Device and method for hollow-core anti-resonance optical fiber connection and optical module

Abstract

The invention discloses a device and method for connecting hollow-core anti-resonance optical fibers and an optical module, and the device comprises two hollow optical fibers which are coaxially arranged in a mirror symmetry manner, the end part of each hollow optical fiber is provided with a connector, and a hollow flange is arranged between the two connectors. An included angle is formed between the end face of each hollow optical fiber and a plane perpendicular to the central axis of the hollow optical fiber, the end faces of the two hollow optical fibers are coaxially arranged in parallel, each connector comprises an outer frame, and the outer frame is provided with a guide groove extending in the axial direction of the hollow optical fiber. A guide boss matched with the guide groove is arranged on the inner wall of the hollow flange. Reflection of an optical fiber connection end face is effectively reduced, and transmission quality and stability of optical signals are improved.

Description

Technical Field

[0001] The invention relates to a device assembly method for hollow-core anti-resonance optical fiber connection, belongs to the technical field of optical modules, and in particular to a device, method and optical module for hollow-core anti-resonance optical fiber connection. Background Art

[0002] With the continuous development of optical communication technology, the demand for high-speed and large-capacity optical signal transmission is increasing. Traditional solid-core optical fibers have problems such as dispersion, nonlinear effects and transmission loss during transmission, which limits the further improvement of their performance. In contrast, hollow-core anti-resonant fiber has the advantages of low loss, low dispersion and high bandwidth, and has broad application prospects in the field of optical communication. As a new type of microstructured optical fiber, hollow-core anti-resonant fiber (HC-ARF) has excellent properties such as low loss, large bandwidth and anti-nonlinearity, and has broad application prospects in optical communication, laser transmission, sensing and other fields. However, due to its special structure and optical properties, the connection and coupling of hollow-core anti-resonant fiber has always been a technical problem, which limits its practical application.

[0003] In particular, during the connection process of hollow-core anti-resonant optical fibers, due to the reflection of the optical fiber end face, the loss of optical signals and the generation of reflected clutter signals will occur, which seriously affects the performance of the optical communication system. In addition, hollow-core anti-resonant optical fibers cannot be polished in the traditional way of optical fibers because they have a hollow microstructure, which becomes fragile when the port is exposed to the air, and it is difficult to remove dust attracted by static electricity. Therefore, it is urgent to develop a device for hollow-core anti-resonant optical fiber connection that can effectively reduce reflection and connect to solve this problem, so as to promote the practical application of hollow-core anti-resonant optical fibers in the field of optical communications. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a device assembly method and an optical module for hollow-core anti-resonant optical fiber connection in response to the technical defects existing in the prior art, which effectively reduces the reflection of the optical fiber connection end face and improves the transmission quality and stability of the optical signal.

[0005] The technical solution adopted by the present invention to solve its technical problem is: the present invention discloses a device for connecting hollow-core anti-resonant optical fibers, which includes two coaxially arranged hollow-core optical fibers in mirror symmetry, a connector is provided at the end of each hollow-core optical fiber, a hollow flange is provided between the two connectors, an angle exists between the end face of each hollow-core optical fiber and a plane perpendicular to its central axis, the end faces of the two hollow-core optical fibers are coaxially arranged in parallel, each connector includes an outer frame, the outer frame is provided with a guide groove extending along the axial direction of the hollow-core optical fiber, and a guide boss matching the guide groove is provided on the inner wall of the hollow flange.

[0006] In a preferred embodiment of the present invention, each connector includes a coaxially arranged tail sleeve, a stopper, a ferrule, an inner frame and an outer frame, the tail sleeve is fixedly connected to the outer peripheral surface of the hollow-core optical fiber, the stopper is coaxially plugged into the end of the tail sleeve, the ferrule sleeved on the hollow-core optical fiber is arranged in the stopper, a spring is arranged between the ferrule and the stopper, the inner frame is fixedly connected to the outer side of the ferrule, and the outer side of the inner frame is fixedly connected to the outer frame.

[0007] In a preferred embodiment of the present invention, the end face of the core of the hollow optical fiber forms an angle of with a plane perpendicular to its central axis; a transition conical surface is provided between the end face of the core of the hollow optical fiber and its outer peripheral surface.

