Highly resistant fiber coupling structure, fiber coupler and method for manufacturing the same

Abstract

Provided herein are a high-resistance optical fiber coupling structure, an optical fiber coupler and a preparation method thereof. The optical fiber coupling structure comprises one input optical fiber; and at least one coupling optical fiber; the input optical fiber is fusedly coupled with the coupling optical fiber to form an optical fiber coupling area; wherein the center optical fiber diameter of the optical fiber coupling area is greater than or equal to 26 μm; the coupling splitting ratio of the optical fiber coupling structure can be any required splitting ratio. The provided optical fiber coupling structure has an optical fiber coupling area with a larger diameter and a longer length, so that the device becomes more robust, the vibration resistance, high-temperature resistance and high-humidity resistance are improved, thereby greatly improving the service life of the device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical communication devices, and relates to a very robust optical fiber coupling structure with high resistance, an optical fiber coupler and a preparation method thereof. BACKGROUND

[0002] With the development of artificial intelligence, 5G communication and other technologies, human society is accelerating towards the direction of intelligentization, and the most prominent feature and requirement is massive information transmission. As the most important carrier of signal transmission, optical fiber is the only choice for realizing low-delay and large-data information transmission. Therefore, passive devices based on optical fiber play a crucial role in the communication industry. For example, an optical fiber coupler is an important device for realizing the redistribution of optical fiber information, and has been widely used in 5G front-end, local area network and optical fiber home scenarios. The optical fiber coupler, also known as an optical splitter or a light splitter, has multiple output ends and can realize power and frequency redistribution of signals, effectively alleviating the finiteness of optical fiber resources. The optical fiber coupler can be divided into two types: a fused taper type and a planar waveguide type. The fused taper type optical fiber coupler is prepared by heating and fusing and tapering optical fibers. Compared with the planar waveguide type, it has the characteristics of low cost, heat insulation connection with optical fiber network (low loss), etc., and accounts for more than 90% of the market supply.

[0003] Due to the influence of application scenarios or environment, the fused taper type optical fiber coupler (optical fiber fusion coupler) has very high requirements for high temperature resistance, high humidity resistance and vibration resistance. However, in some cases, the diameter of the optical fiber coupling region is very small, and the coupling region of the prepared optical fiber coupler is also short, and the device has weak ability to resist high temperature, high humidity and vibration. At present, commercial optical fiber fusion couplers improve the above-mentioned performance of the device by external packaging. For example, the addition of a sleeve and sealing glue can improve the high temperature resistance and high humidity resistance of the device to a certain extent, but the vibration resistance is not significantly improved, which greatly limits the service life of the device and thus limits the application scenarios of the device and increases the replacement cost of users.

[0004] Chinese patent CN 103792620 A discloses a manufacturing method of a bending-resistant optical fiber coupler. In this method, the two ends of a conventional optical fiber are respectively connected with a bending-resistant optical fiber, the coupling region of the conventional optical fiber is heated and fused, a glass tube or a heat shrink tube is used for primary packaging, and finally a metal tube is used for secondary packaging by filling silica gel on both sides. As can be seen, on the one hand, this method must use a bending-resistant optical fiber, which undoubtedly increases the material cost of special optical fibers, and on the other hand, the packaging is still insufficient to reduce the influence of some environments, such as severe vibration. Moreover, the method is relatively complex and difficult to implement. Therefore, it is necessary to develop an optical fiber coupler with simple and efficient production process and high resistance.

[0005] A fused fiber coupler is made by fusing two or more optical fibers side by side, and the energy of the optical signal (input from one fiber) is distributed to other fibers in a certain proportion to achieve the purpose of light splitting. The fused birefringent taper (FBT) method is widely used to manufacture commercial fiber fused couplers at home and abroad. By bringing two (or more) optical fibers without coating together, the fibers are fused at high temperature, and at the same time, the fibers are stretched to both sides by using a stretching platform, so as to form a double-tapered coupling waveguide structure in the heating area. The incident light will be coupled from one waveguide to the adjacent waveguide in the double-tapered structure region, that is, the optical power is redistributed. As shown in Figure 1 , in the ideal case without considering the loss, part of the optical power continues to transmit from the "through arm", and the other part is transmitted to another optical path by the "coupling arm". The optical power P1 of the through arm and the optical power P2 of the coupling arm can be represented by the following equation (1).

[0006]

[0007] Wherein, P0 is the input arm optical power; C is the coupling coefficient between the coupling region optical waveguides, which is inversely proportional to the diameter of the coupling region optical fiber; L is the effective interaction length of the coupling region. The light splitting ratio of the two output ends is defined as CR=P1:P2(2), which can be obtained by simplifying CR=cot 2 (CL)×100%(3), therefore, by adjusting the coupling coefficient C and the coupling region length L, the required light splitting ratio can be achieved. For example, the average diameter of the coupling region of the optical fiber obtained by fused drawing is small (the coupling coefficient C is large), and under the condition that the required light splitting ratio is certain, the required coupling region length L is small.

