Optical fiber coating stripping agent, preparation method thereof and optical fiber welding method

Abstract

The invention relates to the technical field of optical fiber fusion splicing, in particular to an optical fiber coating stripping agent, a preparation method thereof and an optical fiber fusion splicing method. The optical fiber coating stripping agent is prepared from the following raw materials in percentage by weight: 86%-89% of dichloromethane, 5%-6% of formic acid, 5%-6% of phenol, 0.5%-1% of paraffin and the balance of organic glass. Therefore, the problems that the welding processing technology of the existing equipment on the polarization maintaining optical fiber with the small diameter of 60 microns is not mature, and the coating layer is difficult to strip are solved.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber fusion splicing, and in particular to an optical fiber coating stripping agent and a preparation method thereof and an optical fiber fusion splicing method. Background Art

[0002] Optical fiber is the mainstream transmission medium at present, and has the advantages of transmission bandwidth, large communication capacity, low loss, no electromagnetic interference, small diameter, light weight, and abundant raw material sources. Therefore, it is widely used in communication, television, and data transmission networks. For optical fiber devices, the optical fiber diameter directly affects the physical volume of the optical fiber device. For example, when making an optical fiber gyroscope, the use of ultra-fine optical fiber can reduce the volume of the optical fiber gyroscope. The gyroscope of the same volume can increase the optical fiber length to improve the accuracy of the optical fiber gyroscope. In addition, the strain generated by ultra-fine optical fiber at the same radius of curvature is low, which can improve the stability of optical transmission, performance temperature sensitivity, reliability, etc. Therefore, the use of ultra-fine optical fiber is an important trend in the development of optical fiber devices.

[0003] Interferometric fiber optic gyroscope is an angular rate sensor based on Sagnac effect, which is composed of optical path, circuit, mechanical structure, etc. The Sagnac effect is generated by the optical path. The optical devices such as light source, detector, coupler, Y waveguide, fiber ring, etc. are fused to form a closed optical path. The light emitted from the light source is divided into two beams after passing through the coupler and Y waveguide. One beam enters the fiber ring from the fiber optic ring pigtail 1 and propagates clockwise, and the other beam enters the fiber ring from the fiber optic ring pigtail 2 and propagates counterclockwise. After the two beams of light propagate in the fiber ring for one circle, they return to the Y waveguide and interfere. When there is an angular velocity in the normal direction of the fiber ring, there will be a phase difference (Sagnac phase difference) between the two beams of light that is proportional to the input angular velocity, and the intensity of the corresponding interference signal changes. By detecting the intensity of the interference signal through the detector, the magnitude of the input angular velocity can be obtained. The fiber optic ring in the optical path determines the accuracy of the fiber optic gyroscope. The larger the diameter of the fiber optic ring and the longer the fiber length, the higher the accuracy of the gyroscope. The optical fiber used in the optical fiber ring is usually a polarization-maintaining optical fiber with a cladding diameter of 80um. The Y-waveguide pigtail connected to it is also a polarization-maintaining optical fiber with a cladding diameter of 80um. The existing equipment has a relatively mature fusion splicing process for 80um polarization-maintaining optical fibers.

[0004] As the demand for miniaturization of fiber optic gyroscopes increases, some fiber optic rings begin to use 60um fine-diameter polarization-maintaining fibers to make the fiber optic rings smaller and lighter while meeting the accuracy requirements at the same fiber length. However, the current equipment is not mature in the fusion splicing process for 60um fine-diameter polarization-maintaining fibers, and there is a problem of difficulty in stripping the coating layer. In addition, the Y-waveguide pigtail only has one specification of 80um, which does not match the cladding diameter of the 60um fiber. After fusion splicing, problems such as large melting point loss, poor melting point loss consistency, and low melting point strength occur, which affect the qualification rate and reliability of the fiber optic gyroscope. Summary of the invention

[0005] In order to solve the problem that the existing equipment is not mature enough for the fusion splicing process of 60um fine-diameter polarization-maintaining optical fiber and there is difficulty in stripping the coating layer, the present invention provides an optical fiber coating stripping agent and a preparation method thereof and an optical fiber fusion splicing method.

