High-sensitivity particle liquid crystal optical fiber

Abstract

The utility model discloses a high-sensitivity particle liquid crystal optical fiber, which comprises a fiber core and a cladding layer arranged on the periphery of the fiber core, a plurality of air holes are arranged in the cladding layer and form a regular polygon structure, each air hole is filled with liquid crystal, the fiber core is arranged in the center of the cladding layer, a cavity is arranged in the fiber core, and the cladding layer is arranged in the cavity. The cavity is filled with silicon dioxide particles; the method has the advantage that the detection sensitivity and resolution of the sensor can be remarkably improved.

Description

Technical Field

[0001] The utility model relates to an optical fiber, in particular to a high-sensitivity particle liquid crystal optical fiber. Background Art

[0002] In the era of information explosion, optical fiber devices have become a vital component of information transmission and detection instruments. Optical devices based on photonic crystal fiber (PCF), in particular, have gained widespread application in sensing technology due to their unique microstructure and excellent optical properties. PCF, by arranging a series of periodic air holes around its core, forms a unique photonic bandgap structure that effectively guides and manipulates optical signals. This structure not only improves the transmission performance of the fiber but also opens new possibilities for detecting parameters such as temperature, stress, and refractive index.

[0003] In recent years, liquid crystal-filled photonic crystal fiber (PLCF) has garnered widespread attention as an emerging fiber structure. Liquid crystals possess the optical properties of crystals (such as birefringence, polarization, and optical rotation) and the fluidity of liquids, making them highly sensitive to changes in the external environment (such as temperature, electric field, and stress). By filling the air holes of a PCF with liquid crystals, a novel PLCF structure can be formed. This structure not only retains the photonic band gap characteristics of the PCF but also imparts the fiber's high sensitivity to changes in environmental parameters. Therefore, sensors based on PLCFs exhibit significant potential for measuring physical parameters such as temperature, electric field, and stress.

[0004] However, existing PLCF sensors still have several limitations. First, most traditional PLCF sensors use a fully filled structure, where liquid crystal material is filled into all the air holes in the PCF. While this structure is simple and easy to fabricate, the unique nature of the liquid crystal material and the fixed filling position limit the potential for improving sensor sensitivity. Second, during optical signal transmission, the coupling efficiency between the fiber core and the liquid crystal holes in fully filled PLCFs is low, which limits their applications for long-distance transmission and high-sensitivity detection. Furthermore, the response speed and stability of the liquid crystal material's optical properties to changes in external environmental parameters need to be improved. To address these issues, researchers have begun exploring ways to improve the performance of PLCF sensors by introducing novel structures and materials. For example, selectively filling liquid crystal material into some of the air holes in the PCF to form a selective filling structure can effectively improve the sensitivity and stability of the sensor. However, the design and fabrication of selective filling structures are complex and require precise control of the filling position and amount of liquid crystal material, which remains challenging in practical operation.

[0005] In summary, although PLCF-based sensors have made significant progress in many aspects, the existing technology still has problems such as limited sensitivity improvement, low coupling efficiency and complex preparation process. Therefore, this application proposes a high-sensitivity particle liquid crystal fiber to solve the above problems. Utility Model Content

[0006] The purpose of the utility model is to provide a high-sensitivity particle liquid crystal optical fiber, which can significantly improve the detection sensitivity and resolution of the sensor.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a high-sensitivity particle liquid crystal optical fiber, comprising a core and a cladding arranged around the core, wherein a plurality of air holes are arranged in the cladding, and the plurality of air holes form a regular polygonal structure, each of the air holes is filled with liquid crystal, the core is arranged at the center of the cladding, and the core has a cavity, and the cavity is filled with silica particles.

[0008] Preferably, the plurality of air holes are symmetrically distributed in a hexagonal shape, the spacing between adjacent air holes is equal, and the diameter of each air hole is 2-5 microns.

[0009] Preferably, the longitudinal section of the cavity is circular, and the diameter of the cavity is 0.5-2 microns.

[0010] Preferably, the particle size of the silicon dioxide particles is 50-200 nanometers, and the surface of the silicon dioxide particles is silanized.

[0011] Preferably, the liquid crystal is a nematic liquid crystal, the sensitivity of the refractive index change with temperature is greater than 0.001 / °C, and the clearing point temperature of the liquid crystal is between 60-80°C.

[0012] Preferably, the inner wall of each of the air holes is coated with an orientation layer, the orientation layer is made of a polyimide material, and the surface of the orientation layer is subjected to friction treatment to form a microscopic groove structure.

