Manufacturing method and device of long-distance tapering optical fiber with high SBS threshold value and application of long-distance tapering optical fiber

Abstract

The invention discloses a manufacturing method, equipment and application of a long-distance tapering optical fiber with a high SBS threshold value. The manufacturing method comprises the following steps: S1, preprocessing a single-mode optical fiber; s2, the wire drawing speed of the single-mode optical fiber is controlled to be gradually increased to 21 m / min from 14 m / min; s3, after the wire drawing speed reaches 21m / min, controlling the wire drawing speed of the single-mode optical fiber to be gradually reduced from 21m / min to 14m / min; and S4, alternately carrying out the step S2 and the step S3 to obtain the long-distance high-SBS threshold tapered optical fiber of which the diameter is periodically changed along the axial direction of the optical fiber. According to the technical scheme provided by the invention, the technical problem that the compression of the laser line width is limited due to the fact that more stimulated Rayleigh scattering signals cannot be accumulated because the long-distance tapered optical fiber with the high SBS threshold value is difficult to manufacture by an existing tapered optical fiber manufacturing process is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber manufacturing and application, and in particular to a manufacturing method, equipment and application of a long-distance high SBS threshold single-mode optical fiber. Background Art

[0002] At present, ultra-narrow linewidth fiber lasers use the stimulated Rayleigh scattering (STRS) effect in single-mode optical fibers to compress the linewidth. To accumulate more STRS signals to achieve narrower linewidth compression, it is necessary to use longer single-mode optical fibers. However, as the length of the optical fiber increases, the stimulated Brillouin scattering (SBS) effect in the optical fiber will gradually increase, and most of the incident pump light energy will be absorbed by SBS, causing the STRS signal to be quickly annihilated by the SBS signal, affecting the performance of the single-mode optical fiber in compressing the linewidth, thereby affecting the performance of the ultra-narrow linewidth fiber laser. Therefore, in the manufacture of long-distance single-mode optical fibers, it is necessary to increase the SBS threshold to suppress the stimulated Brillouin scattering effect. At the same time, the existing manufacturing process of tapered optical fiber is to strip the coating layer of the single-mode optical fiber and taper the bare fiber of the single-mode optical fiber. The bare fiber is very fragile and can easily break when tapered over a long distance. Re-coating the coating on the bare fiber will be time-consuming and laborious. Therefore, only shorter lengths of tapered optical fiber can be prepared using the existing manufacturing process.

[0003] In summary, it is necessary to propose a method and equipment for manufacturing long-distance high SBS threshold single-mode optical fiber. The obtained tapered optical fiber can have a higher SBS threshold while meeting the requirements of long-distance use, thereby improving the performance of ultra-narrow linewidth fiber lasers. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned prior art, the present invention proposes a method, equipment and application for manufacturing long-distance high SBS threshold tapered optical fiber, so as to solve the technical problems that long-distance tapered optical fiber cannot be manufactured through the existing tapered optical fiber manufacturing process and how to improve the SBS threshold of long-distance tapered optical fiber.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for manufacturing a long-distance high SBS threshold tapered optical fiber, the manufacturing method comprising the following steps: S1, pre-processing of single-mode optical fiber; S2, controlling the drawing speed of the single-mode optical fiber to gradually increase from 14 m / min to 21 m / min; S3, when the drawing speed reaches 21 m / min, controlling the drawing speed of the single-mode optical fiber to gradually decrease from 21 m / min to 14 m / min; S4, alternately performing step S2 and step S3 until the entire single-mode optical fiber is drawn, thereby obtaining a long-distance high SBS threshold tapered optical fiber whose diameter changes periodically along the axial direction of the optical fiber.

[0006] In some embodiments, step S1 includes the following sub-steps: S11, clamping one end of the optical fiber preform on a feeding device; S12, placing the other end of the optical fiber preform in a drawing furnace to obtain the single-mode optical fiber; S13, drawing and winding the single-mode optical fiber coming out of the drawing furnace onto a drawing wheel; S14, winding the single-mode optical fiber coming out of the spinning wheel onto a take-up reel.

[0007] In some embodiments, step S1 further includes: S15, sequentially arranging a bare fiber diameter gauge, a primary coating and curing assembly, a secondary coating and curing assembly, a fiber diameter gauge and a tension measuring instrument on the drawing of the single-mode optical fiber between the drawing furnace and the drawing wheel.

[0008] In some embodiments, step S1 further includes: S16, establish signal connection with each instrument component through the computer.

