Double-core optical fiber double-parameter gas device based on side face polishing and grinding and manufacturing method of double-core optical fiber double-parameter gas device

Abstract

The invention discloses a double-core optical fiber double-parameter gas device based on side face polishing and grinding and a manufacturing method, and relates to the technical field of double-core optical fibers, and the manufacturing method comprises the following steps: verifying the manufactured double-core optical fiber double-parameter gas device, and inverting the variation of gas concentration and temperature; and establishing a temperature calibration sensing matrix of the sensing model, and calibrating the temperature of the sensor. According to the method, the sensing matrix is calibrated through the temperature, so that the sensor can stably work under different temperature conditions, and the long-term stability and application universality of the sensor are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of dual-core optical fibers, in particular to a dual-core optical fiber dual-parameter gas device and system based on side polishing. Background Art

[0002] D-type optical fiber gas sensor is an important component of the gas detection system. It determines whether the gas has decomposed by detecting the gas produced when the gas decomposes. It is widely used in the detection of harmful trace gases.

[0003] The existing D-type optical fiber gas sensor has a contradiction between detection sensitivity and gas selection, and it is difficult to achieve high-sensitivity trace detection of multiple trace gases; the sensor structure is single and cannot be adjusted according to the application scenario to achieve the purpose of simultaneous detection of different physical parameters; and it is difficult to calibrate the temperature of the traditional D-type optical fiber, that is, it is difficult to eliminate the influence of temperature on the gas sensing performance, so the dual parameter detection of gas and temperature is particularly important; and because the D-type optical fiber only uses evanescent waves for sensing, its improvement in sensing sensitivity is limited, and the present invention can improve the sensitivity of the sensor to the target physical quantity by combining sensitive materials. For example, gas molecules react physically or chemically with gas-sensitive materials, and convert gas concentration changes into easily measurable refractive index changes, thickness changes, etc., further improving the detection sensitivity of the sensor to the target parameter, and then the D-type optical fiber sensor based on material coating can achieve high-sensitivity trace gas detection and high-sensitivity temperature detection. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems or problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is: since the D-type optical fiber only uses evanescent waves for sensing, its improvement on sensing sensitivity is limited.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a dual-core optical fiber dual-parameter gas device based on side polishing, which includes a sensing unit, including a D-type optical fiber, wherein the D-type optical fiber is polished by a side polishing technology to polish a part of the cladding and the core of the dual-core optical fiber so that its cross section presents a D shape;

[0008] A gas sensitive material, wherein the gas sensitive material is filled in the first polishing area of ​​the D-type optical fiber so that the gas sensitive material can interact with external gas;

[0009] A temperature-sensitive material, which is filled in the second polishing area of ​​the D-type optical fiber and can expand or contract when the ambient temperature changes, thereby causing its reflection spectrum to drift;

[0010] The optical fiber connection unit includes three sections of dual-core optical fiber and two sections of D-type optical fiber; the dual-core optical fiber is divided into a first dual-core optical fiber, a second dual-core optical fiber and a third dual-core optical fiber; the D-type optical fiber is divided into a first D-type optical fiber and a second D-type optical fiber; each two sections of dual-core optical fiber are respectively arranged before and after each section of D-type optical fiber, and different parameters are sensed through different fiber cores.

[0011] As a preferred solution of the dual-core optical fiber dual-parameter gas device based on side polishing of the present invention, wherein: the D-type optical fiber is obtained by polishing the side surface on the basis of the dual-core optical fiber, and the polishing areas are respectively set in different core areas;

[0012] The gas sensitive material and the temperature sensitive material are filled in the first polishing area and the second polishing area of ​​the D-type optical fiber. The three sections of dual-core optical fiber and the D-type optical fiber form a five-section structure of dual-core optical fiber-D-type optical fiber-dual-core optical fiber-D-type optical fiber-dual-core optical fiber.

[0013] As a preferred solution of the dual-core optical fiber dual-parameter gas device based on side polishing of the present invention, wherein: the polishing depth of the D-type optical fiber is greater than the core area, and the polishing area is in a core-free state;

[0014] The dual-core optical fiber and the D-type optical fiber are constructed on one optical fiber at the same time, and physical parameter sensing is performed through the two fiber cores respectively;

[0015] The gas sensitive material and the temperature sensitive material are in the shape of a cuboid, and are respectively filled in the first polishing area and the second polishing area of ​​the D-type optical fiber, and cover the polished end surface.

