A tapered optical fiber and a method for manufacturing the same

Abstract

The present invention provides a tapered optical fiber and a method for making the tapered optical fiber. The method for making the tapered optical fiber comprises: making a first tapered quartz tube with a tapered through hole; depositing a core layer in the tapered through hole of the first tapered quartz tube; shrinking the first tapered quartz tube with the core layer deposited to prepare a tapered preform; drawing the tapered preform into a tapered optical fiber, wherein the tapered optical fiber comprises a core that conducts light along the axial direction of the tapered optical fiber and a cladding surrounding the core. The method for making the tapered optical fiber provided by the present invention does not require multiple polishing during the entire process, and is formed in one step. The process is simple, greatly reducing the processing difficulty of the tapered optical fiber, and improving the preparation efficiency and precision of the tapered optical fiber.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber preparation, and in particular to a method for preparing a tapered optical fiber. Background Art

[0002] Compared with ordinary fibers with uniform core cladding, tapered fibers can increase the effective mode field area of ​​the fiber by introducing a large core diameter end, which has the advantage of effectively suppressing nonlinear effects. At the same time, tapered fibers also have excellent mode instability suppression performance, beam quality maintenance characteristics, and amplified spontaneous emission (ASE) suppression effects, and have great potential in the field of high-power lasers.

[0003] Tapered optical fibers are often made by melting and taper methods, mechanical polishing methods, or chemical etching methods. By changing the radius of the optical fiber in the axial direction, a tapered region is formed to achieve applications such as optical coupling, optical sensing, nonlinear optics, micro-nano optics, optical fiber devices, and other research fields. However, during the processing of existing tapered optical fibers, the core rod and the glass rod need to be ground separately. The preparation process is complicated and cumbersome, especially the grinding of the inner wall of the glass rod, which is difficult to process and has low precision. At the same time, the inner grinding also limits the length of the glass rod and has disadvantages such as poor adaptability. Summary of the invention

[0004] The invention provides a method for manufacturing a tapered optical fiber, which is used to solve the problem that during the processing of the existing tapered optical fiber, a core rod and a glass rod need to be ground and processed separately, resulting in a complicated and tedious preparation process.

[0005] In a first aspect, the present invention provides a method for manufacturing a tapered optical fiber, comprising:

[0006] Making a first tapered quartz tube having a tapered through hole therein;

[0007] depositing a core layer in the tapered through hole of the first tapered quartz tube;

[0008] The first tapered quartz tube for depositing the core layer is subjected to rod shrinking to prepare a tapered preform;

[0009] The tapered preform is drawn into a tapered optical fiber, which includes a core for guiding light along the axial direction of the tapered optical fiber and a cladding surrounding the core.

[0010] According to a method for manufacturing a tapered optical fiber of the present invention, the step of manufacturing a first tapered quartz tube having a tapered through hole therein comprises:

[0011] The inner wall of the first quartz tube is etched, polished or pickled to form the first tapered quartz tube having the tapered through hole therein.

[0012] According to a method for manufacturing a tapered optical fiber of the present invention, the step of depositing a core layer in the tapered through hole of the first tapered quartz tube comprises:

[0013] acid washing the first tapered quartz tube;

[0014] A loose layer is uniformly deposited in the tapered through hole of the first tapered quartz tube, and rare earth ions are doped into the loose layer.

[0015] According to a method for manufacturing a tapered optical fiber of the present invention, the step of doping rare earth ions in the loose layer comprises:

[0016] Passing a solution containing the rare earth ions into the tapered through hole;

[0017] After soaking for a preset time, the remaining solution containing the rare earth ions is discharged.

[0018] According to a method for manufacturing a tapered optical fiber of the present invention, the step of shrinking the first tapered quartz tube for depositing the core layer to prepare a tapered preform comprises:

[0019] The first tapered quartz tube and the loose layer are sintered to melt and shrink the first tapered quartz tube and the loose layer into the tapered preform rod.

