Optical fiber sensor based on light interference

Abstract

The utility model belongs to the technical field of temperature measurement, and particularly relates to an optical fiber sensor based on light interference, which comprises an optical fiber assembly, a fixed support, a light source assembly and a reading microscope. The optical fiber assembly comprises two optical fibers, and the optical fibers are provided with coating layers. The two optical fibers are fixed at the top end of the fixed bracket in parallel; the light source assembly provides a light source and is aligned with one ends of the two optical fibers, and the reading microscope is used for observing interference fringes and measuring the movement series of the fringes and is placed on the other sides of the two optical fibers. Accurate temperature measurement is realized by observing the movement of the stripes on the reading microscope, and the variation of the temperature can be calculated only by measuring the number of stages of the movement of the stripes and the length of the optical fiber in the heater. The measurement mode is relatively simple and direct, interference possibly introduced in the complex wavelength demodulation process is avoided, and the accuracy and stability of measurement are improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to temperature measurement technical field, concretely relates to a kind of optical fiber sensor based on light interference. BACKGROUND

[0002] Fiber grating temperature sensor is more common temperature measuring device.The core component is the grating structure made in optical fiber, and the working principle is based on the transmission characteristics of light in grating changes with temperature.In manufacturing process, there are different types based on Bragg fiber grating (FBG) and long period fiber grating (LPFG) etc.

[0003] Traditional fiber grating temperature sensor often needs complex wavelength demodulation operation in measurement process.This process not only increases the cost and complexity of measurement system, but also easily introduces additional interference in demodulation process, further reduces the accuracy and stability of measurement.

[0004] In order to solve the above problems, the utility model provides a kind of optical fiber sensor based on light interference, to improve the accuracy of temperature measurement, and do not need complex wavelength demodulation operation. UTILITY MODEL CONTENT

[0005] The utility model aims at providing a kind of optical fiber sensor based on light interference to overcome the problems existing in the prior art fiber grating temperature sensor, improve the accuracy of temperature measurement and do not need complex wavelength demodulation operation, and broaden its application field.

[0006] To achieve the above object, the utility model adopts the following specific technical scheme: a kind of optical fiber sensor based on light interference, including optical fiber assembly, fixed support, light source assembly and reading microscope;

[0007] The optical fiber assembly includes two optical fibers, and the optical fibers are provided with a coating layer;Two optical fibers are fixed in parallel at the top end of the fixed support;

[0008] The light source assembly provides light source and aims at one end of two optical fibers, and the reading microscope is used to observe interference fringe and measure fringe movement level, and is placed on the other side of two optical fibers.

[0009] Further, one of the two optical fibers of the optical fiber assembly is coated with a ceramic-based thermal barrier coating, or is provided with a polyimide thermal barrier sleeve.

[0010] Further, the light source assembly is a helium-neon laser, and the output end of the helium-neon laser aims at one end of two optical fibers to provide light source for two optical fibers.

[0011] Further, the fixing support has two, two fixing supports are arranged at two ends of the optical fiber assembly respectively; a single fixing support comprises a clamp and a support frame, the clamp is installed on the support frame; the clamp is a bayonet structure to fix the end portions of the two optical fibers.

[0012] Further, the coating layer is an aluminum coating.

[0013] Further, the optical fiber is a panda polarization maintaining optical fiber.

[0014] The utility model discloses the following technical effects can be achieved:

[0015] Coating material advantage: using aluminum as the optical fiber coating material, the optical reflection and transmission performance of the optical fiber are significantly improved, thereby optimizing the performance of the optical fiber sensor and greatly improving the accuracy of temperature measurement. The aluminum film can enhance the reflection and transmission efficiency of light in the optical fiber, making the sensor more sensitive to temperature changes and the measurement result more accurate.

[0016] Optical fiber material characteristics: using panda polarization maintaining optical fiber, the polarization state of light can be kept stable, the interference of stress on experimental measurement is reduced, and the signal quality and system performance can be improved. Stable polarization state helps to reduce the influence of external interference on light transmission and improve the stability and measurement accuracy of the sensor in complex environments.

[0017] Accurate measurement method: precise temperature measurement is realized by observing the movement of the stripes on the reading microscope. By measuring the number of stripe movements and the length of the optical fiber in the heater, the temperature change can be calculated. This measurement method is relatively simple and direct, avoiding the interference that may be introduced in the complex wavelength demodulation process, and improving the accuracy and stability of the measurement.

[0018] The traditional optical fiber sensor instrument is complex and costly, and the utility model greatly reduces the cost without affecting the temperature measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The structure of the utility model is shown in the figure.