[0016] Another object of the present invention is to provide a method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing, which can verify the dual-core optical fiber dual-parameter gas device after manufacture, and invert the changes in gas concentration and temperature; establish a temperature calibration sensing matrix of the sensing model to calibrate the temperature of the sensor, thereby solving the problem that the current D-type optical fiber only uses evanescent waves for sensing, and its improvement in sensing sensitivity is limited.

[0017] As a preferred solution of the method for manufacturing the dual-core optical fiber dual-parameter gas device based on side polishing of the present invention, wherein: the dual-core optical fiber is precisely polished to form a first polishing area and a second polishing area;

[0018] Filling the first polishing area with a gas sensitive material to cover the entire first polishing area;

[0019] Filling the temperature sensitive material in the second polishing area to cover the entire second polishing area;

[0020] Verify the completed dual-core optical fiber dual-parameter gas device and invert the changes in gas concentration and temperature;

[0021] A temperature calibration sensing matrix of the sensing model is established to calibrate the temperature of the dual-core optical fiber dual-parameter gas device.

[0022] As a preferred solution of the dual-core optical fiber dual-parameter gas device based on side polishing described in the present invention, the polishing depth of the first polishing area and the second polishing area is greater than the core depth, the light of the core will propagate through the sensitive material until it is reflected at the polished end face, and the reflected light of the two polished end faces interferes to form an FP interferometer, and the cross-section of the D-type optical fiber is D-shaped and includes another section of the core that has not been polished away, which is similar to a single-mode optical fiber with the cladding polished away.

[0023] As a preferred solution of the dual-core optical fiber dual-parameter gas device based on side polishing described in the present invention, wherein: the precision polishing of the dual-core optical fiber includes etching a first polishing area and a second polishing area by laser etching technology, the two polished end surfaces of the first polishing area constitute FP interferometer 1, and the two polished end surfaces of the second polishing area constitute FP interferometer 2.

[0024] As a preferred solution of the dual-core optical fiber dual-parameter gas device based on side polishing of the present invention, wherein: the verification of the dual-core optical fiber dual-parameter gas device after manufacture includes:

[0025] In FP interferometer 1, when the signal enters FP interferometer 1 through the dual-core optical fiber, the signal light is reflected by reflection surface 1 and reflection surface 2 in turn, and the two reflected lights form interference. The light intensity after interference is I FPI1 It is expressed as:

[0026]

[0027] Among them, I 11 and I 12 are the light intensities of the signal light after being reflected by the reflection surface 1 and the reflection surface 2, respectively; L1 is the length of the optical fiber in the polishing area; and λ is the wavelength of the signal light;

[0028] The interference spectrum trough of FP interferometer 1 satisfies:

[0029]

[0030] Among them, m1 is an integer, λ m1 is the wavelength corresponding to the trough of the interference spectrum;

[0031] Get the free spectral range (FSR) of the interference spectrum of FP interferometer 1 FPI1 for:

[0032]

[0033] Differentiating L1, the relationship between the interference spectrum translation of FP interferometer 1 and the length of the FP interferometer 1 cavity is:

[0034]

[0035] Among them, Δλ FPI1 is the translation of the interference spectrum of FP interferometer 1, ΔL1 is the length change of the polishing area;

[0036] In FP interferometer 2, after the signal enters FP interferometer 2 through the dual-core optical fiber, the signal light is reflected by reflection surface 3 and reflection surface 4 in sequence, and the two reflected lights form interference. The light intensity after interference is expressed as:

[0037]

[0038] Among them, I 11 and I 12 are the light intensities of the signal light after being reflected by the reflection surface 3 and the reflection surface 4, respectively; L2 is the length of the optical fiber in the polishing area; and λ is the wavelength of the signal light;

[0039] The interference spectrum trough of FP interferometer 2 satisfies:

[0040]

[0041] Among them, m2 is an integer, λ m2 is the wavelength corresponding to the trough of the interference spectrum;

[0042] Get the free spectral range (FSR) of the interference spectrum of FP interferometer 2 FPI2 for:

[0043]

[0044] Differentiating L2, the relationship between the interference spectrum translation of FP interferometer 2 and the length of the FP interferometer 2 cavity is:

[0045]

[0046] Among them, Δλ FPI2is the translation of the interference spectrum of FP interferometer 2, ΔL2 is the length change of the polishing area; FP interferometer 1 is used for gas concentration sensing, and FP interferometer 2 is used for temperature sensing, so after calculating the drift of the reflection spectrum according to the above formula, the change in the length of the FP interferometer cavity can be obtained, and then the change in gas concentration and temperature can be inverted.

