Chiral multi-core fiber grating array and preparation device

Abstract

The utility model relates to the technical field of fiber bragg grating array manufacturing, in particular to a chiral multi-core fiber bragg grating array and a preparation device. The device is characterized by comprising a rotary fiber feeding module, a grating array fiber, a beam combining module, a coating cup and a fiber collecting device. The rotary fiber feeding module bears 1 + N grating array optical fibers, and the grating array optical fibers can select various indexes such as different grating wavelengths, intervals and reflectivity. In the preparation process of the chiral multi-core fiber bragg grating array, the rotary fiber feeding module and the beam combining module rotate at the same speed in the same direction to increase torsion for 1 + N grating array fibers so as to form the chiral multi-core fiber bragg grating array. According to the chiral multi-core fiber grating array and the preparation device, various indexes such as different grating wavelengths, intervals and reflectivity can be selected, screw pitches can be freely selected, and low-cost long-distance large-scale industrial preparation and torsion monitoring and shape sensing in complex strain conditions can be realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of fiber grating array manufacturing technology, especially to a chiral multicore fiber grating array and preparation device. BACKGROUND

[0002] With the high-speed development of various fields in China, as a sensing sensitive element and transmission signal medium, optical fiber plays an important role in various monitoring systems. As a new type of optical sensing element, fiber grating shape sensing can realize the monitoring of environmental temperature, stress and strain, humidity, pressure and chemical composition changes, etc. It has the advantages of small size, resistance to harsh environment, anti-electromagnetic interference, corrosion resistance, high sensitivity and accuracy, good implantability, etc. Among them, the fiber grating shape sensing technology based on stress and strain monitoring plays an important role in civil engineering, machinery, aerospace engineering and medicine. Fiber grating shape sensing technology can be used for structure monitoring, geographic environment and cable pipeline monitoring in aerospace, industrial machinery and large buildings, and can be used for interventional therapy tracking, medical minimally invasive interventional surgery, intelligent health monitoring, etc. in medical field, and can realize industrial robot production in industry, showing great application potential with its unique advantages.

[0003] Multicore fiber is a special fiber that contains multiple cores, and contains multiple cores in the same cladding. The multicore fiber grating made by writing fiber grating in multicore fiber has all the advantages of multicore fiber and fiber grating. The multicore fiber grating structure has small size, resistance to harsh environment, anti-electromagnetic interference, corrosion resistance, high sensitivity and accuracy, good implantability, and high signal-to-noise ratio. The existing centimeter-level multicore fiber grating array has been applied to medical endoscopes, minimally invasive surgery, wearable devices, industrial robots and other fields. However, due to the small spacing of such multicore fiber gratings and the short length of the fiber grating array, shape monitoring cannot be continuous in space, so the shape of the blank grating area between the measurement points cannot be obtained. Its precision is still inferior to that of the fiber shape sensor with large core spacing. Such multicore fiber grating cannot detect large-scale large-radius deformation, and has limitations in large-scale applications such as pipeline settlement, bridge collapse and engineering monitoring that require long-distance monitoring of deformation.

[0004] In the preparation process of the multicore fiber grating array, the existing preparation technology uses the methods of stripping, single-point grating, non-continuous grating or uses the rotating shaft grating, and the focusing position needs to be manually controlled in the process, which is easy to cause the intensity of incident light irradiation on different positions of the fiber core to be different, the process is difficult to control and has poor repeatability, resulting in inconsistent center wavelength of the written grating, different reflectivity, low quality of the multicore fiber grating array, increased system complexity and application cost, and difficulty in achieving the requirements of low-cost and efficient preparation of multicore fiber gratings, and the multicore fiber grating array cannot be mass-produced, cannot be prepared in a long distance and large scale, and does not have the conditions for industrial production. At the same time, due to the limitation of the preparation method, the arrangement mode between different fiber cores of the multicore fiber grating array is parallel arrangement, and the multicore fiber grating array arranged in this mode has single deformation monitoring, small application range and many errors in actual application, although it can realize the measurement of bending direction and size and complete the curvature measurement on the orthogonal axis, but it is not sensitive to the response of the twist in the deformation monitoring process, the area deformed by the torsion force cannot be quickly positioned, the torsion deformation cannot be restored, and the shape sensing accuracy of the multicore fiber grating is affected.

