CN113959585B - Spiral photonic crystal fiber temperature sensor based on SPR - Google Patents
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- 239000000835 fiber Substances 0.000 title claims abstract description 76
- 239000004038 photonic crystal Substances 0.000 title claims abstract description 33
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 69
- 230000035945 sensitivity Effects 0.000 claims abstract description 37
- 239000007788 liquid Substances 0.000 claims abstract description 31
- 238000005253 cladding Methods 0.000 claims abstract description 26
- 238000001514 detection method Methods 0.000 claims abstract description 11
- 239000010453 quartz Substances 0.000 claims abstract description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000000758 substrate Substances 0.000 claims abstract description 9
- 239000002184 metal Substances 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 5
- 239000000463 material Substances 0.000 claims description 7
- 230000003287 optical effect Effects 0.000 claims description 2
- 238000013519 translation Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 10
- 239000010410 layer Substances 0.000 description 30
- 230000008878 coupling Effects 0.000 description 17
- 238000010168 coupling process Methods 0.000 description 17
- 238000005859 coupling reaction Methods 0.000 description 17
- 239000013307 optical fiber Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 3
- 239000010931 gold Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000011344 liquid material Substances 0.000 description 2
- 238000002198 surface plasmon resonance spectroscopy Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000003574 free electron Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
The invention discloses a spiral photonic crystal fiber temperature sensor based on SPR, which comprises a main body structure formed by photonic crystal fibers, wherein the photonic crystal fibers comprise a fiber core area and a cladding area which are sequentially arranged from inside to outside, the fiber core area is formed by a fiber core center big hole and surrounding quartz substrates, and toluene liquid is filled in the fiber core center big hole to form a liquid core; the cladding region consists of four layers of air holes which are arranged in a regular octagon shape and are symmetrically distributed in a C 8v way, two adjacent layers of air holes which are arbitrarily adjacent to each other form isosceles triangle distribution, and one air hole which is arranged in a staggered way with the first layer of air holes is arbitrarily selected in the second layer from inside to outside to fill metal wires to form a surface plasma die; the photonic crystal fiber is twisted under the heating of a CO 2 laser to form a longitudinal spiral twisting structure. The sensor provided by the invention is processed to form a longitudinal spiral torsion structure, and combines with an SPR effect, so that the sensing sensitivity of a wide temperature detection range, high sensitivity and high torsion rate is realized.
Description
Technical Field
The invention relates to the technical field of optical fiber communication, in particular to a spiral photonic crystal fiber temperature sensor based on SPR.
Background
The optical fiber sensing technology is a novel sensing technology which uses light waves as a carrier and uses optical fibers as a transmission medium to sense and transmit external measurement signals. The surface plasmon (Surface Plasmon Polariton, SPP) is electron density wave in which photons and free oscillation electrons excite each other at a metal-dielectric surface, and by selectively filling metal or metal-plated films in a photonic crystal fiber (Photonic Crystal Fiber, PCF), when the incident light is matched with the free electron phase, resonance coupling occurs when the fiber core mold guided by the fiber and the SPP mold meet the phase matching, namely, the surface plasmon resonance (Surface Plasmon Resonance, SPR) effect is generated. The temperature sensitive material is effectively combined with the SPR effect, so that the resonance peak intensity can be remarkably improved, the resonance position can be adjusted, and the sensitivity and the temperature detection range of the temperature sensor can be improved.
In the prior art, the solutions of PCF temperature sensors commonly used are: (1) Filling temperature sensitive materials in a specific air hole of the PCF, introducing a cladding defect mode into the cladding, and realizing resonance coupling at different wavelengths by changing the temperature by utilizing phase matching conditions generated by introducing the defect mode into the fiber core mode and the cladding, thereby realizing temperature sensing; (2) PCF temperature sensor based on SPR is filled with temperature sensitive material and metal material, and resonance coupling of different wavelengths is realized based on SPR effect by changing temperature, thus completing design of temperature sensing. The technology is to change the refractive index of the temperature-sensitive material by changing two-dimensional structural parameters, adjust the external temperature, combine SPR, realize the temperature sensor by utilizing the resonance coupling of a cladding defect mode and a fiber core mode, but the temperature sensor can not meet the requirement of high sensitivity, and once the structural parameters are fixed, the adjustment of higher sensitivity can not be completed by utilizing a post-treatment technology. In addition, the temperature sensitivity generated by the prior art is almost lower than 10 nm/DEG C, and the detection temperature window is relatively narrow, so that the practicability is affected.