[0008] In some cases, the heating and melting is achieved by fixing the heating source (such as a burner) and moving the optical fiber, or vice versa. The heating source is usually a burner, and the optical fiber is usually moved by a motor-driven mechanical device. Figure 2The melting fiber is heated by a fixed flame, so the heating area is small and the melting area of the fiber is narrow. The melting area is elongated and thinned by stretching the two ends. Then the thinned melting area is heated by the flame while stretching. Since the coupling fiber away from the heating area cannot be stretched after cooling, only the fiber in the heating area is continuously stretched and thinned. Therefore, before the required coupling area length is reached to achieve the required splitting ratio, the fiber coupling area obtained by melting and stretching has a diameter that is large at both ends and thin in the middle, and the diameter of the central area of the fiber coupling area is very small. For example, the coupling area length of a commercial fused taper single-mode coupler with a coupling splitting ratio of 50:50 (or 50%) is about 4mm, but the minimum fiber diameter of the central area of the coupling area (hereinafter referred to as the coupling area central fiber diameter) is only about 20μm. The temperature and humidity of the external environment can cause great loss to the device. Although some effects of temperature and humidity can be offset by packaging technology, external vibration will cause great damage to the device, and even packaging technology cannot effectively solve this problem, which will affect the stability of the splitting ratio and loss of the device. In addition, the thin coupling area central fiber diameter will greatly limit the optical power of the device. The above disadvantages reduce the service life of the coupler or limit the application scenarios, especially in the fields of precision instruments, military and aviation, which not only require optical communication devices to have large data transmission functions, but also require them to have high resistance and strength. The diameter of the fiber coupling area obtained by melting and stretching is very small (the coupling coefficient C is large), and under the condition of a certain splitting ratio, the required coupling area length L is small.

[0009] Therefore, there is an urgent need for a very strong fiber coupler to meet the increasing demand of users for the performance of optical communication devices, and the manufacturing process of such a fiber coupler cannot be too complex. In view of this, the present application aims to provide a high-resistance fiber coupling structure, a fiber coupler and a preparation method thereof. SUMMARY

[0010] Based on the above purpose, the embodiment of the present application provides a high-resistance fiber coupling structure, which comprises an input fiber; and at least one coupling fiber; the input fiber is fusedly coupled with the coupling fiber to form a fiber coupling area, wherein the central fiber diameter of the fiber coupling area is greater than or equal to 26μm; the coupling splitting ratio of the fiber coupling structure can be any required splitting ratio.

[0011] The present application does not limit the type of optical fiber. In some embodiments of the present application, the type of optical fiber can include single-mode optical fiber, multi-mode optical fiber, and polarization-maintaining optical fiber. In some embodiments of the present application, the material of the optical fiber can include at least one of quartz, multi-component glass, plastic, composite material, and infrared material. In some embodiments of the present application, the optical fiber coupling structure includes n optical fibers, where 1 is an input optical fiber, and n-1 is a coupling optical fiber. In some specific embodiments, 2≤n≤6.

[0012] In this article, unless otherwise stated or contradictory to the context, in the case of an optical fiber coupling structure including 2 optical fibers, such as 1 input optical fiber and 1 coupling optical fiber, the center fiber diameter (or simply, the center diameter) of the optical fiber coupling region refers to the side view height of the 2 side-by-side fused coupling optical fibers in the center region of the optical fiber coupling region (equivalent to the diameter of a single optical fiber). In addition, in the case of an optical fiber coupling structure including 2 optical fibers, especially in the case of 2 optical fibers with the same diameter in the coupling region, the 2 fused optical fibers have a certain overlap, resulting in a side-by-side width of the 2 optical fibers less than or equal to the sum of the diameters of the 2 untreated optical fibers. Through the technical solution of the present application, conventional optical fibers are used instead of necessarily using large-diameter or bend-resistant optical fibers to prepare the optical fiber coupling structure, which has high environmental resistance. For example, in the case of using conventional optical fibers with an original diameter of 125 μm, the end-to-end side-by-side width of the optical fiber coupling structure is less than or equal to 250 μm. However, the present application does not exclude the technical solution of using other optical fibers.

[0013] In some embodiments of the present application, the center diameter of the optical fiber coupling region is greater than or equal to 26 μm. Preferably, the center diameter of the optical fiber coupling region is greater than or equal to 32 μm; more preferably, the center diameter of the optical fiber coupling region is greater than or equal to 38 μm; more preferably, the center diameter of the optical fiber coupling region is greater than or equal to 45 μm. In some embodiments, the center diameter of the optical fiber coupling region can be 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, or 45 μm, or within a range between any two of the above.

[0014] The input fiber has its input end in the fiber coupling region and its output end in the same region. The remaining coupling fibers serve as output fibers, with one end in the coupling region being the input end and the other end being the output end. In this document, unless otherwise stated or contradicted by the context, the splitting ratio of the fiber coupling structure / device refers to the ratio of the output power at each output end. Through the technical solution of this invention, the length and center diameter of the fiber coupling structure have wide adjustability, thus making it easy to achieve any desired splitting ratio (between 0-100%) under input light of any wavelength (e.g., 800 to 1600 nm, such as 1310 nm and 1550 nm).

[0015] In some embodiments of the present invention, the coupling splitting ratio of the optical fiber coupling structure is preferably 40-60%; more preferably, the coupling splitting ratio of the optical fiber coupling structure is 45-55%; more preferably, it is 48.5-51.5%; or even more preferably, it is about 50%. Alternatively, when the optical fiber coupling structure includes two optical fibers, the optical fiber coupling structure can be prepared to have a coupling splitting ratio in the range of 1:99 to 50:50, depending on actual needs.

[0016] In this embodiment of the invention, the length of the fiber coupling region can be adjusted according to the required splitting ratio. The fiber coupling structure prepared by the technical solution of this invention can be comparable to commercial fiber couplers in terms of macroscopic dimensions, which is beneficial for subsequent packaging using existing commercial external packaging materials. Compared with the coupling region of commercial fiber couplers, which is large at both ends and thin in the middle, the fiber coupling structure prepared by the technical solution of this invention can have a relatively flat coupling region. In some embodiments, the length of the fiber coupling region is in the range of about 5-20 mm; more preferably, the length of the fiber coupling region is in the range of about 5.5-15 mm; more preferably, the length of the fiber coupling region is in the range of about 6-13 mm; more preferably, the length of the fiber coupling region is in the range of about 7-12 mm. In some embodiments, the center diameter of the fiber coupling region is increased by more than 1.7 times compared to commercial fiber couplers, and the fiber coupling region has an increased average diameter. According to waveguide coupling theory, it is easy to know that the coupling region becomes longer accordingly. In other words, the increased diameter and length of the fiber coupling region make the device more robust, improve its vibration resistance, high temperature resistance, and high humidity resistance, thereby greatly improving the device's lifespan.

