Manufacturing method of optical fiber coupler and optical fiber coupler

Abstract

The invention discloses a manufacturing method of an optical fiber coupler and the optical fiber coupler, and relates to the technical field of optical communication devices.The manufacturing method of the optical fiber coupler comprises the steps that an input optical fiber and N output optical fibers are prefabricated; wherein 2 < = N < = 6; clamping and fixing the prefabricated N + 1 optical fibers on a tapering machine; the N + 1 optical fibers are heated and stretched by a tapering machine according to preset fused biconical taper parameters, so that the input optical fiber and the N output optical fibers form a taper area; monitoring the end faces of the N output optical fibers to obtain N-channel power data and N-path output split light, and calculating parameter indexes based on the N-channel power data and the N-path output split light; when the parameter indexes meet the preset shutdown requirement, the tapering machine stops tapering; carrying out manual point stop stretching on the conical region to obtain a coupling optical fiber product with a coupling section; and packaging the coupling section of the coupling optical fiber product, the substrate, the glass tube and the protective tube to obtain the optical fiber coupler.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical communication devices, in particular to a manufacturing method of an optical fiber coupler and the optical fiber coupler. BACKGROUND

[0002] An optical fiber coupler is an important passive device in optical communication, which is used to realize precise power distribution, wavelength multiplexing / demultiplexing and directional transmission of optical signals, and is widely used in optical fiber sensing, optical access network, data center interconnection and 5G front-end transmission. With the evolution of optical communication network towards high density, large capacity and low latency, higher requirements are put forward for the branching capacity, insertion loss, uniformity and environmental stability of the optical fiber coupler, which promotes the continuous innovation of its structure design and manufacturing process.

[0003] Currently, the hydrogen-oxygen flame tapering method (FBT) is commonly used to manufacture optical fiber couplers. The hydrogen-oxygen flame tapering method melts and tapers multiple optical fibers to obtain a coupling optical fiber, and further encapsulates to obtain an optical fiber coupler. The common branching types of the optical fiber coupler prepared by the hydrogen-oxygen flame tapering method include 1x2, 1x3 and 1x4. However, since the multi-fiber coupling requires high precision in the melting and tapering process, the more optical fibers are coupled by melting and tapering, the higher the precision requirements for clamping positioning, heating and melting, and stretching control in the melting and tapering process. In actual processing, the optical fiber coupler with more than 5 output branches is prone to problems such as substandard splitting ratio and high additional loss due to insufficient melting and tapering precision.

[0004] Therefore, the maximum output branching of a single optical fiber coupler prepared by the hydrogen-oxygen flame tapering method on the market does not exceed 4, and in actual engineering, higher branching requirements need to be achieved by cascading multiple optical fiber couplers, which limits the use of optical fiber couplers in branching communication. SUMMARY

[0005] The main purpose of the present application is to provide a manufacturing method of an optical fiber coupler and the optical fiber coupler, which aims to solve the problem that the maximum output branching of a single optical fiber coupler prepared by the hydrogen-oxygen flame tapering method does not exceed 4.

[0006] To achieve the above-mentioned purpose, the manufacturing method of the optical fiber coupler provided by the present application comprises the following steps:

[0007] preparing an input optical fiber and N output optical fibers; wherein 2≤N≤6;

[0008] clamping and fixing the prepared N+1 optical fibers on a tapering machine;

[0009] heating and stretching the N+1 optical fibers by the tapering machine according to preset melting and tapering parameters, so that the input optical fiber and the N output optical fibers form a tapering zone;

[0010]

[0010] monitoring end faces of the N output optical fibers to obtain N channel power data and N path output light splitting, and calculating a parameter index based on the N channel power data and the N path output light splitting; wherein the parameter index at least includes a light splitting ratio;

[0011] when the parameter index reaches a preset shutdown requirement, the tapering machine stops tapering;

[0012] manually stopping and stretching the tapering zone to obtain a coupled optical fiber product having a coupling section;

[0013] packaging the coupling section of the coupled optical fiber product with a substrate, a glass tube, and a protective tube to obtain an optical fiber coupler.

[0014] In an embodiment, the step of clamping and fixing the N+1 preformed optical fibers on the tapering machine comprises:

[0015] clamping and fixing the N+1 preformed optical fibers on the tapering machine so that the N+1 optical fibers are located in the same plane, and the N output optical fibers are symmetrically arranged around the input optical fiber as a central axis, and the included angle between two adjacent output optical fibers is 4° to 20°.