[0047] As a preferred solution of the method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing of the present invention, wherein: the temperature calibration sensing matrix of the sensing model is established, and the temperature is calibrated, including:

[0048] When the gas concentration and temperature change simultaneously, the drift of the reflection spectrum can be expressed as:

[0049]

[0050] Among them, Δλ FPI1 is the translation of the interference spectrum of FP interferometer 1, Δλ FPI2 is the translation of the interference spectrum of FP interferometer 2, S C1 and S T1 are the concentration sensitivity and temperature sensitivity of FP interferometer 1, S C2 and S T2 are the concentration sensitivity and temperature sensitivity of FP interferometer 2, respectively, the change in ambient gas concentration is ΔC, and the change in ambient temperature is ΔT;

[0051] Substitute the obtained sensitivity value to obtain the temperature calibration sensing matrix of the sensing model, and realize the temperature calibration of the sensor, which is expressed as:

[0052]

[0053] As a preferred solution of the manufacturing method of the dual-core optical fiber dual-parameter gas device based on side polishing described in the present invention, the filling includes uniformly filling the pre-prepared sensitive material in the polishing area of ​​each polished D-type optical fiber to form a uniform dielectric layer.

[0054] As a preferred solution of the method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing described in the present invention, the calibration includes that the sensor sensitivity under different polishing parameters is different, and the sensitivity of the dual-core optical fiber dual-parameter gas device is enhanced by adjusting the optical coupling efficiency and the sensor sensitivity.

[0055] Beneficial effects of the present invention: The present invention achieves a significant improvement in the independence and anti-interference ability of multi-parameter detection through a five-segment structure combining dual-core optical fiber and D-type optical fiber. By separating different sensing functions in their respective fiber cores and using the intermediate transition section optical fiber to reduce the cross-interference between gas and temperature sensing, high-sensitivity and high-precision detection results are ensured in complex environments. By temperature-calibrating the sensing matrix, the sensor can work stably under different temperature conditions, further improving the long-term stability and wide application of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0057] Figure 1 It is a schematic diagram of the overall structure of a dual-core optical fiber dual-parameter gas device based on side polishing in a preferred embodiment of the present invention.

[0058] Figure 2 yes Figure 1 An exploded view of a dual-core fiber dual-parameter gas device based on side polishing is shown.

[0059] Figure 3 yes Figure 1 A cross-sectional view of a dual-core optical fiber dual-parameter gas device based on side polishing is shown.

[0060] Figure 4 yes Figure 1 Schematic diagram of FP interference of FP interferometer 1 and FP interferometer 2 of a dual-core optical fiber dual-parameter gas device based on side polishing.

[0061] Figure 5 The figure is an overall flow chart of the method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing.

[0062] Figure numerals: 1. importing dual-core optical fiber; 2. gas-sensitive polished dual-core optical fiber; 3. dual-core optical fiber; 4. temperature-sensitive material; 5. exporting dual-core optical fiber; 6. gas-sensitive material; 7. temperature-sensitive polished dual-core optical fiber. DETAILED DESCRIPTION

[0063] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0064] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0065] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0066] Example 1

[0067] Reference Figures 1 to 4 , which is an embodiment of the present invention, provides a dual-core optical fiber dual-parameter gas device based on side polishing, comprising:

[0068] The sensing unit includes a D-type optical fiber, wherein the D-type optical fiber is polished by a side polishing technology to polish a part of the cladding and the core of the double-core optical fiber so that the cross section thereof is D-shaped;

[0069] A gas sensitive material, wherein the gas sensitive material is filled in the first polishing area of ​​the D-type optical fiber so that the gas sensitive material can interact with external gas;

[0070] A temperature-sensitive material, which is filled in the second polishing area of ​​the D-type optical fiber and can expand or contract when the ambient temperature changes, thereby causing its reflection spectrum to drift;

[0071] The optical fiber connection unit includes three sections of dual-core optical fiber and two sections of D-type optical fiber; the dual-core optical fiber is divided into a first dual-core optical fiber, a second dual-core optical fiber and a third dual-core optical fiber; the D-type optical fiber is divided into a first D-type optical fiber and a second D-type optical fiber; each two sections of dual-core optical fiber are respectively arranged before and after each section of D-type optical fiber, and different parameters are sensed through different fiber cores.