[0017] In some embodiments of the present application, where the fiber coupling structure comprises one input fiber and one coupling fiber, the side-by-side width of the two fibers of the fiber coupling region is less than or equal to the sum of the diameters of the two fibers before fusion coupling. In this context, the minimum side-by-side width of the two side-by-side fusion coupled fibers in the center region of the fiber coupling region will be referred to as the center side-by-side width, which represents the degree of fusion of the two side-by-side fibers, unless otherwise specified or contradicted by context. In some embodiments, the center side-by-side width of the fiber coupling region is greater than or equal to 50 μιη. Preferably, the center side-by-side width of the fiber coupling region is greater than or equal to 56 μιη; more preferably, the center side-by-side width of the fiber coupling region is greater than or equal to 64 μιη; more preferably, the center side-by-side width of the fiber coupling region is greater than or equal to 76 μιη. In some embodiments, the center diameter of the fiber coupling region can be 50 μιη, 51 μιη, 52 μιη, 53 μιη, 54 μιη, 55 μιη, 56 μιη, 57 μιη, 58 μιη, 59 μιη, 60 μιη, 61 μιη, 62 μιη, 63 μιη, 64 μιη, 65 μιη, 66 μιη, 67 μιη, 68 μιη, 69 μιη, 70 μιη, 71 μιη, 72 μιη, 73 μιη, 74 μιη, 75 μιη, or 76 μιη, or within a range between any two of the foregoing. It should be noted, however, that the present application is not intended to be limited to the center side-by-side width of the resulting fiber coupling structure; the two side-by-side fibers can have varying degrees of fusion while maintaining high environmental resistance.

[0018] In some embodiments, the fiber coupling structure of the present application comprises one input fiber and one coupling fiber; the center diameter of the fiber coupling region is about 32 μιη, the center side-by-side width is about 57 μιη, and the length is about 6 mm; the fiber coupling structure has a 50:50 coupling ratio under 1550 nm input light.

[0019] In some embodiments, the fiber coupling structure of the present application comprises one input fiber and one coupling fiber; the center diameter of the fiber coupling region is about 38 μιη, the center side-by-side width is about 65 μιη, and the length is about 11 mm; the fiber coupling structure has a 50:50 coupling ratio under 1550 nm input light.

[0020] In some embodiments, the fiber coupling structure of the present application comprises one input fiber and one coupling fiber; the center diameter of the fiber coupling region is about 45 μιη, the center side-by-side width is about 76 μιη, and the length is about 14 mm; the fiber coupling structure has a 50:50 coupling ratio under 1550 nm input light.

[0021] In the present text, when the term "about" is used in relation to a numerical value, it is intended to encompass a range of plus or minus 10% of the given value, or preferably a range of plus or minus 5%, more preferably a range of plus or minus 3%, and even more preferably a range of plus or minus 1%.

[0022] The present application also provides a preparation method of a high-resistance fiber coupling structure, comprising the following steps:

[0023] S1. removing the coating layer of the fiber segment to be coupled, fixing the two ends of the fiber segment to be coupled with the coating layer removed on a stretching platform, and bringing the fiber segment to be coupled close to each other,

[0024] S2. heating and melting the fiber segment to be coupled by using a heating source, and stretching to form a fiber coupling structure; wherein the heating source can heat the fiber segment to be coupled with a certain width at the same time or within a short time interval.

[0025] In some embodiments of the present application, the width of the fiber segment to be coupled heated by the heating source is in the range of 1mm-50mm; preferably, the width is in the range of 5mm-50mm; more preferably, the width is in the range of 10mm-50mm; more preferably, the width is in the range of 10mm-30mm; more preferably, the width is in the range of 15mm-30mm; or the width is in the range of 5mm-20mm.

[0026] In some embodiments of the present application, the fiber segment to be coupled with the coating layer removed can be brought close to each other in a twisted or parallel close manner.

[0027] In some embodiments of the preparation method of the present application, the heating source is a real-time moving heating source, i.e. the amplitude of its movement changes in real time during the heating process. In some embodiments, at least one heating source is movably installed on a guide rail, and the movement of the heating source is controlled by a controller electrically connected thereto. For example, the heating source is electrically connected to the controller, and the real-time movement parameters of the heating source are controlled by a computer program, so as to realize real-time control of the width of the heating area of the heating source. The real-time movement parameters of the heating source are controlled by a computer program, so as to control the adiabatic heating condition and the fine control condition during the fiber tapering process by running the program by a computer. According to the embodiments of the present application, the movement parameters of the heating source include the movement speed, movement distance and movement direction of the heating source.

[0028] In some embodiments, the heating source is a burner of a combustible gas; the combustible gas is preferably a combustible clean gas, such as hydrogen. In some embodiments, the burner is connected to a combustible gas source and electrically connected to a controller, and the real-time flow of the combustible gas is controlled by a computer program. According to embodiments of the present application, the control parameter of the heating source includes the flow of the combustible gas. In some embodiments, the combustible gas is hydrogen; the flow of the hydrogen is 50-500 mL / min (SCCM). Preferably, the flow of the hydrogen is 100-300 mL / min (SCCM). More preferably, the flow of the hydrogen is 150-200 mL / min (SCCM).