[0013] Preferably, a protective layer is provided on the outside of the cladding, the protective layer is made of ultraviolet curing resin, the thickness of the protective layer is 10-30 microns, and the surface of the protective layer is coated with a waterproof and moisture-proof coating.

[0014] Preferably, the core and the cladding are both made of quartz, the refractive index of the cladding is smaller than the refractive index of the core, and the refractive index difference between the core and the cladding is maintained between 0.01-0.02.

[0015] Compared with the existing technology, the advantages of the present invention are as follows: the high-sensitivity particle liquid crystal optical fiber forms a unique dual-sensitive structure by providing air holes distributed in a regular polygonal pattern in the cladding and filling them with liquid crystals, while simultaneously filling the central cavity of the fiber core with silica particles. Specifically, the air holes filled with liquid crystals in the cladding form a periodic arrangement. This structure can produce a photonic crystal effect, effectively regulating the transmission characteristics of light. The liquid crystal molecules are very sensitive to physical quantities such as external temperature, electric field, and magnetic field, and their refractive index changes with changes in these physical quantities, thereby modulating the transmission characteristics of the optical signal. The silica particles filled in the fiber core can enhance the interaction between light and matter through scattering and local field enhancement effects. At the same time, the surface of the particles can be functionally modified to provide additional sensing sites. Overall, this structural design not only achieves high-sensitivity detection, but also has the advantages of structural stability, fast response, and strong anti-interference ability, and has important application value in the field of optical fiber sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0017] Figure 1 It is a structural diagram of the utility model;

[0018] Figure 2 It is a schematic diagram of the cross-sectional structure of the utility model;

[0019] Figure 3 For this utility model Figure 2 A partial enlarged schematic diagram of point A in the middle;

[0020] In the figure, 1. Fiber core; 2. Cladding; 3. Air hole; 4. Liquid crystal; 5. Cavity; 6. Silica particles; 7. Protective layer; 8. Waterproof and moisture-proof coating. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0022] Example 1: As shown in the figure, a high-sensitivity particle liquid crystal 4 optical fiber includes a core 1 and a cladding 2 arranged on the periphery of the core 1, a plurality of air holes 3 are arranged in the cladding 2, and the plurality of air holes 3 form a regular polygon structure. Each air hole 3 is filled with liquid crystal 4, the core 1 is arranged at the center of the cladding 2, and the core 1 has a cavity 5, and the cavity 5 is filled with silica particles 6.

[0023] Example 2: As shown in the figure, the difference from Example 1 is that the multiple air holes 3 are symmetrically distributed in a hexagonal shape, the spacing between adjacent air holes 3 is equal, and the diameter of each air hole 3 is 2-5 microns.

[0024] In the above structure, the air holes 3 are symmetrically distributed in a hexagonal pattern with equal spacing, and the design of a diameter of 2-5 microns is of great significance. This periodic arrangement forms a photonic crystal structure, which can effectively control the propagation direction and mode of light. The hexagonal structure has the best space filling efficiency and stress distribution uniformity. The aperture size of 2-5 microns ensures single-mode light transmission conditions, avoids mode coupling loss, and at the same time ensures sufficient liquid crystal 4 filling volume and structural strength.

[0025] In this embodiment, the longitudinal section of the cavity 5 is circular, and the diameter of the cavity 5 is 0.5-2 microns.

[0026] In the above structure, the circular structure design with the diameter of the cavity 5 controlled within the range of 0.5-2 microns can provide appropriate particle filling space while ensuring the mechanical strength of the fiber core 1. The circular cross-section can reduce stress concentration and improve structural stability. In addition, this size range is equivalent to the operating wavelength of the optical fiber, which is conducive to the interaction between the light field and the particles while avoiding multi-mode transmission.

[0027] In this embodiment, the particle size of the silicon dioxide particles 6 is 50-200 nanometers, and the surface of the silicon dioxide particles 6 is silanized.

[0028] In the above structure, the particle size range of 50-200 nanometers enables the particles to be evenly distributed in the cavity 5 and matches the wavelength of light, which can produce effective Rayleigh scattering. The surface silanization treatment not only improves the dispersion of the particles and prevents agglomeration, but also enhances the bonding force with the fiber core 1 material, thereby improving the stability and repeatability of the sensing structure.

[0029] In this embodiment, the liquid crystal 4 is a nematic liquid crystal 4 , the sensitivity of its refractive index change with temperature is greater than 0.001 / ° C., and the clearing point temperature of the liquid crystal 4 is between 60° C. and 80° C.

