Two-dimensional bound multicore fiber grating array and preparation device

Abstract

A two-dimensional bound multi-core fiber grating array and a preparation device, characterized in that the grating array fiber prepared by the on-line integration of a drawing tower is combined into a double-core fiber and then combined with a common single-mode optical fiber to form a flat elliptical shape, which is easy to determine the layout direction and angle, avoids the influence of fiber rolling and rotation on the sensing performance, and has high sensing accuracy for the shape in actual application scenarios. The preparation device of the two-dimensional bound multi-core fiber grating array comprises a fiber feeding unit, a beam combining unit, a coating cup, an ultraviolet curing lamp, a binding unit and a fiber collecting device, and each unit device is arranged in sequence in the vertical direction. The preparation device is simple, has low preparation cost and high efficiency, and can realize industrial production in actual application.

Description

Technical Field

[0001] This utility model relates to the field of fiber optic grating array manufacturing technology, and in particular to a two-dimensional bonded multi-core fiber optic grating array and its fabrication apparatus. Background Technology

[0002] With the development of various fields such as intelligent monitoring, structural safety monitoring, and medical and health monitoring, fiber optic gratings and special optical fibers play a vital role. As a novel optical sensing element, optical fiber possesses advantages such as small size, resistance to harsh environments, resistance to electromagnetic interference, corrosion resistance, high sensitivity and accuracy, and good implantability. Fiber optic shape sensing technology can be used for structural monitoring, geographical environment monitoring, and cable and pipeline monitoring in aerospace, industrial machinery, and large-scale construction. In the medical field, it can be used for interventional treatment tracking, minimally invasive medical procedures, and intelligent health monitoring. In industry, it enables the manufacturing of industrial robots, demonstrating immense application potential due to its unique advantages.

[0003] Multicore fiber is a special type of optical fiber that contains multiple cores within a single cladding. It is commonly used in shape sensing. Currently, centimeter-scale multicore fibers are applied in various fields such as medical endoscopes, minimally invasive surgery, wearable devices, and industrial robots. Multicore fiber grating arrays, fabricated by inscribing fiber gratings into multicore fibers, can more accurately achieve multi-parameter sensing and monitoring of stress, strain, temperature, and shape. However, both multicore fibers and multicore fiber grating arrays have a cylindrical physical structure. In practical applications, the rolling and twisting of multicore fibers cannot be avoided or monitored during deployment. The presence of rolling and twisting leads to wavelength data shifts in the multicore fiber grating array, complicates calibration, and reduces shape reconstruction accuracy.

[0004] Currently, the main fabrication techniques for multi-core fiber grating arrays include grating etching on rotating shafts, single-point grating etching after coating removal, and discontinuous grating etching. These methods are difficult to guarantee the consistency of fiber gratings, and the fabrication time is long and the cost is high, making mass production impossible.

[0005] To address the shortcomings of the aforementioned methods for fabricating multi-core fiber gratings (FBGs), namely: firstly, current fabrication techniques are complex, resulting in poor grating consistency, long processing times, and high costs; secondly, the cylindrical shape of multi-core fibers makes it impossible to avoid or monitor their rolling and twisting during actual deployment, leading to wavelength data offset in the FBG array, complex calibration, and decreased shape reconstruction accuracy. This invention proposes a two-dimensionally bonded FBG array and its fabrication device. Two FBG array fibers are bonded in parallel to form a single dual-core fiber. Two more fibers are then deployed on either side of the dual-core fiber, ultimately forming a two-dimensionally bonded FBG array with a flattened elliptical shape. The FBG array is fabricated online using an integrated drawing tower, allowing for customization and high consistency of grating wavelength, reflectivity, and physical spacing. The fibers exhibit high physical strength, and the fabrication process is simple, enabling industrial production.

[0006] This invention proposes a two-dimensionally bonded multi-core fiber grating array and its fabrication apparatus. The physical structure of the two-dimensionally bonded multi-core fiber grating array consists of a dual-core fiber grating array and two ordinary single-mode fibers bonded together to form a four-core multi-core fiber grating array. The two cores of the dual-core fiber grating array are arranged longitudinally, and the two ordinary single-mode fibers are arranged laterally on both sides of the dual-core fiber grating array. The dual-core fiber grating array is formed by bundling two fiber grating array fibers fabricated online using an integrated drawing tower. The fiber grating wavelength, reflectivity, and physical spacing can be customized. The two ordinary single-mode fibers provide support. The overall physical structure presents a flattened elliptical shape, allowing for precise control of the placement direction and preventing fiber twisting or rolling. This provides high shape sensing accuracy in practical applications. The fabrication apparatus for the two-dimensionally bonded multi-core fiber grating array includes a fiber feeding unit, a bundling unit, a coating cup, an ultraviolet curing lamp, a bonding unit, and a fiber take-up device, all arranged sequentially in the vertical direction. The fabrication apparatus is simple, low-cost, and highly efficient, enabling industrial-scale production in practical applications. Utility Model Content

[0007] This invention provides a two-dimensionally bonded multi-core fiber Bragg grating array and its fabrication apparatus, solving the problems of high fabrication cost and unavoidable rolling and twisting during deployment of conventional multi-core fiber Bragg gratings. The fabrication apparatus is simple, has low production cost, and can be industrialized. In practical applications, this two-dimensionally bonded multi-core fiber Bragg grating array can avoid the twisting and rolling of the optical fiber itself, exhibiting high shape sensing accuracy, great potential, and significant advantages.