In addition, the application document of the patent application number 202010280419.2 discloses a spiral PCF selectively filled double-parameter sensor, wherein a PCF with a spiral hexagonal structure is adopted, toluene liquid is filled in an air hole in the horizontal direction of a second layer of a cladding, and the temperature and the torsion rate are changed by utilizing the phase matching of a toluene liquid cladding die and a fiber core die, and one is a double-parameter sensor with the torsion rate range of 13.8-14.214 rad/mm and the torsion sensing sensitivity of 3.623 multiplied by 10 -6mm2/rad; the other is that the temperature detection range is 15-30 ℃, and the corresponding temperature sensing sensitivity is 2 nm/DEG C. Although this patent uses a longitudinal spiral to effect sensing, because the cladding is filled with toluene liquid at the location of the air hole and the core is separated by an air hole, the air hole is aligned horizontally side by side with the toluene liquid filled hole and the core, so that the core and the cladding liquid mode are completely separated, affecting the resonant coupling of the two modes. In addition, because the fiber core of the disclosed patent is a solid fiber, the uniform longitudinal spiral can affect the fiber core mode and the waveguide mode filled with toluene liquid in the same rule at the same time, namely, the refractive indexes of the two modes are increased or reduced at the same time, so that the drift range of loss peaks of the two modes is reduced, and the sensitivity of the temperature sensor is smaller.
In order to meet the requirements of high sensitivity and wide temperature detection range, it is necessary to design a longitudinal spiral torsion optical fiber sensor based on the SPR effect.
Disclosure of Invention
The invention aims to provide a spiral photonic crystal fiber temperature sensor based on SPR, which designs a longitudinal spiral torsion structure and combines an SPR effect to realize a wide temperature detection range, high sensitivity and high torsion rate sensing sensitivity.
In order to achieve the above object, the present invention provides the following solutions:
A SPR-based spiral photonic crystal fiber temperature sensor, comprising: the main body structure consists of PCF (photonic crystal fiber), wherein the substrate material is quartz, the PCF comprises a fiber core area and a cladding area which are sequentially arranged from inside to outside, the fiber core area consists of a fiber core center big hole and surrounding quartz substrates, and toluene liquid is filled in the fiber core center big hole to form a liquid core; the cladding region consists of four layers of air holes which are arranged in a regular octagon shape, and are symmetrically distributed in a C 8v way, two adjacent layers of air holes are arbitrarily adjacent to each other to form isosceles triangle distribution, wherein the bottom side length of the isosceles triangle is the distance between each layer of air holes and each air hole, the vertex angle of the isosceles triangle is 45 degrees, and one air hole which is arranged in a staggered way with the first layer of air holes is arbitrarily selected in the second layer from inside to outside to be filled with metal wires to form a surface plasma die; the PCF is twisted under the heating of a CO 2 laser to form a longitudinal spiral twisting structure.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects: according to the spiral PCF temperature sensor based on SPR, toluene liquid is filled in the central macropores of the fiber core to form a liquid core, one air hole which is staggered with the first air hole in the second layer of the cladding region is arbitrarily selected to be filled with metal wires, an SPP mode can be formed, the longitudinal direction of the fiber structure is spirally twisted, the SPP mode and the temperature change of the fiber longitudinal spiral torsion which mainly influence the cladding are mainly used for influencing the characteristic of the toluene liquid core, namely, the refractive index of two modes only has a larger influence on one mode when different torsion rates or different temperatures are changed, and the characteristic that the refractive index of two modes of two different types is changed by one mode under different external conditions is hardly changed is utilized, so that the two modes generate higher resonance wavelength drift, higher sensing sensitivity is obtained, and a wide temperature detection range is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1a is a schematic diagram of a two-dimensional end face structure of a SPR-based spiral photonic crystal fiber temperature sensor according to an embodiment of the present invention;