[0016] In an embodiment, the step of manually stopping and stretching the tapering zone to obtain a coupled optical fiber product having a coupling section comprises:

[0017] manually stopping and stretching the tapering zone to obtain a coupled optical fiber product to be detected;

[0018] monitoring N channel power data and N path output light splitting of the coupled optical fiber product to be detected to calculate a parameter index of the coupled optical fiber product to be detected;

[0019] the tension testing step, when the parameter index of the coupled optical fiber product to be detected reaches an index requirement, performing online tension testing on the coupled optical fiber product to be detected to obtain a tension testing result; wherein the index requirement at least includes a light splitting ratio requirement;

[0020] if the tension testing result reaches an expected tension index, the coupled optical fiber product to be detected is a coupled optical fiber product.

[0021] In an embodiment, before the tension testing step, the method further comprises:

[0022] when the parameter index of the coupled optical fiber product to be detected does not reach the index requirement, performing secondary heating and stretching on the coupled optical fiber product to be detected by using the tapering machine until the coupled optical fiber after the secondary heating and stretching reaches the index requirement, and performing the tension testing step.

[0023] In an embodiment, the step of heating and stretching the N+1 optical fibers by using the tapering machine according to preset fusion tapering parameters to form a tapering zone between the input optical fiber and the N output optical fibers comprises:

[0024] The coupling area of ​​the N+1 optical fibers, which are clamped and fixed, is heated and melted using the flame of a tapering machine.

[0025] The N+1 optical fibers are stretched using the tapering machine to make the coupling area thinner and bring the cores of the N+1 optical fibers closer together to form a tapered region.

[0026] In one embodiment, the preset melting taper parameters include at least one of the following: hydrogen-oxygen heating temperature, flame scanning speed, flame scanning width, heating time, stretching speed, and stretching length.

[0027] In one embodiment, the step of prefabricating one input optical fiber and N output optical fibers includes:

[0028] One input fiber and N output fibers are prefabricated, and the coating layer of the coupling area of ​​N+1 fibers is stripped to expose the cladding. The cladding surface is then cleaned with industrial alcohol.

[0029] The present invention also proposes an optical fiber coupler, comprising: a substrate, a glass tube, a protective tube, an input optical fiber, and N output optical fibers; all N output optical fibers are fused tapered and coupled to the input optical fiber to form a coupling section, the coupling section being disposed on the substrate; wherein, 2≤N≤6; the glass tube is sleeved on the outer periphery of the substrate and the coupling; the protective tube is sleeved on the outer periphery of the glass tube.

[0030] In one embodiment, the input optical fiber and the N output optical fibers are all located on the same plane. The N output optical fibers are arranged symmetrically about the input optical fiber as the central axis, and the angle between two adjacent output optical fibers is 4° to 20°. The end of the output optical fiber facing the coupling section is the first end, and the distance between the first ends of two adjacent output optical fibers is 0.05mm to 0.50mm.

[0031] In one embodiment, the substrate has a groove, and the coupling section is encapsulated in the groove; and / or, both ends of the glass tube are fixed to the substrate by adhesive; and / or, there is a gap between the protective tube and the glass tube, and the gap is filled with adhesive.

[0032] The technical solution of this invention achieves a 1×N splitting structure with a single input fiber and N output fibers (2≤N≤6) by prefabricating one input fiber and N output fibers, and simultaneously performing fusion tapering on the N+1 fibers using a tapering machine to form a tapered region. A maximum splitting structure of 1×6 can be achieved. The positioning accuracy of the N+1 fibers is ensured by clamping and fixing them with the tapering machine. The initial processing accuracy of the N+1 fibers is ensured by heating and stretching them according to preset fusion tapering parameters. Real-time monitoring of the power data and output beam splitting at the end faces of the N output fibers ensures a high-precision splitting process. The process involves calculating parameters such as the splitting ratio and stopping the automatic tapering machine when preset shutdown requirements are met. This ensures the tapered region obtained from the fused tapering meets initial performance requirements, preventing overstretching and performance degradation. Subsequently, precise manual stop-stretching further stretches the tapered region to achieve a splitting ratio closer to the desired optical fiber, increasing the number of splitting paths while maintaining splitting performance. Finally, the coupling section of the optical fiber is encapsulated to obtain the fiber coupler. This manufacturing method, employing precise clamping with a tapering machine, initial fused tapering, performance monitoring, and manual stop-stretching, ensures processing accuracy, enabling the fiber coupler to meet performance requirements such as the splitting ratio. This allows for the production of fiber couplers with 2 to 6 output channels, breaking the current limitation of a maximum of 4 output channels for a single fiber coupler and significantly improving its splitting capability. In addition, since this fabrication method can achieve more output splitting with a single fiber coupler without using multiple fiber couplers to achieve the same splitting effect, this fabrication method is also beneficial for the miniaturization of fiber optic communication networks. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 A flowchart illustrating the first embodiment of the method for manufacturing the fiber optic coupler of the present invention;

[0035] Figure 2 A flowchart illustrating the second embodiment of the method for manufacturing the optical fiber coupler of the present invention;

[0036] Figure 3A flowchart illustrating the third embodiment of the method for manufacturing the optical fiber coupler of the present invention;

[0037] Figure 4 A flowchart illustrating the fourth embodiment of the method for manufacturing the optical fiber coupler of the present invention;

[0038] Figure 5 This is a schematic diagram of an embodiment of the fiber optic coupler provided by the present invention.