[0008] In a preferred embodiment of the present invention, the angle between the end face of the hollow core optical fiber and the plane perpendicular to its central axis is 7°

[0009] The present invention discloses a device assembly method for hollow-core anti-resonant optical fiber connection, comprising the following steps: a pre-assembly step: passing the hollow-core optical fiber through a tail sleeve, a stopper and a spring in sequence; a curing step: fixing the hollow-core optical fiber with a core plug; an assembly step: assembling the stopper with an inner frame and an outer frame in sequence; and a grinding step: performing multi-stage grinding treatment on the core plug end face.

[0010] In a preferred embodiment of the present invention, the curing step specifically includes: a stripping step: stripping a preset length of coating from the optical fiber at the ferrule end and cleaning the coating residue; a glue injection step: mixing epoxy resin glue in a predetermined proportion and injecting it into the ferrule from the ferrule tail handle through an injection needle; a curing treatment: inserting the hollow optical fiber into the ferrule after glue injection, and curing it at a preset temperature for a predetermined time.

[0011] In a preferred embodiment of the present invention, the grinding steps are performed in the following order: first grinding stage: using a first grinding tool to remove the cured glue on the core head; second grinding stage: using a second grinding tool assembly to grind at a first speed for a first preset time; third grinding stage: using a third grinding tool assembly to grind at a second speed for a second preset time; fourth grinding stage: using a fourth grinding tool assembly to grind at the second speed for a second preset time; fifth grinding stage: using a precision grinding tool assembly to grind at the second speed for a second preset time.

[0012] In a preferred embodiment of the present invention, the assembly steps include: a first assembly stage: installing the stopper to the inner frame, so that the stopper squeezes the spring, and the multiple card points of the stopper are completely inserted into the card grooves on the side of the inner frame; a second assembly stage: inserting the inner frame into the outer frame, so that the inner frame positioning structure is aligned with the corresponding positioning structure in the outer frame; a third assembly stage: assembling the tail sleeve onto the stopper, and installing the spring clip into the spring clip groove of the hollow flange outer frame; assembly verification: performing a force test on the inner frame in a predetermined direction to confirm that the stopper is firmly connected to the inner frame and does not fall off.

[0013] In a preferred embodiment of the present invention, after the polishing step is completed, the method further comprises: assembling a protective component onto the hollow optical fiber to prevent end face contamination.

[0014] In a preferred embodiment of the present invention, it also includes a device switching step for hollow-core anti-resonant optical fiber connection: switching between devices for hollow-core anti-resonant optical fiber connection is achieved through a hollow flange, wherein the hollow flange is provided with a positioning structure for limiting the direction and insertion depth of a device for hollow-core anti-resonant optical fiber connection.

[0015] In a preferred embodiment of the present invention, the step of switching the device for connecting hollow-core antiresonant optical fibers comprises: inserting a device for connecting hollow-core antiresonant optical fibers into a hollow flange, fixing the hollow flange to the device by an elastic positioning assembly, so that the hollow optical fiber is located at the center of the hollow flange.

[0016] In a preferred embodiment of the present invention, in the assembling step: the cured ferrule is positioned at the center of a device for hollow-core anti-resonant optical fiber connection through the matching structure of the inner frame and the outer frame.

[0017] In a preferred embodiment of the present invention, the positioning structure of the hollow flange cooperates with a device for connecting hollow-core antiresonant optical fibers to achieve precise alignment and connection of the end faces of two hollow-core optical fibers.

[0018] The present invention also discloses an optical module, comprising a device for hollow-core anti-resonance optical fiber connection, wherein the device for hollow-core anti-resonance optical fiber connection is manufactured by an assembly method for the device for hollow-core anti-resonance optical fiber connection.

[0019] The beneficial effects of the present invention are as follows: the hollow-core optical fiber provided by the present invention is a device for precise assembly of hollow-core anti-resonant optical fiber connections, which has multiple technical advantages and practical application value. First, through the designed complete process of pre-assembly, curing, assembly and grinding, high-precision connection of hollow-core optical fibers is achieved, effectively solving the technical difficulties of hollow-core anti-resonant optical fiber connection and coupling. The method adopts a multi-stage grinding process, and through the precise control of grinding parameters and tool configuration, it ensures high-quality processing of the optical fiber end face, significantly reducing the optical signal loss caused by end face reflection.