[0072] The D-type optical fiber is obtained by polishing the side surface on the basis of a double-core optical fiber, and the polishing areas are respectively set in different core areas;

[0073] The gas sensitive material and the temperature sensitive material are filled in the first polishing area and the second polishing area of ​​the D-type optical fiber. The three sections of dual-core optical fiber and the D-type optical fiber constitute a five-section structure of dual-core optical fiber-D-type optical fiber-dual-core optical fiber-D-type optical fiber-dual-core optical fiber. The five-section structure provides greater design flexibility, and can adjust the polishing parameters of each section of optical fiber and the selection of sensitive materials according to different application scenarios. However, the traditional structure has poor flexibility and is difficult to optimize for different detection needs. The high flexibility enables the sensor with a five-section structure to maintain efficient performance in a wider range of application scenarios.

[0074] It should be noted that in the traditional single-segment optical fiber design, gas and temperature sensors are usually integrated together, which is susceptible to cross-interference between different parameters. For example, when performing gas and temperature detection in a single-segment D-type optical fiber, temperature changes may affect the detection accuracy of the gas, and vice versa. In the five-segment structure, the dual-core optical fiber isolates different sensing functions in their respective cores, and effectively reduces the interference between gas and temperature sensing through the transition segment of optical fiber in the middle, so that each sensing segment can work independently, significantly improving the detection accuracy of the sensor.

[0075] In traditional single-segment optical fiber designs, gas and temperature sensors are usually integrated together, which is susceptible to cross-interference between different parameters. For example, when performing gas and temperature detection in a single-segment D-type optical fiber, temperature changes may affect the detection accuracy of the gas, and vice versa. In the five-segment structure, the use of dual-core optical fiber isolates different sensing functions in their respective cores, and effectively reduces the interference between gas and temperature sensing through the transition segment of optical fiber in the middle. The five-segment structure allows each sensing segment to work independently, significantly improving the detection accuracy of the sensor.

[0076] The transition section between the dual-core optical fibers not only plays an isolation role, but also optimizes the signal transmission path, which can reduce the signal loss during transmission, improve the signal strength and quality, and thus improve the overall detection performance of the sensor. The traditional continuous single-segment optical fiber structure will produce greater loss during sensing and signal transmission, affecting the sensitivity and stability of detection.

[0077] The polishing depth of the D-type optical fiber is greater than the core area, and the polishing area is in a core-free state;

[0078] The dual-core optical fiber and the D-type optical fiber are constructed on one optical fiber at the same time, and physical parameter sensing is performed through the two fiber cores respectively;

[0079] The sensitive material is in a rectangular parallelepiped shape, is filled in the polished area of ​​the D-type optical fiber, and covers the polished end surface to enhance the effect of FP interference.

[0080] It should be noted that the D-type optical fiber is polished by a double-core optical fiber through precision polishing technology, and has two side polishing areas in the entire double-core optical fiber. This structural design enables the polishing area to effectively transmit and reflect the optical signal transmitted by the core of the double-core optical fiber, and use the polished end face for reflection, thereby forming a complete optical fiber FP sensing system. The cross-section of the D-type optical fiber is in the shape of 'D', and includes another section of the core that has not been polished away, which is similar to the cross-section of a single-mode optical fiber with the cladding polished off. The polished optical fiber section that has been polished will be more sensitive to changes in environmental physical quantities, and the use of evanescent wave sensing can well detect environmental changes near the polishing surface, such as changes in gas concentration and temperature.

[0081] The dual-core optical fiber is the basis for polishing the D-type optical fiber, and is also the basis for ensuring the simultaneous sensing of the dual parameters of gas and temperature. The polishing area will select the cores of the dual-core optical fiber for polishing respectively, and its polishing depth is greater than the core depth, so its core will be removed. The two cores of the D-type optical fibers at both ends are used for sensing respectively. While utilizing the sensitive characteristics of the D-type optical fiber, the cross-interference of FP interferometer 1 and FP interferometer 2 can also be avoided. FP interferometer 1 is coated with a gas-sensitive material, which is sensitive to gas changes. The FP interferometer is used for gas concentration sensing. FP interferometer 2 is coated with a temperature-sensitive material, which is sensitive to temperature changes. The FP interferometer is used for temperature sensing. Since the two FP interferometers do not affect each other, the dual parameter detection of gas and temperature can achieve less crosstalk.

[0082] The dual-core optical fiber 1 is introduced to introduce light energy into the two fiber cores respectively, and the energy of the two optical fibers is used for gas concentration sensing and temperature sensing respectively.