[0039] Explanation of icon numbers:

[0040] 1. Input optical fiber; 2. Output optical fiber; 3. Protective tube.

[0041] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0044] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0045] Fiber optic couplers are an important class of passive optical communication devices. Their basic functions include precise allocation of optical power, wavelength multiplexing / demultiplexing, and directional transmission of optical signals. They are widely used in fiber optic sensing, optical access networks, data center interconnection, and 5G fronthaul. As optical communication networks evolve towards higher density, larger capacity, and lower latency, higher requirements are placed on the splitting capability, insertion loss, uniformity, and environmental stability of fiber optic couplers, driving continuous innovation in their structural design and manufacturing processes.

[0046] Currently, commercial fiber optic couplers are generally manufactured using the flame fusion taper (FBT) method. The FBT method involves fused tapering multiple optical fibers to obtain the coupled fiber, which is then further encapsulated to form the fiber coupler. Common splitting types for fiber couplers fabricated using the FBT method include 1×2, 1×3, and 1×4. However, due to the high precision requirements of multi-fiber coupling in the fused tapering process, the more fibers involved, the higher the precision requirements for clamping, positioning, heating, melting, and stretching control during the fused tapering process. In actual manufacturing, fiber couplers with 1×5 or more output splits are prone to problems such as substandard splitting ratios and high additional losses due to insufficient fused tapering precision.

[0047] For this reason, the maximum output of a single fiber coupler fabricated by the hydrogen-oxygen flame tapering method currently available on the market is no more than 4 channels. In actual engineering, it is still necessary to achieve higher output requirements by cascading multiple fiber couplers, which results in a significant limitation of fiber couplers in split communication.

[0048] To address the above problems, this invention proposes a method for manufacturing an optical fiber coupler, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the method for manufacturing the fiber optic coupler of the present invention.

[0049] In this embodiment, the method for manufacturing the fiber optic coupler includes steps S10 to S70:

[0050] Step S10: Pre-fabricate one input optical fiber and N output optical fibers; where 2≤N≤6;

[0051] In step S10, one input fiber and N output fibers are prefabricated, where N is any natural number from 2 to 6, i.e., 2 to 6 output fibers are prefabricated, which are then used as coupling fibers for subsequent two-way output splitting to six-way output splitting.

[0052] In one optional implementation, step S10 may include step S11:

[0053] One input fiber and N output fibers are prefabricated, and the coating layer of the coupling area of ​​N+1 fibers is stripped to expose the cladding, and the cladding surface is cleaned with industrial alcohol.

[0054] In this embodiment, the coating layer of the N+1 optical fibers to be coupled is stripped to expose the cladding, allowing the cladding to be directly heated by the heat source of the tapering machine. The cladding of each optical fiber is then coupled together by stretching to form a tapered region. The cladding surface is cleaned with industrial alcohol to remove impurities and dust, ensuring the cleanliness of the optical fiber surface and preventing impurities and dust from affecting the splitting ratio and other performance of the coupled optical fiber obtained after fused tapering.

[0055] Step S20: Fix the prefabricated N+1 optical fibers onto the tapered wire machine;

[0056] Among them, the tapering machine is a commonly used device in the oxyhydrogen flame tapering method. It usually has a clamp, a pulling table and a flame. The flame generates an oxyhydrogen flame heat source to melt the area of ​​the optical fiber to be coupled. The clamp is used to hold and fix the optical fiber to position it. The clamp is fixed on the pulling table, and the pulling table drives the clamp to stretch the optical fiber to achieve the fusion tapering effect of the optical fiber.

[0057] In step S20, the N+1 optical fibers are first arranged in the expected shape, and then the N+1 optical fibers are fixed on the fusion tapering device using a clamp, thereby completing the clamping and fixing of the N+1 optical fibers.

[0058] Step S30: The tapering machine is used to heat and stretch N+1 optical fibers according to preset fusion tapering parameters, so that the input optical fiber and N output optical fibers form a tapered region;

[0059] The preset melting and tapering parameters of the tapering machine may include parameters such as hydrogen-oxygen heating temperature, flame scanning speed, flame scanning width, heating time, stretching speed, and stretching length, which are not limited here.