[0020] According to a method for manufacturing a tapered optical fiber of the present invention, the rare earth ion is Nd 3+ , Yb 3+ , Er 3+ 、Tm 3+ Any one or combination of the following.

[0021] According to a method for manufacturing a tapered optical fiber of the present invention, the step of drawing the tapered preform into a tapered optical fiber comprises:

[0022] The outer wall of the second quartz tube is processed into a cone shape to construct a second cone quartz tube with a through hole therein;

[0023] Using the second tapered quartz tube to sleeve the tapered preform rod to obtain a tapered optical fiber preform rod;

[0024] The tapered optical fiber preform is placed on a drawing tower and drawn into the tapered optical fiber.

[0025] According to a method for manufacturing a tapered optical fiber of the present invention, the step of placing the tapered optical fiber preform on a drawing tower and drawing it into the tapered optical fiber comprises:

[0026] The tapered optical fiber preform is placed on the drawing tower, and the tapered optical fiber is drawn by adjusting drawing parameters.

[0027] According to a method for manufacturing a tapered optical fiber of the present invention, after the step of drawing the tapered preform into a tapered optical fiber, the method further comprises:

[0028] The outer periphery of the cladding is coated twice to form an optical fiber coating.

[0029] In a second aspect, the present invention further provides a tapered optical fiber, wherein the tapered optical fiber is manufactured by any of the methods for manufacturing a tapered optical fiber as described above.

[0030] The method for making a tapered optical fiber provided by the present invention is to set a tapered through hole in a first tapered quartz tube, and directly deposit a core layer in the tapered through hole so as to shrink the rod to form a tapered preform rod, and finally draw the tapered preform rod to form a tapered optical fiber. The whole process does not require multiple polishing, and the molding is done in one time. The process is simple, which greatly reduces the processing difficulty of the tapered optical fiber and improves the preparation efficiency and precision of the tapered optical fiber. Moreover, since the invention processes the quartz tube in the early stage, it can reduce costs and ensure production efficiency compared to the existing process of processing in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is one of the flow diagrams of the method for manufacturing a tapered optical fiber provided by an embodiment of the present invention;

[0033] Figure 2 is a schematic diagram of a first tapered quartz tube provided in an embodiment of the present invention;

[0034] Figure 3 is a schematic diagram of a first tapered quartz tube after a core layer is deposited provided by an embodiment of the present invention;

[0035] Figure 4 is a schematic diagram of a tapered preform provided by an embodiment of the present invention;

[0036] Figure 5 is one of the schematic diagrams of the tapered optical fiber provided by an embodiment of the present invention;

[0037] Figure 6 This is a second flow chart of a method for manufacturing a tapered optical fiber provided in an embodiment of the present invention;

[0038] Figure 7 is a schematic diagram of a tapered optical fiber preform provided by an embodiment of the present invention;

[0039] Figure 8 This is the second schematic diagram of the tapered optical fiber provided by the embodiment of the present invention;

[0040] Reference numerals:

[0041] 1. a first tapered quartz tube; 10. a tapered through hole;

[0042] 2. Core layer;

[0043] 3. Conical preform;

[0044] 4. tapered optical fiber; 41. core; 42. cladding;

[0045] 5. Second tapered quartz tube. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the description of the embodiments of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "front", "back", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] Combine the following Figure 1 The method for making a tapered optical fiber provided by the present invention comprises the following steps:

[0050] Step S101: manufacturing a first tapered quartz tube having a tapered through hole therein.

[0051] First, if Figure 2 As shown, a quartz tube with matching thermal properties, satisfying optical properties and provided with a through hole at the center is selected, and the inner wall of the through hole is surface processed to form a tapered through hole 10, thereby obtaining a first tapered quartz tube 1, and the first tapered quartz tube 1 is placed on a deposition lathe.