[0083] The polished area of ​​the gas-sensitive polished dual-core optical fiber 2 will constitute the FP interferometer 1, and the polished area is filled with a gas-sensitive material 6 to make it have good selectivity for the target gas.

[0084] The transition dual-core optical fiber 3 is arranged between the polished optical fibers at both ends. Since the sensitive material will undergo certain physical changes when the external environment changes, that is, expansion or contraction, when multi-parameter sensing is performed, the isolation effect of the transition optical fiber can eliminate the mutual interference of gas-sensitive and temperature-sensitive materials, thereby improving the sensitivity and stability of the sensor.

[0085] The dual-core optical fiber 5 is led out and arranged at the end of the sensor. The polished end surface of one end of the dual-core optical fiber 5 is used to form the FP interferometer 2, and the FP interferometer 2 is used to realize temperature sensing.

[0086] The polished area of ​​the temperature-sensitive polished dual-core optical fiber 7 will constitute the FP interferometer 2, and the polished area is filled with the temperature-sensitive material 4 to make it more sensitive to temperature changes, thereby improving the sensitivity of temperature sensing.

[0087] It should be noted that the ambient gas directly interacts with the gas-sensitive material, and the cavity length of the FP interferometer changes according to the difference in material changes. When the ambient gas concentration increases, more gas molecules will interact with the gas-sensitive material, causing the gas-sensitive material to expand, and then the FP interference cavity length changes. According to the FP interference principle, the gas concentration can be obtained by analyzing the drift of the reflection spectrum, and the temperature parameter can be measured based on this principle. In this way, real-time measurement of ambient gas concentration and ambient temperature is achieved, and dual-parameter sensing of gas and temperature is realized. The length and depth of the polishing area can be designed and adjusted according to different needs, and multi-gas sensing can be designed according to the complexity of the environment to improve the utilization rate of the sensor.

[0088] Working process: Place the sensor in the target environment, the sensitive material is in full contact with the target environment, and interacts with it, causing the thickness of the material to change. When light passes through the polished area and is reflected on the polished end face, according to the principle of FP interference, the changing cavity length will cause the reflection spectrum to shift, and the gas and temperature detection results can be obtained according to the degree of shift of the reflection spectrum; in addition, by optimizing the polishing depth, polishing length and other parameters, the efficiency and reaction speed of the sensor's contact with the environment can be improved. Since different polishing parameters will lead to changes in the light coupling efficiency on the one hand, and on the other hand, a larger polishing surface will increase the gas contact efficiency, the sensor sensitivity under different polishing parameters will also be different. By weighing the two important parameters of light coupling efficiency and sensor sensitivity, the sensitivity of the detection device can be further enhanced.

[0089] In summary, the present invention achieves a significant improvement in the independence and anti-interference ability of multi-parameter detection through a five-section structure combining dual-core optical fiber and D-type optical fiber. By separating different sensing functions in their respective fiber cores and using the intermediate transition section optical fiber to reduce the cross-interference between gas and temperature sensing, high-sensitivity and high-precision detection results are ensured in complex environments.

[0090] Example 2

[0091] Reference Figures 1 to 5 , as one embodiment of the present invention, provides a method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing, comprising:

[0092] S1: Precision polishing the dual-core optical fiber to form D-type optical fibers at both ends of the first polishing area and the second polishing area.

[0093] Furthermore, the polishing depth of the polishing area is greater than the core depth, and the light of the core will propagate through the sensitive material until it is reflected at the polished end face. The reflected light from the two polished end faces interferes to form an FP interferometer, and the cross-section of the D-type optical fiber is D-shaped and includes another section of the core that has not been polished away, which is similar to a single-mode optical fiber with the cladding polished off.

[0094] Furthermore, the precision polishing of the dual-core optical fiber includes etching a polishing area by laser etching technology, and two polished end surfaces of the polishing area constitute an FP interferometer.

[0095] S2: Fill the first polishing area with the gas sensitive material so that the gas sensitive material can cover the entire first polishing area.

[0096] S3: Fill the second polishing area with the temperature sensitive material so that the temperature sensitive material can cover the entire second polishing area.