[0020] Furthermore, the end face of the core of the hollow optical fiber of the present invention forms an angle of with a plane perpendicular to its central axis; a transition conical surface is provided between the end face of the core of the hollow optical fiber and its outer peripheral surface, and this structural design effectively reduces the area of ​​the end face of the core, facilitating better and more precise docking. The larger the area, the worse the docking accuracy. It is not easy to damage the edge of the plane angle during docking, and collision is prevented. The air can be better discharged to the surroundings. The end face of the APC optical fiber is usually ground into a 7° bevel. The 7° angle bevel makes the end face of the optical fiber tighter, and reflects the light to the cladding through its bevel angle instead of directly returning to the light source, providing better connection performance.

[0021] Secondly, the assembly structure of the present invention is uniquely designed. Through the precise matching of the stopper, the inner frame and the outer frame, the stable positioning of the hollow-core optical fiber in a device for hollow-core anti-resonant optical fiber connection is achieved. In particular, the positioning structure design of the inner frame and the outer frame ensures that the optical fiber is always in the center position of a device for hollow-core anti-resonant optical fiber connection, which is of great significance for reducing insertion loss. At the same time, the positioning structure design of the hollow flange provides a reliable guarantee for the precise alignment of the end faces of the two hollow-core optical fibers, effectively improving the transmission efficiency of the optical signal.

[0022] Furthermore, the present invention fully considers the particularity of hollow antiresonant optical fiber, uses epoxy resin glue for fixation in the curing step, and uses a protective component for protection immediately after grinding, effectively solving the problem that the end face of the hollow optical fiber is easily contaminated and damaged. This method not only protects the hollow microstructure of the optical fiber, but also avoids the contamination of the optical fiber end face caused by electrostatic adsorption of dust.

[0023] Finally, the assembly method of the present invention has strong practicality and operability. By setting up an assembly verification step, the reliability of the assembly of a device for hollow-core antiresonant optical fiber connection is ensured; through the design of an elastic positioning component, a convenient installation and disassembly of a device for hollow-core antiresonant optical fiber connection is achieved. These characteristics enable this method to meet the technical requirements of hollow-core optical fiber connection, and facilitate industrial production and practical application, providing important technical support for the promotion and application of hollow-core antiresonant optical fiber in the fields of high-speed optical communication, laser transmission, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0025] Figure 1 This is an exploded view of a device structure for hollow-core anti-resonant optical fiber connection according to the present invention;

[0026] Figure 2 It is a schematic diagram of a core insertion device structure for hollow core anti-resonant optical fiber connection of the present invention;

[0027] Figure 3 is a schematic diagram of a device structure for hollow-core anti-resonant optical fiber connection according to the present invention;

[0028] Figure 4 It is a schematic diagram of the end of a device structure for hollow-core anti-resonant optical fiber connection of the present invention;

[0029] Figure 5 It is a schematic diagram of the end assembly of a device structure for hollow-core anti-resonant optical fiber connection of the present invention;

[0030] Figure 6 is a schematic diagram of a glass plate with an anti-reflective coating according to the present invention;

[0031] Figure 7 is a side view of a glass plate with an anti-reflective coating according to the present invention;

[0032] Figure 8 is a schematic diagram of an optical fiber end face of the present invention;

[0033] Fig. 9 It is a schematic diagram of the guide groove on the outer frame;

[0034] Fig.10 It is a schematic diagram of the guide boss on the inner wall of the hollow flange. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Example 1

[0037] like Figure 1-5 As shown, this embodiment discloses a device for connecting hollow-core anti-resonant optical fibers, which includes a ceramic ferrule 1, a hollow flange 2, a spring 3, an outer frame 4, an inner frame 5, a ferrule 6, a spring 7, a stopper 8, a tail sleeve 9, a hollow optical fiber 10 and a dust cap 11 arranged in sequence.

[0038] The device for hollow core antiresonant optical fiber connection disclosed in the present invention is an innovative optical fiber connection technology, which aims to solve the problems of precise alignment and stability in optical fiber connection. The specific implementation of the device will be described in detail below.