[0020] In the figure:

[0021] 1, optical fiber; 2, light source assembly; 3, fixing support; 4, reading microscope; 5, heater. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the utility model more clear and clear, the utility model is further described in detail below combined with the drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and do not constitute a limitation on the utility model.

[0023] Reference Figure 1 An optical fiber sensor based on optical interference, comprising an optical fiber assembly, a fixed support 3, a light source assembly 2 and a reading microscope 4;

[0024] The optical fiber assembly comprises two identical elongated cylindrical optical fibers 1, which serve as the transmission medium of light and utilize the characteristic of temperature-induced refractive index change to change the optical path difference of the transmitted light, thereby causing the movement of interference fringes, so as to realize the sensing of temperature. The optical fibers 1 are provided with a coating layer. The coating layer is a thin and continuous aluminum coating film uniformly coated on the surface of the optical fibers 1, which is used to enhance the reflection and transmission capacity of light. The aluminum coating film can reduce the energy loss of light during transmission, making the interference phenomenon more obvious and facilitating measurement. The two optical fibers 1 are fixed in parallel at the top end of the fixed support 3;

[0025] The light source assembly 2 provides a light source to align one end of the two optical fibers 1, for providing a stable coherent light source. The stable coherent light source is the basis for the occurrence of optical interference phenomenon;

[0026] The reading microscope 4 is placed on the other side of the exit end of the optical fibers 1, for observing the interference fringes and measuring the movement level of the fringes. By measuring the movement level of the fringes and the length of the optical fibers 1, the change amount of temperature can be calculated. This measurement method is relatively simple and direct, avoiding the interference that may be introduced in the complex wavelength demodulation process, and improving the stability and measurement accuracy in complex environments to a certain extent.

[0027] In use, the two optical fibers 1 are placed in close contact at both ends and are installed at the top end of the fixed support 3. One end receives the irradiation of the light source assembly 2, and the other end observes the interference fringes with the reading microscope 4. The utility model utilizes the interference phenomenon of light. When light is transmitted in the optical fibers 1, the change of temperature causes the change of refractive index of the optical fibers 1, which in turn causes the change of optical path difference of the two coherent lights, so that the interference fringes move. The change of temperature is calculated by detecting the movement of the fringes. In the measurement method, only the movement level of the fringes under the reading microscope 4 and the length of the optical fibers 1 are needed to calculate the change amount of temperature, which is relatively simple and direct, avoiding the interference that may be introduced in the complex wavelength demodulation process, and improving the stability and measurement accuracy in complex environments to a certain extent.

[0028] Further, in order to improve the accuracy of measurement, one of the two optical fibers 1 serves as a measurement component and the other serves as a reference component. A ceramic-based thermal barrier coating or a polyimide thermal barrier sleeve is coated on the optical fiber 1 serving as the reference component. This has the advantage of protecting the optical fiber 1 serving as the reference component from the other optical fiber 1 and preventing the influence of the external environment.

[0029] Further, the light source assembly 2 is a helium-neon laser, and the output end of the helium-neon laser aligns one end of the two optical fibers 1 to provide a light source for the two optical fibers 1.

[0030] Further, the fixing support 3 is provided with two fixing supports 3 respectively arranged at two ends of the optical fiber 1 assembly; the single fixing support 3 comprises a clamp and a support frame, the clamp is installed on the support frame and used for fixing two ends of the two optical fibers 1, so that the relative position of the two optical fibers 1 is stable during the measurement process.

[0031] Further, the utility model discloses a panda polarization maintaining optical fiber is used;The panda polarization maintaining optical fiber can keep the polarization state of light stable, effectively reduce the influence of stress and other interference factors on light transmission, thereby improving signal quality and system performance, and further improving the measurement accuracy and stability of the sensor.

[0032] The use process of the optical fiber sensor based on light interference of the application comprises the following steps:

[0033] S1, the optical fiber 1 is treated with aluminum film;

[0034] S2, two aluminum-coated and shape-consistent optical fibers 1 are fixed;

[0035] Specifically, the clamp in the fixing support 3 is used to fix the two ends of the two aluminum-coated and shape-consistent optical fibers 1 on the support frame, so that the relative position of the two optical fibers 1 is stable during the measurement process.

[0036] S3, the optical fiber 1 is irradiated with a laser and the optical path is adjusted;

[0037] Specifically, one end of the optical fiber 1 is irradiated with a helium-neon laser, so that the light uniformly enters the two optical fibers 1. At the same time, the condition of the two beams of light at the exit end is observed carefully, and the intensity of the two beams of light is kept consistent by adjusting the incident position of the helium-neon laser.

[0038] S4, the interference fringes are observed and adjusted;

[0039] Specifically, the interference fringes are observed through the reading microscope 4, and the optical path, the position of the optical fiber 1 and the like are fine-tuned according to the definition and stability of the fringes, so that the interference fringes are clear and stable, and the subsequent measurement work is facilitated.

