阅读说明：本技术 一种光纤探头、温度传感器及光纤探头制备方法 (Optical fiber probe, temperature sensor and preparation method of optical fiber probe ) 是由 刘盛春 邹佳航 刘子耕 薛玉新 曹国昕 王立平 于 2021-08-16 设计创作，主要内容包括：本发明提供了一种光纤探头、温度传感器及光纤探头制备方法,其中,光纤探头包括：单模光纤和干涉结构；干涉结构设置于单模光纤的一端；干涉结构的材料为碳化硅；干涉结构的折射率随被测温度场的温度变化而变化；干涉结构的第一端面和干涉结构的第二端面形成法布里珀罗谐振腔；干涉结构的第一端面用于对经单模光纤传输的光信号进行一次反射,得到一次反射后的光信号；干涉结构的第二端面用于对经第一端面透射进入干涉结构的光信号进行二次反射,得到二次反射后的光信号；一次反射后的光信号和二次反射后的光信号在单模光纤中发生干涉。本发明能够应用于温度场快速变化的场景,具有灵敏度高、响应速度快、分辨率高的优点。(The invention provides an optical fiber probe, a temperature sensor and a preparation method of the optical fiber probe, wherein the optical fiber probe comprises the following components: single mode optical fibers and interference structures; the interference structure is arranged at one end of the single-mode optical fiber; the material of the interference structure is silicon carbide; the refractive index of the interference structure changes with the temperature change of the measured temperature field; the first end face of the interference structure and the second end face of the interference structure form a Fabry-Perot resonant cavity; the first end face of the interference structure is used for carrying out primary reflection on an optical signal transmitted by the single-mode optical fiber to obtain an optical signal after primary reflection; the second end face of the interference structure is used for carrying out secondary reflection on the optical signal which is transmitted into the interference structure through the first end face to obtain an optical signal after secondary reflection; the optical signal after the first reflection and the optical signal after the second reflection interfere in the single mode fiber. The invention can be applied to the scene with the rapid change of the temperature field and has the advantages of high sensitivity, high response speed and high resolution.)

1. A fiber optic probe, comprising:

single mode optical fibers and interference structures;

the interference structure is a columnar structure; the interference structure is arranged at one end of the single-mode optical fiber; the single-mode optical fiber and the interference structure are both arranged in a measured temperature field; the interference structure is made of silicon carbide; the refractive index of the interference structure varies with the temperature variation of the measured temperature field;

the first end face of the interference structure and the second end face of the interference structure form a Fabry-Perot resonant cavity; the first end face of the interference structure is used for carrying out primary reflection on the optical signal transmitted by the single-mode optical fiber to obtain an optical signal after primary reflection;

the second end face of the interference structure is used for carrying out secondary reflection on the optical signal which is transmitted into the interference structure through the first end face to obtain an optical signal after secondary reflection;

and the optical signal after the primary reflection and the optical signal after the secondary reflection interfere in the single-mode optical fiber.

2. The fiber optic probe of claim 1, wherein the interference structure is a cylindrical structure.

3. The fiber optic probe of claim 2,

the length range of the interference structure is 1-500 mu m;

the diameters of the first end face and the second end face are both larger than 10 mu m.

4. The fiber optic probe of claim 1, wherein the single mode fiber specifically comprises:

a single-mode fiber core and a single-mode fiber cladding;

the single-mode optical fiber cladding is coated outside the single-mode optical fiber core.

5. A temperature sensor, characterized in that the temperature sensor comprises:

a light source, a fiber optic circulator, a spectrometer and a fiber optic probe according to any of claims 1-4;

the light source, one end of the single-mode fiber of the fiber probe, which is not provided with an interference structure, and the spectrometer are respectively connected with a first port, a second port and a third port of the fiber circulator through transmission fibers;

the optical fiber circulator is used for transmitting the optical signal output by the light source to the optical fiber probe;

the optical fiber probe is arranged in a measured temperature field; the optical fiber probe is used for reflecting the optical signal output by the light source twice, so that the optical signal after twice reflection is interfered to obtain an interfered optical signal;

the optical fiber circulator is used for transmitting the interfered optical signal to the spectrometer;

the spectrometer is used for generating a spectrogram of the interfered optical signal; the spectrogram is used to analyze the temperature change of the measured temperature field.

6. The temperature sensor of claim 5, further comprising:

an optical fiber clamp;

the optical fiber clamp is used for fixing the transmission optical fiber.