[0008] The technical solution adopted by this utility model to solve the technical problem is as follows:

[0009] A fabrication device for a two-dimensional bonded multi-core fiber grating array includes a fiber feeding unit (1), two fiber grating array fibers (2), two ordinary single-mode fibers (3), a bundle combining unit (4), a No. 1 coating cup (5), a No. 1 ultraviolet curing lamp (6), a binding unit (7), a No. 2 coating cup (8), a No. 2 ultraviolet curing lamp (9), and a fiber take-up device (10). The above-mentioned devices and apparatus are arranged in sequence in the vertical direction.

[0010] The fiber feeding unit (1) is a rectangular device, including four rollers that can rotate in any direction, used to place the optical fiber to be bound. During actual binding, its rotation direction is set so that the optical fiber to be bound is fed downward in the required direction.

[0011] The two fiber optic grating arrays (2) are fabricated online as an integrated fiber drawing tower. The fiber grating array is written during the drawing process, which can customize the fiber grating wavelength and reflectivity, resulting in high consistency and high tensile strength of the fiber.

[0012] The two ordinary single-mode optical fibers (3) are drawn from preforms without the need for grating, and the drawing speed is fast and the preparation cost is low.

[0013] The bundle-combining unit (4) is an elliptical device formed by two tangent circular holes. Each hole can be connected by a grating array fiber for bundling the two grating array fibers. The two grating array fibers are arranged vertically after bundling to form an elliptical dual-core fiber grating array.

[0014] The No. 1 coating cup (5) has a bowl-shaped structure and is used in conjunction with the No. 1 ultraviolet curing lamp (6) for coating dual-core optical fibers to protect the optical fiber structure.

[0015] The binding unit (7) is a ring-shaped structure, including a central hole and two edge holes. The central hole is the same size as the bundling unit and is used to confine the dual-core fiber grating array so that it can pass through it. There is a circular edge hole on each side of the central hole, which is used to confine two ordinary single-mode fibers so that they can pass through it. The dual-core fiber grating array and the two ordinary single-mode fibers are bundled together by the binding unit to form a two-dimensionally bound multi-core fiber grating array.

[0016] The No. 2 coating cup (8) has a bowl-shaped structure and is used in conjunction with the No. 2 UV curing lamp (9) for coating the two-dimensional bonded multi-core fiber grating array to protect the fiber structure.

[0017] The fiber take-up device (10) consists of two rollers of different sizes. The two-dimensional bonded multi-core fiber grating array prepared by the above device is taken into a reel after passing through the two rollers of different sizes.

[0018] The two-dimensionally bonded multi-core fiber grating array has a physical structure consisting of a dual-core fiber grating array and two ordinary single-mode fibers bonded together to form a four-core multi-core fiber grating array. The dual-core fiber grating array is formed by bundling two fiber grating arrays together. The fiber grating array is fabricated online as an integrated fiber drawing tower, and the fiber grating array with specific fiber grating reflection wavelength, reflectivity, and physical spacing is written during the fiber drawing process. The two cores of the dual-core fiber grating array are arranged longitudinally, and the two ordinary single-mode fibers are arranged laterally on both sides of the dual-core fiber grating array to provide support. The overall physical structure of the two-dimensionally bonded multi-core fiber grating array has a flat elliptical shape, which can accurately control the laying direction and prevent the fiber from twisting or rolling.

[0019] The beneficial effects of this utility model are as follows:

[0020] (1) The two-dimensional bonded multi-core fiber grating array proposed in this utility model has a flat elliptical shape in appearance. When laying multi-core optical fibers in practical applications, it can avoid the rolling and twisting of multi-core optical fibers and will not cause automatic wavelength shift or chirping of gratings. It has high shape sensing accuracy and good shape reconstruction effect.

[0021] (2) This invention combines a dual-core fiber grating array with two ordinary single-mode optical fibers to form a two-dimensional bonded multi-core fiber grating array. The fabrication device is simple and the process is easy to understand. Moreover, it allows for the selection of specific fiber core spacing and grating spacing within the fiber cores according to different application requirements, making it flexible in application.

