A manufacturing device and manufacturing method of flexible structure modulation type grating

Abstract

The present invention discloses a manufacturing device for a flexible structure modulated grating, comprising a cladding solution microfluidic pump, a core liquid microfluidic pump, a cladding solution circulation pipeline, a core liquid circulation pipeline, and a solution coagulation pool, wherein the core liquid circulation pipeline is arranged in the cladding solution circulation pipeline and is coaxially arranged with the cladding solution circulation pipeline, the top of the core liquid circulation pipeline is connected with the core liquid microfluidic pump, the bottom of the core liquid circulation pipeline is provided with a core liquid nozzle, the top of the cladding solution circulation pipeline is connected with the cladding solution microfluidic pump, the bottom of the cladding solution circulation pipeline is provided with a cladding solution nozzle, the solution coagulation pool is arranged below the cladding solution nozzle and the core liquid nozzle, and the solution coagulation pool is arranged on a displacement adjustment table. The present invention adopts a manufacturing device for a flexible structure modulated grating of the above structure and a manufacturing method thereof, so that the growth period and length of the flexible grating are controlled, and the grating is ensured to have good bio-interface compatibility and high shear resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible gratings, and in particular to a manufacturing device and a manufacturing method of a flexible structure modulation type grating. Background Art

[0002] Among the various types of fiber optic sensors, fiber Bragg grating sensors have been widely studied and applied to various strain monitoring applications such as bridge structure safety monitoring and geological deformation monitoring due to their low insertion loss, long service life, and easy networking. With the widespread application of gratings, the preparation process of gratings has been gradually studied and improved. The advent of structure-modulated fiber Bragg gratings has greatly reduced the complexity of the traditional grating preparation process, eliminating the need for hydrogen loading, UV writing, annealing, and other processes. Structure-modulated fiber Bragg gratings use a coupling mechanism that produces periodic geometric deformations on the surface of the optical fiber, providing more possibilities for the preparation of new gratings.

[0003] At present, with the progress of science and technology and the development of artificial intelligence, flexible sensor devices have become an important research direction for the development of future intelligent devices, and have broad application prospects in the fields of intelligent wearable devices, intelligent skin, human-computer interaction, etc. Although traditional optical fiber sensor devices can be bent, their application in the field of artificial intelligence is limited. Traditional optical fiber sensor devices are brittle and easy to break. They are very easy to break under the action of strong shear force. If used in smart wearable devices, the broken optical fiber can easily penetrate the skin and cause damage to the human body. In addition, due to their extremely limited stretchability, traditional optical fiber sensor devices have poor compatibility with biological interfaces. Therefore, they cannot match the changes of muscles under muscle contraction and stretching, which reduces the accuracy of optical fiber sensing and limits the application scenarios. In contrast, flexible optical sensors have faster sensing speeds and stronger anti-interference capabilities, and are compatible with optical neural networks. Therefore, flexible optical devices are the key direction of future research and development, and have broad application prospects in the field of artificial intelligence. At present, some work has proposed the preparation of flexible fiber gratings.

[0004] The Chinese invention patent with application number CN201710595128.0 proposes a miniaturized flexible fiber Bragg grating strain sensor, which is coated with a high elastic modulus polymer material coating on the surface of the fiber Bragg grating, and a low elastic modulus polymer material coating layer and a high elastic modulus polymer material interlayer, etc., to overcome the problems of high rigidity and large volume of the traditional packaged fiber Bragg grating strain sensor. There are many similar works on coating the traditional fiber Bragg grating with flexible or highly elastic materials to protect the grating, but this does not change the nature of the fiber Bragg grating itself, which has poor shear resistance and poor compatibility with biological interfaces.

[0005] The Chinese invention patent with application number CN201610157840.8 provides a light-driven flexible adjustable grating and a method for preparing the same. A flexible adjustable grating is obtained by coating polydimethylsiloxane on a grating template, and the graphene-polydimethylsiloxane film on both sides of the grating can be controlled by a near-infrared laser to undergo expansion and contraction deformation to change the grating spacing. This method achieves the preparation of a flexible grating, but the flexible grating made using the mask method is not only limited in length by the mask, but the initial period of the flexible grating is also determined by the period of the grating mask, and the prepared grating period cannot be modified at will during the preparation process. In addition, the mask method has a relatively complex preparation process for preparing flexible gratings, and the prepared grating is difficult to be compatible with existing optical fiber communication systems due to its morphology, so its current and future applications are limited. Summary of the invention

[0006] The purpose of the present invention is to provide a manufacturing device and a manufacturing method for a flexible structure modulated grating, so that the period of the flexible grating can be modulated in a controllable manner during the preparation process, and the grating writing length can be arbitrarily long or short, ensuring that the grating has good bio-interface compatibility and high shear resistance.

[0007] To achieve the above-mentioned purpose, the present invention provides a manufacturing device for a flexible structure modulated grating, comprising a cladding solution microfluidic pump, a core liquid microfluidic pump, a cladding solution circulation pipeline, a core liquid circulation pipeline, and a solution coagulation pool, wherein the core liquid circulation pipeline is arranged in the cladding solution circulation pipeline and is coaxially arranged with the cladding solution circulation pipeline, the top end of the core liquid circulation pipeline is connected with the core liquid microfluidic pump, the bottom end of the core liquid circulation pipeline is provided with a core liquid nozzle, the top end of the cladding solution circulation pipeline is connected with the cladding solution microfluidic pump, the bottom end of the cladding solution circulation pipeline is provided with a cladding solution nozzle, the core liquid nozzle is arranged in the cladding solution nozzle, the solution coagulation pool is arranged below the cladding solution nozzle and the core liquid nozzle, and the solution coagulation pool is arranged on a displacement adjustment platform.

[0008] Preferably, the side of the cladding solution circulation pipe is fixed by a fixing fixture.

[0009] Preferably, the cladding solution nozzle and the core solution nozzle are both conical nozzles made of metal or glass.