[0006] In a first aspect, the present invention provides an optical fiber coating stripping agent, which is made of the following raw materials in weight ratio: 86% to 89% of dichloromethane, 5% to 6% of formic acid, 5% to 6% of phenol, 0.5% to 1% of paraffin, and the balance is organic glass.

[0007] In some embodiments, the mass concentration of the formic acid is 65% to 80%.

[0008] In some embodiments, the melting point of the paraffin wax is 30°C to 70°C.

[0009] On the other hand, the present invention provides a method for preparing the optical fiber coating stripping agent as described above, comprising the following steps:

[0010] 1) Add paraffin and organic glass into a container, heat the paraffin to melt, add dichloromethane while stirring to form a uniform system, the temperature is 30℃~55℃;

[0011] 2) Add phenol and stir until dissolved;

[0012] 3) Add formic acid and continue stirring evenly.

[0013] In a third aspect, the present invention provides a method for optical fiber fusion splicing, comprising the following steps:

[0014] (1) Remove the optical fiber coating and wipe it clean with anhydrous ethanol;

[0015] (2) cutting the optical fiber from which the optical fiber coating is removed;

[0016] (3) Place the cut optical fiber in a fusion splicer for fusion splicing;

[0017] The optical fiber coating is removed by chemical stripping, and the optical fiber coating stripping agent as described above is used to strip the optical fiber coating.

[0018] In some embodiments, in step (3), when the optical fibers are placed in a fusion splicer for fusion splicing, the overlap amount of the optical fibers to be fused is greater than or equal to 8 μm and less than or equal to 12 μm.

[0019] In some embodiments, in step (1), the optical fiber is immersed in the optical fiber coating stripping agent for 10 seconds to 20 seconds before stripping the optical fiber coating.

[0020] In some embodiments, in step (3), the cladding diameter of the optical fiber is input into the fusion splicer, the cleaning discharge power is set to 150bit~200bit, the cleaning discharge time is set to 60~80ms, the fiber pre-melting power is set to 150bit~170bit, the fiber pre-melting time is set to 10~15ms, the main discharge power is set to 210bit~230bit, and the main discharge time is set to 2800~3200ms.

[0021] In some embodiments, after step (3), the method further includes: using a coating machine to coat the fusion splicing point of the optical fiber after the fusion splicing is completed.

[0022] In some embodiments, the cladding diameter of the optical fiber is 50-70 μm.

[0023] In order to solve the problem that the existing equipment is not mature in the fusion splicing process of 60um fine-diameter polarization-maintaining optical fiber and it is difficult to strip the coating layer, the present invention has the following advantages:

[0024] By adopting the technical solution of the present invention, the optical fiber coating layer can be quickly removed to achieve complete stripping without damaging the fiber core and cladding. DETAILED DESCRIPTION

[0025] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0026] As used herein, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "based at least in part on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or positional relationship, some of the above terms may also be used to indicate other meanings, such as the term "on" in some cases may also be used to indicate a certain dependency or connection relationship. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, the meaning of "plurality" is two or more.