[0009] In some embodiments, steps S2 and S3 specifically control the speed of the drawing wheel by the computer to control the drawing speed.

[0010] In some embodiments, the spinning wheel includes a first spinning wheel and a second spinning wheel, and the speeds of the first spinning wheel and the second spinning wheel, and between the spinning wheel and the take-up drum are matched by controlling the computer.

[0011] In some embodiments, the manufacturing method further comprises: S5, controlling the spinning wheel to return to the initial drawing speed through the computer, retaining a section of the head fiber and the tail fiber for easy connection with other structures.

[0012] In a second aspect, the present invention provides a manufacturing device for a long-distance high SBS threshold tapered optical fiber, which is used to implement a manufacturing method for a long-distance high SBS threshold tapered optical fiber provided in the first aspect of the present invention, and the manufacturing device comprises: feeding device; A wire drawing furnace, wherein the feeding end of the wire drawing furnace faces the feeding device; A drawing wheel, wherein a feeding end of the drawing wheel faces a discharging end of the drawing furnace; A wire take-up drum, wherein a feeding end of the wire take-up drum faces a feeding end of the spinning wheel.

[0013] In some embodiments, the manufacturing equipment also includes a bare fiber diameter gauge, a primary coating curing component, a secondary coating curing component, a fiber diameter gauge and a tension measuring instrument, and the bare fiber diameter gauge, the primary coating curing component, the secondary coating curing component, the fiber diameter gauge and the tension measuring instrument are arranged in sequence according to the direction of the fiber drawing process.

[0014] In a third aspect, the present invention provides an application of a long-distance high SBS threshold tapered optical fiber, comprising applying the long-distance high SBS threshold tapered optical fiber produced by the manufacturing process provided by the first aspect of the present invention to the manufacture of an ultra-narrow linewidth fiber laser.

[0015] Compared with the prior art, the long-distance high SBS threshold tapered optical fiber manufactured by the manufacturing method of the present invention has a diameter that changes periodically along the axial direction of the optical fiber, which can suppress the transmission of sound waves and thus increase the SBS threshold. Therefore, the tapered optical fiber can have a higher SBS threshold on the basis of meeting the long-distance requirements, so that the SBS effect in the optical fiber is effectively suppressed, thereby better stimulating stimulated Rayleigh scattering (STRS), using the stimulated Rayleigh scattering effect to compress the line width, and obtaining an ultra-narrow line width optical fiber with better performance, thereby broadening the scope of use of the tapered optical fiber. At the same time, the production process of the present invention only needs to control the drawing speed, so it is simple to operate, can be mass-produced, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of the manufacturing method of the present invention; Figure 2 is a flow chart of step S1 of the manufacturing method of the present invention; Figure 3 is an overall schematic diagram of the manufacturing equipment of the present invention; Figure 4 It is a schematic diagram of the structure of a tapered optical fiber manufactured by the manufacturing method of the present invention.

[0017] The following are the descriptions of the reference numerals: 100, feeding device; 200, wire drawing furnace, 300, wire drawing wheel, 310, first wire drawing wheel, 320, second wire drawing wheel, 400, take-up reel, 500, bare optical fiber diameter gauge, 600, primary coating and curing assembly, 610, primary coating device, 620, primary UV curing oven, 700, secondary coating and curing assembly, 710, secondary coating device, 720, secondary UV curing oven, 800, optical fiber diameter gauge, 900, tension measuring instrument; A represents optical fiber preform, and B represents single-mode optical fiber. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] In view of the technical problem that tapered optical fibers manufactured by the existing tapered optical fiber manufacturing process are prone to produce SBS effect at longer distances, which is not conducive to compressing the optical fiber line width through stimulated Rayleigh scattering effect, the present invention provides a manufacturing method, equipment and application of long-distance high SBS threshold tapered optical fibers.

[0020] It should be noted that the basic principle of the present invention is: The mechanism of stimulated Brillouin generation in optical fiber is that the forward propagating pump wave and the optical fiber medium generate acoustic waves through electrostriction, and the pump wave is scattered by the refractive index grating generated by the acoustic wave to form a backward Stokes wave. Therefore, suppressing the propagation of acoustic waves in the optical fiber can effectively suppress backward Brillouin scattering. There are multiple modes of acoustic wave transmission in a single-mode optical fiber at the same time. If the mode field distribution of the optical fiber is changed, the transmission of acoustic waves in certain modes can be suppressed. Therefore, the transmission of acoustic waves can be suppressed by periodically changing the diameter of the single-mode optical fiber to suppress backward Brillouin scattering. As we all know, in the process of drawing optical fiber using a drawing tower, the diameter of the optical fiber is directly related to the drawing speed. Therefore, by controlling the drawing speed, the diameter of the optical fiber can be changed periodically along the axial direction, thereby suppressing backward Brillouin scattering, increasing the SBS threshold in the optical fiber, and ultimately achieving the purpose of suppressing the stimulated Brillouin effect (SBS) and stimulating the stimulated Rayleigh scattering effect (STRS) in the optical fiber.