[0052] In this embodiment, the tapered through hole 10 is arranged at the center of the first tapered quartz tube 1, and the tapered through hole 10 extends from one end of the first tapered quartz tube 1 to the other end of the first tapered quartz tube 1, and the aperture of the tapered through hole 10 gradually decreases from one end to the other end, forming a truncated cone shape.

[0053] Step S102: depositing a core layer in the tapered through hole of the first tapered quartz tube.

[0054] After the first tapered quartz tube 1 with the tapered through hole 10 is manufactured, the gas or liquid raw material can be introduced through the tapered through hole 10 while the first tapered quartz tube 1 is controlled to rotate, and the gas or liquid raw material is deposited on the inner wall of the tapered through hole 10 to form the core layer 2. Figure 3 shown.

[0055] Step S103: shrinking the first tapered quartz tube on which the core layer is deposited to prepare a tapered preform.

[0056] After the core layer 2 is deposited in the tapered through hole 10 of the first tapered quartz tube 1, the first tapered quartz tube 1 is shrunk. The tapered through hole 10 forms a tapered hole that wraps the core layer 2 during the shrunk process, thereby constructing a tapered preform 3, such as Figure 4 shown.

[0057] During the shrinking process, oxygen is introduced to purge the core layer 2 and the first tapered quartz tube 1, and the temperature is raised to 1700° C. The temperature is continued to rise, and the moving speed of the heat source is reduced to 2.5 to 20 mm / min, the pressure difference between the gas outlet end and the atmospheric pressure is maintained, and the temperature is controlled at 1850 to 2150° C. The first tapered quartz tube 1 on which the core layer 2 is deposited is made into a tapered preform 3.

[0058] S104: Drawing the tapered preform into a tapered optical fiber.

[0059] After the conical preform rod 3 is manufactured, the conical preform rod 3 is placed on a drawing tower. Figure 5 As shown, a tapered optical fiber 4 with a core-to-cladding ratio is drawn. The tapered optical fiber 4 includes a core 41 for guiding light along the axial direction of the tapered optical fiber and a cladding surrounding the core 41.

[0060] The tapered optical fiber 4 has a constant cladding diameter and a gradually changing core 41 diameter. The core-to-cladding ratio of the optical fiber gradually changes with the length of the optical fiber. Moreover, the diameter of the core 41, the core-to-cladding ratio and the cone angle can be controlled within a certain range according to the needs, and can be specifically adjusted according to the requirements of the passive optical fiber device and the optical system.

[0061] The method for manufacturing a tapered optical fiber provided by the present invention provides a tapered through hole 10 in a first tapered quartz tube 1, and directly deposits a core layer 2 in the tapered through hole 10 so as to shrink the rod to form a tapered preform rod 3, and finally draws the tapered preform rod 3 to form a tapered optical fiber 4. The entire process does not require multiple polishing, and the molding is done in one time. The process is simple, which greatly reduces the processing difficulty of the tapered optical fiber 4 and improves the preparation efficiency and precision of the tapered optical fiber 4. Moreover, since the quartz tube is processed in the early stage in this embodiment, compared with the existing process of processing in the later stage, it can reduce costs and ensure production efficiency.

[0062] Specifically, during the deposition of the core layer 2, the introduction speed of the gas or liquid raw material can be gradually adjusted to adjust the deposition amount of the core layer 2 along the direction of the tapered through hole 10, so that the deposition amount of the core layer 2 changes with the change of the aperture of the tapered through hole 10, such as Figure 3 shown.

[0063] Optionally, the introduction speed of the gas or liquid raw material can be changed continuously, so that the deposition amount of the core layer 2 in the direction of the tapered through hole 10 increases with the increase of the hole diameter; or, the introduction speed of the gas or liquid raw material can also be changed step by step, so that the deposition amount of the core layer 2 in the direction of the tapered through hole 10 increases step by step with the increase of the hole diameter.