[0097] Furthermore, the dual-core optical fiber is precisely polished to make its surface smooth and flat, and the flatness of its polished end face is controlled, finally forming a D-type optical fiber polishing area. Because only through precision polishing can the shape and size of the D-type optical fiber be ensured to meet the requirements of subsequent material filling and FP interferometer;

[0098] The prepared sensitive material is evenly filled in the polished area of ​​the polished D-type optical fiber to form a uniform dielectric layer. The function of this layer of sensitive material is to enhance the sensing performance of the optical fiber, so the filling uniformity and the quality of the material film will directly affect the final performance of the sensor.

[0099] S4: Verify the completed dual-core optical fiber dual-parameter gas device and invert the changes in gas concentration and temperature.

[0100] Furthermore, the verification of the manufactured dual-core optical fiber dual-parameter gas device includes:

[0101] In FP interferometer 1, after the signal enters FP interferometer 1 through the dual-core optical fiber, the signal light is reflected by reflection surface 1 and reflection surface 2 in sequence, and the two reflected lights form interference. The light intensity after interference is expressed as:

[0102]

[0103] Among them, I 11 and I 12 are the light intensities of the signal light after being reflected by reflection surface 1 and reflection surface 2, L1 is the length of the optical fiber in the polishing area, and λ is the wavelength of the signal light; the interference diagram is shown in Figure 4 As shown;

[0104] The interference spectrum trough of FP interferometer 1 satisfies:

[0105]

[0106] Among them, m1 is an integer, λ m1 is the wavelength corresponding to the trough of the interference spectrum;

[0107] Get the free spectral range (FSR) of the interference spectrum of FP interferometer 1 FPI1 for:

[0108]

[0109] Differentiating L1, the relationship between the interference spectrum translation of FP interferometer 1 and the length of the FP interferometer 1 cavity is:

[0110]

[0111] Among them, Δλ FPI1 is the translation of the interference spectrum of FP interferometer 1, ΔL1 is the length change of the polishing area;

[0112] In FP interferometer 2, after the signal enters FP interferometer 2 through the dual-core optical fiber, the signal light is reflected by reflection surface 3 and reflection surface 4 in sequence, and the two reflected lights form interference. The light intensity after interference is expressed as:

[0113]

[0114] Among them, I 11 and I 12 are the light intensities of the signal light after being reflected by the reflection surface 3 and the reflection surface 4, L2 is the length of the optical fiber in the polishing area, and λ is the wavelength of the signal light; the interference diagram is shown in Figure 4 shown.

[0115] The interference spectrum trough of FP interferometer 2 satisfies:

[0116]

[0117] Among them, m2 is an integer, λ m2 is the wavelength corresponding to the trough of the interference spectrum;

[0118] Get the free spectral range (FSR) of the interference spectrum of FP interferometer 2 FPI2 for:

[0119]

[0120] Differentiating L2, the relationship between the interference spectrum translation of FP interferometer 2 and the length of the FP interferometer 2 cavity is:

[0121]

[0122] Among them, Δλ FPI2 is the translation of the interference spectrum of FP interferometer 2, ΔL2 is the length change of the polishing area; FP interferometer 1 is used for gas concentration sensing, and FP interferometer 2 is used for temperature sensing, so after calculating the drift of the reflection spectrum according to the above formula, the change in the length of the FP interferometer cavity can be obtained, and then the change in gas concentration and temperature can be inverted.

[0123] Furthermore, the sensitive material is fixed on the polishing area of ​​the D-type optical fiber by filling. The filling method ensures that the material completely covers the polishing area. The expansion and contraction changes of the material will be more easily reflected in the length of the polishing area, so the sensing sensitivity of the FP interferometer can be effectively improved.

[0124] It should be noted that the sensor is composed of a dual-core optical fiber, a sensitive material and a D-type optical fiber. The sensitive material is filled on the polished area of ​​the D-type optical fiber so that the light energy transmitted by the core can propagate in the sensitive material. When the sensitive material interacts with the target gas, the material will expand and contract, thereby changing the cavity length of the FP interferometer, which in turn causes the FPI to drift. According to the FP sensing principle, the sensor has good sensitivity and accuracy for the detection of trace gases; the unique chemical properties of the sensitive material improve the sensitivity of the sensor and increase the possibility of the sensor to detect different parameters; and since there is no interference between the different cores of the dual-core optical fiber, the method of using different cores to transmit the spectra of different FP interferometers can reduce the cross-interference between different parameters. In this way, when the device is in an environment with a target gas, the volume change of the sensitive material is reflected in the cavity length of the FP cavity, which in turn causes the spectrum of the FP interferometer to drift.