[0060] Additionally, it should be noted that the "cone region" refers to the coupling region of multiple optical fibers. After being subjected to fused tapering, the core and cladding of each fiber in the coupling region will approach each other and couple together to form a coupling region. As the core and cladding are gradually thinned during this process, the diameter of the resulting coupling region is also relatively small. Therefore, a special transition structure is ultimately formed, with the input fiber and multiple output fibers at both ends of the coupling region having a large diameter and the coupling region in the middle having a small diameter. The shape of this special transition structure resembles a cone, hence it is commonly referred to as the "cone region" in the industry.

[0061] Step S40: Monitor the end faces of the N output optical fibers to obtain N channel power data and N output beam splitting, and calculate parameter indicators based on the N channel power data and the N output beam splitting; wherein, the parameter indicators include at least the beam splitting ratio;

[0062] The N-channel power data and N-path output beam splitting can be obtained by using an optical power detector. The optical power detector is inserted into the cut end face of the output bare fiber adapter to monitor the N output optical fibers and obtain the N-channel power data and the N-path output beam splitting. One channel corresponds to the power data of one output optical fiber. Similarly, one output beam splitting corresponds to the beam splitting situation of one output optical fiber.

[0063] In addition, the parameters include at least the splitting ratio (also known as the coupling ratio), and may also include performance indicators such as insertion loss (IL), polarization dependent loss (PDL), and excess loss (EL), so as to measure the optical performance of the current optical fiber after initial coupling through the parameters.

[0064] Step S50: When the parameter index reaches the preset shutdown requirement, the tapering machine stops tapering;

[0065] Step S60: Manually stop and stretch the conical region to obtain a coupled optical fiber product with a coupling section;

[0066] Manual point-stop stretching can be performed by the operator manually controlling the stretching table, or the stretching machine can be pre-programmed with a point-stop stretching program. Each time the operator presses the button, the stretching table of the stretching machine moves a small distance accordingly to achieve precise stretching control and avoid overstretching that could degrade the performance of the coupled optical fiber.

[0067] Step S70: The coupling segment of the coupled optical fiber product is encapsulated with the substrate, glass tube, and protective tube to obtain an optical fiber coupler.

[0068] In this embodiment, by prefabricating one input fiber and N output fibers (2≤N≤6), and simultaneously fusion-tapering the N+1 fibers using a tapering machine to form tapered regions, a 1×N splitting structure with single input and N outputs is achieved, with a maximum 1×6 splitting structure achievable. The tapering machine clamps and fixes the N+1 fibers, ensuring their positioning accuracy. Heating and stretching the N+1 fibers according to preset fusion-tapering parameters ensures the initial processing accuracy. Real-time monitoring of the power data and output beam splitting at the end faces of the N output fibers ensures... The process involves calculating parameters such as the splitting ratio and stopping the automatic tapering machine when preset shutdown requirements are met. This ensures the tapered region obtained from the fused tapering meets initial performance requirements, preventing overstretching and performance degradation. Subsequently, precise manual stop-stretching further stretches the tapered region to achieve a splitting ratio closer to the desired optical fiber, increasing the number of splitting paths while maintaining splitting performance. Finally, the coupling section of the optical fiber is encapsulated to obtain the fiber coupler. This manufacturing method, employing precise clamping with a tapering machine, initial fused tapering, performance monitoring, and manual stop-stretching, ensures processing accuracy, enabling the fiber coupler to meet performance requirements such as the splitting ratio. This allows for the production of fiber couplers with 2 to 6 output channels, breaking the current limitation of a maximum of 4 output channels for a single fiber coupler and significantly improving its splitting capability. In addition, since this fabrication method can achieve more output splitting with a single fiber coupler without using multiple fiber couplers to achieve the same splitting effect, this fabrication method is also beneficial for the miniaturization of fiber optic communication networks.

[0069] In one optional implementation, step S70 may include steps S71 to S73:

[0070] Step S71: The coupling segment of the coupled optical fiber product is encapsulated in the groove of the substrate by dispensing adhesive.

[0071] Since the coupling segment is exposed and susceptible to damage, deformation, and breakage from external forces, it needs to be placed in a groove on the substrate and secured with adhesive. Then, UV adhesive or other suitable adhesive is injected for encapsulation to fix the coupling segment and prevent direct damage from external forces. The substrate can be a quartz substrate, which is resistant to high temperatures and does not easily deform, delaminate, or crack. The two ends of the quartz substrate can be glued together to facilitate the adhesion of the coupling fiber and gentle removal of the coupling fiber from the precision fixture, avoiding damage to the coupling fiber during the removal process.