[0039] The core structure of the device consists of two hollow-core optical fibers 10, which are arranged in a coaxial mirror-symmetrical manner to ensure the symmetry and accuracy of the connection. Each end of the hollow-core optical fiber 10 is equipped with a precisely designed connector, which is not just a simple interface, but also a key component to ensure the precise alignment of the optical fiber.

[0040] Each connector of the present invention is composed of multiple components, including a tail sleeve 9, a stopper 8, a ferrule 6, an inner frame 5 and an outer frame 4, presenting a coaxially arranged precision structure. The tail sleeve 9 is first fixed to the outer peripheral surface of the hollow-core optical fiber 10 to provide a stable installation foundation for subsequent components. At the end of the tail sleeve 9, a stopper 8 is coaxially plugged, and a ferrule 6 mounted on the hollow-core optical fiber 10 is arranged inside the stopper 8. A spring 7 is arranged between the ferrule 6 and the stopper 8. This design can provide fine-tuning and buffering functions, and enhance the flexibility and shock resistance of the connection.

[0041] like Fig. 9 and 10 As shown, the outer side of the ferrule 6 is fixedly connected to the inner frame 5, which is further fixedly connected to the outer frame 4, forming a multi-level structural system. The outer frame 4 is provided with guide grooves 4.1 extending along the axial direction of the hollow optical fiber 10, which play a role in precise positioning and guiding. Correspondingly, the inner wall of the hollow flange 2 is provided with guide bosses 2.1 that cooperate with the guide grooves 4.1, and the precise cooperation between the two ensures the accuracy and stability of the connection.

[0042] The design of the end face of the hollow-core optical fiber 10 is also unique. There is a 7° angle between the end face of each hollow-core optical fiber 10 and the plane perpendicular to its central axis. This small but critical angle design helps to optimize the alignment and connection performance of the optical fiber. The end faces of the two hollow-core optical fibers 10 are designed to be coaxially arranged in parallel, further ensuring the accuracy of optical transmission. The 7° angle bevel makes the fiber end face tighter and reflects the light to the cladding through its bevel angle instead of returning directly to the light source, providing better connection performance.

[0043] The hollow flange 2 plays a key role in connection and positioning in the whole device. It is located between the connectors of the two hollow optical fibers 10, and through its precisely designed inner wall and guide boss 2.1, it realizes the precise positioning and fixation of the two optical fibers.

[0044] The connection device of the present invention has many technical advantages. First, the multi-level connector structure and the design of the spring 7 provide extremely high connection accuracy and shock resistance. Second, the precise matching of the guide groove 4.1 and the guide boss 2.1 ensures stable alignment of the optical fiber. Furthermore, the 7° end face angle design helps to optimize optical performance and reduce losses during signal transmission.

[0045] Example 2

[0046] This embodiment provides a complete process flow for realizing the assembly of the present invention, which mainly includes key steps such as pre-assembly, curing, assembly, grinding and a device switching for hollow core anti-resonant optical fiber connection.

[0047] In the pre-assembly stage, the hollow-core fiber is first passed through the tail sleeve, stopper, and spring in sequence. Although this step is simple to operate, special attention should be paid to the installation direction of each component to avoid rework during the subsequent assembly process.

[0048] Curing treatment is a key step to ensure reliable connection between the hollow-core optical fiber and the ferrule. Specifically, first use a professional wire stripper to strip 13-15mm of the hollow-core optical fiber coating at the end of the ferrule, and then use a dust-free cloth dipped in alcohol to carefully clean the coating residue to ensure that there are no impurities on the surface of the optical fiber. Next, select 353ND epoxy resin glue and accurately mix it in a ratio of 10:1, and slowly inject the glue from the tail handle of the ferrule through a syringe. After the glue injection is completed, carefully insert the pre-treated hollow-core optical fiber into the ferrule and place it in a temperature-controlled oven at 120±5℃ for 20 minutes.