[0010] A method for manufacturing a flexible structure modulated grating, the steps are as follows:

[0011] S1, the cladding solution circulation pipeline and the core liquid circulation pipeline are coaxially arranged, the core liquid nozzle is installed and connected to the tail end of the core liquid circulation pipeline, and the cladding solution nozzle is installed and connected to the tail end of the cladding liquid circulation pipeline;

[0012] S2. Prepare a coating solution, and inject the coating solution into the coating solution circulation pipe until the liquid fills the entire coating solution circulation pipe and the coating solution nozzle, wherein the coating solution is a sodium alginate solution, and the mass concentration of the sodium alginate solution includes any proportion between 2%wt, 3%wt, 4%wt and 7%wt.

[0013] S3. Prepare the core liquid and inject the core liquid into the core liquid circulation conduit until the liquid fills the entire core liquid circulation conduit and the core liquid nozzle, wherein the core liquid includes one or more of a glycerol aqueous solution, an inorganic salt solution, and an organic liquid for making a liquid fiber core; a gelatin aqueous solution for making a gelatin gel fiber core; a polydimethylsiloxane-curing agent mixed solution, an acrylamide mixed solution, and a photopolymerized glue for making a solid fiber core.

[0014] S4, configuring a calcium chloride solution as the solution in the solution coagulation tank, and injecting the calcium chloride solution into the solution coagulation tank;

[0015] S5, using the displacement adjustment platform to adjust the position of the solution coagulation pool until the core solution nozzle and the cladding solution nozzle are located below the liquid level of the solution in the solution coagulation pool;

[0016] S6, the cladding solution micro-flow pump is used to control the flow rate of the cladding solution to be constant so as to spray it out through the cladding solution nozzle, after the cladding solution contacts the solution in the solution coagulation pool, the calcium ions of the calcium chloride in the solution coagulation pool react with the sodium ions of the sodium alginate to form a hydrogel with a cross-linked network structure, and as the cladding solution is ejected at a uniform speed, a hydrogel coreless optical fiber with uniform diameter is instantly formed;

[0017] S7, the cladding solution flow rate is controlled by the cladding solution micro-fluid pump to be constantly ejected through the core liquid nozzle, the core liquid micro-fluid pump periodically changes the core liquid flow rate, and the core diameter is periodically changed, so as to obtain a flexible grating with a periodically modulated core diameter and a core in a liquid state, which is protected by the formed hydrogel coreless optical fiber, and the core liquid will not leak from the end face of the flexible optical fiber, and is protected by the instantly formed hydrogel cladding, and the core liquid will not leak from the side wall of the flexible optical fiber;

[0018] S8, controlling the cladding solution to be uniformly ejected from the cladding solution nozzle by the cladding solution micro-flow pump, connecting a hydrogel coreless optical fiber with uniform diameter to the end of the flexible grating with periodically modulated core diameter, so as to play a protective role;

[0019] S9, taking out the prepared flexible fiber grating from the solution solidification pool.

[0020] Preferably, in S3, the glycerol aqueous solution is formed by mixing glycerol and water in a certain volume ratio, and the ratio includes any ratio between 1:1, 1:2, 1:3 and 1:20; the inorganic salt solution includes sodium chloride solution and phosphate solution; the organic liquid includes siloxane and ethanol.

[0021] Preferably, in S3, the gelatin aqueous solution is prepared by dissolving gelatin particles in deionized water, heating the water to 80°C to prepare a gelatin aqueous solution with a mass concentration of about 10%, then adding glycerol to the gelatin aqueous solution, and mixing the solution evenly; using the gelatin aqueous solution as the core liquid, after taking out the flexible optical fiber Bragg grating in S9, standing it at room temperature for 24 hours, a flexible optical fiber Bragg grating with a gelatin gel core can be formed.

[0022] Preferably, in S3, the polydimethylsiloxane-curing agent mixed solution is obtained by mixing polydimethylsiloxane and the curing agent in a mass ratio of 10:1 and removing bubbles from the mixed solution; the polydimethylsiloxane-curing agent mixed solution is used as the core liquid, and after the flexible optical fiber Bragg grating is taken out in S9, the taken out grating is placed in an incubator and heated at 80°C for 2 hours, and the core changes from liquid to solid, thereby forming a flexible optical fiber Bragg grating with a solid core.

[0023] Preferably, in S3, the acrylamide mixed solution is prepared by dissolving acrylamide monomer in deionized water and stirring to obtain an acrylamide solution, and then adding a crosslinking agent N, N-methylenebisacrylamide and a photoinitiator 2, 2'-azo (2-methylpropionic acid amide) to the solution, and stirring the solution to obtain a flexible fiber grating. Using the acrylamide mixed solution, after taking out the flexible fiber grating in S9, it is irradiated with ultraviolet light for 2 hours, and the core changes from liquid to solid, thereby forming a flexible fiber grating with a solid core.

[0024] Preferably, in S3, photopolymerized glue is used as the core liquid, and after the flexible fiber grating is taken out in S9, the grating is illuminated with light of a specific wavelength for 2 hours, and the core changes from liquid to solid, forming a flexible fiber grating with a solid core.

[0025] The beneficial effects of the present invention are:

[0026] 1) The present invention discloses a method and a device for manufacturing a structure-modulated flexible grating, which can manufacture various types of flexible gratings, including flexible structure-modulated flexible gratings with liquid cores or solid cores, and structure-modulated flexible gratings with constant period, chirp period or multi-period cascade, to meet the manufacturing requirements of different types of flexible structure-modulated gratings; the core and cladding diameters of the manufactured flexible structure-modulated gratings can be controlled by replacing the solution nozzle and adjusting the solution flow rate, to meet the manufacturing requirements of flexible structure-modulated gratings of different sizes; the refractive index of the core and cladding of the manufactured flexible structure-modulated grating can be modulated by appropriately adding chemical substances to the core liquid or cladding solution, to meet the manufacturing requirements of flexible structure-modulated gratings with different refractive indices.