FIG. 1b is a schematic diagram of a longitudinal spiral structure of a SPR-based spiral photonic crystal fiber temperature sensor according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of resonant coupling distribution of a circularly polarized core mode and an SPP mode according to an embodiment of the present invention;
FIG. 3a is a diagram of a left-hand circularly polarized core mold that is uncoupled in accordance with an embodiment of the present invention;
FIG. 3b is a diagram of the mode field of an uncoupled SPP mode according to an embodiment of the present invention;
FIG. 3c is a diagram of a mode field for coupling a left-hand circularly polarized core mode with an SPP mode according to an embodiment of the present invention;
FIG. 4a is a graph showing a temperature sensitivity change histogram with twist rate according to an embodiment of the present invention;
FIG. 4b is a graph of the loss of temperature from 10℃to 30℃for an embodiment of the invention with a twist rate fixed at 6 rad/mm;
FIG. 4c is a graph of loss for an embodiment of the invention with a temperature change from 40℃to 60℃when the twist rate is fixed at 6 rad/mm;
FIG. 4d is a plot of resonance wavelength versus temperature for a temperature change from 10℃to 60℃for a twist rate of 6rad/mm in accordance with an embodiment of the present invention;
FIG. 5a is a graph of the loss of twist rate from 2rad/mm to 6rad/mm at a fixed temperature of 30℃for an embodiment of the present invention;
FIG. 5b is a plot of resonant wavelength versus twist rate for an embodiment of the invention with a temperature of 30℃fixed, and with a twist rate varying from 2rad/mm to 6 rad/mm;
reference numerals: 1. a large hole is formed in the center of the fiber core; 2. filling the hole; 3. an air hole; 4. a substrate; 5. and (3) coating.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a spiral photonic crystal fiber temperature sensor based on SPR, which designs a longitudinal spiral torsion structure and combines an SPR effect to realize a wide temperature detection range, high sensitivity and high torsion rate sensing sensitivity.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
As shown in fig. 1a and 1b, a spiral photonic crystal fiber temperature sensor based on SPR according to an embodiment of the present invention includes: the PCF (photonic crystal fiber) comprises a main body structure formed by PCF (photonic crystal fiber), wherein a substrate 4 is made of quartz, a coating layer 5 is wrapped outside, the PCF comprises a fiber core area and a cladding area which are sequentially arranged from inside to outside, the fiber core area is formed by a fiber core center macropore 1 and surrounding quartz substrates, and toluene liquid is filled in the fiber core center macropore 1 to form a liquid core, namely a fiber core mould; the cladding region consists of four layers of air holes 3 which are arranged in a regular octagon shape and are symmetrically distributed in C 8v, two adjacent layers of air holes are arbitrarily adjacent to each other to form isosceles triangle distribution, wherein the bottom side length of the isosceles triangle is the distance between each layer of air holes and each air hole, the vertex angle of the isosceles triangle is 45 degrees, one air hole which is arranged in a staggered layer with the first layer of air holes is arbitrarily selected in the second layer from inside to outside to fill metal wires, for example, the filling holes 2 are filled with metal wires, SPP (surface plasma) mode is formed, the resonance coupling of a fiber core mode and the SPP mode can be better realized, meanwhile, the two mode field positions are prevented from being too close, and the two modes are fused in the whole working wave band, so that peak loss is not obvious; the PCF is twisted under the heating of a CO 2 laser to form a longitudinal spiral twisting structure.
The four layers of air holes are arranged in a regular octagon shape, namely a first layer, a second layer, a third layer and a fourth layer from inside to outside, wherein the number of the air holes of the first layer is 8, the number of the air holes of the second layer is 16, the number of the air holes of the third layer is 24, and the number of the air holes of the fourth layer is 32.
