Zirconium fluoride-based glass optical fiber welding method

Abstract

The invention discloses a zirconium fluoride-based glass optical fiber welding method, which comprises the following steps: at least partially removing a coating layer of a zirconium fluoride-based glass optical fiber, cleaning a bare fiber part of the zirconium fluoride-based glass optical fiber, and vertically cutting by using an optical fiber cutting machine to obtain a first zirconium fluoride-based glass optical fiber and a second zirconium fluoride-based glass optical fiber with flat and smooth end surfaces; respectively fixing the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber in a first optical fiber clamp and a second optical fiber clamp of an optical fiber fusion splicer, butting one end of the first zirconium fluoride-based glass optical fiber with a tail fiber of a single-mode optical fiber laser, aligning a probe of an optical power meter to the other end of the second zirconium fluoride-based glass optical fiber, and starting a fiber core alignment function of the optical fiber fusion splicer; aligning the other end of the first zirconium fluoride-based glass optical fiber with the fiber core at one end of the second zirconium fluoride-based glass optical fiber, observing the reading change of the optical power meter in the alignment process, and when the reading reaches the maximum, indicating that the alignment operation is completed; welding the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber; and measuring the loss and mechanical strength of the welding point.

Description

Technical Field

[0001] The invention relates to the field of all-fiber lasers, and in particular to a method for fusing zirconium fluoride-based glass optical fibers. Background Art

[0002] Fiber lasers can be used in aerospace, national defense, medical treatment, laser processing and other fields. In particular, mid-infrared fiber lasers with a working band of about 3~5 μm are widely used in remote sensing, atmospheric monitoring, spectroscopy, military fields and laser medical treatment because they are located at the absorption peak of water molecules and many gas molecules in the atmosphere.

[0003] Traditional fiber lasers mostly use quartz glass as gain fiber, but the phonon energy of quartz material is as high as 1100 cm -1 Therefore, when the wavelength is greater than 2.2 μm, the transmission loss will be very large, and it cannot be used to make fiber lasers with wavelengths exceeding 2.2 μm. Therefore, in order to obtain fiber lasers in the mid-infrared band, special optical fibers with lower phonon energy are required.

[0004] To meet the requirements, soft glass optical fibers are currently used to develop mid-infrared fiber lasers, including special optical fibers such as fluoride fibers, tellurite fibers, and chalcogenide fibers. However, when coupling the laser of the pump source laser into the special optical fiber, many methods are spatial coupling. This coupling method will damage the fiber end face when pumped at high power, and the optical path formed is extremely unstable, which is not convenient for widespread application. In addition, the spatial coupling efficiency is also relatively low, which limits the increase in output laser power. If the mid-infrared fiber laser is converted into an all-fiber system, the above problems can be effectively solved.

[0005] Therefore, technicians in this field are committed to developing a method for fusion splicing zirconium fluoride-based glass optical fibers, thereby obtaining low-loss, high-mechanical-strength fusion splicing points and improving the stability and reliability of the system. Summary of the invention

[0006] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is how to provide a method for fusing zirconium fluoride-based glass, wherein the fusing point has the advantages of low loss and high mechanical strength.

[0007] To achieve the above object, the present invention provides a method for fusion splicing zirconium fluoride-based glass optical fibers, comprising the following steps: Step 1, at least partially removing the coating layer of the zirconium fluoride-based glass optical fiber, cleaning the bare fiber portion of the zirconium fluoride-based glass optical fiber, and vertically cutting the bare fiber portion of the zirconium fluoride-based glass optical fiber using a fiber cutting machine to obtain a first zirconium fluoride-based glass optical fiber and a second zirconium fluoride-based glass optical fiber with a flat and smooth end face; Step 2, fix the first zirconium fluoride-based glass fiber and the second zirconium fluoride-based glass fiber obtained in step 1 in the first fiber clamp and the second fiber clamp of the fiber fusion splicer respectively, then dock one end of the first zirconium fluoride-based glass fiber with the pigtail of the single-mode fiber laser, align the optical power meter probe with the other end of the second zirconium fluoride-based glass fiber, start the fiber core alignment function of the fiber fusion splicer, align the other end of the first zirconium fluoride-based glass fiber with the core of one end of the second zirconium fluoride-based glass fiber, observe the change of the reading of the optical power meter during the alignment process, and when the reading of the optical power meter reaches the maximum, it means that the alignment operation has been completed; Step 3, fusing the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber according to the fusing parameters; Step 4, measuring the loss and mechanical strength of the fusion point: using the truncation method to determine the fusion loss of the fusion point of the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber after fusion, and using the tension monitoring in the fiber optic cutting machine software to determine the mechanical strength of the fusion point.