[0030] In the above structure, a nematic liquid crystal 4 with a refractive index temperature sensitivity greater than 0.001 / °C and a clearing point temperature of 60-80°C is selected to ensure that the sensor has high sensitivity and a wide measurement range. The orientation of the nematic liquid crystal 4 molecules changes significantly with temperature. While maintaining the phase state of the liquid crystal 4, it can achieve effective modulation of the light signal, and the higher clearing point temperature ensures the stable operation of the sensor within the commonly used temperature range.

[0031] Embodiment 3: As shown in the figure, the difference from embodiment 2 is that the inner wall of each air hole 3 is coated with an orientation layer, which is made of polyimide material and its surface is friction-treated to form a microscopic groove structure.

[0032] In the above structure, a friction-treated polyimide alignment layer is used on the inner wall of the air hole 3 to form a microscopic groove structure. This design can force the liquid crystal 4 molecules to align in a specific direction.

[0033] Polyimide material has excellent thermal and chemical stability, and the microscopic groove structure provides the orientation basis of liquid crystal molecules, ensuring that the liquid crystal molecules can be arranged in an orderly manner and improving the efficiency of optical signal modulation.

[0034] In this embodiment, a protective layer 7 is provided on the outside of the cladding 2 . The protective layer 7 is made of ultraviolet curing resin and has a thickness of 10-30 microns. The surface of the protective layer 7 is coated with a waterproof and moisture-proof coating 8 .

[0035] In the above structure, a protective layer 7 with a thickness of 10-30 microns is made of ultraviolet light-curing resin and coated with a waterproof and moisture-proof coating 8, forming a multi-protection system. The ultraviolet light-curing resin has good mechanical properties and fast curing characteristics. The appropriate thickness ensures the protective effect without significantly increasing the diameter of the optical fiber. The waterproof and moisture-proof coating 8 further improves the environmental adaptability and service life of the optical fiber.

[0036] In this embodiment, the core 1 and the cladding 2 are both made of quartz, the refractive index of the cladding 2 is smaller than that of the core 1 , and the refractive index difference between the core 1 and the cladding 2 is maintained between 0.01 and 0.02.

[0037] In the above structure, quartz material is selected to make the fiber core 1 and cladding 2, and the refractive index difference is controlled between 0.01 and 0.02. This design ensures good transmission characteristics of the optical signal. Quartz material has excellent optical transparency and mechanical strength. The precisely controlled refractive index difference ensures good confinement and transmission of light in the fiber core 1, while avoiding excessive dispersion and loss.

[0038] The above is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A high-sensitivity particle liquid crystal optical fiber comprising a core and a cladding disposed around the core, wherein the cladding is provided with a plurality of air holes, the plurality of air holes forming a regular polygonal structure, characterized in that: Each of the air holes is filled with liquid crystal. The fiber core is arranged at the center of the cladding. The fiber core has a cavity therein, and the cavity is filled with silicon dioxide particles.

2. The high-sensitivity particle liquid crystal optical fiber according to claim 1, characterized in that: The plurality of air holes are symmetrically distributed in a hexagonal shape, the spacing between adjacent air holes is equal, and the diameter of each air hole is 2-5 microns.

3. The high-sensitivity particle liquid crystal optical fiber according to claim 1, characterized in that: The longitudinal section of the cavity is circular, and the diameter of the cavity is 0.5-2 microns.

4. The high-sensitivity particle liquid crystal optical fiber according to claim 1, characterized in that: The particle size of the silicon dioxide particles is 50-200 nanometers, and the surface of the silicon dioxide particles is silanized.

5. The high-sensitivity particle liquid crystal optical fiber according to claim 1, characterized in that: The liquid crystal is a nematic liquid crystal, the sensitivity of its refractive index change with temperature is greater than 0.001 / °C, and the clearing point temperature of the liquid crystal is between 60-80°C.

6. The high-sensitivity particle liquid crystal optical fiber according to claim 1, characterized in that: The inner wall of each air hole is coated with an alignment layer, which is made of a polyimide material and has a surface that is subjected to friction treatment to form a microscopic groove structure.

7. The high-sensitivity particle liquid crystal optical fiber according to claim 1, characterized in that: A protective layer is provided on the outside of the cladding. The protective layer is made of ultraviolet curing resin and has a thickness of 10-30 microns. The surface of the protective layer is coated with a waterproof and moisture-proof coating.

8. The high-sensitivity particle liquid crystal optical fiber according to claim 1, characterized in that: The fiber core and the cladding are both made of quartz, the refractive index of the cladding is smaller than the refractive index of the fiber core, and the refractive index difference between the fiber core and the cladding is maintained between 0.01 and 0.02.

Images