The PCF is twisted to form a longitudinal spiral torsion structure under the heating of a CO 2 laser, and permanent torsion can be applied to the untwisted PCF, and the PCF specifically comprises:
When the motor rotates, the steering mirror fixed on the precise electric translation stage is used to scan the focused 10 mu m laser beam along the PCF, the shutter type adjustable optical attenuator arranged on the CO 2 laser beam path is used to adjust the laser power and the exposure time, the torsion period of the electric rotation stage and the length of the PCF sample are set, the corresponding laser power and the scanning speed are selected, and the PCF is heated to soften and twisted, thus the longitudinal spiral torsion of the PCF is completed.
The torsion rate a=2pi/L, wherein L is a torsion period, and the value range of the torsion rate is 2-6 rad/mm.
The diameter d c of the central macropore of the fiber core is 2.1-2.12 mu m; the diameter d of each layer of air hole is 1.8-1.82 mu m;
The hole spacing lambda between the air holes in the same layer is 2.2-2.22 mu m; the hole spacing Λ 1 between the air holes of two adjacent layers is as follows: the isosceles triangle apex angle was 45 °, the base length was Λ, and the isosceles triangle waist length Λ 1 =0.5 Λ/sin (pi/8) =0.5 Λ/sin (22.5 °).
The temperature detection range of the sensor is 10 ℃ to 60 ℃, and the average temperature sensitivity is up to 17.77 nm/DEG C.
The sensor has a twist sensitivity of up to 6.25 x 10 -5mm2/rad.
The helical twist in the longitudinal direction of the PCF has an increasing effect on its optical fiber mode refractive index from the center to the outer layer. The PCF fiber core mould is formed by filling toluene liquid in a fiber core center macroporous 1, the refractive index of the toluene liquid is higher than that of a substrate quartz, the total internal reflection transmission of limited light is mainly determined by the material of a high refractive index fiber core, and the change of the boundary condition of a cladding region (the boundary condition of a cylindrical coordinate is changed into the boundary condition of a spiral coordinate) has little influence on the high refractive index fiber core, so that the influence of a longitudinal spiral torsion structure on the liquid core mould formed by the toluene liquid is little; the longitudinal spiral torsion structure can change the refractive index of cladding modes to a great extent, and the longitudinal torsion of the pure solid PCF greatly influences the transmission of the fiber core mode of the pure solid PCF, and the solid PCF is used for limiting the transmission of light in the fiber core area by virtue of air holes periodically arranged in the cladding.
The longitudinal spiral torsion has a larger influence on the cylindrical holes filled with the gold wires on the second layer of the cladding region, so that the refractive index of the surface plasma mode generated by the filling of the gold wires is greatly influenced; when the SPP mode is phase matched to the liquid core mode, a resonant coupling of the core and SPP modes at a particular wavelength is created. The toluene liquid is filled into the central hole and the gold wire is filled into the air hole of the cladding, so that the longitudinal spiral torsion mainly changes the refractive index of the SPP mode and the refractive index of the core mode is extremely little influenced, and therefore, the longitudinal spiral torsion with different torsion rates can realize larger resonance wavelength drift and obtain higher torsion sensing. The change of temperature mainly affects the refractive index of the liquid core fiber core mould, hardly affects the refractive index of the SPP mode, and can also generate higher resonance wavelength drift and obtain higher temperature sensing sensitivity according to the characteristic that the refractive indexes of two different types of modes are changed one by one and hardly changed one by different temperatures.
The PCF structure provided by the invention not only can change structural parameters on a two-dimensional end surface, but also can change the torsion degree of a three-dimensional direction (longitudinal direction), the PCF is heated by a post-processing CO 2 laser, the optical fiber is rotated by combining with an accurate rotating platform, the torsion period of the optical fiber is changed, and the sensitivity of a temperature sensor is increased. Due to the spiral of the optical fiber in the longitudinal direction, the conventional linearly polarized light is divided into circularly polarized light, i.e., left circularly polarized light and right circularly polarized light, and PCF of a spiral structure can generate left circularly polarized light and right circularly polarized light with different propagation constants. Since the left circularly polarized light can generate higher resonant coupling, the invention selects the left circularly polarized light as a fiber core mode of temperature sensing.
