application provides a sealing device for the end face of a hollow optical fiber, used to prepare the aforementioned sealing structure, specifically including:

[0010] Clamping module, used to fix the hollow fiber body and its end face to be sealed;

[0011] The pressurizing module is detachably connected to the clamping module. When the two are connected, a sealed pressurizing chamber is formed between the clamping module and the pressurizing module, and the end face to be sealed is exposed in the pressurizing chamber.

[0012] The pressurizing module has a pressurizing interface that communicates with the pressurizing chamber. Pressurizing medium is introduced into the pressurizing chamber through the pressurizing interface to pressurize the sealant applied to the end face to be sealed.

[0013] Compared with the prior art, the sealing device, through the above-described technical solution conceived in this application, uses a clamping module to stably fix the hollow optical fiber body and its end face to be sealed. At the same time, the pressurizing module and the clamping module cooperate to form a sealed pressurizing chamber, exposing the end face to be sealed. Pressurizing medium is introduced for pressurization. During the pressurization process, the sealant pre-coated on the end face to be sealed can be subjected to uniform and controllable pressure. Under the pressure, the sealant can penetrate into the hollow optical fiber body to a certain depth, while effectively expelling air bubbles in the sealant. This promotes the complete spread of the sealant and its tight adhesion to the end face to be sealed, forming a flat sealing layer. This can achieve the beneficial effect of improving the density and adhesion strength of the sealing layer on the end face of the hollow optical fiber body, thereby improving the sealing quality of the end face to be sealed.

[0014] As a further preferred embodiment, the clamping module includes:

[0015] Clamping part, used to fix the hollow optical fiber body;

[0016] The forming part is connected to the clamping part and has a flat reference surface; when the hollow fiber body is fixed, the end face to be sealed is flush with the reference surface, so that the sealant applied to the end face to be sealed can be formed with the reference surface as the boundary.

[0017] As a further preferred embodiment, a sealing assembly is provided between the clamping module and the pressurizing module to ensure the airtightness of the pressurizing chamber during the pressurization process.

[0018] As a further preferred embodiment, the pressurizing medium is a gas or a liquid.

[0019] As a further preferred embodiment, the clamping part is provided with multiple fiber positioning slots for simultaneously clamping multiple hollow fiber bodies.

[0020] As a further preferred embodiment, the pressurizing module has a pressurizing groove, and the forming part is threadedly connected to the pressurizing groove to form the pressurizing chamber.

[0021] As a further preferred embodiment, the reference surface is coated with an anti-stick coating.

[0022] This application also provides a sealing method for the end face of a hollow optical fiber, which uses the above-mentioned sealing device and includes the following steps:

[0023] S1: After pre-treating the end face of the hollow fiber body to be sealed, the hollow fiber body is fixed by a clamping module, and liquid sealant is applied to the end face to be sealed, and then the liquid sealant is scraped flat.

[0024] S2: Connect the pressurizing module and the clamping module to form a pressurizing chamber, so that the end face to be sealed, coated with liquid sealant, is exposed in the pressurizing chamber;

[0025] S3: Pressurizing medium is introduced into the pressurizing chamber through the pressurizing interface to pressurize the liquid sealant on the end face to be sealed, thereby forming a sealing layer on the end face to be sealed and inside the hollow fiber body.

[0026] As a further preferred embodiment, the pretreatment in step S1 includes cutting and plasma cleaning the end face of the hollow fiber body to be sealed, coating the end face to be sealed with silane coupling agent and heating it at a temperature of 100℃-120℃ for 10min-30min.

[0027] As a further preferred embodiment, the sealing method further includes: performing steps S1 to S3 multiple times, and then curing the sealing layer to complete the sealing of the end face to be sealed.

[0028] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages:

[0029] 1. This application sets up a clamping module with a flat reference surface, so that after the hollow fiber body is fixed, the end face to be sealed can be aligned with the reference surface, so as to facilitate the application of sealant to the end face to be sealed. During the pressurization process, the liquid sealant enters into the hollow fiber body to a certain depth under pressure and adheres to the reference surface, thereby forming a sealing layer with a flat surface and uniform thickness on the end face to be sealed of the hollow fiber body.