[0040] S5, the optical fiber 1 is heated and the data is recorded;

[0041] Specifically, the heater 5 is started to heat, the temperature of one of the optical fibers 1 is changed constantly, until the reading microscope 4 is close to the central 0, and the temperature on the heater 5 is recorded at this time; from the beginning, the heater 5 is continuously started to heat, and the heating is continued until 100 DEG C, and according to the temperature indication on the heater 5, the moving order of the clear fringes relative to the central 0 is recorded at intervals of 5 DEG C.

[0042] S6, the temperature is calculated according to the recorded data and the accuracy is verified.

[0043] Specifically, the temperature change amount is calculated, and the theoretical temperature is obtained by adding the temperature when the fringe order is 0; the theoretical temperature is compared with the actual temperature recorded, and if the relative error is within 5%, the accuracy of the temperature measurement of the utility model is ensured.

[0044] The temperature is displayed in real time by the heater 5, the temperature change amount is calculated through the relationship, and the calculated temperature is compared with the temperature displayed on the heater 5, so as to verify the accuracy and feasibility of the experiment. This verification method is more scientific and effective. Real-time comparison and calculation of temperature and actual temperature can timely find the error in the measurement process, and ensure the reliability of the sensor measurement result.

[0045] Example one:

[0046] The temperature of the fish growth in the aquarium is measured in real time; a 20cm aluminized film panda type polarization maintaining optical fiber is selected, and the experiment is carried out according to the above operation steps. The optical fiber 1 as the measurement component is placed in the aquarium to simulate the measurement of fish growth temperature. In the process of heating the aquarium to simulate different temperatures, the fringe order, relative error and theoretical temperature under different actual temperatures are recorded. The experimental data are shown in the following table:

[0047]

[0048] Table 1

[0049] The experimental results show that the relative error of the measurement is within 5%, which verifies the accuracy and feasibility of the utility model in measuring the temperature of fish growth in the aquarium.

[0050] Example two:

[0051] Temperature measurement of chemical reactor; the optical fiber sensor of the utility model is applied to the temperature measurement of the chemical reactor. The experiment is carried out according to the operation steps, and the fringe order, theoretical temperature under different actual temperatures are recorded. The experimental data are shown in the following table:

[0052]

[0053] Table 2

[0054] The experimental results show that the optical fiber sensor of the utility model can accurately measure the temperature of the chemical reactor, which further proves its effectiveness and reliability in practical application.

[0055] It can be seen from the above embodiments that the optical fiber sensor based on optical interference can realize accurate temperature measurement in different scenes, and has wide application prospect and practical value. In actual application, the parameters (such as aluminum film thickness, optical fiber length, etc.) of the sensor can be optimized and adjusted according to different requirements and scenes to meet higher measurement accuracy and stability requirements.

[0056] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0057] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

[0058] The specific embodiments of the present application do not constitute a limitation on the scope of protection of the present application. Any other corresponding changes and modifications made according to the technical concept of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A fiber optic sensor based on optical interference, characterized in that, It includes an optical fiber assembly, a mounting bracket (3), a light source assembly (2), and a reading microscope (4); The optical fiber assembly includes two optical fibers (1), and the optical fibers (1) are coated with a coating layer; the two optical fibers (1) are fixed in parallel at the top of the fixing bracket (3); The light source assembly (2) provides a light source and is aligned with one end of the two optical fibers (1), and the reading microscope (4) is used to observe interference fringes and measure the fringe shift order, and is placed on the other side of the two optical fibers (1).

2. The fiber optic sensor based on optical interference according to claim 1, characterized in that, One of the two optical fibers (1) is coated with a ceramic-based thermal insulation coating or is provided with a polyimide thermal insulation sleeve.

3. The fiber optic sensor based on optical interference according to claim 1, characterized in that, The light source component (2) is a helium-neon laser, and the output end of the helium-neon laser is aligned with one end of the two optical fibers (1) to provide a light source for the two optical fibers (1).

4. The fiber optic sensor based on optical interference according to claim 1, characterized in that, There are two fixing brackets (3), which are respectively set at both ends of the optical fiber assembly; each fixing bracket (3) includes a clamp and a support frame, and the clamp is installed on the support frame; the clamp is a bayonet structure to fix the ends of the two optical fibers (1).

5. The fiber optic sensor based on optical interference according to claim 1, characterized in that, The coating layer is an aluminum-plated film.

6. The fiber optic sensor based on optical interference according to claim 2, characterized in that, The optical fiber (1) is a panda-type polarization-maintaining optical fiber.

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