[0049] The assembly phase needs to be carried out in strict accordance with the steps. First, install the stopper to the inner frame and make it produce appropriate compression force on the spring, ensuring that the two card points of the stopper are fully embedded in the card slots on both sides of the inner frame; secondly, test the left and right rotation of the inner frame by hand to verify the firmness of the connection between the stopper and the inner frame; then, carefully insert the assembled inner frame into the outer frame, paying attention to the precise alignment of the inner frame corners with the outer frame corners, and ensuring that the protrusions on both sides of the inner frame are accurately inserted into the notches on the side of the outer frame; finally, install the tail sleeve on the stopper and install the spring into the spring slot of the hollow flange outer frame.

[0050] The grinding stage uses a five-step progressive precision grinding process. The first step is to use a 30U sandpaper pad to remove excess curing glue at the end of the ferrule; the second step is to use a 65# grinding pad with a 30U grinding sheet to grind at a speed of 130RPM for 25-40 seconds; the third step is to use a 65# grinding pad with a 9U grinding sheet to grind at a speed of 140RPM for 45 seconds; the fourth step is to use a 70# grinding pad with a 1U grinding sheet to maintain a speed of 140RPM for 45 seconds; the last step is to use a 70# grinding pad with an ADS grinding sheet to complete the fine grinding at the same speed and time. After grinding is completed, install the dust cap immediately to protect the fiber end face.

[0051] In the device transfer configuration link for hollow-core anti-resonant optical fiber connection, a precise transfer between devices for hollow-core anti-resonant optical fiber connection is achieved through a hollow flange. Specifically, the hollow flange is fixed to the device using a spring clip, wherein two positioning grooves designed on the cross-section of the top of the hollow flange are used to limit the insertion direction and depth of a device for hollow-core anti-resonant optical fiber connection. When a device for hollow-core anti-resonant optical fiber connection is inserted into the hollow flange, it is necessary to ensure that the hollow-core optical fiber is located at the center of the hollow flange, and the precise docking of the end faces of two devices for hollow-core anti-resonant optical fiber connection can be achieved through the precise guiding structure of the hollow flange.

[0052] Through the precise control of the above process flow, the assembly quality of the hollow-core optical fiber, a device for hollow-core anti-resonant optical fiber connection, can be effectively guaranteed, ensuring its reliable performance in practical applications. In addition, each step of the method is equipped with corresponding quality control points, which is conducive to timely discovery and resolution of potential problems in the assembly process, thereby improving the qualified rate of the product.

[0053] Example 3

[0054] Furthermore, the hollow-core optical fiber 10 of this embodiment includes a three-layer structure: a core, a cladding, and a coating. The core and the cladding are respectively composed of glass materials with different refractive indices, specifically a high-refractive-index glass core formed by germanium-doped silica in the center, and a low-refractive-index silica glass cladding composed of pure silica on the periphery. This structural design is based on the principle of total reflection of light, so that the incident light can be totally reflected at the interface between the core and the cladding, thereby realizing the effective transmission of optical signals.

[0055] The core and cladding of the hollow optical fiber 10 of this embodiment are composed of glasses with different refractive indices, with a high refractive index glass core (germanium-doped silica) in the center and a low refractive index silicon glass cladding (pure silica) in the middle. Light enters the optical fiber at a specific incident angle, and total emission occurs between the optical fiber and the cladding (because the refractive index of the cladding is slightly lower than that of the core), so that it can propagate in the optical fiber. Therefore, the optical fiber wants to transmit light, and the principle adopted is the principle of total reflection of optics, and light will be lost during the transmission process. Among them, the return loss is the power loss caused by the discontinuity of the transmission link and the reflection of part of the signal back to the signal source during transmission. In layman's terms, it is used in the industry to determine how much light is reflected back. It is usually expressed in negative dB values, and the higher the value parameter, the better. The typical specification range is -15 to -60dB. Factors affecting the return loss include end face dirtiness, which will lead to a smaller return loss value; the fiber height is controlled at + / -20nm to obtain a better return loss value; and the precision alignment of the optical fiber. In order to make the end faces of the two optical fibers contact better and reduce light reflection, the end faces of the fiber optic patch cord are usually polished into different structures. The end faces are polished into a 7-degree angle bevel, which can make part of the reflected light reflect to the cladding at a certain angle, thereby reducing more reflected light in the fiber core and returning to the light source, increasing the return loss of the fiber head. The return loss can reach -65dB or lower

[0056] The hollow core optical fiber 10 of this embodiment is physically contacted with the bevel. The optical fiber end face is usually polished into a 7° bevel. The 7° bevel makes the optical fiber end face closer and reflects the light to the cladding through its bevel angle instead of directly returning to the light source, providing better connection performance.