[0022] (3) The present invention proposes a two-dimensional bonded multi-core fiber grating array, which selects two grating array fibers prepared by a drawing tower and bundles them together to form a dual-core fiber grating array. The grating array fiber is prepared by point-by-point grating during the fiber preparation process in the drawing tower, which can achieve flexible configuration of the number and spacing of gratings, and the grating wavelength and reflectivity are highly consistent. The method of preparing the multi-core fiber grating array replaces the method of grating on existing multi-core fibers, which eliminates the need for point-by-point fiber core positioning and grating, and eliminates the need for complex fiber fan-in and fan-out devices, greatly reducing the preparation cost of the multi-core fiber grating array. It ensures grating consistency and writing efficiency while meeting the needs of low-cost industrial production and satisfying the conditions for industrial preparation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the fabrication device for a two-dimensional bonded multi-core fiber grating array according to the present invention.

[0024] Figure 2 This is a schematic diagram of a two-dimensional bonded multi-core fiber optic grating array according to the present invention. Detailed Implementation

[0025] The invention will now be further described with reference to the accompanying drawings.

[0026] See appendix Figure 1 This utility model discloses a two-dimensional bonded multi-core fiber grating array fabrication device, including a fiber feeding unit (1), two grating array fibers (2), two ordinary single-mode fibers (3), a bundle combining unit (4), a No. 1 coating cup (5), a No. 1 ultraviolet curing lamp (6), a binding unit (7), a No. 2 coating cup (8), a No. 2 ultraviolet curing lamp (9), and a fiber taking-up device (10). The fiber feeding unit (1) uniformly feeds out the two grating array fibers (2) and the two ordinary single-mode fibers (3) at a uniform speed. The bundle combining unit (4) completes the fabrication of the dual-core fiber grating array. The binding unit combines the dual-core fiber grating array and the two ordinary single-mode fibers to form a two-dimensional bonded multi-core fiber grating array. The fiber feeding unit (1), the bundle combining unit (4), the No. 1 coating cup (5), the No. 1 ultraviolet curing lamp (6), the binding unit (7), the No. 2 coating cup (8), the No. 2 ultraviolet curing lamp (9), and the fiber taking-up unit (10) are arranged in sequence in the vertical direction.

[0027] See appendix Figure 2 This is a schematic diagram of a two-dimensional bonded multi-core fiber grating array related to this utility model. It consists of four optical fibers, of which the two middle fibers are grating array fibers, which are combined to form a dual-core fiber grating array. The two side fibers are ordinary single-mode fibers, which are combined with the dual-core fiber grating array to form a two-dimensional bonded multi-core fiber grating array (11). The overall physical structure is a flat elliptical shape that can avoid fiber twisting and rolling.

[0028] The working method of this utility model is as follows: The fiber feeding unit (1) feeds out two grating array optical fibers and two ordinary single-mode optical fibers. After the two grating array optical fibers are fed out at a uniform speed, they reach the bundling unit. The bundling unit is an elliptical device formed by two tangent circular holes. The two grating array optical fibers pass through the two circular holes respectively. After bundling, they enter the No. 1 coating cup. After coating, they are cured by the No. 1 ultraviolet curing lamp to form a dual-core fiber grating array. Two ordinary single-mode optical fibers are fed uniformly to the binding unit at a constant speed through the fiber feeding unit. The binding unit is a circular structure, including a central hole and two edge holes. The central hole is the same size as the bundling unit and is used to confine the dual-core fiber grating array so that it can pass through it. There is a circular edge hole on each side of the central hole, which is used to confine the two ordinary single-mode optical fibers so that they can pass through it. The dual-core fiber grating array is inserted into the No. 2 coating cup through the central hole, and the two ordinary single-mode optical fibers are inserted into the No. 2 coating cup through the edge holes. They are bundled into a two-dimensional bound multi-core fiber grating array, cured by the No. 2 ultraviolet curing lamp, and finally collected into a reel by the fiber taking-up unit.

[0029] The key technologies enabling the fabrication of two-dimensional bonded multi-core fiber Bragg grating arrays in this device include:

[0030] 1. When placing the grating array fiber on the four rollers of the fiber feeding unit, the grating array fiber is placed on the two middle rollers, and the ordinary single-mode fiber is placed on the rollers on both sides. When the fiber feeding unit starts feeding, the two middle rollers are turned on first to feed the fiber at the same speed. After the fiber is bundled into a dual-core fiber by the bundling unit, the rollers on both sides are turned on to release the fiber. The fiber release speed is controlled at 5-10 meters / minute.

[0031] 2. The two circular tangent holes in the bundling unit must have the same diameter as the coating diameter of the selected grating array fiber. This restricts and fixes the position of the two grating array fibers, preventing them from tangling during bundling. The central hole of the binding unit must have the same diameter as the diameter of the bundled dual-core fiber, and the two edge holes must have the same diameter as the coating diameter of the selected ordinary single-mode fiber. This also restricts and fixes the fiber position.