[0072] Step S72: Place the glass tube around the outer periphery of the substrate and use glue to fix both ends of the glass tube to the substrate.

[0073] The adhesive can be epoxy adhesive, etc., and is not limited here. After fixing the two ends of the glass tube to the substrate with adhesive, the short fiber end of the input optical fiber near the output optical fiber is placed and protected with adhesive to avoid damage to the short fiber end of the input optical fiber.

[0074] In step S72, a glass tube is used to cover the outer periphery of the substrate. Since the glass tube has high hardness, it is not easy to crack or delaminate, so it is suitable for fixing and connecting with the substrate and providing protection for the substrate.

[0075] Step S73: The protective tube is fitted around the outer periphery of the glass tube, and glue is applied to the gap between the protective tube and the glass tube to fix the protective tube and the glass tube in place, thus obtaining the fiber optic coupler.

[0076] Specifically, the protective tube can be sealed with adhesive using a packaging tool of appropriate size, forming a tapered cap structure at both ends. When the output or input optical fiber is stretched or bent, the stress in the output or input optical fiber can be smoothly dispersed through the tapered cap structure, preventing stress concentration at the glass tube port or the internal coupling section tapered area. Alternatively, the protective tube can be made of steel.

[0077] In this embodiment, the coupling segment of the coupled optical fiber product is encapsulated in the groove of the substrate by dispensing adhesive, thereby the substrate provides protection for the coupling segment and prevents the coupling segment from being directly exposed to the outside and being damaged, deformed, or broken. By sleeved onto the substrate with a glass tube and sleeved onto the glass tube with a protective tube, and then connected and fixed with adhesive, multiple protective effects are formed, effectively preventing damage to the coupling segment.

[0078] Based on the above embodiments, in the second embodiment of the fiber optic coupler manufacturing method of the present invention, the contents that are the same as or similar to those in the first embodiment of the fiber optic coupler manufacturing method can be referred to the above description and will not be repeated hereafter. Based on this, refer to... Figure 2 Step S20 includes step S21:

[0079] Step S21: The prefabricated N+1 optical fibers are clamped and fixed on the tapering machine, so that the N+1 optical fibers are located in the same plane, and the N output optical fibers are arranged symmetrically with the input optical fiber as the central axis, and the adjacent two output optical fibers form an angle of 4° to 20°.

[0080] In this embodiment, by clamping and fixing N+1 optical fibers onto the tapering machine, and symmetrically arranging the N output optical fibers around the input fiber as the central axis, with adjacent output optical fibers forming an angle of 4° to 20°, and all fibers arranged coplanarly, this structural arrangement optimizes the optical field coupling symmetry and thermodynamic uniformity of multiple fibers during the fused tapering process. This ensures a highly balanced energy distribution of the input optical power during the lateral coupling from the tapered region to each output fiber. Actual measurements show that the difference in optical power between each output channel can be controlled within ≤2%, effectively solving the problem of non-uniform beam splitting caused by traditional asymmetrical arrangements. Furthermore, the symmetrical arrangement ensures that the heating and stress states of each fiber tend to be consistent during the tapering process, thereby improving process stability and batch consistency. This provides a structural prerequisite for subsequent precise manual stop-and-go stretching, thus achieving a high splitting capacity of 1×N while ensuring that each output channel possesses excellent beam splitting uniformity, low loss characteristics, and high environmental stability.

[0081] In one optional implementation, the end of the output optical fiber facing the coupling section is designated as the first end, and the spacing between the first ends of two adjacent output optical fibers is 0.05 mm to 0.50 mm. This spacing range avoids the risk of fusion bonding or structural collapse caused by excessively small fiber spacing, while ensuring sufficient coupling overlap to maintain high coupling efficiency and low insertion loss.

[0082] Based on the above embodiments, in the third embodiment of the fiber optic coupler manufacturing method of the present invention, the contents that are the same as or similar to those in the first embodiment of the fiber optic coupler manufacturing method can be referred to the above description and will not be repeated hereafter. Based on this, refer to... Figure 3 Step S60 includes steps S61 to S65:

[0083] Step S61: Manually stop and stretch the cone region to obtain the coupled optical fiber test sample;

[0084] Step S62: Monitor the N-channel power data and N-path output splitting of the coupled optical fiber test object to calculate the parameter indicators of the coupled optical fiber test object.

[0085] The monitoring of N-channel power data and N-path output beam splitting can be performed using the aforementioned optical power detector. Parameters must include at least the splitting ratio (also known as the coupling ratio), and may also include performance indicators such as insertion loss, polarization-dependent loss, and additional loss.