[0027] The optical device pigtails in the optical path of the fiber optic gyroscope are connected together by optical fiber fusion splicing. The principle of optical fiber fusion splicing is to use an optical fiber fusion splicer to align the geometric spatial positions of the core and cladding of the two optical fibers to be fused, set the gap, align the stress axis, and then use the instantaneous high temperature generated by the high-voltage discharge at the tip of the electrode to make the optical fiber reach a molten state, and then push each other to connect the two optical fibers together. The optical fiber fusion splicing process is: optical fiber coating removal → optical fiber cleaning → optical fiber cutting → fusion splicing. For optical fibers with a cladding diameter of 80um and above, existing special tools and equipment can handle and fusion well. For 60um thin-diameter optical fibers, there are currently no special tools to handle them. When fusion splicing with 80um optical fibers, the operation method and steps are as follows: 1) Optical fiber coating removal: The 80um optical fiber coating is stripped using a special optical fiber thermal stripper RS03-80. Since there is no thermal stripping tool for the 60um optical fiber coating, first use the optical fiber thermal stripper RS03-80 to strip it. If the coating cannot be stripped after multiple attempts, use Miller pliers to strip it; 2) Optical fiber cleaning: Use an ultrasonic cleaner to clean the optical fiber with the coating stripped; 3) Optical fiber cutting: Use an optical fiber cutter to cut the optical fiber end face; 4) Fusion: Select the 80um optical fiber fusion program for fusion.

[0028] The following shortcomings exist in the current fusion splicing of 60um fine-diameter optical fiber and 80um optical fiber: (1) When using the 80um optical fiber thermal stripper RS03-80 to strip the 60um optical fiber coating, there are cases where the coating cannot be stripped or is not stripped cleanly. If the 60um optical fiber coating is stripped using Miller pliers, this method belongs to mechanical cold stripping, which has the risk of damaging the optical fiber cladding and affecting the reliability of the optical path; (2) The optical path of the optical fiber gyroscope requires that the loss of the optical fiber fusion point is no more than 0.5dB and the melting point strength is greater than 2N. However, after the 60um optical fiber is fused with the 80um optical fiber, the melting point loss is generally greater than 0.5dB, and the loss consistency is poor. At the same time, the melting point strength is also low. The qualified rate of fusion splicing of 60um and 80um optical fibers is only about 40%, which seriously affects the production efficiency and the reliability of the gyroscope.

[0029] This embodiment discloses an optical fiber coating stripper and a preparation method thereof. The optical fiber coating stripper is made of the following raw materials in weight ratio: 86% to 89% of dichloromethane, 5% to 6% of formic acid, 5% to 6% of phenol, 0.5% to 1% of paraffin wax, and the balance is organic glass. The melting point of the paraffin wax is 30°C to 70°C.

[0030] In the first embodiment, the preparation method of the optical fiber coating stripping agent, measured by a total weight of 1 kg, comprises the following steps:

[0031] 1) Add 5 grams of paraffin wax and 5 grams of organic glass into a container, heat to 55°C to melt, add 890 grams of dichloromethane while stirring, and form a uniform system; specifically, the container can be a corrosion-resistant container such as ceramic or glass. Dichloromethane will help the paraffin wax to melt, and the heating temperature is preferably 30°C to 55°C.

[0032] 2) Add 50 grams of phenol and stir until dissolved.

[0033] 3) Add 50 grams of formic acid with a mass concentration of 70%, continue to stir evenly, and obtain an optical fiber coating stripping agent. In the present application, the mass concentration of formic acid is preferably 65% ​​to 80%.

[0034] Further, the optical fiber fusion splicing method comprises the following steps:

[0035] (1) Remove the optical fiber coating and wipe it clean with anhydrous ethanol; specifically, the optical fiber coating is removed by chemical stripping, and the optical fiber coating stripper as described above is used to strip the optical fiber coating. The optical fiber coating can be stripped after being placed in the optical fiber coating stripper and soaked for 10 to 20 seconds; alternatively, a toothpick is used to dip the reagent and directly apply it to the optical fiber coating. After 10 to 20 seconds, the optical fiber coating swells, and the optical fiber is wiped with dust-free paper dipped in anhydrous ethanol to remove the residual chemical reagent and coating. In the present application, the length is controlled according to the length of the optical fiber coating to be stripped, and the specific length of the optical fiber coating to be removed can be 30 mm, 32 mm, 34 mm, 36 mm or 40 mm, and the present application is not limited thereto.