[0030] 2. This application forms an independent sealed pressurization chamber by cooperating with the clamping module and the pressurization module. The end face of the hollow fiber body to be sealed is placed in the pressurization chamber. This structural design can apply uniform and controllable pressure to the sealant on the end face to be sealed. The pressure direction is perpendicular to the end face to be sealed, ensuring that the sealant has a dense internal structure after curing, effectively reducing or eliminating defects such as bubbles and micropores, and significantly improving the mechanical strength and sealing reliability of the sealing layer.

[0031] 3. This application employs pretreatment steps such as plasma cleaning, coating with silane coupling agent, and heat treatment on the hollow fiber body end face before applying adhesive. This effectively cleans and activates the end face to be sealed, introduces organic functional groups into the glass surface, enhances the chemical bonding and physical adsorption between the subsequent liquid sealant and the inorganic glass fiber, improves the thermal bonding strength between the sealant and the glass material, and ensures the long-term stability of the sealing layer. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the sealing device provided in the embodiments of this application;

[0033] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure;

[0034] Figure 3 This is a schematic diagram of the overall structure of the clamping module provided in the embodiments of this application;

[0035] Figure 4 This is a schematic diagram of the overall structure of the pressurization module provided in the embodiments of this application;

[0036] Figure 5 This is a schematic diagram of the overall structure of the hollow fiber body end face sealing structure provided in the embodiments of this application.

[0037] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0038] 1. Clamping module; 11. Clamping part; 111. Fiber positioning groove; 12. Forming part; 121. Reference surface; 2. Pressurizing module; 21. Pressurizing interface; 22. Pressurizing groove; 3. Pressurizing chamber; 4. Sealing assembly; 5. Hollow fiber body; 51. End face to be sealed; 61. Connecting layer; 62. Sealing layer. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0040] Reference Figures 1-2 This application discloses a sealing device for the end face of a hollow optical fiber. By constructing a precisely aligned, airtight, and pressure-controllable sealing environment, the end face of the hollow optical fiber coated with sealant is placed within this sealing environment, thus sealing the end face of the hollow optical fiber. This solves the problems of air bubble generation, incomplete coating, insufficient adhesion, and mismatch of thermal expansion coefficients that exist in traditional sealing methods using sealant to seal the end face of hollow optical fibers, thereby improving the sealing effect of the end face of the hollow optical fiber. The device mainly includes a clamping module 1, a pressurizing module 2, and a sealing component 4.

[0041] Specifically, the clamping module 1 is the positioning basis for the hollow fiber body 5 in this embodiment, used to fix the hollow fiber body 5 and its end face 51 to be sealed. It includes two parts: a clamping part 11 and a forming part 12. The two work together to ensure that the end face 51 to be sealed of the hollow fiber body 5 is stably fixed, so as to facilitate the sealing operation of the end face 51 to be sealed. The clamping part 11 is one of the core components of the clamping module 1, which can fix the hollow fiber body 5 firmly and without damage. More specifically, the clamping part 11 includes two symmetrical clamping members on the left and right. This symmetrical structure not only ensures the balance of clamping the hollow fiber body 5, but also makes the clamping process more stable and reliable. On the side of the two clamping members that are close to each other, multiple fiber positioning grooves 111 are precisely machined. The diameter of the fiber positioning grooves 111 matches the outer diameter of the hollow fiber body 5, which can realize the parallel clamping of multiple hollow fiber bodies 5 at the same time, improving the efficiency of end face sealing of multiple hollow fiber bodies 5. When the two clamping parts are closed together by screws or clamps, they together form a complete cylindrical clamping structure, which provides uniform radial clamping force for the hollow fiber body 5. This not only prevents the hollow fiber body 5 from sliding or rotating, but also avoids damage to the hollow fiber body 5 caused by excessive local stress.

[0042] The forming part 12 is another core component of the clamping module 1. It is connected to the end of the clamping part 11 and works in conjunction with the clamping part 11 to ensure the clamping stability of the hollow fiber body 5. The forming part 12 is also composed of two symmetrical forming parts on the left and right, which are fixedly connected to the corresponding clamping parts respectively. After the two forming parts are closed, their end faces away from the clamping parts together form a flat reference surface 121. The reference surface 121 is precision ground and has a high flatness. When the hollow fiber body 5 is firmly fixed by the clamping part 11, its end face (i.e., the end face 51 to be sealed) is strictly coplanar with the reference surface 121 of the forming part 12, ensuring that the end face 51 to be sealed is flush with the reference surface 121 and is basically in the same plane. This makes the end face 51 to be sealed no longer protrude in isolation, but is integrated with the flat reference surface 121. By making the end face 51 to be sealed of the hollow fiber body 5 coplanar with the reference surface 121, it can be ensured that in the subsequent sealing process, the sealant can be evenly covered on the end face 51 to be sealed and the reference surface 121, and the sealant can be formed with the reference surface 121 as the boundary to form a flat and uniform sealing layer.