[0086] Step S64, tension test step: When the parameter indicators of the coupled optical fiber under test meet the indicator requirements, an online tension test is performed on the coupled optical fiber under test to obtain the tension test results; wherein, the indicator requirements include at least the splitting ratio requirement;

[0087] In step S64, an online tension test is performed on the coupled fiber optic sample that meets the required specifications. This involves applying a controllable axial tension directly to the sample on a tapering machine without disassembling the clamp holding it in place, while simultaneously monitoring for optical parameter drift or degradation. This allows for the identification of defects such as incomplete fusion splicing, localized stress concentration in the tapered region, fiber microcracks, or cladding damage. Defective samples can be promptly detected, corrected, or rejected, preventing them from directly entering the subsequent packaging process.

[0088] In one optional implementation, step S63 is included before step S64:

[0089] Step S63: When the parameter index of the coupled optical fiber to be tested does not meet the index requirements, the coupled optical fiber to be tested is subjected to secondary heating and stretching using the tapering machine until the coupled optical fiber after secondary heating and stretching meets the index requirements, and the tension test step is performed.

[0090] In this embodiment, when the parameters of the coupled optical fiber under test do not meet the requirements, it indicates that the optical performance of the coupled optical fiber under test, such as the splitting ratio, is not up to standard. Therefore, the coupled optical fiber under test is subjected to secondary heating and stretching using a tapering machine to correct the coupled optical fiber under test and improve its optical performance until the coupled optical fiber after secondary heating and stretching meets the requirements, and then the tension test step is performed.

[0091] Step S65: If the tension test result reaches the expected tension index, then the coupled optical fiber to be tested is the coupled optical fiber product.

[0092] In this embodiment, the coupled optical fiber to be tested is obtained by manually stopping and stretching the conical region. Its N-channel power data and N-path output beam splitting are monitored in real time to calculate key parameters such as the splitting ratio. This ensures that the optical performance initially meets the standards before proceeding to the tension test. This phased closed-loop control method combines flexibility and precision in the stretching operation, avoiding irreversible degradation of the coupling structure due to excessive stretching at once. Furthermore, online tension testing is conducted after the parameters meet the requirements to verify the structural stability and optical performance retention of the coupled section of the coupled optical fiber under mechanical stress. Only when the tension test results reach the expected tension index is the coupled optical fiber product considered qualified. This ensures that the coupled products meet both optical performance and mechanical reliability standards, effectively eliminating defective products with defects such as localized stress concentration in the conical region. This method not only improves the yield and batch consistency of coupled products but also ensures that they can resist installation stress and environmental vibration during subsequent packaging, wiring, and long-term service, maintaining core performance characteristics such as stable splitting ratio, low insertion loss, and strong environmental adaptability.

[0093] Based on the above embodiments, in the fourth embodiment of the fiber optic coupler manufacturing method of the present invention, the contents that are the same as or similar to those in the first embodiment of the fiber optic coupler manufacturing method can be referred to the above description and will not be repeated hereafter. On this basis, refer to... Figure 4 Step S30 includes steps S31 to S32:

[0094] Step S31: Use the flame of the tapered machine to heat and melt the coupling area of ​​the N+1 optical fibers after they are clamped and fixed, so that the coupling area melts.

[0095] Step S32: The N+1 optical fibers are stretched using the tapering machine to make the coupling area thinner and bring the cores of the N+1 optical fibers closer together to form the tapered region.

[0096] As an optional implementation, the preset melting and tapering parameters include at least one of the following: hydrogen-oxygen heating temperature, flame scanning speed, flame scanning width, heating time, stretching speed, and stretching length. Thus, by setting the melting and tapering parameters in detail, the tapering machine can accurately perform the melting and tapering process, which helps to ensure the accuracy of the melting and tapering process.

[0097] In this embodiment, the flame of the tapering machine is used to precisely heat and melt the coupling area of ​​N+1 optical fibers, softening the fiber cladding and bringing it into a high viscoelastic state. Then, axial tensile force is applied simultaneously with the tapering table, making the coupling area uniformly thinner and the fiber core spacing gradually smaller, thereby achieving coupling between the input fiber and N output fibers in the tapered region. This heating and stretching coordinated control method can make the temperature field distribution uniform and the stretching rate stable during the melting process, minimizing fiber core displacement, structural distortion or stress cracks caused by local overheating or sudden stretching.

[0098] Please see Figure 5 The present invention also proposes an optical fiber coupler, which includes a substrate (not shown in the figure), an input optical fiber 1, a glass tube (not shown in the figure), a protective tube 3, and N output optical fibers 2. All N output optical fibers 2 are coupled to the input optical fiber 1 by fused tapering to form a coupling section, and the coupling section is disposed on the substrate; wherein, 2≤N≤6; the glass tube is sleeved on the substrate and the outer periphery of the coupling; the protective tube 3 is sleeved on the outer periphery of the glass tube.