FIG. 2 shows the resonant coupling of a left-hand circularly polarized core mode with an SPP mode at a temperature of 20deg.C and a twist rate of 6rad/mm, and the resonant coupling at the phase matching point produces peak loss when the core mode and SPP mode refractive indices are the same.
Fig. 3a to 3c show, to the right, the corresponding left-hand circularly polarized core mode without coupling, the SPP mode without coupling, and the mode field diagram with coupling of the left-hand circularly polarized core mode and the SPP mode, respectively, of fig. 2. As can be seen from fig. 3a to 3c, the left-hand circularly polarized core mode and the SPP mode are limited to propagation of the respective modes when the coupling is not performed; and when coupling occurs, a significant portion of the energy of the left-hand circularly polarized core mode is transferred to the SPP mode field, resulting in peak loss of the core mode, consistent with the results of FIG. 2.
FIG. 4a shows that when the temperature is changed from 10℃to 20℃and the twist rates are 2rad/mm, 4rad/mm and 6rad/mm, respectively, the corresponding temperature sensitivities thereof reach 17 nm/DEG C, 18 nm/DEG C and 19 nm/DEG C, respectively, it is known that the temperature sensitivity thereof gradually increases as the twist rate increases.
FIG. 4b shows a graph of losses at a fixed twist rate of 6rad/mm with a temperature change from 10℃to 30 ℃. The refractive index equation of the toluene liquid with temperature is that,Σ=3.94×10 -4/°c represents the thermal coefficient of toluene. The change in temperature changes the refractive index of the toluene liquid, thereby changing the refractive index of the core mode, while the change in temperature hardly affects the refractive index of the surface plasmon mode field, so that a wider resonance wavelength shift can be obtained. As can be seen from FIG. 4b, the resonance wavelengths corresponding to the temperatures of 10 ℃, 20 ℃ and 30 ℃ are 1.99 μm,2.18 μm and 2.36 μm respectively, and the formula/> is calculated according to the sensitivity of the temperature sensorΔλ peak represents the shift amount of the resonance wavelength, and Δt represents the change amount of the temperature, whereby the corresponding temperature sensing sensitivities are 19nm/°c and 18nm/°c, respectively.
FIG. 4c shows a graph of the loss of toluene from 40℃to 60℃by varying the temperature of the temperature-sensitive liquid material at a fixed twist rate of 6 rad/mm. As can be seen from FIG. 4c, the temperatures were 40℃and 50℃and the corresponding resonant wavelengths were 2.54. Mu.m, 2.71. Mu.m, and 2.88. Mu.m, respectively, and the corresponding temperature sensitivities were 17 nm/. Degree.C.and 16 nm/. Degree.C.respectively.
FIG. 4d shows that when the twist rate is 6rad/mm, the temperature is in the range of 10-60℃and the resonance wavelengths are 1.99 μm,2.18 μm,2.36 μm, 2.54 μm, 2.71 μm, 2.88 μm, respectively, per 10℃interval. In fig. 4d, a linear straight line fitting is performed on the relation between the temperature and the resonance wavelength, the linear fitting equation is y=0.01777x+1.82133, the fitting linearity reaches 0.999, the average sensitivity is up to 17.77 nm/DEG C in the range of 10-60 ℃, and the temperature sensitivity is about 5 times higher than that realized in the prior art.
FIG. 5a shows fiber loss profiles with twist rates of 2rad/mm, 4rad/mm, and 6rad/mm, respectively, at a fixed temperature of 30 ℃. As can be seen from FIG. 5a, the resonance wavelengths corresponding to the twist rates of 2rad/mm, 4rad/mm and 6rad/mm are 2.11 μm, 2.22 μm and 2.36 μm, respectively, and the twist rate sensitivity calculation formula is based onWhere Δα represents the amount of change in twist rate, from which it is known that the corresponding twist sensitivities are 5.5X10 -5mm2/rad and 7X 10 -5mm2/rad, respectively.
Fig. 5b shows a linear fit of the resonant wavelength and twist at a temperature of 30 ℃ and a twist rate of 2-6 rad/mm, the equation of the linear fit being λ=62.5α+1.98, the linearity of the fit reaching 0.99, the twist sensitivity reaching 6.25x10 -5mm2/rad over a twist rate range of 2-6 rad/mm, which is 17 times higher than the effect in the prior published patent 202010280419.2.