7. A method for preparing a fiber optic probe, comprising:

performing coating removal treatment on one end of the single mode fiber;

performing end face cutting on one end of the single-mode optical fiber subjected to coating layer removing treatment, and coating ultraviolet curing glue on the end face;

the other end of the single-mode optical fiber is respectively connected with a light source and a spectrometer through an optical fiber circulator;

and opening the light source, moving the single-mode optical fiber by using the optical fiber clamp under an optical microscope, enabling the end face of the single-mode optical fiber to be in contact with the first end face of the interference structure, and curing the ultraviolet curing adhesive to obtain the optical fiber probe when an interference spectrum appears on the spectrometer.

8. The method for preparing an optical fiber probe according to claim 7, wherein the length of the single mode fiber subjected to the coating removal treatment is 1.5 cm.

Technical Field

The invention relates to the technical field of temperature measurement, in particular to an optical fiber probe, a temperature sensor and a preparation method of the optical fiber probe.

Background

The optical fiber temperature sensor is widely concerned due to the advantages of small volume, light weight, electromagnetic interference resistance and the like. The most widely used fiber grating type temperature sensor has low sensitivity and slow response speed due to the limitation of fiber materials, and can only be used in an application scene with a slowly changing temperature field; in addition, the fiber grating structure is large in volume, and the length of the fiber grating structure is usually between 0.5 and 2mm, so that the temperature spatial resolution of the fiber grating structure is limited.

Therefore, a temperature measuring device with high sensitivity and fast response speed is needed to adapt to the scene of fast change of the temperature field.

Disclosure of Invention

The invention aims to provide an optical fiber probe, a temperature sensor and a preparation method of the optical fiber probe, which can be applied to a scene with a rapidly changing temperature field and have the advantages of high sensitivity, high response speed and high resolution.

In order to achieve the purpose, the invention provides the following scheme:

a fiber optic probe, comprising:

single mode optical fibers and interference structures;

the interference structure is a columnar structure; the interference structure is arranged at one end of the single-mode optical fiber; the single-mode optical fiber and the interference structure are both arranged in a measured temperature field; the interference structure is made of silicon carbide; the refractive index of the interference structure varies with the temperature variation of the measured temperature field;

the first end face of the interference structure and the second end face of the interference structure form a Fabry-Perot resonant cavity; the first end face of the interference structure is used for carrying out primary reflection on the optical signal transmitted by the single-mode optical fiber to obtain an optical signal after primary reflection;

the second end face of the interference structure is used for carrying out secondary reflection on the optical signal which is transmitted into the interference structure through the first end face to obtain an optical signal after secondary reflection;

and the optical signal after the primary reflection and the optical signal after the secondary reflection interfere in the single-mode optical fiber.

Optionally, the interference structure is a cylindrical structure.

Alternatively to this, the first and second parts may,

the length range of the interference structure is 1-500 mu m;

the diameters of the first end face and the second end face are both larger than 10 mu m.

Optionally, the single-mode optical fiber specifically includes:

a single-mode fiber core and a single-mode fiber cladding;

the single-mode optical fiber cladding is coated outside the single-mode optical fiber core.

A temperature sensor, comprising:

the device comprises a light source, an optical fiber circulator, a spectrometer and the optical fiber probe;

the light source, one end of the single-mode fiber of the fiber probe, which is not provided with an interference structure, and the spectrometer are respectively connected with a first port, a second port and a third port of the fiber circulator through transmission fibers;

the optical fiber circulator is used for transmitting the optical signal output by the light source to the optical fiber probe;

the optical fiber probe is arranged in a measured temperature field; the optical fiber probe is used for reflecting the optical signal output by the light source twice, so that the optical signal after twice reflection is interfered to obtain an interfered optical signal;

the optical fiber circulator is used for transmitting the interfered optical signal to the spectrometer;

the spectrometer is used for generating a spectrogram of the interfered optical signal; the spectrogram is used to analyze the temperature change of the measured temperature field.

Optionally, the temperature sensor further includes:

an optical fiber clamp;

the optical fiber clamp is used for fixing the transmission optical fiber.

A method for preparing an optical fiber probe comprises the following steps:

performing coating removal treatment on one end of the single mode fiber;

performing end face cutting on one end of the single-mode optical fiber subjected to coating layer removing treatment, and coating ultraviolet curing glue on the end face;

the other end of the single-mode optical fiber is respectively connected with a light source and a spectrometer through an optical fiber circulator;

and opening the light source, moving the single-mode optical fiber by using the optical fiber clamp under an optical microscope, enabling the end face of the single-mode optical fiber to be in contact with the first end face of the interference structure, and curing the ultraviolet curing adhesive to obtain the optical fiber probe when an interference spectrum appears on the spectrometer.