[0021] According to the above principle, firstly, Figure 1 As shown, the present invention proposes a method for manufacturing a long-distance high SBS threshold tapered optical fiber, the manufacturing method comprising the following steps: S1, pre-processing the single-mode optical fiber B; S2, controlling the drawing speed of the single-mode optical fiber B to gradually increase from 14 m / min to 21 m / min; S3, when the drawing speed reaches 21 m / min, the drawing speed of the single-mode optical fiber B is controlled to gradually decrease from 21 m / min to 14 m / min; S4, alternately perform step S2 and step S3 until the entire single-mode optical fiber B is drawn, thereby obtaining a long-distance high SBS threshold tapered optical fiber with a diameter that changes periodically along the axial direction of the optical fiber.

[0022] Different from the prior art, the manufacturing method of the present invention can produce a long-distance high SBS threshold tapered optical fiber, which can have a high SBS threshold on the basis of meeting the long-distance requirements, so that the SBS effect in the optical fiber is effectively suppressed, thereby better stimulating stimulated Rayleigh scattering (STRS), so as to compress the line width by using the stimulated Rayleigh scattering effect, obtain an ultra-narrow line width optical fiber with better performance, and broaden the scope of use of the tapered optical fiber. At the same time, the production process of the present invention only needs to control the drawing speed, so it is simple to operate, can be mass-produced, and improves production efficiency.

[0023] The following is a detailed description of a method for manufacturing a long-distance high SBS threshold tapered optical fiber provided by the present invention, which specifically includes: S1, pre-processing the single-mode optical fiber; Figure 2 As shown, the step S2 specifically includes: S11, clamping one end of the optical fiber preform A on the feeding device 100; S12, placing the other end of the optical fiber preform A in the drawing furnace 200 S13, drawing the single-mode optical fiber B coming out of the drawing furnace 200 and winding it on the drawing wheel 300; S14, winding the single-mode optical fiber B coming out of the spinning wheel 300 onto the take-up reel 400; S15, sequentially arranging a bare fiber diameter gauge 500, a primary coating and curing assembly 600, a secondary coating and curing assembly 700, a fiber diameter gauge 800 and a tension measuring instrument 900 on the drawing of the single-mode optical fiber B between the drawing furnace 200 and the drawing wheel 300; S16, connecting signals with various instrument components through the computer; It should be noted that in step S1, the optical fiber preform A is first used to make a single-mode optical fiber B, and then the single-mode optical fiber B is used to prepare a long-distance high SBS threshold tapered optical fiber.

[0024] S2, controlling the drawing speed of the single-mode optical fiber B to gradually increase from 14 m / min to 21 m / min, so that the diameter of the single-mode optical fiber B gradually decreases from 125 μm to 100 μm; S3, when the drawing speed reaches 21 m / min, the drawing speed of the single-mode optical fiber B is controlled to gradually decrease from 21 m / min to 14 m / min, and the diameter of the single-mode optical fiber B gradually increases from 100 μm to 125 μm; S4, alternately perform step S2 and step S3 until the entire single-mode optical fiber B is drawn, and the diameter of the single-mode optical fiber B changes periodically along the axial direction of the optical fiber, such as Figure 4As shown, the axial length a of a single cone region is 25-30 m, the cone regions are arranged at equal distances, and the axial center interval b between two adjacent cone regions is 25-30 m, that is, a long-distance high SBS threshold tapered optical fiber with a periodic diameter change along the axial direction of the optical fiber is obtained; S5, controlling the spinning wheel to return to the initial drawing speed through the computer, retaining a section of the head fiber and the tail fiber for easy connection with other structures.

[0025] In one embodiment, the steps S2 and S3 are specifically to control the speed of the drawing wheel 300 by the computer to control the drawing speed.

[0026] In one embodiment, the spinning wheel 300 includes a first spinning wheel 310 and a second spinning wheel 320, and the speeds of the first spinning wheel 310 and the second spinning wheel 320, and between the spinning wheel and the take-up drum are matched by controlling the computer.