In summary, the SPR-based spiral photonic crystal fiber temperature sensor provided by the invention consists of a single fiber core die, and a cladding consists of air holes formed by 4 layers of octagon structures. The liquid core is formed by filling temperature-sensitive liquid material toluene in a central macropore of the fiber core, and the total internal reflection transmission satisfied by the liquid core mainly depends on the high refractive index distribution of toluene liquid because the refractive index of toluene is higher than that of quartz, so that the liquid core fiber core mold is formed; the surface plasma die can be formed by arbitrarily selecting one air hole with staggered arrangement with the air holes of the first layer in the second layer of the cladding to fill metal wires. The longitudinal direction of the optical fiber structure is spirally twisted, the SPP mode of the cladding is mainly influenced by the longitudinal spiral twisting of the optical fiber, the characteristic that the temperature change mainly influences the toluene liquid core is utilized, namely, when the refractive indexes of two modes are changed at different twisting rates or different temperatures, the refractive index of one mode is only greatly influenced, and the characteristic that the refractive index of two modes of different types is changed by changing one mode under different external conditions and is hardly changed is utilized, so that the two modes generate higher resonance wavelength drift, and higher sensing sensitivity is obtained. When the torsion rate is 6rad/mm, the fitted fiber core of the resonance wavelength along with the temperature change reaches 0.999 within the temperature change range from 10 ℃ to 60 ℃, and the average temperature sensitivity within the detection range from 10 ℃ to 60 ℃ can be obtained and is up to 17.77 nm/DEG C, which is about 5 times higher than the temperature sensitivity realized by the prior art. In addition, when the twist rate is changed from 2rad/mm to 6rad/mm, the linear fitting equation of the twist rate and the resonance wavelength is λ=62.5α+1.98 when the temperature is fixed at 20 ℃, and the sensitivity of the twist rate reaches through 6.25X10 -5mm2/rad. Compared with the published patent 202010280419.2, the structural torsion rate sensing is 17 times higher than that of the structural torsion rate sensing. When the twist rate is changed from 2 to 6rad/mm, the temperature sensitivity of the temperature change from 20 ℃ to 30 ℃ is 17 nm/DEG C, 18 nm/DEG C and 19 nm/DEG C respectively.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In summary, the present description should not be construed as limiting the invention.
Claims (6)
1. The spiral photonic crystal fiber temperature sensor based on SPR comprises a main body structure formed by photonic crystal fibers, wherein a substrate material is quartz, and the temperature sensor is characterized in that the photonic crystal fibers comprise a fiber core area and a cladding area which are sequentially arranged from inside to outside, the fiber core area is formed by a fiber core center big hole and surrounding quartz substrates, and toluene liquid is filled in the fiber core center big hole to form a liquid core; the cladding region consists of four layers of air holes which are arranged in a regular octagon shape, and are symmetrically distributed in a C 8v way, two adjacent layers of air holes are arbitrarily adjacent to each other to form isosceles triangle distribution, wherein the bottom side length of the isosceles triangle is the distance between each layer of air holes and each air hole, the vertex angle of the isosceles triangle is 45 degrees, and one air hole which is arranged in a staggered way with the first layer of air holes is arbitrarily selected in the second layer from inside to outside to be filled with metal wires to form a surface plasma die;
The photonic crystal fiber is twisted to form a longitudinal spiral twisting structure by heating with a CO 2 laser, and specifically comprises:
When the motor rotates, a steering mirror fixed on the precise electric translation stage is used for scanning the focused 10 mu m laser beam along the photonic crystal fiber, a shutter type adjustable optical attenuator arranged on a CO 2 laser beam path is used for adjusting laser power and exposure time, the torsion period of the electric rotation stage and the length of a photonic crystal fiber sample are set, the corresponding laser power and scanning speed are selected, the photonic crystal fiber is heated to be softened, and the photonic crystal fiber is twisted according to the set torsion rate, so that the longitudinal spiral torsion of the photonic crystal fiber is completed.