[0057] When the three-layer hollow-core optical fiber 10 of this embodiment is ground, the process design of the grinding stage fully considers the control requirements of return loss. Return loss is the power loss caused by the discontinuity of the transmission link causing part of the signal to be reflected back to the signal source. It is usually expressed as a negative dB value. The higher the value (such as -60dB compared to -15dB), the better the performance. In order to minimize the return loss, this embodiment pays special attention to the following key factors in the grinding process:

[0058] The hollow core optical fiber 10 of the three-layer structure in this embodiment needs to complete the end face cleanliness control:

[0059] After each grinding stage, the end face needs to be cleaned with a dust-free cloth dipped in a special cleaning fluid to prevent dirt from reducing the return loss value.

[0060] The end face height control of the three-layer hollow-core optical fiber 10 in this embodiment: through the precise grinding equipment and strict control of process parameters, the height deviation of the optical fiber end face is ensured to be controlled within the range of ±20nm, which is crucial to obtain the ideal return loss value.

[0061] The bevel grinding process of the hollow-core optical fiber 10 with a three-layer structure in this embodiment: The ultimate goal of the grinding process is to form a bevel structure with a 7-degree angle. This special end face structure design can make part of the reflected light be reflected into the cladding at a specific angle, significantly reducing the amount of reflected light returning to the light source, thereby achieving a return loss of -65dB or less. The specific grinding steps are optimized as follows:

[0062] The end face alignment accuracy of the three-layer hollow-core optical fiber 10 of this embodiment is controlled: through the precise guiding structure of the hollow flange 2, the 7-degree bevels of the two end faces of the device for connecting hollow-core antiresonant optical fibers can be accurately aligned, which is crucial for obtaining the best optical performance.

[0063] The end face protection measures of the three-layer hollow-core optical fiber 10 in this embodiment are as follows: During the connection process, the cleanliness of the end face must be ensured. Before each connection, a special cleaning tool must be used to clean the end face to maintain good return loss performance.

[0064] The connection stability of the three-layer structure of the hollow optical fiber 10 in this embodiment is ensured by utilizing the two positioning grooves on the cross-section of the top end of the hollow flange 2, which can not only limit the insertion direction and depth of a device for connecting hollow-core antiresonant optical fibers, but also ensure that the two beveled end faces always maintain a stable relative position, thereby ensuring the stable transmission of optical signals.

[0065] Through the above-mentioned optimized process flow and strict quality control measures, the hollow-core optical fiber of this embodiment, a device for hollow-core antiresonant optical fiber connection, can achieve excellent optical performance, especially in terms of return loss, which can reach a level of -65dB or lower, meeting the strict requirements of high-speed optical communication systems.

[0066] Example 4

[0067] like Figure 6-7 As shown, based on Embodiments 1 and 2, this embodiment discloses a structure with an AR anti-reflection coating. This anti-reflection coating structure is innovatively designed for the connection problem of hollow core anti-resonant fiber (HC-ARF), which can effectively reduce the reflection loss of the optical fiber end face and improve the transmission quality of the optical signal.

[0068] First, let’s look at the specific composition of this anti-reflective coating structure:

[0069] Protective layer: This layer has excellent anti-friction, anti-corrosion, and anti-scratch properties, and will not be scratched even after long-term use. This layer is adsorbed and fixed with chemical material silicone, which will not cause any damage to the protective layer itself, thereby better protecting the surface. The excellent properties of this protective layer can ensure that the entire anti-reflective coating structure can maintain excellent durability even in harsh environments.

[0070] AB layer: Generally, when optical media such as glass are used in an air environment, their end faces will produce a certain degree of reflection. In order to suppress this reflection, the refractive index of the AB layer is specially designed to be close to 1.23, which is lower than that of common coating materials such as magnesium fluoride (refractive index 1.38), so that it can effectively block the reflection of light. Through this careful design, the AB layer can achieve the best balance between optical performance and optical characteristics.