[0032] 3. When customizing the grating wavelength, reflectivity, and physical spacing of the grating array fiber, attention should be paid to calibrating the grating position to ensure that each group of gratings is in the same horizontal position when the bundle is combined.

[0033] In one specific embodiment of this invention, the fiber feeding unit delivers four conventional single-mode fibers (G625) at a speed of 20 m / min, with a core diameter of 8.2 μm and a cladding diameter of 125 μm. Two of these fibers are etched with gratings and are grating array fibers. The center wavelengths of the fiber gratings are 1530 nm and 1548 nm, the bandwidth is 0.15 nm, the reflectivity is 0.1%, and the physical spacing between the fiber gratings is 2 m. The dual-core fiber grating array formed by bundling the two grating array fibers is elliptical, with tangent cores, a major axis of 325 μm, and a minor axis of 200 μm. After the dual-core fiber grating array and the two conventional single-mode fibers are bound together by a binding unit, a two-dimensional bound multi-core fiber grating array is formed. The two conventional single-mode fibers are symmetrically arranged on both sides of the dual-core fiber grating array, with their cores 140 μm away from the center point of the dual-core fiber grating array. A schematic diagram of the two-dimensional bound multi-core fiber grating array is shown below. Figure 2 The optical fiber has a flattened elliptical shape with a major axis of 600 μm, a minor axis of 325 μm, and a total length of 1 km. The two-dimensional bonded multi-core fiber grating array fabrication method proposed in this invention can effectively achieve long-distance industrial production at the meter and even kilometer levels, with low cost and a simple system. Its flattened elliptical physical appearance provides better shape sensing accuracy and reconstruction effect in practical applications.

[0034] The above description illustrates the basic principles and main features of this utility model. The fiber optic dimensions and parameters mentioned in this utility model are examples of this utility model. This utility model also has various other examples not mentioned. Without departing from the spirit and scope of this utility model, all variations and improvements of this utility model fall within the scope of this utility model as claimed.

Claims

1. A fabrication apparatus for a two-dimensional bonded multi-core fiber Bragg grating array, characterized in that, It includes a fiber feeding unit, a grating array fiber, a common single-mode fiber, a bundle combining unit, a No. 1 coating cup, a No. 1 UV curing lamp, a bonding unit, a No. 2 coating cup, a No. 2 UV curing lamp, and a fiber take-up device. The aforementioned units and devices are arranged in sequence in the vertical direction; The fiber feeding unit is a rectangular device that includes four rollers that can rotate in any direction to hold the optical fiber to be bound. During actual binding, the rotation direction is set so that the optical fiber to be bound is fed downward in the required direction. The fiber optic array is fabricated online as an integrated fiber drawing tower, and the fiber optic array with specific fiber optic grating reflection wavelength, reflectivity and physical spacing is written during the fiber drawing process. The two ordinary single-mode optical fibers are directly drawn from the preform; The bundle-combining unit is an elliptical device formed by two tangent circular holes. Each hole can pass through a grating array fiber for bundling the two grating array fibers together to form a dual-core fiber. The No. 1 coating cup has a bowl-shaped structure and is used in conjunction with the No. 1 UV curing lamp for coating dual-core optical fibers to protect the fiber structure. The binding unit is a circular structure, including a central hole and two edge holes. The central hole is the same size as the bundling unit and is used to confine the dual-core fiber grating array so that it can pass through it. There is a circular edge hole on each side of the central hole, which is used to confine two ordinary single-mode fibers so that they can pass through it. The dual-core fiber grating array and the two ordinary single-mode fibers are bundled together by the binding unit to form a two-dimensionally bound multi-core fiber grating array. The No. 2 coating cup has a bowl-shaped structure and is used in conjunction with the No. 2 UV curing lamp for coating two-dimensionally bonded multi-core fiber grating arrays to protect the fiber structure. The fiber take-up device consists of two rollers of different sizes. The two-dimensional bonded multi-core fiber grating array prepared by the above device is taken up into a reel after passing through the two rollers.

2. A two-dimensionally bound multicore fiber grating array, characterized by, A four-core multi-core fiber grating array is formed by binding a dual-core fiber grating array with two ordinary single-mode fibers. The dual-core fiber grating array is formed by bundling two fiber grating arrays together. The fiber grating array is fabricated online as an integrated drawing tower, and the fiber grating array with specific fiber grating reflection wavelength, reflectivity, and physical spacing is written during the drawing process. The two cores of the dual-core fiber grating array are arranged longitudinally, and the two ordinary single-mode fibers are arranged laterally on both sides of the dual-core fiber grating array to provide support. The overall physical structure of the two-dimensionally bound multi-core fiber grating array is a flat elliptical shape to avoid fiber twisting and rolling.

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