[0043] To further optimize the process, an anti-stick coating is applied to the reference surface 121. This anti-stick coating possesses excellent chemical stability and low surface energy characteristics, such as a Teflon coating or a silicone release coating. The Teflon coating exhibits high temperature resistance, corrosion resistance, and a low coefficient of friction, effectively preventing the liquid sealant from adhering to the reference surface 121 during curing. The silicone release coating offers good flexibility and release properties, similarly ensuring that the sealant can be easily separated from the reference surface 121 after curing. In actual operation, when the liquid sealant is applied to the fiber end face and the reference surface 121 and pressure is applied, the anti-stick coating forms a physical isolation layer, preventing the sealant molecules from chemically bonding or physically adsorbing onto the reference surface 121. After curing, the clamping module 1 can smoothly separate from the cured, flat sealing layer without causing any damage to the sealing layer surface. This not only ensures the integrity and surface quality of the sealing layer but also reduces product scrap rates due to poor demolding, thereby significantly improving production efficiency and product yield. Furthermore, the use of this anti-stick coating reduces the cleaning and maintenance work on the reference surface 121. Because the coating effectively prevents sealant residue, the reference surface 121 is easier to clean after each use and is less susceptible to chemical corrosion or physical wear, thereby extending the service life of the molding section 12 and reducing equipment maintenance costs. In addition, the extremely low surface energy of the anti-stick coating (e.g., a contact angle greater than 110°) guides the liquid sealant to preferentially wet and shrink towards the fiber end face region during pressurization, resulting in a slightly inward-curving arc-shaped edge at the edge of the sealing layer after curing, effectively reducing edge stress and the risk of peeling.

[0044] Reference Figures 3-4Furthermore, the pressurizing module 2 is the pressure generation and control unit of the sealing device in this embodiment. It is detachably connected to the clamping module 1. When the two are connected, a sealed pressurizing chamber 3 is formed between the clamping module 1 and the pressurizing module 2, exposing the end face 51 to be sealed to the pressurizing chamber 3. A pressurizing groove 22 is machined on the main structure of the pressurizing module 2. The size of the pressurizing groove 22 is adapted to the outer contour of the forming part 12 in the clamping module 1. The forming part 12 (also a cylindrical structure) can be screwed into the pressurizing groove 22 by a threaded connection and locked therewith. The threaded connection can provide a stable and uniform axial locking force, ensuring that the connection between the clamping module 1 and the pressurizing module 2 is tight and stable during the pressurization of the sealant on the end face 51 to be sealed, and there will be no loosening or deformation. When the clamping module 1 and the pressurizing module 2 are tightly engaged by threads, the end of the forming part 12 (i.e., the side with the reference surface 121) and the bottom of the pressurizing groove 22 are enclosed to form a sealed pressurizing chamber 3. At this time, the end face 51 to be sealed, which is flush with the reference surface 121, is completely exposed in this pressurizing chamber 3, so that the end face 51 to be sealed can directly contact the sealant in the pressurizing chamber 3 and be subjected to uniform pressure during the pressurization process. The pressurizing module 2 is provided with a pressurizing interface 21 that communicates with the pressurizing chamber 3. The pressurizing interface 21 is connected to an external pressurizing device, and a pressurizing medium (gas or liquid) is introduced into the pressurizing chamber 3 through the pressurizing interface 21 to pressurize the sealant applied to the end face 51 to be sealed. In this embodiment, the connection between the clamping module 1 and the pressurizing module 2 is not limited to a threaded connection. Quick-release buckles, flange bolt connections, or magnetic sealing connections can also be used, as long as stable locking and sealing between the two can be achieved.