[0125] S5: Establish a temperature calibration sensing matrix of the sensing model to calibrate the temperature of the sensor.

[0126] Furthermore, the establishment of the temperature calibration sensing matrix of the sensing model to calibrate the temperature of the sensor includes:

[0127] When the gas concentration and temperature change simultaneously, the drift of the reflection spectrum can be expressed as:

[0128]

[0129] Among them, Δλ FPI1 is the translation of the interference spectrum of FP interferometer 1, Δλ FPI2 is the translation of the interference spectrum of FP interferometer 2, S C1 and S T1 are the concentration sensitivity and temperature sensitivity of FP interferometer 1, S C2 and S T2are the concentration sensitivity and temperature sensitivity of FP interferometer 2, respectively, the change in ambient gas concentration is ΔC, and the change in ambient temperature is ΔT;

[0130] Substitute the obtained sensitivity value to obtain the temperature calibration sensing matrix of the sensing model, and realize the temperature calibration of the sensor, which is expressed as:

[0131]

[0132] The filling includes uniformly filling the pre-prepared sensitive material in the polished area of ​​each D-type optical fiber that has been polished to form a uniform dielectric layer.

[0133] The calibration includes that the sensor sensitivity under different polishing parameters is different, and the sensitivity of the dual-core optical fiber dual-parameter gas device is enhanced by adjusting the optical coupling efficiency and the sensor sensitivity.

[0134] In summary, the application scope of the sensor is broadened and the stability of the sensor is improved; the gas sensor of the present invention has a simple structure, good overall stability, a long service life, low manufacturing cost, and is suitable for practical use.

[0135] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0136] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0137] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0138] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0139] It should be noted that the above embodiments are only used to illustrate the technical solutions 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 the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A dual-core optical fiber dual-parameter gas device based on side polishing, characterized in that: include, The sensing unit includes a D-type optical fiber, wherein the D-type optical fiber is polished by a side polishing technology to polish a part of the cladding and the core of the double-core optical fiber so that the cross section thereof is D-shaped; A gas sensitive material, wherein the gas sensitive material is filled in the first polishing area of ​​the D-type optical fiber so that the gas sensitive material can interact with external gas; A temperature-sensitive material, which is filled in the second polishing area of ​​the D-type optical fiber and can expand or contract when the ambient temperature changes, thereby causing its reflection spectrum to drift; The optical fiber connection unit includes three sections of dual-core optical fiber and two sections of D-type optical fiber; the dual-core optical fiber is divided into a first dual-core optical fiber, a second dual-core optical fiber and a third dual-core optical fiber; the D-type optical fiber is divided into a first D-type optical fiber and a second D-type optical fiber; each two sections of dual-core optical fiber are respectively arranged before and after each section of D-type optical fiber, and different parameters are sensed through different fiber cores.

2. The dual-core optical fiber dual-parameter gas device based on side polishing as claimed in claim 1, characterized in that: The D-type optical fiber is obtained by polishing the side surface on the basis of a double-core optical fiber, and the polishing areas are respectively set in different core areas; The gas sensitive material and the temperature sensitive material are filled in the first polishing area and the second polishing area of ​​the D-type optical fiber. The three sections of dual-core optical fiber and the D-type optical fiber form a five-section structure of dual-core optical fiber-D-type optical fiber-dual-core optical fiber-D-type optical fiber-dual-core optical fiber.

3. The dual-core optical fiber dual-parameter gas device based on side polishing as claimed in claim 2, characterized in that: The polishing depth of the D-type optical fiber is greater than the core area, and the polishing area is in a core-free state; The dual-core optical fiber and the D-type optical fiber are constructed on one optical fiber at the same time, and physical parameter sensing is performed through the two fiber cores respectively; The gas sensitive material and the temperature sensitive material are in the shape of a cuboid, and are respectively filled in the first polishing area and the second polishing area of ​​the D-type optical fiber, and cover the polished end surface.

4. A method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing as claimed in any one of claims 1 to 3, comprising: Precision polishing the dual-core optical fiber to form a first polishing area and a second polishing area; Filling the first polishing area with a gas sensitive material to cover the entire first polishing area; Filling the temperature sensitive material in the second polishing area to cover the entire second polishing area; Verify the completed dual-core optical fiber dual-parameter gas device and invert the changes in gas concentration and temperature; A temperature calibration sensing matrix of the sensing model is established to calibrate the temperature of the dual-core optical fiber dual-parameter gas device.