[0029] In some embodiments, the stretching platform is controlled by a controller electrically connected thereto. For example, the stretching platform is electrically connected to a controller, and the real-time movement parameters of the stretching platform are controlled by a computer program.

[0030] Embodiments of the present application also provide a fusion tapering device for preparing the above-mentioned optical fiber coupling structure, which comprises the above-mentioned heating source, the stretching platform, and the controller.

[0031] Embodiments of the present application also provide a controller, which comprises at least one processor and at least one memory electrically connected to the processor, and the memory stores a computer program executable by the at least one processor. The computer program is executed by the at least one processor to enable the at least one processor to control the fusion tapering device to perform the preparation method of the optical fiber coupling structure.

[0032] Embodiments of the present application also provide a computer readable storage medium, which stores a computer program, wherein the computer program is executed by a processor to control the fusion tapering device to perform the preparation method of the optical fiber coupling structure.

[0033] Embodiments of the present application provide an optical fiber coupler with high resistance, which comprises the above-mentioned optical fiber coupling structure and an outer package for packaging the optical fiber coupling structure. In some embodiments, the outer package of the optical fiber coupler comprises at least one of a glass tube, a heat shrink tube, or a metal tube. In some specific embodiments, the glass tube or the heat shrink tube is used for primary packaging; the metal tube is used for secondary packaging.

[0034] The application provides a preparation method of a high-resistance fiber coupler, comprising the following steps: providing the fiber coupling structure in the above embodiment or the fiber coupling structure prepared by the fiber coupling structure preparation method, and performing one-time packaging on the fiber coupling structure by using a glass tube or a heat-shrink tube to obtain the fiber coupler. In some embodiments, the preparation method of the fiber coupler further comprises coating the fiber coupling structure before one-time packaging. In some embodiments, the preparation method of the fiber coupler further comprises the following steps: placing the one-time packaged fiber coupler into a metal tube and filling silica gel on both sides to perform two-time packaging.

[0035] It is worth noting that, in some embodiments of the application, since the fiber coupling structure has excellent vibration resistance, high-temperature resistance and high-humidity resistance, the packaging material used in the fiber coupler of the application does not necessarily have the strength of the packaging material of a commercial fiber coupler. In other words, the fiber coupler using the fiber coupling structure of some embodiments of the application still has resistance comparable to that of a commercial fiber coupler even if the packaging material used is of lower strength than that of a commercial fiber coupler. For example, in some embodiments, the fiber coupling structure prepared by the application can be shaken to a large extent without packaging, and the performance of the device does not change at all after being placed flat.

[0036] Advantages:

[0037] The embodiments of the application greatly increase the length of the fiber coupling region and the diameter of the fiber in the coupling region (the central diameter of the fiber in the coupling region of a commercial fiber coupler is difficult to exceed 25 μm, and the central diameter of the fiber in the fiber coupling structure of the embodiments of the application can reach about 45 μm) by using an innovative preparation method, and a very solid fiber fusion coupler with high environmental resistance is realized, thereby greatly improving the service life of the fiber fusion coupler. BRIEF DESCRIPTION OF DRAWINGS

[0038] The embodiments of the application will be described below with reference to the accompanying drawings, which are exemplary and do not constitute a limitation on the embodiments of the application, unless otherwise specified, and the drawings in the accompanying drawings do not constitute a proportional limitation.

[0039] Figure 1 A schematic diagram of a fiber fusion coupling structure in some cases.

[0040] Figure 2 A schematic diagram of a preparation method of a fiber fusion coupling structure in some cases.

[0041] Figure 3 A schematic diagram of a fusion tapering device of an embodiment of the application.

[0042] Figure 4Microscope images of the fiber coupling structures obtained in Examples 1-3 of the present application; wherein Figure 4 a shows the fiber coupling region length of a common commercial fiber coupler and the fiber coupler of the present application; Figure 4 b shows the fiber coupling region center diameter and center side-by-side width of a common commercial fiber coupler and the fiber coupler of the present application.

[0043] Figure 5 is the anti-drop and anti-vibration performance of the fiber coupler obtained in Examples 1-3 of the present application; wherein Figure 5a shows the spectral comparison of a common commercial fiber coupler and the fiber coupler of the present application after dropping at 2m; Figure 5b shows the spectral comparison of a common commercial fiber coupler and the fiber coupler of the present application after dropping at 3m; Figure 5c shows the spectral comparison of a common commercial fiber coupler and the fiber coupler of the present application after vibration.

[0044] Figure 6 is a schematic diagram of a controller according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] Fused taper method (FBT) is generally used at home and abroad to prepare commercial fiber fusion couplers. In some cases, fusion is achieved by melting the optical fiber with a fixed heating source (e.g. a flame of hydrogen burning in air), thereby achieving the coupling of the optical fiber. The fixed flame is used to heat the optical fiber, and the heating area is small, and the fusion area of the optical fiber is narrow. The fusion area is elongated and thinned by stretching from both ends. Then the thinned fusion area is heated by the flame while being stretched. Since the coupling optical fiber that is away from the heating area cannot be stretched after natural cooling, only the optical fiber in the heating area is continuously stretched and thinned. Therefore, before the desired coupling region length is reached to achieve the desired splitting ratio, the optical fiber in the heating area is continuously thinned, resulting in a coupling structure with large ends and a thin middle. The diameter of the fiber coupling region obtained by fusion stretching is very small. The coupling region fiber diameter of the currently commercial coupler is generally about 20 μm and cannot exceed 25 μm. The length of the coupling region is also relatively short due to strength limitations. Thus, the temperature and humidity of the outside environment can cause great loss to the device. Even with packaging technology, the influence of the external environment cannot be completely reduced. Moreover, since the coupling region fiber diameter of the currently commercial fiber coupler is small, it is also not conducive to the control of the splitting ratio and loss of the device. Therefore, the fiber coupler prepared by the related preparation method has not yet met the performance required for application in specific scenarios, especially in the technical fields of military and aviation, which not only require optical communication devices to have large data information transmission functions, but also require them to have high resistance and strength.