[0099] In this embodiment, the coupling section formed by the fused taper of the input optical fiber 1 and N output optical fibers 2 is fixed to the substrate. The substrate provides stable support and protection for the coupling section, preventing it from being directly damaged by external forces. A glass tube is sleeved around the substrate and the coupling section. Due to its high hardness, the glass tube is not easily cracked, making it suitable for fixed connection with the substrate and providing protection. A protective tube 3 is further sleeved on the outside of the glass tube, providing additional mechanical protection and enhancing the overall structure's resistance to bending, compression, and impact. The fiber optic coupler of this invention has a maximum output splitting capability of 6 channels, meeting high output splitting requirements. Furthermore, this fiber optic coupler has a simple structure, is easy to manufacture, and has high production efficiency. The substrate, glass tube, and protective tube 3 of this fiber optic coupler provide excellent protection for the coupling section, ensuring the fiber optic coupler's service life under high and low temperatures.

[0100] As an optional implementation, the protective tube 3 can be a steel tube to provide rigid protection. The substrate can be a quartz substrate, which is resistant to high temperatures and is not prone to deformation, delamination, or cracking.

[0101] Please see Figure 5 In an embodiment of the present invention, the input optical fiber 1 and the N output optical fibers 2 are all located on the same plane, and the N output optical fibers 2 are arranged symmetrically about the input optical fiber 1 as the central axis, with an angle of 4° to 20° between adjacent output optical fibers 2; the end of the output optical fiber 2 facing the coupling section is the first end, and the distance between the first ends of adjacent output optical fibers 2 is 0.05mm to 0.50mm.

[0102] In this embodiment, the input fiber 1 and N output fibers 2 are arranged coplanarly, and the N output fibers 2 are arranged symmetrically about the input fiber 1 as the central axis, with adjacent output fibers 2 forming an angle of 4° to 20°. This structural arrangement can optimize the optical field coupling symmetry and thermodynamic uniformity of multiple fibers during the fused tapering process, ensuring a highly balanced energy distribution of the input optical power during the lateral coupling of the tapered region to each output fiber 2. This allows the difference in optical power between each output channel to be controlled within ≤2%, effectively solving the problem of uneven beam splitting caused by traditional asymmetric arrangements. At the same time, the distance between the first ends (i.e., the ends facing the coupling section) of two adjacent output fibers 2 is limited to 0.05mm to 0.50mm. This distance range ensures that each output fiber 2 has sufficient physical spacing in the early stage of fused tapering, avoiding unexpected adhesion or structural collapse during heating, and also ensures that the fiber cores can get close enough to achieve efficient coupling during the tapering process.

[0103] In an embodiment of the present invention, the substrate is provided with a groove, and the coupling section is encapsulated in the groove; and / or, the two ends of the glass tube are fixed to the substrate by adhesive; and / or, there is a gap between the protective tube 3 and the glass tube, and the gap is filled with adhesive.

[0104] In this embodiment, since the exposed coupling segment is susceptible to damage, deformation, and breakage due to external forces, a groove is provided on the substrate and the coupling segment is encapsulated within the groove, thereby preventing direct damage from external forces. Embedding the coupling segment inside the substrate not only effectively reduces the overall packaging height and improves space utilization, but also physically limits the coupling segment through the sidewalls of the groove, preventing lateral displacement or warping during packaging or use, thus enhancing structural stability. Furthermore, the two ends of the glass tube are fixed to the substrate with adhesive. Because the glass tube is relatively hard, it is not prone to cracking or delamination; therefore, the glass tube is suitable for forming a stable connection with the substrate through adhesive and provides protection for the substrate and the coupling segment on the substrate. In addition, a gap is reserved between the protective tube 3 and the glass tube and glue is filled in. After curing, the glue layer forms an elastic buffer layer that can absorb external impact and vibration energy. At the same time, filling the gap avoids direct rigid contact between the protective tube 3 and the glass tube, reducing the risk of glass tube breakage due to friction or compression. The above structural design works together to significantly improve the mechanical stability, environmental sealing and thermal stress adaptability of the packaging structure without increasing the complexity of the assembly process, providing a strong guarantee for the long-term reliable operation of the 1×N fiber coupler under complex working conditions.

[0105] In one optional implementation, the glue filled in the gap forms a conical cap structure at both ends of the protective tube 3, thereby using the conical cap structure to disperse stress; when the output optical fiber 2 or the input optical fiber 1 is stretched or bent, the stress of the output optical fiber 2 or the input optical fiber 1 can be smoothly dispersed through the conical cap structure, avoiding stress concentration at the glass tube port or the internal coupling section.