2. The SPR-based spiral photonic crystal fiber temperature sensor according to claim 1, wherein the four layers of air holes are arranged in a regular octagon shape, and the four layers are respectively a first layer, a second layer, a third layer and a fourth layer from inside to outside, wherein the number of the air holes of the first layer is 8, the number of the air holes of the second layer is 16, the number of the air holes of the third layer is 24, and the number of the air holes of the fourth layer is 32.
3. The SPR-based spiral photonic crystal fiber temperature sensor of claim 1, wherein the twist rate a=2pi/L, wherein L is a twist period, and the twist rate has a value ranging from 2 to 6rad/mm.
4. The SPR-based spiral photonic crystal fiber temperature sensor of claim 1, wherein the core center macropore diameter dc is 2.1 to 2.12 μm; the diameter d c of each layer of air hole is 1.8-1.82 mu m;
The hole spacing lambda between the air holes in the same layer is 2.2-2.22 mu m; the hole spacing Λ 1 between the air holes of adjacent layers is 0.5Λ/sin (22.5 °).
5. The SPR-based spiral photonic crystal fiber temperature sensor of claim 1, wherein the temperature detection range of the sensor is 10 ℃ to 60 ℃ and the average temperature sensitivity is up to 17.77nm/°c.
6. The SPR-based spiral photonic crystal fiber temperature sensor of claim 3, wherein the twist sensitivity of the sensor is up to 6.25 x 10 -5mm2/rad.
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| CN202111240321.5A CN113959585B (en) | 2021-10-25 | 2021-10-25 | Spiral photonic crystal fiber temperature sensor based on SPR |
| ZA2021/10526A ZA202110526B (en) | 2021-10-25 | 2021-12-17 | Spr-based spiral photonic crystal fiber temperature sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105974515A (en) * | 2016-07-06 | 2016-09-28 | 天津理工大学 | Photonic crystal fiber and surface plasma resonance biosensor filled with gold threads |
| CN106226271A (en) * | 2016-09-12 | 2016-12-14 | 华中科技大学 | A kind of SPR PCF sensor based on helix core |
| CN110907399A (en) * | 2019-11-20 | 2020-03-24 | 河北科技大学 | Photonic crystal fiber structure and refractive index sensor |
| CN111366081A (en) * | 2020-04-10 | 2020-07-03 | 桂林电子科技大学 | Double-parameter sensor based on spiral photonic crystal fiber selective filling |
| CN113514423A (en) * | 2021-06-30 | 2021-10-19 | 泰山学院 | Plasma resonance refractive index sensor based on notch type D-type photonic crystal fiber |
-
2021
- 2021-10-25 CN CN202111240321.5A patent/CN113959585B/en active Active
- 2021-12-17 ZA ZA2021/10526A patent/ZA202110526B/en unknown
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105974515A (en) * | 2016-07-06 | 2016-09-28 | 天津理工大学 | Photonic crystal fiber and surface plasma resonance biosensor filled with gold threads |
| CN106226271A (en) * | 2016-09-12 | 2016-12-14 | 华中科技大学 | A kind of SPR PCF sensor based on helix core |
| CN110907399A (en) * | 2019-11-20 | 2020-03-24 | 河北科技大学 | Photonic crystal fiber structure and refractive index sensor |
| CN111366081A (en) * | 2020-04-10 | 2020-07-03 | 桂林电子科技大学 | Double-parameter sensor based on spiral photonic crystal fiber selective filling |
| CN113514423A (en) * | 2021-06-30 | 2021-10-19 | 泰山学院 | Plasma resonance refractive index sensor based on notch type D-type photonic crystal fiber |
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| Title |
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| Advances on Photonic Crystal Fiber Sensors and Applications;Vincenza Portosi et al;《Sensor》;全文 * |
| 基于表面等离子体共振和定向耦合的D形光子晶体光纤折射率和温度传感器;施伟华 等;物理学报(第22期);全文 * |
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| CN113959585A (en) | 2022-01-21 |
| ZA202110526B (en) | 2022-04-28 |
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