[0045] Reference Figure 2 To ensure the airtightness of the pressurizing chamber 3 during the pressurization process, a sealing component 4 is provided at the mating surface of the clamping module 1 and the pressurizing module 2. This component is typically an annular elastic sealing ring (such as an O-ring), installed in a pre-set sealing groove. In this embodiment, the annular elastic sealing ring is installed at the mating surface of the clamping part 11 and the pressurizing module 2. When the clamping module 1 and the pressurizing module 2 are locked together, the sealing ring is compressed, thereby reliably sealing all possible leakage paths of the pressurizing chamber 3 and ensuring that the pressurizing medium does not leak out.

[0046] This application also discloses a sealing method for the end face of a hollow optical fiber, which uses the above-mentioned sealing device and includes the following steps:

[0047] S1: First, the end face 51 of the hollow fiber body 5 to be sealed is pre-treated to ensure the smooth progress and high quality of the subsequent sealing process. Pre-treatment includes flattening and plasma cleaning of the end face 51 of the hollow fiber body 5. Specifically, a high-precision cutting device is used to flatten the end face 51 of the hollow fiber body 5 to ensure it is flat and smooth, providing a good foundation for subsequent sealant coating and sealing processes. The flatness of the end face 51 directly affects the quality and sealing effect of the sealing layer; therefore, the flattening operation requires strict precision control to ensure that the end face has no obvious steps or unevenness. After flattening the end face 51, plasma cleaning is performed on the end face 51 of the hollow fiber body 5. Plasma cleaning is a highly efficient surface treatment technology. Through the action of high-energy plasma particles, it effectively removes impurities such as organic matter, dust, and oil from the end face 51 of the hollow optical fiber body 5 that needs to be sealed. This not only improves the cleanliness of the end face 51 but also enhances its surface energy, activating it and strengthening the adhesion between the subsequently applied sealant and the end face 51. The plasma cleaning process is typically carried out in dedicated plasma cleaning equipment. By controlling the plasma power, gas flow rate, and processing time, optimal cleaning results are ensured.

[0048] A layer of silane coupling agent is uniformly coated onto the end face 51 of the hollow optical fiber body 5 to be sealed after plasma cleaning. Silane coupling agent is a chemical substance that can significantly improve the adhesion between inorganic materials (such as optical fiber end faces) and organic materials (such as sealants). By coating the end face 51 with silane coupling agent, a chemical bond bridge can be formed, enhancing the bonding strength between the sealant and the optical fiber end face, thereby improving the reliability and durability of the sealing layer. After coating, the optical fiber body is placed in a heating device for heat treatment. Heating promotes the curing and cross-linking reaction of the silane coupling agent, forming a uniform and stable chemical film on the optical fiber end face. The heating temperature is controlled between 100℃ and 120℃, and the heating time is set to 10 minutes to 30 minutes. By precisely controlling the heating temperature and time, the performance of the silane coupling agent can be ensured to reach its optimal state, while avoiding end face damage or other adverse effects caused by excessive temperature or time. One end of the coupling agent molecule reacts with the silanol groups on the glass surface, and the other end can react with organic sealant. After a short heating, it forms a strong chemical bond with the glass.

[0049] After the above pretreatment steps, the hollow fiber body 5 is securely fixed in the device using the clamping module 1. The clamping module 1 ensures the stability of the hollow fiber body 5 during subsequent processes, preventing fiber displacement or damage due to external forces. After the hollow fiber body 5 is fixed, a layer of liquid sealant is uniformly applied to the end face 51 to be sealed, and then the liquid sealant is smoothed to ensure uniform thickness, avoiding poor sealing effect or insufficient sealing layer strength due to uneven application. The sealant is a condensation-type single-component organosilicon with excellent toughness and high and low temperature resistance, capable of withstanding temperatures from -60℃ to 200℃, ensuring that the sealant itself is not prone to failure under environmental changes.