[0064] Optionally, the first tapered quartz tube 1 can be a conical quartz tube, and the contraction direction of the outer conical surface is opposite to the contraction direction of the tapered through hole 10, so that the core-to-wrapper ratio of the finally formed tapered optical fiber 4 at the same optical fiber length varies more greatly, which is convenient to meet actual usage requirements.

[0065] In one embodiment, step S101: the step of manufacturing a first tapered quartz tube having a tapered through hole therein comprises: etching, pickling or polishing the inner wall of the first quartz tube to form the first tapered quartz tube having the tapered through hole therein.

[0066] In this embodiment, the inner wall of the first quartz tube is etched, pickled or polished so that the inner diameter of the inner wall of the quartz tube gradually changes along the through hole direction to form a tapered through hole 10, thereby manufacturing the first tapered quartz tube 1.

[0067] Optionally, the etching includes wet etching or dry etching.

[0068] Specifically, a first quartz tube with a through hole in the center is selected, and an etching liquid or etching gas (such as hydrofluoric acid or sulfur hexafluoride, etc.) is introduced into the through hole. The etching liquid or etching gas reacts with the inner wall of the through hole to produce volatile products, thereby changing the aperture of the through hole. By adjusting the concentration of the etching liquid or etching gas on the inner wall of the quartz tube along the direction of the through hole, the etching rate of the inner wall of the quartz tube can be gradually increased or decreased along the direction of the through hole, and then the etching depth of the inner wall of the quartz tube can be gradually increased or decreased along the direction of the through hole, so that the inner diameter of the inner wall of the quartz tube gradually changes along the direction of the through hole, forming a tapered through hole 10, so as to make the first tapered quartz tube 1. Finally, the impurities in the tapered through hole 10 are removed by flushing or exhausting; the whole process does not require grinding, and the processing adaptability is better.

[0069] In one embodiment, step S102: depositing a core layer in the tapered through hole of the first tapered quartz tube, such as Figure 6 As shown, the following steps are included:

[0070] Step S1021: pickling the first tapered quartz tube.

[0071] Step S1022: uniformly depositing a loose layer in the tapered through hole of the first tapered quartz tube, and doping the loose layer with rare earth ions.

[0072] Specifically, if Figure 6 As shown, after the first conical quartz tube 1 with the conical through hole 10 is manufactured, the first conical quartz tube 1 is first cleaned by pickling. For example, the entire first conical quartz tube 1 can be pickled with a hydrofluoric acid solution. The impurities in the first conical quartz tube 1 are effectively removed by pickling, thereby ensuring the processing quality.

[0073] After pickling, the air inlet section of the first conical quartz tube 1 is equipped with a rotary joint, and the first conical quartz tube 1 is installed on a deposition lathe. Modified Chemical Vapor Deposition (MCVD) can be used to deposit a loose layer, and rare earth ions are doped in the deposited loose layer.

[0074] Specifically, the first conical quartz tube 1 is preheated externally with an oxyhydrogen flame. During the preheating process, the temperature of the first conical quartz tube 1 is gradually increased to 1200° C. Then, a gas raw material is introduced into the first conical quartz tube 1 at a preset flow rate. The gas raw material is SiCl 4 , BCl 3 、GeCl 4 POCl 3 Prior to this, it is also necessary to introduce SF into the first conical quartz tube 1. 6 , O 2The inner wall of the first tapered quartz tube 1 is etched several times, and the first tapered quartz tube 1 is continuously heated and a gas raw material is introduced. When the gas raw material is introduced, the temperature of the reaction tube needs to be heated to 1500° C. to 1800° C. During the repeated rotation of the first tapered quartz tube 1, a loose layer of a specified thickness is deposited on the inner wall. During the deposition process or after the deposition is completed, rare earth ions can be doped into the loose layer.