[0036] (2) Cutting the optical fiber with the coating removed; specifically, using a clamp to clamp the optical fiber, and allowing the optical fiber with the coating to extend 1 to 2 mm out of the clamp, and using a cutting machine to cut the optical fiber, specifically, using a CT-38 cutting knife to cut the optical fiber end face.

[0037] (3) placing the cut optical fiber in a fusion splicer for fusion splicing; specifically, inputting the cladding diameter of the optical fiber into the fusion splicer, setting the cleaning discharge power to 150-200 bits, specifically 150 bits, 160 bits, 170 bits, 180 bits, 190 bits or 200 bits, setting the cleaning discharge time to 60-80 ms, specifically 60 ms, 650 ms, 70 ms, 75 ms or 80 ms, setting the optical fiber end face spacing to 10-15 μm, and setting the optical fiber pre-melting power to 150-170 bits, specifically 150 bits , 155bit, 160bit, 165bit or 170bit, the optical fiber pre-melting time is 10-15ms, specifically 10ms, 12ms, 13ms or 15ms, the main discharge power is 210bit-230bit, specifically 210bit, 215bit, 220bit, 225bit or 230bit, the main discharge time is 2800-3200ms, specifically 2800ms, 2900ms, 3000ms, 3100ms or 3200ms, and the overlap of the optical fiber to be fused is 8μm. In the present application, the difference between the optical fiber pre-melting power and the main discharge power does not exceed 80bit.

[0038] (4) Using a coating machine to coat the fusion point of the fused optical fiber; specifically, the cladding diameter of the ultra-fine optical fiber is 50-70 μm, and the optical fiber is a Panda type polarization-maintaining optical fiber.

[0039] In this embodiment, the optical fiber coating stripping agent and optical fiber fusion method provided by the present application can achieve non-destructive removal of the coating of a 60μm thin optical fiber, with short removal time and good effect. By using the optical fiber fusion parameters provided by the present invention to fusion-splice a 60μm thin-diameter optical fiber with an 80μm optical fiber, the melting point loss of the fusion point can be reduced to 0.3dB, and the melting point strength can be increased to more than 2N, which has practical value in miniaturized optical fiber gyroscopes.

[0040] In the second embodiment, the preparation method of the optical fiber coating stripping agent, measured by a total weight of 1 kg, comprises the following steps:

[0041] 1) Add 10 g of paraffin wax and 10 g of organic glass into a container, heat to 45°C to melt, add 860 g of dichloromethane while stirring to form a uniform system; specifically, the container can be a corrosion-resistant container such as ceramic or glass.

[0042] 2) Add 60 grams of phenol and stir until dissolved.

[0043] 3) Add 60 grams of formic acid with a mass concentration of 70%, continue to stir evenly, and obtain an optical fiber coating stripping agent. In the present application, the mass concentration of formic acid is preferably 65% ​​to 80%.

[0044] Further, the optical fiber fusion splicing method comprises the following steps:

[0045] (1) Remove the optical fiber coating and wipe it clean with anhydrous ethanol; specifically, the optical fiber coating is removed by chemical stripping, and the optical fiber coating stripper as described above is used to strip the optical fiber coating. The optical fiber coating can be stripped after being placed in the optical fiber coating stripper and soaked for 10 to 20 seconds; alternatively, a toothpick is used to dip the reagent and directly apply it to the optical fiber coating. After 10 to 20 seconds, the optical fiber coating swells, and the optical fiber is wiped with dust-free paper dipped in anhydrous ethanol to remove the residual chemical reagent and coating. In the present application, the length is controlled according to the length of the optical fiber coating to be stripped, and the specific length of the optical fiber coating to be removed can be 30 mm, 32 mm, 34 mm, 36 mm or 40 mm, and the present application is not limited thereto.

[0046] (2) Cutting the optical fiber with the coating removed; specifically, using a clamp to clamp the optical fiber, and allowing the optical fiber with the coating to extend 1 to 2 mm out of the clamp, and using a cutting machine to cut the optical fiber, specifically, using a CT-38 cutting knife to cut the optical fiber end face.