[0027] 2) The period of the flexible grating prepared by the structure-modulated flexible grating preparation device and preparation method disclosed in the present invention can be modulated in a controllable manner during the preparation process, and the grating writing length can be arbitrarily long or short without being restricted by the length of the template used in the traditional mask method. Flexible fiber gratings of arbitrary length can be prepared continuously, thereby reducing the preparation cost of the flexible grating. The prepared flexible grating can be directly connected to a flexible optical fiber during the preparation process, which greatly facilitates the preparation of the flexible grating and its compatibility with existing optical fiber communication or detection systems, and is conducive to promoting the research and application of flexible gratings.

[0028] 3) The flexible grating prepared by the structure-modulated flexible grating manufacturing device and manufacturing method disclosed in the present invention has high shear resistance and good bio-interface compatibility, and can be used for stress and strain monitoring; antigens, antibodies and other proteins with specific recognition functions can also be added to the cladding solution during the preparation of the flexible fiber grating to functionalize the prepared flexible structure-modulated grating and give it specific recognition function.

[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of an embodiment of a manufacturing device for a flexible structure modulation type grating of the present invention;

[0031] Figure 2 A schematic diagram of manufacturing a relatively long period flexible structure modulation grating according to an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of manufacturing a short-period flexible structure modulation grating according to an embodiment of the present invention.

[0033] Reference numerals

[0034] 1. Cladding solution microfluidic pump; 2. Cladding solution circulation pipeline; 3. Core liquid circulation pipeline; 4. Core liquid microfluidic pump; 5. Fixing fixture; 6. Cladding solution nozzle; 7. Core liquid nozzle; 8. Solution coagulation tank; 9. Displacement adjustment table; 10. Coreless optical fiber; 11. Fiber core produced under low core liquid flow rate; 12. Fiber core produced under high core liquid flow rate. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0036] like Figure 1 As shown, a manufacturing device for a flexible structure modulated grating includes a cladding solution microfluidic pump 1, a core liquid microfluidic pump 4, a cladding solution circulation pipeline 2, a core liquid circulation pipeline 3, and a solution coagulation pool 8. The core liquid circulation pipeline 3 is arranged in the cladding solution circulation pipeline 2 and is coaxially arranged with the cladding solution circulation pipeline 2. The side of the cladding solution circulation pipeline 2 is fixed by a fixing fixture 5.

[0037] The top of the core liquid circulation conduit 3 is connected to the core liquid microfluidic pump 4, and the bottom of the core liquid circulation conduit 3 is provided with a core liquid nozzle 7. The core liquid microfluidic pump 4 controls the speed of the core liquid ejected from the core liquid nozzle 7. When the core liquid microfluidic pump 4 changes the core liquid flow rate periodically at a certain frequency, the core liquid flow rate at the core liquid nozzle 7 also changes accordingly. When the core liquid is ejected at a higher flow rate, just like squeezing a drop of aqueous solution from a dropper, the ejected core liquid has a circular outer wall under the action of the liquid surface tension and the diameter exceeds the inner diameter of the ejection nozzle. The formed cladding hydrogel is coated with different amounts of core liquid at all times and filled inside, resulting in the formed cladding hydrogel having a periodically changing inner diameter. The fiber core 11 obtained under a stable low core liquid flow rate is a cylindrical shape with uniform diameter, and the fiber core 12 obtained under a high core liquid flow rate will form a protruding spherical shape, resembling a string of beads. When the change frequency of the core liquid microfluidic pump 4 is faster, the core diameter changes faster and the cycle is shorter, such as Figure 3 When the change frequency of the core liquid microfluidic pump 4 is slow, the core diameter changes slowly and the cycle is long, such as Figure 2 shown.

[0038] The top of the cladding solution circulation pipe 2 is connected to the cladding solution microfluidic pump 1, and the bottom of the cladding solution circulation pipe 2 is provided with a cladding solution nozzle 6, and the cladding solution microfluidic pump 1 controls the rate at which the cladding solution is sprayed from the cladding solution nozzle 6. The core liquid nozzle 7 is arranged in the cladding solution nozzle 6, and both the cladding solution nozzle 6 and the core liquid nozzle 7 are conical nozzles made of metal or glass. The conical nozzle determines the diameter of the coreless optical fiber 10 and the core. By using a replaceable nozzle, flexible optical fiber gratings of different specifications can be formed.

[0039] When the cladding solution microfluidic pump 1 controls the cladding liquid flow rate to be constant and the core liquid microfluidic pump 4 controls the core liquid flow rate to change periodically, a flexible structure modulated grating with uniform cladding diameter but periodically changing core can be obtained. But when the cladding solution microfluidic pump 1 controls the cladding liquid flow rate to change periodically and the core liquid microfluidic pump 4 controls the core liquid flow rate to be constant, a flexible structure modulated grating with periodically changing cladding diameter but uniform core diameter can be obtained.

[0040] The solution coagulation pool 8 is arranged below the cladding solution nozzle 6 and the core liquid nozzle 7, and the solution coagulation pool 8 is arranged on the displacement adjustment platform 9. The displacement adjustment platform 9 can adjust the positional relationship between the solution coagulation pool 8 and the cladding solution nozzle 6 and the core liquid nozzle 7, so that the cladding solution nozzle 6 and the core liquid nozzle 7 are immersed in or separated from the liquid surface of the solution coagulation pool 8. Calcium chloride solution is injected into the solution coagulation pool 8, and after contacting with the sodium alginate solution as the cladding solution, the calcium ions of the calcium chloride in the solution coagulation pool 8 and the sodium ions of the sodium alginate undergo an ion exchange reaction to form a hydrogel with a cross-linked network structure, thereby forming a coreless optical fiber 10, which can protect the core liquid inside.