[0008] Furthermore, the core diameter of the zirconium fluoride-based glass optical fiber in step 1 is 10 μm, the cladding diameter is 227 μm, and the length is 1.6 m.

[0009] Furthermore, in the step 1, the cutting force of the optical fiber cutter when cutting the zirconium fluoride-based glass optical fiber is 265-288 gf.

[0010] Furthermore, in step 2, the clamping force of the first optical fiber clamp is 1400-1550 gf, and the clamping force of the second optical fiber clamp is 1550-1750 gf.

[0011] Furthermore, the optical fiber fusion splicer in step 2 uses carbon dioxide laser heating fusion.

[0012] Furthermore, in step 2, the core alignment position is manually fine-tuned during the alignment process.

[0013] Furthermore, in the step 3, a non-offset fusion method is adopted, the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber are placed in the first optical fiber clamp and the second optical fiber clamp respectively, the heating head of the optical fiber fusion splicer is placed in the middle of the end faces of the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber, the position of the heating head is not offset, and the fusion of the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber is achieved by setting the fusion parameters.

[0014] Furthermore, the fusion parameters in step 3 include fiber end face distance, preheating power, preheating time, fiber overlap distance, main fusion light power, main fusion light time, and flame head offset distance.

[0015] Furthermore, in step 3, the fiber end face distance is 5-8 μm, the preheating power is 40-50 bit, the preheating time is 60 ms, the fiber overlap distance is 10 μm, the main fusion light power is 20-30 bit, the main fusion light time is 100 ms, and the fire head offset distance is 0 μm.

[0016] Furthermore, when the truncation method is used to determine the fusion loss of the fusion point in step 4, the length of the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber cut off each time is greater than 10 cm, and the length of the remaining part is greater than 10 cm.

[0017] The beneficial effects of the present invention are: (1) The present invention has strong repeatability and simple operation. The minimum loss at the welding point is 0.12 dB, the welding success rate is 92%, and the maximum mechanical strength is 282 gf.

[0018] (2) The present invention is based on the fusion splicing of zirconium fluoride-based glass optical fibers and is also applicable to other soft glass optical fibers.

[0019] (3) The present invention uses carbon dioxide laser for heating, which can quickly and accurately form a stable and controllable temperature field around the fused optical fiber. The low-loss and high-mechanical-strength fusion point obtained by fusion improves its stability and reliability in practical applications, can be mass-produced, and is conducive to promoting the development of all-fiber lasers.

[0020] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a method flow chart of a preferred embodiment of the present invention; Figure 2 is an end view of a zirconium fluoride-based glass optical fiber used in a preferred embodiment of the present invention; Figure 3 It is a schematic diagram of an experimental device of a preferred embodiment of the present invention; Figure 4 This is a fiber fusion diagram obtained by a preferred embodiment of the present invention.

[0022] Among them, 1-CCD camera, 2-heating head, 31-first zirconium fluoride-based glass optical fiber, 32-second zirconium fluoride-based glass optical fiber, 41-first optical fiber clamp, 42-second optical fiber clamp, 5-single-mode fiber laser, 6-optical power meter. DETAILED DESCRIPTION

[0023] The following describes the preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0024] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings. Example

[0025] This embodiment provides a method for fusion splicing zirconium fluoride-based glass optical fibers. Figure 1 As shown, the specific steps include: Step 1. Processing of the end face of the zirconium fluoride-based glass optical fiber: First, use a blade to scrape off the coating layer of the zirconium fluoride-based glass optical fiber, and then use dust-free paper soaked in anhydrous ethanol to clean its bare fiber part to ensure that it is not contaminated by impurities during the fusion process; then use a large-core fiber cutting machine to vertically cut the bare fiber part of the zirconium fluoride-based glass optical fiber to obtain the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber with smooth end faces. Before cutting, the parameters of the cutting machine need to be adjusted to ensure a smooth fiber end face.