[0047] (3) placing the cut optical fiber in a fusion splicer for fusion splicing; specifically, inputting the cladding diameter of the optical fiber into the fusion splicer, setting the cleaning discharge power to 150-200 bits, specifically 150 bits, 160 bits, 170 bits, 180 bits, 190 bits or 200 bits, setting the cleaning discharge time to 60-80 ms, specifically 60 ms, 650 ms, 70 ms, 75 ms or 80 ms, setting the optical fiber end face spacing to 10-15 μm, and setting the optical fiber pre-melting power to 150-170 bits, specifically 150 bits , 155bit, 160bit, 165bit or 170bit, the optical fiber pre-melting time is 10-15ms, specifically 10ms, 12ms, 13ms or 15ms, the main discharge power is 210bit-230bit, specifically 210bit, 215bit, 220bit, 225bit or 230bit, the main discharge time is 2800-3200ms, specifically 2800ms, 2900ms, 3000ms, 3100ms or 3200ms, and the overlap of the optical fiber to be fused is 10μm. In the present application, the difference between the optical fiber pre-melting power and the main discharge power does not exceed 80bit.

[0048] (4) Using a coating machine to coat the fusion point of the fused optical fiber; specifically, the cladding diameter of the ultra-fine optical fiber is 50-70 μm, and the optical fiber is a Panda type polarization-maintaining optical fiber.

[0049] In the third embodiment, the preparation method of the optical fiber coating stripping agent, measured by a total weight of 1 kg, comprises the following steps:

[0050] 1) Add 7 grams of paraffin wax and 8 grams of organic glass into a container, heat to 30°C to melt, add 875 grams of dichloromethane while stirring to form a uniform system; specifically, the container can be a corrosion-resistant container such as ceramic or glass.

[0051] 2) Add 55 grams of phenol and stir until dissolved.

[0052] 3) Add 55 grams of formic acid with a mass concentration of 70%, continue to stir evenly, and obtain an optical fiber coating stripping agent. In the present application, the mass concentration of formic acid is preferably 65% ​​to 80%.

[0053] Further, the optical fiber fusion splicing method comprises the following steps:

[0054] (1) Remove the optical fiber coating and wipe it clean with anhydrous ethanol; specifically, the optical fiber coating is removed by chemical stripping, and the optical fiber coating stripper as described above is used to strip the optical fiber coating. The optical fiber coating can be stripped after being placed in the optical fiber coating stripper and soaked for 10 to 20 seconds; alternatively, a toothpick is used to dip the reagent and directly apply it to the optical fiber coating. After 10 to 20 seconds, the optical fiber coating swells, and the optical fiber is wiped with dust-free paper dipped in anhydrous ethanol to remove the residual chemical reagent and coating. In the present application, the length is controlled according to the length of the optical fiber coating to be stripped, and the specific length of the optical fiber coating to be removed can be 30 mm, 32 mm, 34 mm, 36 mm or 40 mm, and the present application is not limited thereto.

[0055] (2) Cutting the optical fiber with the coating removed; specifically, using a clamp to clamp the optical fiber, and allowing the optical fiber with the coating to extend 1 to 2 mm out of the clamp, and using a cutting machine to cut the optical fiber, specifically, using a CT-38 cutting knife to cut the optical fiber end face.