[0046] In view of this, embodiments of the present invention provide a highly resistant optical fiber coupling structure, a method for fabricating the optical fiber coupling structure, and a fused taper apparatus. Embodiments of the present invention achieve a wider heating source by employing a movable heating source; however, the present invention does not exclude other wide heating sources capable of heating a wider optical fiber coupling region. For example, a wider heating source can also be achieved by arranging the outlets of the movable heating source in a manner where two or more outlets are arranged side-by-side, forming a heating source with several parallel outlets that can move along a guide rail.

[0047] This invention provides a method for controlling the scanning distance of the heating source in real time, thereby achieving real-time variation in the width of the heating area. In this document, "real-time control" refers to dividing the preparation process into several time intervals, using consistent parameters within each interval, and achieving real-time control by varying the parameters across different intervals.

[0048] Depending on the specific needs, the required heating temperature during the fabrication process varies. Parameters for real-time temperature control mainly include real-time control movement parameters and heating parameters. In some embodiments, the real-time control movement parameters include movement speed, movement distance, and the reciprocating motion pattern. In some embodiments, the real-time control heating parameters include the flow rate of the combustible gas. By refining various parameters during the fabrication process, the desired coupling region length, coupling region fiber diameter, and coupling splitting ratio can be achieved.

[0049] The present invention will now be described in detail with reference to specific embodiments. These embodiments are intended to illustrate the invention and not to further limit it. It should be understood that the invention is not limited to any single specific embodiment or the listed variations. Many modifications, variations, and other implementations of the invention will occur to those skilled in the art, and the invention is intended to cover these modifications, variations, and implementations.

[0050] Fused taper apparatus for optical fiber coupling structures - wide heating zone achieved with a moving single exit port

[0051] This embodiment uses a movable single flame outlet to achieve a wide heating area. The melting and drawing device in this embodiment, such as... Figure 3 As shown, it includes a mobile heating source 1, a stretching platform 2, and a controller 3.

[0052] The mobile heating source 1 includes a heating source 11 and a heating source guide rail 12. In some examples of this embodiment, the heating source 11 is a ceramic burner. In some examples of this embodiment, the heating source 11 can also be connected to, for example, an oxygen source (e.g., an oxygen cylinder) 13 and a hydrogen source (e.g., a hydrogen cylinder) 14. The oxygen source 13 and the hydrogen source 14 are connected to a flow meter 15 and electrically connected to a controller (e.g., a computer) 3, so that the real-time flow rate of oxygen and hydrogen can be controlled in real time through a computer program.

[0053] The stretching platform 2 comprises a platform plate 21, a clamp 22, and a stretching rail 23. Optionally, the stretching platform 2 further comprises a suction feature, such as a fine groove (not shown in the figure) for accommodating the optical fiber, and the suction feature of the stretching platform 2 is connected with a vacuum pump 24, which is turned on to form a negative pressure on the suction feature, so as to facilitate ensuring that the optical fiber can be attached to the moving platform and kept in an extended state for stretching.

[0054] The controller 3 can use a computer, which comprises at least one processor and at least one memory electrically connected with the processor, and the memory stores a computer program executable by the at least one processor. The computer program is executed by the at least one processor to enable the at least one processor to control the fused taper device to perform the preparation method of the optical fiber coupling structure. The heating source 11, the heating source rail 12, and the stretching rail 23 are electrically connected with the controller 3, so as to control various parameters in the preparation process in real time, and achieve the expected coupling region length, optical fiber diameter, and coupling splitting ratio.

[0055] In some examples of the present embodiment, such as adjusting the optical fiber coupling region diameter, length, or splitting ratio, exploring various parameters in the preparation process of the optical fiber coupling structure, or developing a corresponding computer program, the fused taper device further comprises a light source 4, an optical power meter 5, a microscope 6, and a CCD (charge coupled device) camera 7. The light source 4 is used to emit incident light, such as incident light with a wavelength of 1310 nm or 1550 nm; the optical power meter 5 is used to calculate the coupling splitting ratio in real time (the number of optical power meters can be configured according to the number of output ends, such as Figure 3 The microscope 6 is used to observe the optical fiber coupling region diameter and length; and the CCD camera 7 is used to check the optical fiber cleanliness, so as to adjust the flow rate of flammable gas (such as oxygen and hydrogen). When the controller is used to make the fused taper device repeatedly perform the determined preparation process, and the process error is within an acceptable range, the light source 4, the optical power meter 5, the microscope 6, and the CCD camera 7 are not necessary.

[0056] Method of making optical fiber coupling structures

[0057] One example of the present embodiment provides a preparation method of a high-resistance optical fiber coupling structure, which comprises the following steps:

[0058] The coating layers of the to-be-coupled sections of the two optical fibers are removed, the to-be-coupled sections of the optical fibers with the removed coating layers are fixed on the platform plate of the stretching platform by the clamps, and the to-be-coupled sections of the optical fibers are tightly abutted in parallel, and the stretching rail is electrically connected with the controller;

[0059] Hydrogen gas, hydrogen gas is connected to the ceramic fire head through the flow meter and is fixed on the heating source guide rail, the heating source guide rail is parallel to the optical fiber and has a suitable distance, the ceramic fire head is electrically connected with the heating source guide rail;

[0060] Ignition, control the real-time flow of oxygen and hydrogen through the controller to heat the section of the optical fiber to be coupled; control the real-time movement parameters of the ceramic fire head on the heating source guide rail to realize the real-time change of the heating source width; control the movement of the stretching guide rail to realize the stretching of the optical fiber and form the optical fiber coupling structure.