[0050] S2: Connect the pressurizing module 2 to the clamping module 1. Specifically, the pressurizing module 2 has a pressurizing groove 22 on its main body, the size of which is adapted to the outer contour of the forming part 12 of the clamping module 1. The forming part 12 is a cylindrical structure, which is screwed into the pressurizing groove 22 by means of thread connection. In order to improve the connection efficiency, the end of the forming part 12 is set with a chamfer structure. When the clamping module 1 and the pressurizing module 2 are tightly connected by threads, the end of the forming part 12 (i.e., the end with the reference surface 121) is tightly surrounded by the bottom of the pressurizing groove 22 to form a sealed pressurizing chamber 3. At this time, the end face 51 of the hollow fiber body 5 to be sealed is completely exposed in the pressurizing chamber 3. Before introducing the pressurizing medium into the pressurizing chamber 3, the pressurizing chamber 3 is first evacuated. Specifically, after connecting the pressurizing module 2 to the clamping module 1, a vacuum pump can be connected through the pressurizing interface 21 to evacuate the pressurizing chamber 3 (for example, to -0.1MPa) and maintain it for a certain period of time to remove the air bubbles remaining inside the sealant and in the micropores of the optical fiber. Then, the pressurizing medium is introduced for pressurization.

[0051] S3: A pressurizing medium (such as compressed air, nitrogen, or other suitable inert gas) is introduced into the pressurizing chamber 3 through the pressurizing interface 21. The selection of the pressurizing medium needs to be optimized according to the chemical properties of the sealant and process requirements to ensure that it will not adversely affect the sealant or the fiber end face during pressurization. After the pressurizing medium enters the pressurizing chamber 3, its pressure will act evenly on the liquid sealant. This uniform pressure distribution ensures that the sealant perfectly adheres to the fiber end face during the curing process, forming a flat, uniform, and reliable sealing layer. During pressurization, the liquid sealant will penetrate to a certain depth into the hollow fiber body 5 under pressure, forming a sealing layer inside the end face 51 to be sealed and the hollow fiber body 5. During the pressurization process, precise control of the pressure of the pressurizing medium and the pressurization time is crucial to ensuring sealing quality. According to process requirements, the pressure of the pressurizing medium should be controlled between 10 bar and 30 bar. For the selected condensation-type silicone sealant, under a pressure of 10-30 bar, the sealant penetrates into the hollow fiber body 5, forcing its molecular chains to align tightly. Simultaneously, the pressure promotes the diffusion and expulsion of residual low-molecular-weight substances (such as alcohols) in the system, resulting in a denser final cross-linked network and a significantly reduced porosity, thereby improving the barrier performance and mechanical strength of the sealing layer. Meanwhile, the pressurization time should be controlled between 1 minute and 10 minutes. This time range ensures that the sealant penetrates to a certain depth into the hollow fiber body 5 under pressure, forming a smooth and uniform sealing layer on the end face, without excessive flow due to excessive pressurization time or shallow penetration due to insufficient time. After pressurization, the sealing layer is allowed to cure at room temperature or in a heated environment.

[0052] Repeat steps S1 to S3 as described above multiple times, and then cure the sealing layer to complete the sealing of the end face 51 to be sealed. By applying, smoothing and pressing multiple times, the sealant can be filled to a certain depth inside the hollow optical fiber body 5, avoiding problems such as flow, dripping or accidental wiping away of the sealant during curing, which can lead to incomplete filling of the sealant.

[0053] Reference Figure 5 This application also discloses a sealing structure for the end face of a hollow optical fiber body, which is prepared by the sealing device and sealing method described above. The sealing structure is disposed on the end face of the hollow optical fiber body 5 and includes a connecting layer 61 and a sealing layer 62 arranged sequentially along the direction away from the hollow optical fiber body 5. The connecting layer 61 is a silane coupling agent molecular layer. One side surface of the connecting layer 61 is covalently bonded to the silanol groups on the end face through siloxane bonds, and the other side surface of the connecting layer 61 has active functional groups. The organic sealant layer has active functional groups, and the active functional groups of the organic sealant layer form chemical bonds with the active functional groups on the other side surface of the connecting layer 61.

[0054] The silane coupling agent molecular layer includes one of aminosilane, epoxysilane, methacryloxysilane, or mercaptosilane.

[0055] Since the hollow fiber body 5 is hollow inside, the sealing layer 62 can extend into the hollow fiber body 5, and the extension depth D is at least 5mm. For example, the depth of the sealing layer 62 extending into the hollow fiber body 5 can be 5mm, 5.1mm, 5.2mm, 5.3mm, 5.4mm, 5.5mm, 5.6mm, 5.7mm, 5.8mm, 5.9mm or 6mm, etc. The specific depth can be determined according to the size of the hollow part of the hollow fiber body 5 and the pressure applied, so as to improve the stability of the sealing layer 62.