5. The method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing according to claim 4, characterized in that: The polishing depths of the first polishing area and the second polishing area are greater than the core depth. The light from the core will propagate through the sensitive material until it is reflected at the polished end face. The reflected light from the two polished end faces interferes to form an FP interferometer. The cross-section of the D-type optical fiber is D-shaped and includes another section of the core that has not been polished away, which is similar to a single-mode optical fiber with the cladding polished away.

6. The method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing according to claim 5, characterized in that: The precision polishing of the dual-core optical fiber includes etching a first polishing area and a second polishing area by laser etching technology, wherein the two polished end surfaces of the first polishing area constitute the FP interferometer 1 , and the two polished end surfaces of the second polishing area constitute the FP interferometer 2 .

7. The method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing according to claim 6, characterized in that: The verification of the manufactured dual-core optical fiber dual-parameter gas device includes: In FP interferometer 1, when the signal enters FP interferometer 1 through the dual-core optical fiber, the signal light is reflected by reflection surface 1 and reflection surface 2 in turn, and the two reflected lights form interference. The light intensity after interference is I FPI1 It is expressed as: Among them, I 11 and I 12 are the light intensities of the signal light after being reflected by the reflection surface 1 and the reflection surface 2, respectively; L1 is the length of the optical fiber in the polishing area; and λ is the wavelength of the signal light; The interference spectrum trough of FP interferometer 1 satisfies: Among them, m1 is an integer, λ m1 is the wavelength corresponding to the trough of the interference spectrum; Get the free spectral range (FSR) of the interference spectrum of FP interferometer 1 FPI1 for: Differentiating L1, the relationship between the interference spectrum translation of FP interferometer 1 and the length of the FP interferometer 1 cavity is: Among them, Δλ FPI1 is the translation of the interference spectrum of FP interferometer 1, ΔL1 is the length change of the polishing area; In FP interferometer 2, when the signal enters FP interferometer 2 through the dual-core optical fiber, the signal light is reflected by reflection surface 3 and reflection surface 4 in turn, and the two reflected lights form interference. The light intensity after interference is I FPI2 It is expressed as: Among them, I 11 and I 12 are the light intensities of the signal light after being reflected by the reflection surface 3 and the reflection surface 4, L2 is the length of the optical fiber in the polishing area, and λ is the wavelength of the signal light; The interference spectrum trough of FP interferometer 2 satisfies: Among them, m2 is an integer, λ m2 is the wavelength corresponding to the trough of the interference spectrum; Get the free spectral range (FSR) of the interference spectrum of FP interferometer 2 FPI2 for: Differentiating L2, the relationship between the interference spectrum translation of FP interferometer 2 and the length of the FP interferometer 2 cavity is: Among them, Δλ FPI2 is the translation of the interference spectrum of FP interferometer 2, ΔL2 is the length change of the polishing area; FP interferometer 1 is used for gas concentration sensing, and FP interferometer 2 is used for temperature sensing, so after calculating the translation of the reflection spectrum according to the above formula, the change in the length of the FP interferometer cavity can be obtained, and then the change in gas concentration and temperature can be inverted.

8. The method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing according to claim 7, characterized in that: The temperature calibration sensing matrix of the sensor model is established to calibrate the temperature, including: When the gas concentration and temperature change simultaneously, the drift of the reflection spectrum can be expressed as: Among them, Δλ FPI1 is the translation of the interference spectrum of FP interferometer 1, Δλ FPI2 is the translation of the interference spectrum of FP interferometer 2, S C1 and S T1 are the concentration sensitivity and temperature sensitivity of FP interferometer 1, S C2 and S T2 are the concentration sensitivity and temperature sensitivity of FP interferometer 2, respectively, the change in ambient gas concentration is ΔC, and the change in ambient temperature is ΔT; Substitute the obtained sensitivity value to obtain the temperature calibration sensing matrix of the sensing model, and realize the temperature calibration of the sensor, which is expressed as:

9. The method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing according to any one of claims 5 to 8, characterized in that: The filling includes uniformly filling the pre-prepared sensitive material in the polished area of ​​each D-type optical fiber that has been polished to form a uniform dielectric layer.

10. The method for manufacturing a dual-core optical fiber dual-parameter gas device based on side polishing according to any one of claims 5 to 8, characterized in that: The calibration includes that the sensor sensitivity under different polishing parameters is different, and the sensitivity of the dual-core optical fiber dual-parameter gas device is enhanced by adjusting the optical coupling efficiency and the sensor sensitivity.

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