[0061] In some cases of adjusting process parameters, the fused taper device further comprises a light source and an optical power meter. The input end of the input optical fiber is connected with the light source, and the output ends of the input optical fiber and the output optical fiber are connected with the optical power meter. The preparation method of the optical fiber coupling structure of one specific example of the embodiment further comprises the following steps before ignition: connecting the input end of the input optical fiber with the light source, connecting the output ends of the input optical fiber and the output optical fiber with the optical power meter, and electrically connecting the light source and the optical power meter with the controller. In some specific embodiments, the light source is a 1310nm and 1550nm dual-wavelength incident light, and the target splitting ratio is 50:50, so as to obtain a 1310nm and 1550nm dual-wavelength 50:50 splitting ratio dual-window optical fiber coupler.

[0062] In one specific but not exclusive example, the entire preparation process is divided into three stages according to time, and the total time is about 120 seconds. The distance between the ceramic fire head and the optical fiber is preferably the center of the outer flame of the ceramic fire head in contact with the optical fiber; in some specific embodiments, the distance between the ceramic fire head and the optical fiber is 100μm.

[0063] In the first time period, the parameters are set as follows: the heating source moving speed is 1000-20000μm / s, the reciprocating moving distance is 1000-50000μm, the flow rate of hydrogen gas is set to 50-500SCCM, the flow rate of oxygen gas is set to 100-100SCCM, and the stretching platform speed is zero, only heating without stretching. The purpose of the first time period is to provide sufficient preheating time for the two optical fibers, so that the optical fibers reach a certain temperature, which can not only prepare for the next step, but also reduce the loss caused by stretching the optical fibers later.

[0064] The second time period is set as follows: the heating source scanning speed is 1000-20000 pm / s, the reciprocating movement distance is 1000-50000 pm, the stretching speed is 50-500 pm / s, the hydrogen flow is set as 50-500 SCCM, and the oxygen flow is set as 100-100 SCCM. The processing in the second time period is the most core step, and the purpose is to realize wide heating source through the reciprocating movement of the heating source, so the speed needs to be adjusted from large to small as much as possible, but too large will affect the stability of the device platform. Meanwhile, the reciprocating movement distance also determines the width of the heating area, and also needs to be adjusted from large to small as much as possible. The two parameters need to be coordinated. The stretching speed needs to be adjusted from small to large as much as possible, otherwise the heating source temperature is not enough, which is easy to cause additional stretching loss. The amount of hydrogen also needs to be adjusted from large to small as much as possible. In this stage, the two optical fibers have begun to be coupled.

[0065] The third time period is set as follows: the heating source scanning speed is 1000-20000 pm / s, the reciprocating movement distance is 1000-50000 pm, the stretching speed is 50-500 pm / s, the hydrogen flow is set as 50-500 SCCM, and the oxygen flow is set as 0-100 SCCM. Since the coupling has begun in the last stage, it indicates that the optical fiber has reached a small enough diameter, so the hydrogen flow can be appropriately reduced in this stage. The purpose is to be able to achieve the required splitting ratio, otherwise it is difficult to achieve a 50:50 splitting ratio, which is easy to exceed the target set splitting ratio value.

[0066] Highly resistant optical fiber coupling structure - example 1

[0067] In this example, two single-mode optical fibers with a diameter of 125 pm and a core diameter of 9 pm are used. The coating layers of the two optical fibers to be coupled are removed. The two ends of the optical fibers to be coupled are fixed on the platform plate of the stretching platform by clamps, and the optical fibers to be coupled are parallel and close to each other. The highly resistant optical fiber coupling structure is prepared by using the fusion splicing device and the preparation method of the above example. The whole preparation process is divided into three stages according to time, and the total time is about 120 seconds. The distance between the ceramic flame head and the optical fiber to be coupled is 100 pm. Among them:

[0068] The first time period is about 0-10 seconds, and the parameters are set as follows: the heating source moving speed is 5000 pm / s, the reciprocating movement distance is 10000 pm, the hydrogen flow is set as 170 SCCM, the oxygen flow is set as 40 SCCM, and the stretching platform speed is zero.

[0069] The second time period is about 10-85 seconds, and the parameters are set as follows: the heating source scanning speed is 5000 pm / s, the reciprocating movement distance is 10000 pm, the hydrogen flow is set as 170 SCCM, the oxygen flow is set as 40 SCCM, and the stretching speed is 100 pm / s.

[0070] The third time period is approximately 85-120 seconds. The parameters are set as follows: heating source moving speed is 5000 μm / s, reciprocating moving distance is 10000 μm, hydrogen flow rate is 170 SCCM, oxygen flow rate is zero, and stretching platform speed is 100 μm / s.

[0071] A highly resistant fiber coupling structure was obtained according to Example 1, such as... Figure 4 As shown, the structure includes two optical fibers forming a fiber coupling region. The center diameter of the fiber coupling region is 32.48 μm, the center side-by-side width is 56.84 μm, and the length of the coupling region is 5.76 mm. The fiber coupling structure has a coupling splitting ratio of 50:50 under an input light of 1550 nm. The overall size of the final fiber coupling structure is consistent with that of commercially available fiber couplers, which facilitates subsequent encapsulation using existing commercial packaging materials. The preparation process of Example 1 is repeated to prepare the fiber coupling structure of Example 1 required for testing.