[0041] Example 1

[0042] Fabrication of a fixed-period flexible structure modulation grating with a liquid core

[0043] 1) Select a core liquid nozzle 7 with an inner diameter of 8 μm at the outlet end, select a cladding solution nozzle 6 with an inner diameter of 125 μm at the outlet end, first install the core liquid nozzle 7 to the tail end of the core liquid circulation pipeline 3, and then install the cladding solution nozzle 6 to the tail end of the cladding liquid circulation pipeline;

[0044] 2) preparing a sodium alginate solution with a mass concentration of 3%wt as the cladding solution and glycerol as the core liquid, and injecting the cladding solution and the core liquid into the cladding liquid circulation channel and the core liquid circulation channel 3 respectively until the liquid fills the entire circulation channel and the nozzle;

[0045] 3) preparing a calcium chloride solution with a mass concentration of 5%wt and injecting it into the solution coagulation tank 8;

[0046] 4) Using the displacement adjustment platform 9 to adjust the position of the solution coagulation pool 8 until the nozzle is located below the liquid level of the solution in the solution coagulation pool 8;

[0047] 5) Using the cladding solution micro-flow pump 1 to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, the cladding solution immediately forms a hydrogel coreless optical fiber 10 with uniform diameter after contacting the solution in the solution coagulation pool 8;

[0048] 6) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed. At the same time, the cladding solution microfluidic pump 1 is still used to control the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed. The refractive index of glycerol is higher than that of the hydrogel cladding, thereby forming a step-refractive-index flexible optical fiber with a liquid core of uniform diameter;

[0049] 7) The cladding solution microfluidic pump 1 is used to keep the flow rate of the cladding solution constant, and the core liquid microfluidic pump 4 periodically switches the core liquid flow rate between 0.1 mL / min and 0.3 mL / min at a frequency of 1 MHz. The core liquid flow rate at the core liquid nozzle 7 is switched between approximately 3.3×104 mm / s and 9.9×104 mm / s, forming a structural modulation type flexible grating with a periodic change in the core diameter, and its period is about 130 μm;

[0050] 8) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed, and at the same time, the cladding solution microfluidic pump 1 still controls the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed, and a step-refractive-index flexible optical fiber can be connected to the other side of the manufactured structure-modulated flexible optical fiber grating;

[0051] 9) Use the cladding solution microfluidic pump 1 to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, and at the same time stop the flow of the core liquid, then connect the hydrogel coreless optical fiber 10 with uniform diameter to the tail end of the manufactured step-refractive index flexible optical fiber to protect the core liquid in the manufactured flexible optical fiber grating from leaking out; at this point, the fixed-period structure modulated flexible optical fiber grating with both ends directly connected to the flexible optical fiber and having a liquid core is completed and can be taken out from the solution solidification pool 8.

[0052] Example 2

[0053] Preparation method of fixed period flexible structure modulation grating with gelatin gel as core

[0054] 1) Select a core liquid nozzle 7 with an inner diameter of 8 μm at the outlet end, select a cladding solution nozzle 6 with an inner diameter of 125 μm at the outlet end, first install the core liquid nozzle 7 to the tail end of the core liquid circulation pipeline 3, and then install the cladding solution nozzle 6 to the tail end of the cladding liquid circulation pipeline;

[0055] 2) preparing a sodium alginate solution with a mass concentration of 3%wt as a cladding solution, and injecting the cladding solution into the cladding liquid circulation pipe until the liquid fills the entire circulation pipe and the cladding solution nozzle 6;

[0056] 3) dissolving 10 g of gelatin particles in 90 mL of deionized water, heating the water to 80° C. to prepare a gelatin aqueous solution with a mass concentration of about 10%, adding 1 mL of glycerol to the gelatin aqueous solution, mixing the solutions evenly, using the mixed gelatin aqueous solution as the core liquid, and injecting the core liquid into the core liquid circulation channel 3 until the liquid fills the entire circulation channel and the core liquid nozzle 7;

[0057] 4) preparing a calcium chloride solution with a mass concentration of 5%wt and injecting it into the solution coagulation tank 8;

[0058] 5) Using the displacement adjustment platform 9 to adjust the position of the solution coagulation pool 8 until the nozzle is located below the liquid level of the solution in the solution coagulation pool 8;

[0059] 6) Using the cladding solution micro-flow pump 1 to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, the cladding solution immediately forms a hydrogel coreless optical fiber 10 with uniform diameter after contacting the solution in the solution coagulation pool 8;

[0060] 7) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed, and at the same time, the cladding solution microfluidic pump 1 is still used to control the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed. The refractive index of the gelatin aqueous solution is higher than that of the hydrogel cladding, thereby forming a step-refractive-index flexible optical fiber with a liquid core of uniform diameter;

[0061] 8) The cladding solution microfluidic pump 1 is used to keep the flow rate of the cladding solution constant, and the core liquid microfluidic pump 4 periodically switches the core liquid flow rate between 0.1 mL / min and 0.3 mL / min at a frequency of 1 MHz. The core liquid flow rate at the core liquid nozzle 7 is switched between approximately 3.3×104 mm / s and 9.9×104 mm / s, forming a structural modulation type flexible grating with a periodic change in the core diameter, and its period is about 130 μm;

[0062] 9) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed, and at the same time, the cladding solution microfluidic pump 1 is still used to control the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed, and a step-refractive-index flexible optical fiber can be connected to the other side of the manufactured structure-modulated flexible optical fiber grating;

[0063] 10) The cladding solution is controlled to be ejected from the cladding solution nozzle 6 at a uniform speed by using the cladding solution microfluidic pump 1, and the flow of the core liquid is stopped at the same time. Then, a hydrogel coreless optical fiber 10 with uniform diameter is connected to the tail end of the manufactured step-refractive-index flexible optical fiber to protect the core liquid in the manufactured step-refractive-index flexible optical fiber and the structural modulation type flexible optical fiber grating from leaking out. At this point, the short-period structural modulation type flexible optical fiber grating with liquid core and directly connected to the flexible optical fiber at both ends is completed.

[0064] 11) The prepared short-period structure-modulated flexible optical fiber Bragg grating with a liquid core is taken out from the solution coagulation pool 8 and allowed to stand at room temperature for 24 hours, and the liquid core liquid coagulates into a solid state, thereby producing a fixed-period structure-modulated flexible optical fiber Bragg grating with a core of solid stretchable gelatin.