[0071] AC layer: In addition to optical performance, structural strength is also a key factor that must be considered in the anti-reflective coating structure. The role of the AC layer is to provide reliable tensile and compressive resistance for the entire structure, ensuring that the layers can be firmly combined and withstand various external mechanical loads.

[0072] PET layer: This layer has excellent airtightness and moisture resistance. It is worth mentioning that PET material has excellent mechanical properties, and its toughness is superior among all thermoplastics. Its tensile strength and impact strength are also much higher than ordinary films. At the same time, PET also has excellent heat resistance, cold resistance, chemical resistance and oil resistance. These characteristics ensure that the PET layer can provide reliable protection for the entire structure in various harsh environments.

[0073] ABS layer: This layer allows the adhesive to quickly and firmly bond to any smooth surface. Even when the surface of the adherend is damaged, the ABS layer will not cause surface contamination. This is due to the unique properties of the ABS layer itself - it has the viscoelastic characteristics of both liquid viscosity and solid elasticity, and can withstand various factors in the bonding and destruction process.

[0074] Isolation film: The outermost layer of the entire anti-reflective coating structure is a thin film that plays an isolating and protective role. This isolation film is usually made of polymer materials and has certain air permeability, water permeability and isolation properties. A special coating is also applied on the surface to prevent the product from being contaminated, scratched or worn, while also improving the overall aesthetics and added value of the product.

[0075] Through the careful design and coordination of the above-mentioned multi-layer structure, this anti-reflection coating can provide all-round protection for HC-ARF optical fiber.

[0076] It should be emphasized that a small groove is specially made in this embodiment at each end of the ferrule port for HC-ARF coupling. Then, the bottom of the HCF glass plate (7H) with AR anti-reflection coating is processed into a 2° bevel and placed in the groove. Finally, the HC-ARF optical fiber is inserted from the tail of the ferrule, contacts the anti-reflection coating glass plate, and fixed with glue.

[0077] Through this structural design, an HCF glass plate with anti-reflection coating is set on the core end face of the HC-ARF optical fiber. This can not only effectively reduce the reflection loss of the optical fiber end face, but also realize the stable and reliable connection between the HC-ARF optical fiber and the external equipment.

[0078] The reason why a small groove with a 2° bevel is made at the ferrule port and the bottom of the glass plate is also processed into a 2° bevel is that this can form a close physical contact between the fiber end face and the glass plate. Usually, the fiber end face is polished into a 7° bevel, the purpose is also to reduce reflection, so that the light is reflected to the cladding through the bevel angle instead of directly returning to the light source. Therefore, this design of the present embodiment can further optimize optical coupling and reduce reflection loss.

[0079] In summary, this HC-ARF connection structure with AR anti-reflection coating can not only effectively reduce the reflection loss of the optical fiber end face and improve the transmission quality of the optical signal, but also has the following advantages:

[0080] 1. Excellent durability: The materials of each layer in the multi-layer structure have excellent performance and can withstand various physical and chemical factors in harsh environments, ensuring the long-term stability and reliability of the connection structure.

[0081] 2. Good bonding performance: The unique viscoelasticity of the ABS layer makes the bonding between the connection structure and the optical fiber firm and reliable, and not easy to fall off.

[0082] 3. Low manufacturing cost: The overall structure is simple and easy to mass produce without significantly increasing costs.

[0083] 4. Strong versatility: good compatibility, can be widely used in various types of optical fibers. A device for connecting hollow-core anti-resonant optical fibers.

[0084] Therefore, this HC-ARF anti-reflection coating connection structure undoubtedly provides an excellent solution to the connection problem of HC-ARF optical fiber in practical applications. It can not only significantly improve the optical signal transmission performance, but also has obvious advantages in reliability, cost-effectiveness and versatility, which will definitely have a positive impact on the promotion and application of HC-ARF optical fiber.

[0085] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0086] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A device for hollow core antiresonant optical fiber connection, characterized in that: The invention comprises two hollow-core optical fibers (10) arranged coaxially and mirror-symmetrically, a connector being arranged at the end of each hollow-core optical fiber (10), a hollow flange (2) being arranged between the two connectors, an angle existing between the end face of each hollow-core optical fiber (10) and a plane perpendicular to its central axis, the end faces of the two hollow-core optical fibers (10) being arranged coaxially and in parallel, each connector comprising an outer frame (4), the outer frame (4) being provided with a guide groove (4.1) extending along the axial direction of the hollow-core optical fiber (10), and a guide boss (2.1) cooperating with the guide groove being provided on the inner wall of the hollow flange (2).