[0026] The zirconium fluoride based glass optical fiber used is Figure 2 As shown, preferably, the core diameter is 10 μm, the cladding diameter is 227 μm, the length is 1.6 m, and the cutting force of the optical fiber cutting machine used to cut the zirconium fluoride-based glass optical fiber is 265~288gf.

[0027] Step 2: Fixing and aligning zirconium fluoride-based glass optical fiber: The experimental device is shown in the figure Figure 3 As shown, it mainly includes a charge-coupled device (CCD) camera 1, a heating head 2, a single-mode fiber laser 5 and an optical power meter 6. The CCD camera 1 is used to photograph and detect the end face position of the optical fiber. The function of the heating head 2 is to melt the end face of the optical fiber through a high-temperature arc or laser beam, so that the cores of the two optical fibers can be fused at the molecular level in a state of precise alignment, thereby forming a low-loss, high-strength optical fiber fusion point.

[0028] The first zirconium fluoride-based glass optical fiber 31 and the second zirconium fluoride-based glass optical fiber 32 with smooth end faces obtained in step 1 are fixed in the first fiber clamp 41 and the second fiber clamp 42 on the left and right sides of the fiber fusion splicer, respectively. Then, one end of the first zirconium fluoride-based glass optical fiber 31 is connected to the pigtail of the single-mode fiber laser 5 (wavelength 980 nm), and the optical power meter 6 probe is aligned with the other end of the second zirconium fluoride-based glass optical fiber 32. The fiber core alignment function of the fiber fusion splicer is started to align the cores of the other end of the first zirconium fluoride-based glass optical fiber 31 and one end of the second zirconium fluoride-based glass optical fiber 32. During the alignment process, the reading change of the optical power meter 6 is observed. If necessary, the core alignment position can be manually fine-tuned. When the reading of the optical power meter 6 reaches the maximum, it means that the alignment operation has been completed.

[0029] Preferably, the clamping force of the first optical fiber clamp 41 is 1400-1550 gf, and the clamping force of the second optical fiber clamp 42 is 1550-1750 gf.

[0030] Preferably, the optical fiber fusion splicer uses carbon dioxide laser heating fusion splicing.

[0031] Step 3: Fusion splicing zirconium fluoride-based glass optical fibers: Since the same type of soft glass optical fibers are being fused, there is no difference in the transition temperature (Tg~265°C) between the glasses, so a non-offset fusion method is used.

[0032] The first zirconium fluoride-based glass optical fiber 31 and the second zirconium fluoride-based glass optical fiber 32 are placed in the first optical fiber clamp 41 and the second optical fiber clamp 42 on the left and right sides of the 250 μm specification (which can clamp 250 μm optical fiber). The heating head 2 of the optical fiber fusion splicer is placed in the middle of the end faces of the first zirconium fluoride-based glass optical fiber 31 and the second zirconium fluoride-based glass optical fiber 32, and the position of the heating head is not offset (that is, the offset distance is 0), and then the first zirconium fluoride-based glass optical fiber 31 and the second zirconium fluoride-based glass optical fiber 32 are fused by setting the fusion parameters.

[0033] Preferably, the fusion splicing parameters include the distance between the end faces of the first zirconium fluoride-based glass optical fiber 31 and the second zirconium fluoride-based glass optical fiber 32 (fiber end face distance), preheating power, preheating time, fiber overlap distance, main fusion light power, main fusion light time, and flame head offset distance: the fiber end face distance is 5~8 μm, the preheating power is 40~50 bit, the preheating time is 60 ms, the fiber overlap distance is 10 μm, the main fusion light power is 20~30 bit, the main fusion light time is 100 ms, and the flame head offset distance is 0 μm.

[0034] By repeatedly performing experiments and gradually optimizing the welding parameters in step 3, the present invention can obtain a stable and effective welding point with low loss and high mechanical strength.

[0035] Step 4, measuring the loss and mechanical strength of the fusion point: the fusion loss of the first zirconium fluoride-based glass optical fiber 31 and the second zirconium fluoride-based glass optical fiber 32 after fusion is determined by the truncation method, and the mechanical strength of the fusion point is determined by the tension monitoring in the optical fiber cutting machine software.

[0036] Preferably, when the truncation method is used to determine the fusion loss of the fusion point, the length of the first zirconium fluoride-based glass optical fiber 31 and the second zirconium fluoride-based glass optical fiber 32 cut off each time is greater than 10 cm, and the length of the remaining part is greater than 10 cm, so as to ensure that the accurate fusion loss is measured.