[0027] In one embodiment, the primary coating and curing assembly 600 includes a primary coating device 610 and a primary UV curing oven; the secondary coating and curing assembly 700 includes a secondary coating device 710 and a secondary UV curing oven 720; the spinning wheel 300 includes a first spinning wheel 310 and a second spinning wheel 320, and the diameter of the first spinning wheel 310 is greater than the diameter of the second spinning wheel 320.

[0028] It should be noted that the faster the drawing speed, the smaller the diameter of the optical fiber, and the slower the drawing speed, the larger the diameter of the optical fiber.

[0029] Second, as Figure 3 As shown, the present invention provides a manufacturing device for long-distance high SBS threshold tapered optical fiber, which is used to implement the manufacturing method provided by the first aspect of the present invention. The manufacturing device includes a feeding device 100, a drawing furnace 200, a drawing wheel 300, a take-up reel 400, a bare optical fiber diameter gauge 500, a primary coating and curing assembly 600, a secondary coating and curing assembly 700, an optical fiber diameter gauge 800 and a tension measuring instrument 900. The feeding end of the drawing furnace 200 faces the feeding device 100, the loading end of the drawing wheel 300 faces the discharging end of the drawing furnace 200, and the loading end of the take-up reel 400 faces the unloading end of the drawing wheel 300.

[0030] When using the above-mentioned manufacturing equipment to manufacture tapered optical fibers, first, one end of the optical fiber preform is fixed on the feeding device 100, and the other end is set in the drawing furnace 200. Then, the optical fiber filament coming out of the drawing furnace 200 is wound on the straight take-up drum 400 under the action of the drawing wheel 300. In this process, the diameter of the bare optical fiber can be measured by the bare optical fiber diameter gauge 500, the optical fiber can be coated and cured multiple times by the primary coating and curing assembly 600 and the secondary coating and curing assembly 700, the diameter of the optical fiber can be measured by the optical fiber diameter gauge 800, the tension of the optical fiber is controlled by the tension measuring instrument 900, and the optical fiber is stored on the take-up drum 400 by the drawing wheel 300; at the same time, through the signal connection between the computer and various electrical components, the speed of the drawing wheel 300 is adjusted under the measurement and monitoring of the bare optical fiber diameter gauge 500 and the optical fiber diameter gauge 800, so that the drawing speed of the optical fiber changes according to a certain periodic law, thereby obtaining a tapered optical fiber whose optical fiber diameter changes periodically along the axial direction. The obtained tapered optical fiber is as follows. Figure 4 shown.

[0031] In one embodiment, the spinning wheel 300 includes a first spinning wheel 310 and a second spinning wheel 320; the first-level coating and curing assembly 600 includes a first-level coater 610 and a first-level UV curing oven 620; the second-level coating and curing assembly 700 includes a second-level coater 710 and a second-level UV curing oven 720.

[0032] In one of the embodiments, the feeding device 100, the drawing furnace 200, the bare fiber diameter gauge 500, the primary coater 610, the primary UV curing furnace 620, the secondary coater 710, the secondary UV curing furnace 720, the fiber diameter gauge 800, the tension measuring instrument 900, the first drawing wheel 310, the second drawing wheel 320 and the take-up reel 400 are arranged in sequence according to the direction of the optical fiber drawing process.

[0033] In a third aspect, the present invention provides an application of a long-distance high SBS threshold tapered optical fiber, comprising applying the long-distance high SBS threshold tapered optical fiber produced by the manufacturing process described in the first aspect of the present invention to the manufacture of an ultra-narrow linewidth fiber laser.

[0034] In the existing technology, ultra-narrow linewidth fiber lasers with extremely low frequency noise and excellent short-time frequency stability have important applications in research fields such as high-resolution laser spectroscopy, optical atomic clocks, gravitational wave detection, low-noise microwave signal generation, and measurement of physical laws. At present, ultra-narrow linewidth fiber lasers use the stimulated Rayleigh scattering effect in distributed feedback fiber (single-mode fiber) to compress the linewidth, but the cross-sectional area of ​​the single-mode fiber core is about 80μm 2, it is easy to generate a high enough power density to form stimulated Brillouin scattering (SBS). Since the gain coefficient of SBS is two orders of magnitude higher than that of stimulated Rayleigh, as the optical power increases, the Rayleigh scattering signal is quickly annihilated by the Brillouin signal, which makes it difficult to observe the stimulated Rayleigh scattering effect in ordinary single-mode optical fibers over long distances.