[0065] Example 3

[0066] Preparation method of fixed period flexible structure modulation grating with polydimethylsiloxane as core

[0067] 1) Select a core liquid nozzle 7 with an inner diameter of 8 μm at the outlet end, select a cladding solution nozzle 6 with an inner diameter of 125 μm at the outlet end, first install the core liquid nozzle 7 to the tail end of the core liquid circulation pipeline 3, and then install the cladding solution nozzle 6 to the tail end of the cladding liquid circulation pipeline;

[0068] 2) preparing a sodium alginate solution with a mass concentration of 3%wt as a cladding solution, and injecting the cladding solution into the cladding liquid circulation pipe until the liquid fills the entire circulation pipe and the cladding solution nozzle 6;

[0069] 3) polydimethylsiloxane and curing agent are mixed evenly in a mass ratio of 10:1, and then the mixed liquid is placed in a closed box and the air in the closed box is completely evacuated by a vacuum pump, so that there are no bubbles in the mixed polydimethylsiloxane liquid, and then the polydimethylsiloxane-curing agent mixed solution with bubbles removed is used as the core liquid, and the core liquid is injected into the core liquid circulation pipeline 3 until the liquid fills the entire circulation pipeline and the core liquid nozzle 7;

[0070] 4) preparing a calcium chloride solution with a mass concentration of 5%wt and injecting it into the solution coagulation tank 8;

[0071] 5) Using the displacement adjustment platform 9 to adjust the position of the solution coagulation pool 8 until the nozzle is located below the liquid level of the solution in the solution coagulation pool 8;

[0072] 6) Using the cladding solution micro-flow pump 1 to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, the cladding solution immediately forms a hydrogel coreless optical fiber 10 with uniform diameter after contacting the solution in the solution coagulation pool 8;

[0073] 7) The core liquid microfluidic pump 4 is used to control the core liquid to be uniformly ejected from the core liquid nozzle 7, while the cladding solution microfluidic pump 1 is still used to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, and the refractive index of polydimethylsiloxane is higher than that of the hydrogel cladding, thereby forming a step-refractive-index flexible optical fiber with a liquid core of uniform diameter;

[0074] 8) The cladding solution microfluidic pump 1 is used to keep the flow rate of the cladding solution constant, and the core liquid microfluidic pump 4 periodically switches the core liquid flow rate between 0.1 mL / min and 0.3 mL / min at a frequency of 1 MHz. The core liquid flow rate at the core liquid nozzle 7 is switched between approximately 3.3×104 mm / s and 9.9×104 mm / s, forming a fixed period structure modulation type flexible grating with a periodic change in the core diameter, and its period is about 130 μm;

[0075] 9) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed, and at the same time, the cladding solution microfluidic pump 1 is still used to control the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed, and a step-refractive-index flexible optical fiber can be connected to the other side of the manufactured structure-modulated flexible optical fiber grating;

[0076] 10) The cladding solution is controlled to be ejected from the cladding solution nozzle 6 at a uniform speed by using the cladding solution microfluidic pump 1, and the flow of the core liquid is stopped at the same time. Then, a hydrogel coreless optical fiber 10 with uniform diameter is connected to the tail end of the manufactured step-refractive-index flexible optical fiber to protect the core liquid in the manufactured step-refractive-index flexible optical fiber and the structural modulation type flexible optical fiber grating from leaking out. At this point, the fixed-period structural modulation type flexible optical fiber grating with liquid core and directly connected to the flexible optical fiber at both ends is completed.

[0077] 11) The prepared structure-modulated flexible optical fiber Bragg grating with a liquid core is taken out from the solution coagulation pool 8, placed in an incubator and heated at 80°C for 2 hours, and then taken out. The liquid core is solidified into a solid state, and a fixed-period structure-modulated flexible optical fiber Bragg grating with a solid-state stretchable polydimethylsiloxane core is produced.

[0078] Example 4

[0079] Preparation method of fixed period flexible structure modulation grating with polyacrylamide as core

[0080] 1) Select a core liquid nozzle 7 with an inner diameter of 8 μm at the outlet end, select a cladding solution nozzle 6 with an inner diameter of 125 μm at the outlet end, first install the core liquid nozzle 7 to the tail end of the core liquid circulation pipeline 3, and then install the cladding solution nozzle 6 to the tail end of the cladding liquid circulation pipeline;

[0081] 2) preparing a sodium alginate solution with a mass concentration of 3%wt as a cladding solution, and injecting the cladding solution into the cladding liquid circulation pipe until the liquid fills the entire circulation pipe and the cladding solution nozzle 6;

[0082] 3) 47.6 g of acrylamide monomer was dissolved in 52.4 g of deionized water and stirred to obtain an acrylamide solution with a mass concentration of 47.6% wt, and 0.07 g of a cross-linking agent N, N-methylenebisacrylamide and 0.03 g of a photoinitiator 2, 2'-azo (2-methylpropionic acid amide) were added to the solution, and the solution was stirred to be uniform as the core liquid, and the core liquid was injected into the core liquid circulation channel 3 until the liquid filled the entire circulation channel and the core liquid nozzle 7;

[0083] 4) preparing a calcium chloride solution with a mass concentration of 5%wt and injecting it into the solution coagulation tank 8;

[0084] 5) Using the displacement adjustment platform 9 to adjust the position of the solution coagulation pool 8 until the nozzle is located below the liquid level of the solution in the solution coagulation pool 8;

[0085] 6) Using the cladding solution micro-flow pump 1 to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, the cladding solution immediately forms a hydrogel coreless optical fiber 10 with uniform diameter after contacting the solution in the solution coagulation pool 8;

[0086] 7) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed. At the same time, the cladding solution microfluidic pump 1 is still used to control the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed. The refractive index of the acrylamide mixed solution is higher than that of the hydrogel cladding, thereby forming a step-refractive-index flexible optical fiber with a liquid core of uniform diameter;

[0087] 8) The cladding solution microfluidic pump 1 is used to keep the flow rate of the cladding solution constant, and the core liquid microfluidic pump 4 periodically switches the core liquid flow rate between 0.1 mL / min and 0.3 mL / min at a frequency of 1 MHz. The core liquid flow rate at the core liquid nozzle 7 is switched between approximately 3.3×104 mm / s and 9.9×104 mm / s, forming a structural modulation type flexible grating with a periodic change in the core diameter, and its period is about 130 μm;