[0072] Highly Resistant Fiber Coupling Structure – Example 2

[0073] The single-mode optical fiber, fused taper device, and fabrication method used in this embodiment are similar to those in Embodiment 1; wherein:

[0074] The first time period is approximately 0-10 seconds. The parameters are set as follows: heating source moving speed is 5000μm / s, reciprocating moving distance is 15000μm, hydrogen flow rate is 190SCCM, oxygen flow rate is 45SCCM, and stretching platform speed is zero.

[0075] The second time period is approximately 10-85 seconds. The parameters are set as follows: heating source scanning speed 5000 μm / s, reciprocating movement distance 15000 μm, hydrogen flow rate 190 SCCM, oxygen flow rate 45 SCCM, and stretching speed 100 μm / s.

[0076] The third time period is approximately 85-120 seconds. The parameters are set as follows: heating source moving speed is 5000 μm / s, reciprocating moving distance is 15000 μm, hydrogen flow rate is set to 170 SCCM, oxygen flow rate is set to zero, and stretching platform speed is 100 μm / s.

[0077] A highly resistant fiber coupling structure was obtained according to Example 2, such as... Figure 4As shown, it includes two optical fibers, forming a fiber coupling region, the center diameter of the fiber coupling region is 38.16 μm, the center side-by-side width is 64.53 μm, and the coupling region length is 11.46 mm; the fiber coupling structure has a 50:50 coupling ratio under 1550 nm input light. The preparation process of Example 2 is repeated to prepare the fiber coupling structure of Example 2 required for testing.

[0078] Highly resistant fiber coupling structure - Example 3

[0079] The single-mode optical fiber, the fused-taper device, and the preparation method used in this example are similar to those of Example 1; wherein:

[0080] The first time period is about 0-10 seconds, and the parameters are set as follows: the heating source moving speed is 5000 μm / s, the reciprocating moving distance is 20000 μm, the hydrogen flow rate is set to 210 SCCM, the oxygen flow rate is set to 50 SCCM, and the stretching platform speed is zero;

[0081] The second time period is about 10-85 seconds, and the parameters are set as follows: the heating source scanning speed is 5000 μm / s, the reciprocating moving distance is 20000 μm, the hydrogen flow rate is set to 210 SCCM, the oxygen flow rate is set to 50 SCCM, and the stretching speed is 100 μm / s;

[0082] The third time period is about 85-120 seconds, and the parameters are set as follows: the heating source moving speed is 5000 μm / s, the reciprocating moving distance is 20000 μm, the hydrogen flow rate is set to 170 SCCM, the oxygen flow rate is set to zero, and the stretching platform speed is 100 μm / s.

[0083] According to Example 3, a highly resistant fiber coupling structure is obtained, as shown in Figure 4 As shown, it includes two optical fibers, forming a fiber coupling region, the center diameter of the fiber coupling region is 44.71 μm, the center side-by-side width is 76.01 μm, and the coupling region length is 14.03 mm; the fiber coupling structure has a 50:50 coupling ratio under 1550 nm input light. The preparation process of Example 3 is repeated to prepare the fiber coupling structure of Example 3 required for testing.

[0084] However, those skilled in the art can obtain fiber coupling structures of other sizes and with required splitting ratios by reasonably adjusting various control parameters of the above examples without departing from the spirit and scope of the present disclosure.

[0085] The preparation method of the embodiment of the present application makes the coupling region of the fiber coupler longer and the fiber diameter of the coupling region larger, and the vibration resistance, high temperature resistance and high humidity resistance of the fiber coupling structure are greatly improved. For example, the coupling structure of the present application can be shaken greatly without packaging, and the performance does not change at all when the device is placed flat. The ordinary commercial device cannot be moved at will and must be packaged immediately, which shows that the vibration resistance of the fiber coupling structure of the present application has been greatly improved.

[0086] The vibration resistance and drop resistance of the fiber coupling structures prepared in Examples 1-3 of the present application were tested, and an ordinary commercial coupling device was purchased as a comparative example. The comparative fiber coupling device is a commercial fusion taper single-mode coupler (single-wavelength fiber splitter, model: 1*2(N)) purchased from Shandong Kaipule Optoelectronic Technology Co., Ltd. Ten fiber coupling structures / devices were tested for each test, and the tested devices were not reused.

[0087] In the drop resistance test, the fiber coupling structure prepared in Example 1 was packaged once using the same outer packaging (glass tube) as the commercial coupler of the comparative example to prepare the fiber coupler of Example 1. The drop resistance test method: the fiber coupler of Example 1 and the ordinary commercial coupler were dropped from a height of 2m and 3m; the change in wavelength (Wave length) and insertion loss (Insertion Loss, IL) of the two output ends of the device before and after dropping was tested, and the test results are shown in Table 1, Figure 5a (2m) and Figure 5b (3m) respectively show the representative test results (as shown in bold in Table 1) of the fiber coupling structures of Examples 1-3 and the ordinary commercial coupler.

[0088] In the vibration resistance test, the fiber coupling structures prepared in Examples 1-3 were not packaged, and the commercial coupler of the comparative example was unpackaged. The vibration resistance test method: the fiber coupling structures prepared in Examples 1-3 and the ordinary commercial coupler were subjected to vibration test with a vibration frequency of 50Hz and a vibration amplitude of 5mm, and the duration was 30 minutes. The change in wavelength and IL of the two output ends of the device before and after vibration was tested. The test results are shown in Table 1, Figure 5c show the representative test results (as shown in bold in Table 1) of the fiber coupling structures of Examples 1-3 and the ordinary commercial coupler.