[0075] Specifically, during the repeated rotation of the first conical quartz tube 1, the introduction speed of the gas raw material can be gradually changed, and the deposited loose layer can be gradually increased or decreased along the direction of the conical through hole 10, so that the loose layer gradually becomes thicker or thinner along the direction of the conical through hole 10 with the aperture; or, the introduction speed of the gas raw material can also be changed step by step, so that the loose layer gradually becomes thicker or thinner along the direction of the conical through hole 10 with the aperture.

[0076] It should be noted that, according to actual needs, the loose layer can also be deposited by outside vapor deposition (OVD), axial chemical vapor deposition (VAD) or plasma chemical vapor deposition (PCVD), and rare earth ions can be doped into the deposited loose layer.

[0077] In this embodiment, during the process of doping rare earth ions, a solution containing rare earth ions may be first passed into the tapered through hole 10, and after soaking for a preset time, the remaining solution containing rare earth ions is discharged to obtain a loose layer containing rare earth ions.

[0078] Specifically, a solution containing rare earth doping ions is introduced into the first conical quartz tube 1 and soaked for a preset time, which is more than 30 minutes, to dope the deposited loose layer with rare earth ions. Specifically, the rare earth doping ions and the dissolving solution are mixed according to a preset ratio to obtain a solution of rare earth doping ions, wherein the rare earth ions are Nd 3+ , Yb 3+ , Er 3+ 、Tm 3+ Any one or a combination of the above. The dissolving liquid is a chloride solution or a nitrate solution. After the solution containing rare earth doping ions is prepared, the first conical quartz tube 1 is taken out, and then the first conical quartz tube 1 is immersed in the solution of rare earth doping ions of a specified concentration. After the immersion, the solution containing rare earth ions can be discharged and dried, so that a deposited loose layer containing rare earth ions can be obtained in the conical through hole 10.

[0079] Optionally, in some embodiments, according to actual needs, rare earth ions may not be doped into the deposited loose layer, so as to produce a passive optical fiber that does not contain rare earth ions.

[0080] Based on the above embodiments, in some embodiments, step S103: shrinking the first conical quartz tube for depositing the core layer to prepare a conical preform rod includes: sintering the first conical quartz tube and the loose layer to melt and shrink the first conical quartz tube and the loose layer into the conical preform rod.

[0081] like Figure 4 As shown, after the core layer 2 is deposited, the first conical quartz tube 1 and the loose layer are sintered at high temperature to vitrify the loose layer containing rare earth ions, and then the vitrified loose layer and the first conical quartz tube 1 are melted and shrunk into a solid conical preform rod 3, and the gap between the loose layer and the first conical quartz tube 1 is effectively removed by shrinking the rod.

[0082] Based on the above embodiments, in some embodiments, step S104: drawing the tapered preform into a tapered optical fiber specifically includes: after the tapered preform 3 is manufactured, Figure 4 As shown, the conical preform rod 3 can be placed on a drawing tower, and a high temperature furnace is used to heat and soften the conical preform rod 3. The adjustable experimental parameters include heating rate, drawing temperature, drawing tension, etc. The conical preform rod 3 is softened by a high temperature wire furnace and then drawn to form a conical optical fiber 4. Figure 5 As shown, the tapered optical fiber 4 includes a core 41 that conducts light along the axial direction of the tapered optical fiber and a cladding 42 surrounding the core 41. The tapered optical fiber 4 with a gradual core-to-cladding ratio has a gradual core 41 diameter and a constant cladding diameter. The core-to-cladding ratio of the optical fiber gradually changes with the length of the optical fiber, and the diameter of the core 41, the core-to-cladding ratio and the cone angle ratio can be adjusted within a certain range according to the needs, and can be specifically adjusted according to the requirements of the passive optical fiber device and the optical system.