[0088] 9) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed, and at the same time, the cladding solution microfluidic pump 1 is still used to control the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed, and a step-refractive-index flexible optical fiber can be connected to the other side of the manufactured structure-modulated flexible optical fiber grating;

[0089] 10) The cladding solution is controlled to be ejected from the cladding solution nozzle 6 at a uniform speed by using the cladding solution microfluidic pump 1, and the flow of the core liquid is stopped at the same time. Then, a hydrogel coreless optical fiber 10 with uniform diameter is connected to the tail end of the manufactured step-refractive-index flexible optical fiber to protect the core liquid in the manufactured step-refractive-index flexible optical fiber and the structural modulation type flexible optical fiber grating from leaking out. At this point, the fixed-period structural modulation type flexible optical fiber grating with liquid core and directly connected to the flexible optical fiber at both ends is completed.

[0090] 11) The prepared fixed-period structure modulated flexible optical fiber Bragg grating with a liquid core is taken out from the solution coagulation pool 8 and irradiated with ultraviolet light for 2 hours. The liquid acrylamide solution is coagulated into polyacrylamide hydrogel under the action of the crosslinker and the photoinitiator under the ultraviolet light, thereby producing a fixed-period structure modulated flexible optical fiber Bragg grating with a solid stretchable polyacrylamide hydrogel as the core.

[0091] Example 5

[0092] Preparation method of chirped flexible structure modulation grating

[0093] 1) Select a core liquid nozzle 7 with an inner diameter of 8 μm at the outlet end, select a cladding solution nozzle 6 with an inner diameter of 125 μm at the outlet end, first install the core liquid nozzle 7 to the tail end of the core liquid circulation pipeline 3, and then install the cladding solution nozzle 6 to the tail end of the cladding liquid circulation pipeline;

[0094] 2) preparing a sodium alginate solution with a mass concentration of 3%wt as a cladding solution, and injecting the cladding solution into the cladding liquid circulation pipe until the liquid fills the entire circulation pipe and the cladding solution nozzle 6;

[0095] 3) polydimethylsiloxane and curing agent are mixed evenly in a mass ratio of 10:1, and then the mixed liquid is placed in a closed box and the air in the closed box is completely evacuated by a vacuum pump, so that there are no bubbles in the mixed polydimethylsiloxane liquid, and then the polydimethylsiloxane-curing agent mixed solution with bubbles removed is used as the core liquid, and the core liquid is injected into the core liquid circulation pipeline 3 until the liquid fills the entire circulation pipeline and the core liquid nozzle 7;

[0096] 4) preparing a calcium chloride solution with a mass concentration of 5%wt and injecting it into the solution coagulation tank 8;

[0097] 5) Using the displacement adjustment platform 9 to adjust the position of the solution coagulation pool 8 until the nozzle is located below the liquid level of the solution in the solution coagulation pool 8;

[0098] 6) Using the cladding solution micro-flow pump 1 to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, the cladding solution immediately forms a hydrogel coreless optical fiber 10 with uniform diameter after contacting the solution in the solution coagulation pool 8;

[0099] 7) The core liquid microfluidic pump 4 is used to control the core liquid to be uniformly ejected from the core liquid nozzle 7, while the cladding solution microfluidic pump 1 is still used to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, and the refractive index of polydimethylsiloxane is higher than that of the hydrogel cladding, thereby forming a step-refractive-index flexible optical fiber with a liquid core of uniform diameter;

[0100] 8) The cladding solution microfluidic pump 1 is used to keep the flow rate of the cladding solution constant, and the core liquid microfluidic pump 4 periodically switches the core liquid flow rate between 0.1 mL / min and 0.3 mL / min at a monotonically decreasing frequency. The core liquid flow rate at the core liquid nozzle 7 is switched between approximately 3.3×104 mm / s and 9.9×104 mm / s. The frequency of the periodic change of the core liquid flow rate monotonically decreases from 1 MHz to 500 KHz within 1 s. As the solution is ejected, a chirped periodic structure modulated flexible grating with a periodic change in the core diameter and a period gradually monotonically increasing from approximately 130 μm to approximately 260 μm is formed;

[0101] 9) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed, and at the same time, the cladding solution microfluidic pump 1 is still used to control the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed, and a step-refractive-index flexible optical fiber can be connected to the other side of the manufactured structure-modulated flexible optical fiber grating;

[0102] 10) The cladding solution is controlled to be ejected from the cladding solution nozzle 6 at a uniform speed by using the cladding solution microfluidic pump 1, and the flow of the core liquid is stopped at the same time. Then, a hydrogel coreless optical fiber 10 with a uniform diameter is connected to the tail end of the manufactured step-refractive-index flexible optical fiber to protect the core liquid in the manufactured step-refractive-index flexible optical fiber and the structure-modulated flexible optical fiber grating from leaking out. At this point, the chirped periodic structure-modulated flexible optical fiber grating with a liquid core and directly connected to the flexible optical fiber at both ends is completed.

[0103] 11) The prepared chirped periodic structure modulated flexible optical fiber Bragg grating with a liquid core is taken out from the solution solidification pool 8, placed in an incubator and heated at 80°C for 2 hours, and then taken out. The liquid core liquid solidifies into a solid state, thus producing a structurally modulated chirped periodic flexible optical fiber Bragg grating with a solid-state stretchable polydimethylsiloxane core.

[0104] Chirp means the sound of birds, and here it refers to the situation where the periodic changes are not fixed.