[0089] Table 1 Change in drop height characteristic quantity of the fiber coupler of the embodiment of the present application and the ordinary commercial coupler

[0090]

[0091]

[0092] As shown in Table 1 and Fig. 5, the wavelength and IL of the common coupler change greatly after falling from a height of 2m and 3m, and even completely damaged after vibration. The high-resistance coupler prepared by the embodiment of the present application has no change in the parameters of the fiber coupler after vibration and falling from a height of 2m and 3m, which verifies that the anti-vibration performance of the fiber coupling device of the present application is far superior to that of the common commercial coupler.

[0093] The embodiment of the present application also provides a controller, as shown in the figure, comprising at least one processor 81 and at least one memory 82 electrically connected with the processor 81, the memory 82 storing a computer program executable by the at least one processor 81, and the computer program is executed by the at least one processor 81 to enable the at least one processor 81 to control the fusion taper device to perform the preparation method of the fiber coupling structure. Figure 6

[0094] The embodiment of the present application also provides a computer readable storage medium storing a computer program, wherein the computer program is executed by a processor to control the fusion taper device to perform the preparation method of the fiber coupling structure.

[0095] Those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment preparation method can be completed by a computer program instructing related hardware, the computer program is stored in a storage medium, and includes a plurality of instructions for enabling a device (which can be a single-chip microcomputer, a chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various storage program codes.

[0096] The embodiment of the present application provides a high-resistance fiber coupler, which comprises the above-mentioned fiber coupling structure and a packaging material for packaging the fiber coupling structure. In some embodiments, the fiber coupler further comprises an interface for connecting a transmitting optical fiber with a receiving optical fiber.

[0097] ​The embodiment of the present application provides a high-resistance optical fiber coupling structure and a preparation method thereof, a fusion taper device, a controller and a computer readable storage medium, a wider heating source is designed to realize a wider real-time adjustable heating area, the optical fiber coupling structure prepared by the technical scheme of the present application can be the same in size as a commercial optical fiber coupler, and is beneficial to later packaging. In some embodiments, the diameter of the optical fiber coupling area can reach more than 1.7 times that of the commercial optical fiber coupler, according to the waveguide coupling theory, in order to obtain the same light splitting ratio, the length of the coupling area is proportional to the diameter of the optical fiber in the coupling area, so it is easy to know that the coupling area also becomes longer. In other words, the increase of the diameter of the optical fiber coupling area and the lengthening of the optical fiber coupling area make the device more robust, improve the vibration resistance, high temperature resistance and high humidity resistance, thereby greatly improving the service life of the device.

[0098] Those skilled in the art can understand that the above-mentioned embodiments are only some embodiments of the present application and are not used to limit the present application. For those skilled in the art, in practical application, various changes and changes can be made in form and detail without departing from the spirit and scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and scope of the present application shall be included in the protection scope of the present application.

Claims

1.A method for preparing a fiber coupling structure, applied to a device for preparing a fiber coupling structure, comprising a heating source, a stretching platform and a controller, wherein: the heating source is movably installed on a guide rail; the movement of the heating source is controlled by the controller electrically connected thereto; the stretching platform is controlled by the controller electrically connected thereto; the method comprises the following steps: S1. removing the coating layer of a fiber coupling section, fixing the two ends of the fiber coupling section with the removed coating layer on the stretching platform, and bringing the fiber coupling section close together, S2. using the heating source to heat and melt the fiber coupling section, and stretching to form a fiber coupling structure; wherein the heating source can heat and melt the fiber coupling section of a certain width at the same time or within a short time interval; the fiber coupling structure comprises one input fiber and at least one coupling fiber; the input fiber and the coupling fiber are fused and coupled to form a fiber coupling area; wherein the central fiber diameter of the fiber coupling area is greater than or equal to 26 μm; the length of the fiber coupling area is in the range of 5-20 mm; the coupling light splitting ratio of the fiber coupling structure is in the range of 1:99 to 50:50; the entire preparation process is divided into three stages according to time: in the first time period, the parameters are set as follows: the moving speed of the heating source is 1000-20000 μm / s, the reciprocating moving distance is 1000-50000 μm, the flow rate of hydrogen is set to 50-500 SCCM, the flow rate of oxygen is set to 100-100 SCCM, and the stretching platform speed is zero; in the second time period, the parameters are set as follows: the scanning speed of the heating source is 1000-20000 μm / s, the reciprocating moving distance is 1000-50000 μm, the stretching speed is 50-500 μm / s, the flow rate of hydrogen is set to 50-500 SCCM, and the flow rate of oxygen is set to 100-100 SCCM; in the third time period, the parameters are set as follows: the scanning speed of the heating source is 1000-20000 μm / s, the reciprocating moving distance is 1000-50000 μm, the stretching speed is 50-500 μm / s, the flow rate of hydrogen is set to 50-500 SCCM, and the flow rate of oxygen is set to 0-100 SCCM. The material of the fiber comprises at least one of quartz, multi-component glass, plastic, composite material and infrared material. Under the input light of 800-1600 nm wavelength, the coupling light splitting ratio of the fiber coupling structure is 40-60%. The fiber coupling structure comprises one input fiber and one coupling fiber, and the central fiber diameter of the fiber coupling area is greater than or equal to 32 μm. The fiber coupling structure comprises one input fiber and one coupling fiber, and the diameter of the input fiber and the coupling fiber before being fused and coupled is 125 μm; the central side-by-side width of the fiber coupling area is greater than or equal to 50 μm. ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. The production method according to claim 1, characterized by, ​ 3. The production method according to claim 1, characterized by, ​ 4. The production method according to claim 1, characterized by, ​ 5. The production method according to claim 1, characterized by, ​

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