[0083] Based on the above embodiments, in other embodiments, step S104: drawing the tapered preform into a tapered optical fiber specifically includes: after the tapered preform is made, if it is found that the tapered preform does not meet the specifications and requires a sleeve, such as Figure 7As shown, firstly, a second quartz tube with matching thermal properties, satisfying optical properties and having a through hole adapted to the tapered preform 3 is selected, and the through hole extends from one end of the second quartz tube to the other end thereof; according to the actual design and use requirements, the outer wall of the second quartz tube is processed, and the outer wall can be processed into a tapered surface by grinding, etching and other methods to obtain a second tapered quartz tube 5; then the tapered preform 3 is sleeved with the second tapered quartz tube to obtain a tapered optical fiber preform, and the tapered contraction direction of the outer wall of the second tapered quartz tube 5 is opposite to the contraction direction of the tapered through hole 10, and a tapered optical fiber preform that meets the requirements is obtained after melting and shrinking. Then, the tapered optical fiber preform is placed on a drawing tower, and a high-temperature furnace is used to heat and soften the tapered optical fiber preform. The adjustable experimental parameters include heating rate, drawing temperature, drawing tension and the like. The tapered optical fiber preform rod is softened in a high-temperature furnace and then drawn into a tapered optical fiber. Drawing after the sleeve can fully ensure the sealing performance, make it easier to control the drawing, and suppress the concentricity error. Figure 8 As shown, the tapered optical fiber 4 includes a core 41 that conducts light along the axial direction of the tapered optical fiber and a cladding 42 surrounding the core 41; wherein the cladding 42 is formed after the second tapered quartz tube 5 and the first tapered quartz tube 1 are sleeved. The tapered optical fiber 4 has a gradually changing core 41 diameter, and the variation trend of the cladding diameter is opposite to the variation trend of the core 41 diameter, so that the core-to-clad ratio of the optical fiber gradually changes with the length of the optical fiber, and the diameter, core-to-clad ratio, and taper angle ratio of the core 41 can be adjusted within a certain range according to the requirements, and can be specifically adjusted according to the requirements of the passive optical fiber device and the optical system; in addition, since the variation trend of the cladding diameter is opposite to the variation trend of the core 41 diameter, the core-to-clad ratio of the tapered optical fiber 4 at the same optical fiber length changes more, which is convenient to meet the actual use requirements.

[0084] Finally, if Figure 8 As shown, the outer periphery of the cladding 42 may be coated with a low-refractive coating twice, thereby forming an optical fiber coating outside the cladding 42 .

[0085] Specifically, the first coating is performed to form an inner coating of the optical fiber; and the second coating is performed on the peripheral wall of the inner coating of the optical fiber to form an outer coating.

[0086] In the above-mentioned preparation process, the embodiment is essentially to apply the inner coating of the optical fiber to the peripheral wall of the optical fiber cladding. The inner coating of the optical fiber is a low-refractive index coating, and the refractive index of the inner coating of the optical fiber is lower than the refractive index of the optical fiber cladding to ensure the reliability of the tapered optical fiber.

[0087] In addition, the present application also provides two specific embodiments.

[0088] Example 1:

[0089] A double-clad ytterbium-doped tapered optical fiber is prepared using the following steps:

[0090] Step 1: Etch the inner wall of a cylindrical high-purity quartz tube into a cone shape using hydrofluoric acid.

[0091] Step 2: Place a quartz tube with a tapered inner wall on a lathe to evenly deposit the core layer.

[0092] Step 3: Place the deposited core rod on a lathe to shrink it into a tapered optical fiber preform rod.

[0093] Step 4: Place the tapered optical fiber preform on a drawing tower and draw it into a tapered optical fiber.

[0094] Example 2:

[0095] A double-clad ytterbium-doped tapered optical fiber is prepared using the following steps:

[0096] Step 1: Etch the inner wall of a cylindrical high-purity quartz tube into a cone shape using sulfur hexafluoride.

[0097] Step 2: Place a quartz tube with a tapered inner wall on a lathe to evenly deposit the core layer.

[0098] Step 3: Place the deposited core rod on a lathe to shrink it into a tapered optical fiber preform rod.