[0005] In view of the above-mentioned deficiencies in the preparation method of the multicore fiber grating, firstly, the existing preparation technology has high cost in various aspects, not only various devices are needed to complete the fiber core coupling and grating area calibration, but also the optical fiber coating layer needs to be stripped, which increases the preparation steps and time and labor consumption, a large number of devices are needed, the preparation system is complex, it is difficult to form industrialized preparation and the grating consistency is difficult to control. Secondly, the multicore fiber grating has small spacing and short array length, and the shape monitoring has a blind area of measuring points, the precision is not as good as that of the multicore fiber grating shape sensor with large fiber core spacing, and it cannot detect long-distance, large-range and large-radius deformation. Thirdly, the previously parallel arranged multicore fiber grating array has the problems of single deformation condition that can be monitored in actual application, small application range, many errors and inability to monitor torsional strain. Fourthly, the prepared multicore fiber grating has poor flexibility and is difficult to flexibly configure the number of gratings and fiber core spacing according to actual conditions. The chiral multicore fiber grating array and preparation device disclosed by the utility model are based on fixed-point grating inscription in the process of preparing optical fiber in a drawing tower, utilize the advantage that the drawing tower can prepare optical fiber grating for a long distance, and adopt the preparation method disclosed by the utility model patent, so that the preparation of a long-distance large-scale multicore fiber grating array with a length of meters to kilometers can be realized, the process is simple and smooth, the industrialized production needs with low cost can be realized, the prepared multicore fiber grating array can be used for long-distance monitoring of stress and strain in a macro area, and the application gap of long-distance monitoring of stress and strain in a whole large area in engineering application is filled. The grating array fiber prepared by the device is subjected to a beam combining operation with increased torque, so that the spiral sensitivity of the multicore fiber grating is realized in the process of fiber beam combining, the influence of torque on the deformation process can be monitored in actual application, the torsional error is eliminated, the shape sensing accuracy is improved, the spiral sensitivity degree is controlled, the torque is controlled, the multicore fiber grating array is prepared, the multicore fiber grating array can be flexibly configured according to actual conditions, so that more flexible sensing distance and more various shape change span shape monitoring can be realized.

[0006] The utility model provides a kind of hand type multicore fiber grating array and preparation device, the preparation device is based on long distance fiber preparation of wire drawing tower, in the process of wire drawing, the fiber grating writing of the reflectivity consistency, grating pitch on-demand customization is completed, determine fiber core distance, the long distance grating array fiber passes through rotating fiber feeding module and beam combining module, and under the rotation of rotating fiber feeding module and beam combining module, it is subjected to torsion and forms a kind of hand type multicore fiber grating array, the spiral torque of the hand type multicore fiber grating array can be controlled by the rotation speed of rotating fiber feeding module and beam combining module.A kind of hand type multicore fiber grating array prepared according to the device has the purposes of low preparation cost, meeting industrial production conditions, can realize large-scale long-distance preparation multicore fiber grating array, the fiber grating consistency on each fiber core is high, the center wavelength is consistent, the reflectivity is same, the quality of multicore fiber grating array is high, and when monitoring complex strain condition, the strain monitoring of torsion can be realized. Utility model content

[0007] The utility model provides a kind of hand type multicore fiber grating array and preparation device, solve general multicore fiber grating preparation cost is high, need long time, cannot realize industrial production and long-distance large-scale strain monitoring, cannot distinguish whether structural deformation is caused by torsion problem.Preparation process is simple, preparation step is simple, preparation cost is low, can realize industrial production, can fill in the blank of engineering monitoring in practical application.The hand type multicore fiber grating array and preparation device provided by the utility model in structural monitoring application not only can enrich the stress strain variety of monitoring, and can realize large-scale long-distance monitoring and quickly locate complex torsion strain condition, has remarkable advantage on large-scale engineering structural health monitoring.

[0008] The utility model aims at realizing as follows:

[0009] A kind of hand type multicore fiber grating array and preparation device, need to select a group of rotating fiber feeding module, 1+N root grating array fiber, beam combining module, coating cup, fiber collection device;

[0010] Rotating fiber feeding module aims at completing the fiber feeding work of multiple fiber gratings, and simultaneously has the ability of automatic rotation, the grating array fiber is prepared by wire drawing tower, grating writing is completed in preparation process, grating pitch is regulated and controlled in the process of wire drawing tower preparation grating array fiber, and fiber outer diameter is determined, fiber outer diameter is the fiber core distance of multicore fiber;The beam combining module rotates with rotating fiber feeding module, and drives grating array fiber to combine in hand type mode;The coating cup has a certain length, to ensure that the hand type grating array multicore fiber is fully cured;Finally, the hand type multicore fiber grating array is arranged to fiber collection disc, and the hand type grating array multicore fiber prepared is reasonably protected;