[0056] In addition, this application also provides a hybrid optical cable formed by combining hollow and solid optical fibers. The hybrid optical cable includes multiple optical units, including a first optical unit with hollow optical fibers and a second optical unit with solid optical fibers. The solid optical fibers can be G.652D, G.654E, or G.655, etc. The ends of the hollow optical fibers in the first optical unit are sealed using the end-face sealing structure described above.

[0057] It should be understood that expressions such as "comprising" and "may include" as used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "comprising" and / or "having" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but should not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0058] It should be understood that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0059] Furthermore, the terms "first" and "second" 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0060] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0061] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A hollow fiber body end face sealing structure, disposed on the end face of a hollow fiber body (5), characterized in that, It includes a connecting layer (61) and a sealing layer (62) arranged sequentially. The connecting layer (61) is a silane coupling agent molecular layer. One side of the connecting layer (61) is covalently bonded to the silanol group of the end face through siloxane bonds, and the other side of the connecting layer (61) has active functional groups. The sealing layer (62) is an organic sealant layer, which has active functional groups. The active functional groups of the organic sealant layer form chemical bonds with the active functional groups on the other side surface of the connecting layer (61). The hollow fiber body (5) is hollow inside, and the sealing layer (62) extends into the hollow fiber body (5) with an extension depth of at least 5 mm.

2. A sealing device for the end face of a hollow optical fiber, used to prepare the sealing structure as described in claim 1, characterized in that, include: Clamping module (1) is used to fix the hollow fiber body (5) and its end face (51) to be sealed. The pressurizing module (2) is detachably connected to the clamping module (1). When the two are connected, a sealed pressurizing chamber (3) is formed between the clamping module (1) and the pressurizing module (2), and the end face (51) to be sealed is exposed in the pressurizing chamber (3). The pressurizing module (2) is provided with a pressurizing interface (21) that communicates with the pressurizing chamber (3). Pressurizing medium is introduced into the pressurizing chamber (3) through the pressurizing interface (21) to pressurize the sealant applied to the end face (51) to be sealed. The clamping module (1) includes: Clamping part (11) is used to fix the hollow fiber body (5); The forming part (12) is connected to the clamping part (11) and is provided with a flat reference surface (121). The reference surface (121) is coated with an anti-stick coating. When the hollow fiber body (5) is fixed, the end face (51) to be sealed is flush with the reference surface (121), so that the sealant applied to the end face (51) to be sealed can be formed with the reference surface (121) as the boundary.

3. The sealing device for the end face of a hollow optical fiber as described in claim 2, characterized in that, The clamping part (11) is provided with multiple fiber positioning slots (111) for simultaneously clamping multiple hollow fiber bodies (5).

4. The sealing device for the end face of a hollow optical fiber as described in claim 2, characterized in that, The pressurizing module (2) has a pressurizing groove (22), and the molding part (12) is threadedly connected to the pressurizing groove (22) to form the pressurizing chamber (3).

5. A sealing method for the end face of a hollow optical fiber, comprising using the sealing device as described in any one of claims 2-4, characterized in that, Includes the following steps: S1: After pre-processing the end face (51) to be sealed of the hollow fiber body (5), the hollow fiber body (5) is fixed by the clamping module (1), and liquid sealant is applied to the end face (51) to be sealed, and then the liquid sealant is scraped flat. S2: Connect the pressurizing module (2) and the clamping module (1) to form a pressurizing chamber (3), so that the end face (51) to be sealed, coated with liquid sealant, is exposed in the pressurizing chamber (3); S3: Pressurizing medium is introduced into the pressurizing chamber (3) through the pressurizing interface (21) to pressurize the liquid sealant on the end face (51) to be sealed, thereby forming a sealing layer inside the end face (51) to be sealed and the hollow fiber body (5).

6. The sealing method for the end face of a hollow optical fiber as described in claim 5, characterized in that, The pretreatment in step S1 includes cutting and plasma cleaning the end face (51) of the hollow fiber body (5) to be sealed, coating the end face (51) with silane coupling agent and heating it. The heating temperature is 100℃-120℃ and the time is 10min-30min.

7. The sealing method for the end face of a hollow optical fiber as described in claim 5, characterized in that, The sealing method further includes: performing steps S1 to S3 multiple times, and then curing the sealing layer to complete the sealing of the end face (51) to be sealed.

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