[0099] Step 4: Place the tapered optical fiber preform on a drawing tower and draw it into a tapered optical fiber.

[0100] On the other hand, in some embodiments of the present application, a tapered optical fiber is provided, which is manufactured by the method for manufacturing a tapered optical fiber as provided in any of the above embodiments. Therefore, the tapered optical fiber also includes all the beneficial effects of the method for manufacturing a tapered optical fiber as provided in any of the above embodiments, which will not be described again here to avoid repetition.

[0101] The device embodiments described above are merely illustrative, and some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. A person skilled in the art may understand and implement the present invention without creative effort.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a tapered optical fiber, characterized in that: include: Making a first tapered quartz tube having a tapered through hole therein; depositing a core layer in the tapered through hole of the first tapered quartz tube; The first tapered quartz tube for depositing the core layer is subjected to rod shrinking to prepare a tapered preform; Drawing the tapered preform into a tapered optical fiber, wherein the tapered optical fiber includes a core for guiding light along the axial direction of the tapered optical fiber and a cladding surrounding the core; The step of manufacturing a first tapered quartz tube having a tapered through hole therein comprises: A first quartz tube having a through hole at the center is selected, and an etching liquid or an etching gas is introduced into the through hole; the concentration of the etching liquid or the etching gas on the inner wall of the first quartz tube along the direction of the through hole is adjusted so that the inner diameter of the inner wall of the first quartz tube gradually changes along the direction of the through hole, so as to manufacture the first tapered quartz tube having the tapered through hole.

2. The method for manufacturing a tapered optical fiber according to claim 1, characterized in that: The step of depositing a core layer in the tapered through hole of the first tapered quartz tube comprises: acid washing the first tapered quartz tube; A loose layer is uniformly deposited in the tapered through hole of the first tapered quartz tube, and rare earth ions are doped into the loose layer.

3. The method for manufacturing a tapered optical fiber according to claim 2, characterized in that: The step of doping rare earth ions in the loose layer comprises: Passing a solution containing the rare earth ions into the tapered through hole; After soaking for a preset time, the remaining solution containing the rare earth ions is discharged.

4. The method for manufacturing a tapered optical fiber according to claim 2, characterized in that: The step of shrinking the first tapered quartz tube for depositing the core layer to prepare a tapered preform comprises: The first tapered quartz tube and the loose layer are sintered to melt and shrink the first tapered quartz tube and the loose layer into the tapered optical fiber preform.

5. The method for manufacturing a tapered optical fiber according to claim 2, characterized in that: The rare earth ion is Nd 3+ , Yb 3+ , Er 3+ 、Tm 3+ Any one or combination of the following.

6. The method for manufacturing a tapered optical fiber according to claim 4, characterized in that: The step of drawing the tapered preform into a tapered optical fiber comprises: The outer wall of the second quartz tube is processed into a cone shape to construct a second cone quartz tube with a through hole therein; Assembling the second tapered quartz tube and the tapered preform rod, placing them on a sleeve lathe, and obtaining a solid tapered optical fiber preform rod; The tapered optical fiber preform is placed on a drawing tower and drawn into the tapered optical fiber.

7. The method for manufacturing a tapered optical fiber according to claim 4, characterized in that: The step of placing the tapered optical fiber preform on a drawing tower and drawing it into the tapered optical fiber comprises: The tapered optical fiber preform is placed on the drawing tower, and the tapered optical fiber is drawn by adjusting drawing parameters.

8. The method for manufacturing a tapered optical fiber according to any one of claims 1 to 7, characterized in that: After the step of drawing the tapered preform into a tapered optical fiber, the step further includes: The outer periphery of the cladding is coated twice to form an optical fiber coating.

9. A tapered optical fiber, characterized in that: The tapered optical fiber is manufactured by the method for manufacturing a tapered optical fiber according to any one of claims 1 to 8.

Images