[0106] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for manufacturing an optical fiber coupler, characterized in that, include: One input fiber and N output fibers are prefabricated; where 2≤N≤6; The prefabricated N+1 optical fibers are clamped and fixed on the tapered machine; The tapering machine is used to heat and stretch N+1 optical fibers according to preset fusion tapering parameters, so that the input optical fiber and N output optical fibers form a tapered region; Monitor the end faces of N output optical fibers to obtain N channel power data and N output beam splitting, and calculate parameter indicators based on the N channel power data and the N output beam splitting; wherein, the parameter indicators include at least the beam splitting ratio; When the parameter indicators reach the preset shutdown requirements, the tapering machine stops tapering; The conical region is manually stretched at point stops to obtain a coupled optical fiber product with a coupling section; The coupling segment of the coupled optical fiber product is encapsulated with a substrate, a glass tube, and a protective tube to obtain an optical fiber coupler.

2. The method for manufacturing an optical fiber coupler as described in claim 1, characterized in that, The step of clamping and fixing the prefabricated N+1 optical fibers onto the tapering machine includes: The prefabricated N+1 optical fibers are clamped and fixed on the tapering machine, so that the N+1 optical fibers are located in the same plane, and the N output optical fibers are arranged symmetrically with the input optical fiber as the central axis, and the two adjacent output optical fibers form an angle of 4° to 20°.

3. The method for manufacturing an optical fiber coupler as described in claim 1, characterized in that, The step of manually stopping and stretching the conical region to obtain a coupled optical fiber product with a coupling section includes: The cone region is manually stretched at point stops to obtain the coupled optical fiber test sample. Monitor the N-channel power data and N-channel output splitting of the coupled optical fiber under test to calculate the parameter indicators of the coupled optical fiber under test; The tension testing step involves performing an online tension test on the coupled optical fiber when the parameter indicators of the test object meet the indicator requirements, thereby obtaining the tension test results; wherein, the indicator requirements include at least the splitting ratio requirement; If the tension test result meets the expected tension index, then the coupled optical fiber to be tested is the coupled optical fiber product.

4. The method for manufacturing an optical fiber coupler as described in claim 3, characterized in that, Prior to the tension test step, the following steps are also included: When the parameters of the coupled optical fiber under test do not meet the requirements, the coupled optical fiber under test is subjected to secondary heating and stretching using the tapering machine until the coupled optical fiber after secondary heating and stretching meets the requirements, and the tension test step is performed.

5. The method for manufacturing an optical fiber coupler as described in claim 1, characterized in that, The step of heating and stretching N+1 optical fibers using the tapering machine according to preset fusion tapering parameters to form a tapered region between the input optical fiber and the N output optical fibers includes: The coupling area of ​​the N+1 optical fibers, which are clamped and fixed, is heated and melted using the flame of the tapering machine. The N+1 optical fibers are stretched using the drawing table of a tapering machine to make the coupling area thinner and bring the cores of the N+1 optical fibers closer together to form the tapered region.

6. The method for manufacturing an optical fiber coupler as described in claim 5, characterized in that, The preset melting taper parameters include at least one of the following: hydrogen-oxygen heating temperature, flame scanning speed, flame scanning width, heating time, stretching speed, and stretching length.

7. The method for manufacturing an optical fiber coupler as described in any one of claims 1 to 6, characterized in that, The step of prefabricating one input optical fiber and N output optical fibers includes: One input fiber and N output fibers are prefabricated, and the coating layer of the coupling area of ​​N+1 fibers is stripped to expose the cladding, and the cladding surface is cleaned with industrial alcohol.

8. An optical fiber coupler, characterized in that, include: substrate; Input fiber; N output optical fibers, each of which is fused tapered coupled to the input optical fiber to form a coupling segment, the coupling segment being disposed on the substrate; wherein, 2≤N≤6; A glass tube, which is sleeved on the outer periphery of the substrate and the coupling; A protective tube is fitted around the outer periphery of the glass tube.

9. The fiber optic coupler as described in claim 8, characterized in that, The input optical fiber and the N output optical fibers are all located on the same plane. The N output optical fibers are arranged symmetrically about the input optical fiber as the central axis, and the angle between two adjacent output optical fibers is 4° to 20°. The end of the output optical fiber facing the coupling section is the first end, and the distance between the first ends of two adjacent output optical fibers is 0.05mm to 0.50mm.

10. The fiber optic coupler as described in claim 8 or 9, characterized in that, The substrate has a groove, and the coupling segment is encapsulated in the groove; And / or, the two ends of the glass tube are fixed to the substrate with glue; And / or, there is a gap between the protective tube and the glass tube, and the gap is filled with glue.

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