[0035] According to the generation mechanism and characteristics of SBS, the most important suppression method is to increase the threshold of SBS in the optical fiber. Therefore, the long-distance high SBS threshold single-mode optical fiber provided by the present invention just meets the conditions for manufacturing ultra-narrow linewidth fiber lasers, that is, the ultra-narrow linewidth fiber lasers manufactured by using the single-mode optical fiber manufactured by the manufacturing process and manufacturing equipment of the present invention as the optical fiber raw material can obtain more backscattered Rayleigh scattering signals to achieve ultra-narrow linewidth output.

[0036] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for manufacturing a long-distance high SBS threshold tapered optical fiber, characterized in that: The manufacturing method comprises the following steps: S1, pre-processing of single-mode optical fiber; S2, controlling the drawing speed of the single-mode optical fiber to gradually increase from 14 m / min to 21 m / min; S3, when the drawing speed reaches 21 m / min, controlling the drawing speed of the single-mode optical fiber to gradually decrease from 21 m / min to 14 m / min; S4, alternately performing step S2 and step S3 until the entire single-mode optical fiber is drawn, thereby obtaining a long-distance high SBS threshold tapered optical fiber whose diameter changes periodically along the axial direction of the optical fiber.

2. The method for manufacturing a long-distance high SBS threshold tapered optical fiber according to claim 1, characterized in that: The step S1 comprises the following sub-steps: S11, clamping one end of the optical fiber preform on a feeding device; S12, placing the other end of the optical fiber preform in a drawing furnace to obtain the single-mode optical fiber; S13, drawing and winding the single-mode optical fiber coming out of the drawing furnace onto a drawing wheel; S14, winding the single-mode optical fiber coming out of the spinning wheel onto a take-up reel.

3. The method for manufacturing a long-distance high SBS threshold tapered optical fiber according to claim 2, characterized in that: The step S1 further comprises: S15, sequentially arranging a bare fiber diameter gauge, a primary coating and curing assembly, a secondary coating and curing assembly, a fiber diameter gauge and a tension measuring instrument on the drawing of the single-mode optical fiber between the drawing furnace and the drawing wheel.

4. The method for manufacturing a long-distance high SBS threshold tapered optical fiber according to claim 3, characterized in that: The step S1 further comprises: S16, establish signal connection with each instrument component through the computer.

5. The method for manufacturing a long-distance high SBS threshold tapered optical fiber according to claim 4, characterized in that: The steps S2 and S3 specifically control the speed of the drawing wheel by the computer to control the drawing speed.

6. The method for manufacturing a long-distance high SBS threshold single-mode optical fiber according to claim 5, characterized in that: The spinning wheel comprises a first spinning wheel and a second spinning wheel, and the speeds of the first spinning wheel and the second spinning wheel, and the speeds of the spinning wheel and the take-up drum are matched by controlling the computer.

7. The method for manufacturing a long-distance high SBS threshold tapered optical fiber according to claim 6, characterized in that: Also includes: S5, controlling the spinning wheel to return to the initial drawing speed through the computer, retaining a section of the head fiber and the tail fiber for easy connection with other structures.

8. A manufacturing device for a long-distance high SBS threshold tapered optical fiber, used to implement the manufacturing method for a long-distance high SBS threshold tapered optical fiber according to any one of claims 1 to 7, characterized in that: The manufacturing equipment comprises: feeding device; A wire drawing furnace, wherein the feeding end of the wire drawing furnace faces the feeding device; A drawing wheel, wherein a feeding end of the drawing wheel faces a discharging end of the drawing furnace; A wire take-up drum, wherein a feeding end of the wire take-up drum faces a feeding end of the spinning wheel.

9. The manufacturing equipment for long-distance high SBS threshold tapered optical fiber according to claim 8, characterized in that: The manufacturing equipment also includes a bare fiber diameter gauge, a primary coating curing component, a secondary coating curing component, a fiber diameter gauge and a tension measuring instrument. The bare fiber diameter gauge, the primary coating curing component, the secondary coating curing component, the fiber diameter gauge and the tension measuring instrument are arranged in sequence according to the direction of the fiber drawing process.

10. An application of a long-distance high SBS threshold tapered optical fiber, characterized in that: The method comprises applying the long-distance high SBS threshold tapered optical fiber manufactured by the manufacturing process described in any one of claims 1 to 7 to the manufacture of an ultra-narrow linewidth optical fiber laser.

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