[0105] Example 6

[0106] Preparation method of multi-period cascade flexible structure modulation grating

[0107] 1) Select a core liquid nozzle 7 with an inner diameter of 8 μm at the outlet end, select a cladding solution nozzle 6 with an inner diameter of 125 μm at the outlet end, first install the core liquid nozzle 7 to the tail end of the core liquid circulation pipeline 3, and then install the cladding solution nozzle 6 to the tail end of the cladding liquid circulation pipeline;

[0108] 2) preparing a sodium alginate solution with a mass concentration of 3%wt as a cladding solution, and injecting the cladding solution into the cladding liquid circulation pipe until the liquid fills the entire circulation pipe and the cladding solution nozzle 6;

[0109] 3) polydimethylsiloxane and curing agent are mixed evenly in a mass ratio of 10:1, and then the mixed liquid is placed in a closed box and the air in the closed box is completely evacuated by a vacuum pump, so that there are no bubbles in the mixed polydimethylsiloxane liquid, and then the polydimethylsiloxane-curing agent mixed solution with bubbles removed is used as the core liquid, and the core liquid is injected into the core liquid circulation pipeline 3 until the liquid fills the entire circulation pipeline and the core liquid nozzle 7;

[0110] 4) preparing a calcium chloride solution with a mass concentration of 5%wt and injecting it into the solution coagulation tank 8;

[0111] 5) Using the displacement adjustment platform 9 to adjust the position of the solution coagulation pool 8 until the nozzle is located below the liquid level of the solution in the solution coagulation pool 8;

[0112] 6) Using the cladding solution microfluidic pump 1 to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, the cladding solution contacts and reacts with the solution in the solution coagulation pool 8, and instantly forms a hydrogel coreless optical fiber 10 with uniform diameter;

[0113] 7) The core liquid microfluidic pump 4 is used to control the core liquid to be uniformly ejected from the core liquid nozzle 7, while the cladding solution microfluidic pump 1 is still used to control the cladding solution to be uniformly ejected from the cladding solution nozzle 6, and the refractive index of polydimethylsiloxane is higher than that of the hydrogel cladding, thereby forming a step-refractive-index flexible optical fiber with a liquid core of uniform diameter;

[0114] 8) The cladding solution microfluidic pump 1 is used to maintain a constant flow rate of the cladding solution. The core liquid microfluidic pump 4 periodically switches the core liquid flow rate between 0.1 mL / min and 0.3 mL / min at a frequency of 1 MHz. The core liquid flow rate at the core liquid nozzle 7 is switched between approximately 3.3×104 mm / s and 9.9×104 mm / s, forming a structurally modulated flexible grating with a periodic change in the core diameter, and its period is approximately 130 μm.

[0115] 9) The cladding solution microfluidic pump 1 is used to maintain a constant flow rate of the cladding solution, and the core liquid microfluidic pump 4 periodically switches the core liquid flow rate between 0.1 mL / min and 0.3 mL / min at a frequency of 500 KHz. The core liquid flow rate at the core liquid nozzle 7 is switched between approximately 3.3×104 mm / s and 9.9×104 mm / s, forming a structurally modulated flexible grating with a periodic change in the core diameter, and its period is approximately 260 μm.

[0116] 10) The cladding solution microfluidic pump 1 is used to maintain a constant flow rate of the cladding solution, and the core liquid microfluidic pump 4 periodically switches the core liquid flow rate between 0.1 mL / min and 0.3 mL / min at a frequency of 380 KHz. The core liquid flow rate at the core liquid nozzle 7 is switched between approximately 3.3×104 mm / s and 9.9×104 mm / s, forming a structurally modulated flexible grating with a periodic change in the core diameter, and its period is approximately 350 μm.

[0117] 11) The core liquid microfluidic pump 4 is used to control the core liquid to be ejected from the core liquid nozzle 7 at a uniform speed. At the same time, the cladding solution microfluidic pump 1 still controls the cladding solution to be ejected from the cladding solution nozzle 6 at a uniform speed. A step-refractive-index flexible optical fiber can be connected to the other side of the manufactured structurally modulated flexible optical fiber grating.

[0118] 12) Use the cladding solution microfluidic pump 1 to control the cladding solution to spray out from the cladding solution nozzle 6 at a uniform speed, and at the same time stop the flow of the core liquid, then connect the hydrogel coreless optical fiber 10 with uniform diameter to the tail end of the manufactured step-refractive index flexible optical fiber to protect the core liquid in the manufactured step-refractive index flexible optical fiber and the structural modulation type flexible optical fiber grating from leaking; at this point, the multi-period cascaded flexible structural modulation type grating, which is directly connected to the flexible optical fiber at both ends and has a liquid core and is formed by cascading three structural modulation type flexible optical fiber gratings with different uniform periods, is completed.

[0119] 13) The prepared multi-period cascade structure modulated flexible optical fiber Bragg grating with a liquid core is taken out from the solution coagulation pool 8, placed in an incubator and heated at 80°C for 2 hours, and then taken out. The liquid polydimethylsiloxane core is coagulated into a solid state, thus producing a multi-period cascade structure modulated flexible optical fiber Bragg grating with a solid-state stretchable polydimethylsiloxane core.

[0120] As described above, the core refractive index of the prepared flexible structure modulated grating and the flexible gratings connected on both sides thereof is higher than the cladding refractive index, satisfying the total reflection condition of the optical waveguide theory. Therefore, there is a lower light transmission loss in light guiding and specific applications, and it is compatible with the existing light transmission and detection systems. At the same time, because the cladding hydrogel formed by the selected cladding solution has good flexibility, elasticity and ductility, the core liquid has fluidity and can adapt to any deformation, and the solid core obtained after high temperature or light treatment also has good flexibility, elasticity and ductility, the prepared structure modulated flexible fiber grating has good flexibility, elasticity and ductility, has strong shear resistance and is compatible with biological change interfaces such as muscle contraction and stretching, can meet a variety of application scenarios, and maintain good sensing accuracy when monitoring continuously changing biological interfaces.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A device for manufacturing a flexible structure modulated grating, characterized in that: It includes a cladding solution microfluidic pump, a core liquid microfluidic pump, a cladding solution circulation pipeline, a core liquid circulation pipeline, and a solution coagulation pool. The core liquid circulation pipeline is arranged in the cladding solution circulation pipeline and is coaxially arranged with the cladding solution circulation pipeline. The top end of the core liquid circulation pipeline is connected with the core liquid microfluidic pump. The bottom end of the core liquid circulation pipeline is provided with a core liquid nozzle. The top end of the cladding solution circulation pipeline is connected with the cladding solution microfluidic pump. The bottom end of the cladding solution circulation pipeline is provided with a cladding solution nozzle. The core liquid nozzle is arranged in the cladding solution nozzle. The solution coagulation pool is arranged below the cladding solution nozzle and the core liquid nozzle. The solution coagulation pool is arranged on a displacement adjustment platform.