[0011] The combined beam module is formed by a large-diameter hole and N small-diameter holes around the large-diameter hole, wherein the central grating array optical fiber is sent out from the large-diameter hole at the center of the combined beam module, and the N grating array optical fibers are sent out from the small-diameter holes; when a chiral multicore fiber grating array is prepared, the 1+N grating array optical fibers are sent into the combined beam module at the same speed from the rotating fiber feeding module, and are combined into a single multicore fiber grating array under the torsion of the rotating action of the rotating fiber feeding module; the internal structure of the single multicore fiber grating array is a chiral multicore fiber grating array formed by the 1+N grating array optical fibers in a spiral shape;

[0012] The 1+N grating array optical fibers are sent out from the rotating fiber feeding module and then sent into the combined beam module, the small holes are one-to-one corresponding to the optical fibers, the 1+N grating array optical fibers passing through the combined beam module are sent into the coating cup, the coating cup is fixed and does not rotate, the coating cup has a certain length, and the chiral grating array multicore fiber is ensured to be fully cured;

[0013] The 1+N grating array optical fiber discs are arranged on the rotating fiber feeding module, the rotating fiber feeding module rotates automatically and feeds fibers, the rotating fiber feeding module drives the combined beam module to rotate together, the coating cup is fixed and does not move, and the 1+N grating array optical fibers passing through the combined beam module are combined into a single multicore fiber grating in a spiral state around the central fiber grating due to the rotating torsion; the spiral sensitivity effect of a certain torque can be realized by controlling the rotating speed, and according to different rotating speeds, the range of torsional strain and the sensitivity of the chiral multicore fiber grating monitoring structure system can be determined;

[0014] The rotating fiber feeding module and the combined beam module rotate at the same speed and in the same direction, so that the 1+N grating array optical fibers form a chiral multicore fiber grating in the same direction due to the torsion, and the coating cup is completed and cured;

[0015] The chiral multicore fiber grating array after coating and curing is collected into the fiber collection disc through the fiber collection device;

[0016] The fiber collection device is driven by two large rollers, small rollers and finally connects the fiber collection disc; the chiral multicore fiber grating array after coating and curing is collected into the fiber collection disc through the fiber collection device.

[0017] The device adopted by the utility model to solve the technical problem:

[0018] Its characterized in that: by rotating the fiber feeding module, grating array optical fiber, beam combining module, coating cup, fiber collection device composition;The beam combining module is surrounded by a large diameter hole and surrounding N small diameter holes;1+N grating array optical fiber is sent out from the rotating fiber feeding module and enters the coating cup after the beam combining module, the rotating fiber feeding module and the beam combining module rotate at the same speed and in the same direction, so that 1+N grating array optical fiber is formed into a chiral multicore fiber grating from the same direction due to torsion, and the coating is completed and solidified in the coating cup, and finally collected by the fiber collection device to the fiber collection disc.

[0019] Compared with the prior art, the utility model has the advantages of:

[0020] (1) the utility model discloses a chiral multicore fiber grating array and preparation device, the utility model selects the grating array optical fiber prepared with the wire drawing tower, completes fixed point grating in the process of preparing the optical fiber of wire drawing tower, carries out the beam combining operation of increasing torsion to the grating array optical fiber prepared with the method, realizes the preparation of the multicore fiber grating array of flexible configuration of grating quantity and spacing, and the process is simple and smooth, the method of the multicore fiber grating array is used instead of the multicore fiber grating array preparation method of grating on the existing multicore fiber, and the preparation cost of the multicore fiber grating array is greatly reduced, the grating consistency and writing efficiency are guaranteed, and the needs of low-cost industrial production are realized, and the industrial preparation conditions are met.

[0021] (2) the utility model selects 1+N grating array optical fiber as the multiple cores of the multicore fiber, can select the determined core spacing and grating spacing in the core according to different application demands, and application is flexible, not only can prepare the multicore fiber grating array of small core spacing, be used for the shape sensing of small device, such as medical endoscope, robot arm etc., but also can prepare the multicore fiber grating array of large core spacing, to realize the deformation monitoring of large range long distance, and have remarkable advantages in engineering structure, road bridge and other large scale strain monitoring fields, can realize long distance deformation measurement of high sensitivity and high accuracy in geological subsidence, bridge collapse, pipeline subsidence and other aspects.