2. The device for hollow core antiresonant optical fiber connection according to claim 1, characterized in that: Each connector comprises a coaxially arranged tail sleeve (9), a stopper (8), a core insert (6), an inner frame (5) and an outer frame (4); the tail sleeve (9) is fixedly connected to the outer peripheral surface of the hollow-core optical fiber (10); the end of the tail sleeve (9) is coaxially plugged with the stopper (8); the core insert (6) sleeved on the hollow-core optical fiber (10) is arranged inside the stopper (8); a spring (7) is arranged between the core insert (6) and the stopper (8); the outer side of the core insert (6) is fixedly connected to the inner frame (5); and the outer side of the inner frame (5) is fixedly connected to the outer frame (4).

3. The device for hollow core anti-resonant optical fiber connection according to claim 1, characterized in that: The end face of the core of the hollow optical fiber (10) forms an angle of with a plane perpendicular to its central axis; a transition conical surface is provided between the end face of the core of the hollow optical fiber (10) and its outer peripheral surface.

4. A method for assembling a hollow core antiresonant optical fiber, characterized in that: The method for connecting hollow-core antiresonant optical fibers using the device for connecting hollow-core antiresonant optical fibers as described in any one of claims 1 to 3 comprises the following steps: Pre-assembly steps: pass the hollow core optical fiber through the tail sleeve, stopper and spring in sequence; Curing step: fixing the hollow optical fiber and the ferrule; Assembling step: assembling the stopper with the inner frame and the outer frame in sequence; and Grinding steps: Perform multi-stage grinding on the end face of the ferrule.

5. A method for connecting hollow core anti-resonant optical fibers according to claim 4, characterized in that: The grinding steps are carried out in the following order: First grinding stage: using the first grinding tool to remove the cured glue on the ferrule head; Second grinding stage: grinding at a first rotation speed for a first preset time using a second grinding tool assembly; The third grinding stage: grinding at a second speed for a second preset time using a third grinding tool assembly; Fourth grinding stage: using a fourth grinding tool assembly to grind at the second rotation speed for a second preset time; The fifth grinding stage: using the precision grinding tool assembly to grind at the second rotation speed for a second preset time.

6. The method for connecting hollow core antiresonant optical fibers according to claim 4, characterized in that: The curing step specifically includes: Stripping step: strip the coating of the optical fiber at the ferrule end to a preset length and clean the coating residue; Glue injection step: prepare epoxy resin glue according to a predetermined ratio, and inject it into the plug from the plug tail handle through an injection needle; Curing treatment: Insert the hollow-core optical fiber into the core after glue injection and cure it at a preset temperature for a predetermined time.

7. The method for connecting hollow core antiresonant optical fibers according to claim 4, characterized in that: The assembly steps include: First assembly stage: install the stopper to the inner frame, make the stopper squeeze the spring, and completely insert the multiple card points of the stopper into the card slots on the side of the inner frame; The second assembly stage: insert the inner frame into the outer frame so that the positioning structure of the inner frame is aligned with the corresponding positioning structure in the outer frame; The third assembly stage: assemble the tail sleeve onto the stopper and install the spring clip into the spring clip groove of the flange outer frame; Assembly verification: Perform a force test on the inner frame in the predetermined direction to confirm that the stopper is firmly connected to the inner frame and does not fall off.

8. The method for connecting hollow core antiresonant optical fibers according to claim 4, characterized in that: After the polishing step is completed, the method further includes: assembling a protective component onto the hollow optical fiber to prevent end face contamination.

9. The method for connecting hollow core antiresonant optical fibers according to claim 4, characterized in that: In the assembly step: the cured ferrule is positioned at the center of the connector through the matching structure of the inner frame and the outer frame, and the precise alignment and connection of the two hollow optical fiber end faces are achieved through the matching of the positioning structure of the flange and the connector.

10. An optical module, characterized in that: The invention comprises a device for connecting hollow-core antiresonant optical fibers as described in any one of claims 1 to 3.

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