2. The manufacturing device of a flexible structure modulated grating according to claim 1, characterized in that: The side surface of the cladding solution circulation channel is fixed by a fixing fixture.

3. The manufacturing device of a flexible structure modulated grating according to claim 1, characterized in that: The cladding solution nozzle and the core solution nozzle are both conical nozzles made of metal or glass.

4. A method for manufacturing a flexible structure modulated grating according to any one of claims 1 to 3, characterized in that: Here are the steps: S1, the cladding solution circulation pipeline and the core liquid circulation pipeline are coaxially arranged, the core liquid nozzle is installed and connected to the tail end of the core liquid circulation pipeline, and the cladding solution nozzle is installed and connected to the tail end of the cladding liquid circulation pipeline; S2, preparing a coating solution, injecting the coating solution into the coating solution circulation pipe until the liquid fills the entire coating solution circulation pipe and the coating solution nozzle, the coating solution is a sodium alginate solution, and the mass concentration of the sodium alginate solution includes any ratio between 2%wt, 3%wt, 4%wt and 7%wt; S3, preparing a core liquid, injecting the core liquid into the core liquid circulation channel until the liquid fills the entire core liquid circulation channel and the core liquid nozzle, wherein the core liquid includes one or more of a glycerol aqueous solution, an inorganic salt solution, and an organic liquid for making a liquid fiber core; a gelatin aqueous solution for making a gelatin gel fiber core; a polydimethylsiloxane-curing agent mixed solution, an acrylamide mixed solution, and a photopolymerized glue for making a solid fiber core; S4, configuring a calcium chloride solution as the solution in the solution coagulation tank, and injecting the calcium chloride solution into the solution coagulation tank; S5, using the displacement adjustment platform to adjust the position of the solution coagulation pool until the core solution nozzle and the cladding solution nozzle are located below the liquid level of the solution in the solution coagulation pool; S6, the cladding solution micro-flow pump is used to control the flow rate of the cladding solution to be constant so as to spray it out through the cladding solution nozzle, after the cladding solution contacts the solution in the solution coagulation pool, the calcium ions of the calcium chloride in the solution coagulation pool react with the sodium ions of the sodium alginate to form a hydrogel with a cross-linked network structure, and as the cladding solution is ejected at a uniform speed, a hydrogel coreless optical fiber with uniform diameter is instantly formed; S7, the cladding solution flow rate is controlled by the cladding solution micro-fluid pump to be constantly ejected through the core liquid nozzle, the core liquid micro-fluid pump periodically changes the core liquid flow rate, and the core diameter is periodically changed, so as to obtain a flexible grating with a periodically modulated core diameter and a core in a liquid state, which is protected by the formed hydrogel coreless optical fiber, and the core liquid will not leak from the end face of the flexible optical fiber, and is protected by the instantly formed hydrogel cladding, and the core liquid will not leak from the side wall of the flexible optical fiber; S8, controlling the cladding solution to be uniformly ejected from the cladding solution nozzle by the cladding solution micro-flow pump, connecting a hydrogel coreless optical fiber with uniform diameter to the end of the flexible grating with periodically modulated core diameter, so as to play a protective role; S9, taking out the prepared flexible fiber grating from the solution solidification pool.

5. The method for manufacturing a flexible structure modulation grating according to claim 4, characterized in that: In S3, the glycerol aqueous solution is formed by mixing glycerol and water in a certain volume ratio, and the ratio includes any ratio between 1:1, 1:2, 1:3 and 1:20; the inorganic salt solution includes sodium chloride solution and phosphate solution; the organic liquid includes siloxane and ethanol.

6. The method for manufacturing a flexible structure modulation grating according to claim 4, characterized in that: In S3, the gelatin aqueous solution is prepared by dissolving gelatin particles in deionized water, heating the water to 80°C to prepare a gelatin aqueous solution with a mass concentration of about 10%, then adding glycerol to the gelatin aqueous solution, and mixing the solution evenly; the gelatin aqueous solution is used as the core liquid, and after the flexible optical fiber Bragg grating is taken out in S9, it is allowed to stand at room temperature for 24 hours to form a flexible optical fiber Bragg grating with a gelatin gel core.

7. The method for manufacturing a flexible structure modulation grating according to claim 4, characterized in that: In S3, the polydimethylsiloxane-curing agent mixed solution is obtained by mixing polydimethylsiloxane and a curing agent in a mass ratio of 10:1 and removing bubbles from the mixed solution; the polydimethylsiloxane-curing agent mixed solution is used as the core liquid, and after the flexible optical fiber Bragg grating is taken out in S9, the taken out grating is placed in an incubator and heated at 80°C for 2 hours, and the core changes from liquid to solid, thereby forming a flexible optical fiber Bragg grating with a solid core.

8. The method for manufacturing a flexible structure modulation grating according to claim 4, characterized in that: In S3, the acrylamide mixed solution is prepared by dissolving acrylamide monomer in deionized water and stirring to obtain an acrylamide solution, and then adding a crosslinking agent N, N-methylenebisacrylamide and a photoinitiator 2, 2'-azo (2-methylpropionic acid amide) to the solution, and stirring the solution to obtain an acrylamide solution; The flexible fiber Bragg grating is taken out at S9 by using an acrylamide mixed solution and then irradiated with ultraviolet light for 2 hours, so that the core changes from liquid to solid, forming a flexible fiber Bragg grating with a solid core.

9. The method for manufacturing a flexible structure modulation grating according to claim 4, characterized in that: In S3, photopolymerized glue is used as the core liquid. After the flexible fiber grating is taken out in S9, the grating is illuminated with light of a specific wavelength for 2 hours, and the core changes from liquid to solid, forming a flexible fiber grating with a solid core.

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