[0056] (3) placing the cut optical fiber in a fusion splicer for fusion splicing; specifically, inputting the cladding diameter of the optical fiber into the fusion splicer, setting the cleaning discharge power to 150-200 bits, specifically 150 bits, 160 bits, 170 bits, 180 bits, 190 bits or 200 bits, setting the cleaning discharge time to 60-80 ms, specifically 60 ms, 650 ms, 70 ms, 75 ms or 80 ms, setting the optical fiber end face spacing to 10-15 μm, and setting the optical fiber pre-melting power to 150-170 bits, specifically 150 bits , 155bit, 160bit, 165bit or 170bit, the optical fiber pre-melting time is 10-15ms, specifically 10ms, 12ms, 13ms or 15ms, the main discharge power is 210bit-230bit, specifically 210bit, 215bit, 220bit, 225bit or 230bit, the main discharge time is 2800-3200ms, specifically 2800ms, 2900ms, 3000ms, 3100ms or 3200ms, and the overlap of the optical fiber to be fused is 12μm. In the present application, the difference between the optical fiber pre-melting power and the main discharge power does not exceed 80bit.

[0057] (4) Using a coating machine to coat the fusion point of the fused optical fiber; specifically, the cladding diameter of the ultra-fine optical fiber is 50-70 μm, and the optical fiber is a Panda type polarization-maintaining optical fiber.

[0058] In summary, the present invention realizes the rapid and non-destructive removal of the coating layer of a 60um fine-diameter optical fiber through chemical reagents, and the provided fusion program parameters can reduce the fiber fusion point loss and improve the fusion point strength, thereby improving the optical path qualification rate of the fiber optic gyroscope and ensuring its reliability.

[0059] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0060] In addition, it should be understood that although the present specification is described according to embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that those skilled in the art can understand.

Claims

1. An optical fiber coating stripping agent, characterized in that: The invention is prepared from the following raw materials in weight ratio: 86% to 89% of dichloromethane, 5% to 6% of formic acid, 5% to 6% of phenol, 0.5% to 1% of paraffin, and the balance is organic glass.

2. The optical fiber coating stripping agent according to claim 1, characterized in that: The mass concentration of the formic acid is 65% to 80%.

3. The optical fiber coating stripping agent according to claim 1, characterized in that: The melting point of the paraffin wax is 30°C to 70°C.

4. A method for preparing the optical fiber coating stripping agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: 1) Add paraffin and organic glass into a container, heat the paraffin to melt, add dichloromethane while stirring to form a uniform system, the temperature is 30℃~55℃; 2) Add phenol and stir until dissolved; 3) Add formic acid and continue stirring evenly.

5. A method for optical fiber fusion splicing, characterized in that: The following steps are involved: (1) Remove the optical fiber coating and wipe it clean with anhydrous ethanol; (2) cutting the optical fiber from which the optical fiber coating is removed; (3) Place the cut optical fiber in a fusion splicer for fusion splicing; The optical fiber coating is removed by chemical stripping, and the optical fiber coating stripping agent as claimed in any one of claims 1 to 3 is used to strip the optical fiber coating.

6. The optical fiber fusion splicing method according to claim 5, characterized in that: In step (3), when the optical fibers are placed in a fusion splicer for fusion splicing, the overlap amount of the optical fibers to be fused is greater than or equal to 8 μm and less than or equal to 12 μm.

7. The optical fiber fusion splicing method according to claim 5, characterized in that: In step (1), the optical fiber is immersed in the optical fiber coating stripping agent for 10 seconds to 20 seconds, and then the optical fiber coating is stripped.

8. The optical fiber fusion splicing method according to claim 5, characterized in that: In step (3), the cladding diameter of the optical fiber is input into the fusion splicer, the cladding diameter of the optical fiber to be fused is set in the fusion splicer, the cleaning discharge power is set to 150bit~200bit, the cleaning discharge time is set to 60~80ms, the fiber pre-melting power is set to 150bit~170bit, the fiber pre-melting time is set to 10~15ms, the main discharge power is set to 210bit~230bit, and the main discharge time is set to 2800~3200ms.

9. The optical fiber fusion splicing method according to claim 5, characterized in that: After step (3), the method further includes: using a coating machine to coat the fusion splicing point of the fused optical fiber.

10. The optical fiber fusion splicing method according to claim 8, characterized in that: The cladding diameter of the optical fiber is 50-70 μm.