[0022] (3) the rotating fiber feeding device and the beam combining device selected by the utility model can orderly complete the fiber feeding work, and at the same time, the spiral sensitivity of the multicore fiber grating array is enhanced due to the rotation of itself, the rotation torque of the multicore fiber can be controlled by controlling the speed of rotation in the process of sensitivity enhancement, the torsion error is eliminated, the shape sensing accuracy is improved, and the multi-dimensional shape sensing of positioning fast, wide range and high precision is realized. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the overall device structure schematic diagram of the utility model.

[0024] Figure 2 A hand type multi-core fiber grating array schematic diagram of the utility model. DETAILED DESCRIPTION

[0025] The utility model is further described below in combination with drawings.

[0026] Referring to the accompanying drawings Figure 1 The utility model discloses a kind of hand type multi-core fiber grating array and preparation device, including rotating fiber feeding module (1), 1+N grating array optical fiber (2), beam combining module (3), coating cup (4), fiber collecting device (5);Wherein beam combining module (3) is formed by one large diameter hole and surrounding N small diameter holes;Rotating fiber feeding device (1) is used as fiber feeding positioning device and rotates automatically, beam combining module (3) completes hand type grating array optical fiber beam combining work, with rotating fiber feeding device (1) same speed rotation, form a kind of hand type multi-core fiber grating array in rotating process.

[0027] Referring to the accompanying drawings Figure 2 For the hand type multi-core fiber grating array schematic diagram of the utility model, 1+N grating array optical fiber is with N taking 4 as an example, it is formed by 4 grating array optical fibers around 1 center grating array optical fiber A kind of hand type multi-core fiber grating array, 1 grating array optical fiber is located at the position of center core, 4 grating array optical fibers are hand type spiral around center core four, form a kind of hand type multi-core fiber grating array (6).

[0028] The working mode of the utility model is as follows: rotating fiber feeding module (1) sends out 1+N grating array optical fiber (2) at same speed, then with small hole one-to-one corresponding and passes into beam combining module (3), beam combining module (3) is formed by one large diameter hole and its surrounding N small diameter holes, wherein center fiber grating is sent out from large diameter hole, N grating array optical fibers are sent out from small diameter hole, when preparing the hand type multi-core fiber grating array, 1+N grating array optical fiber (2) is twisted under the rotation of rotating fiber feeding module (1) and is combined into single multi-core fiber grating array, the internal structure of this single multi-core fiber grating array is a kind of hand type multi-core fiber grating array formed by 1+N grating array optical fiber (2) spiral. The hand type multi-core fiber grating array is sent into coating cup (4) and completes coating and solidification, finally after fiber collecting device (5) is inducted into fiber collecting disc.

[0029] The utility model relates to a kind of hand type multicore fiber grating array and preparation device, grating array fiber prepared with wire drawing tower is selected, fixed point grating is completed in the process of wire drawing tower preparation fiber, the method of preparation of the multicore fiber grating array is replaced in the grating multicore fiber grating array preparation method of having on existing multicore fiber, without point-by-point core positioning grating, avoid the loss generated between single-mode fiber and multicore fiber coupling, greatly reduce the preparation cost of multicore fiber grating array, ensure that grating consistency and write efficiency while realizing the need of low-cost industrial production, meet industrial preparation conditions.

[0030] The grating array fiber (2) selected by the utility model can select grating array fiber with appropriate fiber outer diameter, grating spacing and reflectivity intensity according to different application needs, and when penetrating into the rotating fiber feeding module (1) and the beam combining module (3), the grating array fiber (2) is one-to-one corresponding with the hole, so that the position of each core of the multicore fiber grating is fixed, the core spacing of the multicore fiber grating can be freely adjusted, which can not only realize the monitoring and recovery of micro deformation, but also fill the gap of large bending radius, large range and long distance structure deformation monitoring; the rotating fiber feeding module (1) and the beam combining module (3) rotate at the same speed and in the same direction, so that 1+N grating array fibers form a hand type multicore fiber grating array under the action of torsion force; the hand type multicore fiber grating array can monitor the influence of torsion force on deformation due to its special structure during stress and strain monitoring, and the control of rotation speed can realize the control of torque of the hand type multicore fiber grating array, thereby realizing the range and sensitivity control of torsion monitoring, and the application is flexible and widely used.