[0037] The fusion diagram of the zirconium fluoride-based glass optical fiber obtained by the method of the present invention is as follows: Figure 4 shown.

[0038] The invention has strong repeatability and simple operation. The minimum loss of the fusion point is 0.12 dB, the fusion success rate is 92%, and the maximum mechanical strength is 282 gf. The invention is based on the fusion of zirconium fluoride-based glass optical fibers and is also applicable to other soft glass optical fibers. The invention uses carbon dioxide laser for heating, which can quickly and accurately form a stable and controllable temperature field around the fusion optical fiber. The low-loss and high-mechanical-strength fusion point obtained by fusion improves its stability and reliability in practical applications, can be mass-produced, and is conducive to promoting the development of all-fiber lasers.

[0039] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for fusion splicing zirconium fluoride-based glass optical fibers, characterized in that: The following steps are involved: Step 1, at least partially removing the coating layer of the zirconium fluoride-based glass optical fiber, cleaning the bare fiber portion of the zirconium fluoride-based glass optical fiber, and vertically cutting the bare fiber portion of the zirconium fluoride-based glass optical fiber using a fiber cutting machine to obtain a first zirconium fluoride-based glass optical fiber and a second zirconium fluoride-based glass optical fiber with a flat and smooth end face; Step 2, fix the first zirconium fluoride-based glass fiber and the second zirconium fluoride-based glass fiber obtained in step 1 in the first fiber clamp and the second fiber clamp of the fiber fusion splicer respectively, then dock one end of the first zirconium fluoride-based glass fiber with the pigtail of the single-mode fiber laser, align the optical power meter probe with the other end of the second zirconium fluoride-based glass fiber, start the fiber core alignment function of the fiber fusion splicer, align the other end of the first zirconium fluoride-based glass fiber with the core of one end of the second zirconium fluoride-based glass fiber, observe the change of the reading of the optical power meter during the alignment process, and when the reading of the optical power meter reaches the maximum, it means that the alignment operation has been completed; Step 3, fusing the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber according to the fusing parameters; Step 4, measuring the loss and mechanical strength of the fusion point: using the truncation method to determine the fusion loss of the fusion point of the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber after fusion, and using the tension monitoring in the fiber optic cutting machine software to determine the mechanical strength of the fusion point.

2. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 1, characterized in that: The core diameter of the zirconium fluoride-based glass optical fiber in step 1 is 10 μm, the cladding diameter is 227 μm, and the length is 1.6 m.

3. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 1, characterized in that: In the step 1, the cutting force of the optical fiber cutter when cutting the zirconium fluoride-based glass optical fiber is 265-288 gf.

4. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 1, wherein: In step 2, the clamping force of the first optical fiber clamp is 1400-1550 gf, and the clamping force of the second optical fiber clamp is 1550-1750 gf.

5. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 1, characterized in that: The optical fiber fusion splicer in step 2 uses carbon dioxide laser heating and fusion.

6. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 1, characterized in that: In step 2, the core alignment position is manually fine-tuned during the alignment process.

7. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 1, characterized in that: In the step 3, a non-offset fusion method is adopted, the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber are placed in the first optical fiber clamp and the second optical fiber clamp respectively, and the heating head of the optical fiber fusion splicer is placed in the middle of the end faces of the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber. The position of the heating head is not offset, and the fusion of the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber is achieved by setting the fusion parameters.

8. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 7, characterized in that: The fusion parameters in step 3 include fiber end face distance, preheating power, preheating time, fiber overlap distance, main fusion light power, main fusion light time, and flame head offset distance.

9. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 8, characterized in that: In step 3, the fiber end face distance is 5-8 μm, the preheating power is 40-50 bit, the preheating time is 60 ms, the fiber overlap distance is 10 μm, the main fusion light power is 20-30 bit, the main fusion light time is 100 ms, and the flame head offset distance is 0 μm.

10. The method for fusion splicing zirconium fluoride-based glass optical fibers according to claim 1, characterized in that: When the truncation method is used to determine the fusion loss of the fusion point in step 4, the length of the first zirconium fluoride-based glass optical fiber and the second zirconium fluoride-based glass optical fiber cut off each time is greater than 10 cm, and the length of the remaining part is greater than 10 cm.

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