[0031] In one specific embodiment of the utility model, the five grating array fibers sent out by the rotating fiber feeding module at a speed of 50 m / min are prepared by using conventional ordinary single-mode fiber (G652), and a hand type multicore fiber grating array is formed as shown in FIG. 4. Figure 2The center wavelength of each grating array is λ1, λ2, λ3, λ4 and λ5, and the corresponding numerical value is 1530 nm, 1535 nm, 1540 nm, 1545 nm and 1550 nm, the bandwidth of each wavelength is 0.15 nm, the reflectivity is 0.1%, and the interval between the fiber gratings is 2 m. The power of the rotating fiber feeding module is 500 w, and the rotating speed is 30 r / min, and the torque is 159 N.m according to the formula torque = 9550*power / speed (the torque unit is N.m, the power unit is kw, and the speed unit is r / min). In the preparation of the chiral multicore fiber grating array, the center fiber in the five fibers is always kept vertical to the fiber feeding, and the other four fibers are twisted around the center fiber to form a single multicore fiber grating array under the action of the rotating fiber feeding module, the length of the coating cup is 15 cm, and the fiber diameter of the chiral multicore fiber grating array formed after coating and curing through the coating cup is 3 mm, and the total length is 1 km. The chiral fiber grating array preparation method can effectively realize the industrial production of long distance of meter level or even kilometer level, and has the advantages of low cost and simple system; the wavelength change difference of the inner and outer diameters of the fiber core is large during deformation, compared with the traditional multicore, it is more suitable for large span and long distance deformation monitoring; and the chiral characteristics of the fiber grating array can realize the monitoring of the torsion in the complex strain condition.

[0032] The principle and implementation mode of the specific examples are described in the utility model, and the above embodiment is only used for helping to understand the method and core idea of the utility model; meanwhile, according to the idea of the utility model, the specific implementation mode and application range will be changed by the general technical personnel in the field. In conclusion, the content of the specification should not be understood as the limitation of the utility model, and the utility model has various changes and improvements without departing from the spirit and range of the utility model, and these changes and improvements all fall into the range of the utility model to be protected.

Claims

1. A device for fabricating a chiral multicore fiber grating array, characterized by: It comprises a rotating fiber feeding module, 1+N grating array optical fibers, a beam combining module, a coating cup, and a fiber collecting device. A plurality of grating array optical fiber discs are arranged on the rotating fiber feeding module, and the rotating fiber feeding module completes the fiber feeding work and realizes the spiral sensitization of the one-handed type multi-core fiber grating array by rotating itself and driving the beam combining module. The 1+N grating array optical fibers correspond to the grating array optical fiber discs carried by the rotating fiber feeding module, and can select different coating thicknesses, different wavelengths, different reflectivities, different grating spacings, and different numbers of grating arrays for the preparation of the one-handed type multi-core fiber grating array. The beam combining module comprises a large-diameter hole and N small-diameter holes. The large-diameter hole is located at the center of the beam combining module, and the N small-diameter holes are uniformly distributed around the large-diameter hole. The center grating array optical fiber passes through the large-diameter hole and always maintains a central vertical state. The N grating array optical fibers pass through the N small-diameter holes and rotate together with the rotating fiber feeding module to combine the 1+N grating array optical fibers after spiral sensitization, and then pass through the coating cup for coating and solidification. The coating cup has a circular hole with a diameter that can ensure the passage of the one-handed type multi-core fiber grating array, and a length that can ensure sufficient coating and solidification of the one-handed type multi-core fiber grating array. The fiber collecting device comprises two large rollers, one small roller, and a fiber collecting disc. The one-handed type multi-core fiber grating array passes through the two large rollers, connects the small roller, and is finally collected in the fiber collecting disc.

2. A one-handed type multi-core fiber grating array, The fabrication is carried out using the chiral multi-core fiber grating array fabrication apparatus according to claim 1, characterized in that: It is composed of a plurality of cores, and the plurality of cores are a plurality of grating array optical fibers. The grating wavelengths, grating spacings, and grating reflectivities of the grating array optical fibers are the same or different, and the number of cores is 1+N. The center core is located at the center vertical position in the one-handed type multi-core fiber grating array, and the N edge cores are evenly distributed around the center core in a spiral winding manner. The 1+N cores form a one-handed type multi-core fiber grating array in a one-handed manner.

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