Optionally, the length of the single-mode optical fiber subjected to the coating removal treatment is 1.5 cm.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the invention provides an optical fiber probe, a temperature sensor and a preparation method of the optical fiber probe, wherein the optical fiber probe comprises the following components: single mode optical fibers and interference structures; the interference structure is a columnar structure; the interference structure is arranged at one end of the single-mode optical fiber; the single-mode optical fiber and the interference structure are both arranged in a measured temperature field; the material of the interference structure is silicon carbide; the refractive index of the interference structure changes along with the temperature change of a measured temperature field, and the interference light signal changes along with the change of the refractive index; the first end face of the interference structure and the second end face of the interference structure form a Fabry-Perot resonant cavity; the first end face of the interference structure is used for carrying out primary reflection on an optical signal transmitted by the single-mode optical fiber to obtain an optical signal after primary reflection; the second end face of the interference structure is used for carrying out secondary reflection on the optical signal which is transmitted into the interference structure through the first end face to obtain an optical signal after secondary reflection; the optical signal after the first reflection and the optical signal after the second reflection interfere in the single mode fiber. The optical signal is reflected twice by the interference structure to form interference, so that the optical signal interference device can be applied to scenes with rapidly changing temperature fields, and has the advantages of high sensitivity, high response speed and high resolution.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic structural diagram of a fiber-optic probe according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a temperature sensor according to an embodiment of the present invention;

FIG. 3 is a schematic process diagram of a method for manufacturing an optical fiber probe according to an embodiment of the present invention;

FIG. 4 is a flow chart of a method for manufacturing an optical fiber probe according to an embodiment of the present invention;

description of the drawings: 1-1 single mode fiber cladding; 1-2-single mode fiber core; 1-3 first end face; 1-4 second end faces; 2-1 light source; 2-2 fiber optic circulators; 2-3 optical fiber clips; 2-4 measured temperature field; 2-5 fiber probe; 2-6 spectrometer; 1 a first port; 2 a second port; 3 third port.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide an optical fiber probe, a temperature sensor and a preparation method of the optical fiber probe, which can be applied to a scene with a rapidly changing temperature field and have the advantages of high sensitivity, high response speed and high resolution.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Fig. 1 is a schematic structural diagram of an optical fiber probe according to an embodiment of the present invention, and as shown in fig. 1, the present invention provides an optical fiber probe including:

single mode optical fibers and interference structures;

the interference structure is a columnar structure; the interference structure is arranged at one end of the single-mode optical fiber; the single-mode optical fiber and the interference structure are both arranged in a measured temperature field; the material of the interference structure is silicon carbide; the refractive index of the interference structure changes with the temperature change of the measured temperature field;

the first end face 1-3 of the interference structure and the second end face 1-4 of the interference structure form a Fabry-Perot resonant cavity; the first end face of the interference structure is used for carrying out primary reflection on an optical signal transmitted by the single-mode optical fiber to obtain an optical signal after primary reflection;

the second end face of the interference structure is used for carrying out secondary reflection on the optical signal which is transmitted into the interference structure through the first end face to obtain an optical signal after secondary reflection;

the optical signal after the first reflection and the optical signal after the second reflection interfere in the single mode fiber.

Wherein, the interference structure is a cylindrical structure. The length range of the interference structure is 1-500 μm; the diameters of the first end face and the second end face are both larger than 10 mu m.

Specifically, the single-mode optical fiber specifically includes:

a single-mode fiber core 1-2 and a single-mode fiber cladding 1-1;

the single-mode optical fiber cladding is coated outside the single-mode optical fiber core.

Fig. 2 is a schematic structural diagram of a temperature sensor in an embodiment of the present invention, and as shown in fig. 2, the present invention further provides a temperature sensor, including:

the device comprises a light source 2-1, an optical fiber circulator 2-2, a spectrometer 2-6 and an optical fiber probe 2-5;

the light source, one end of the single mode fiber of the fiber probe, which is not provided with the interference structure, and the spectrometer are respectively connected with a first port 1, a second port 2 and a third port 3 of the fiber circulator through transmission fibers;

the optical fiber circulator is used for transmitting the optical signal output by the light source to the optical fiber probe;

the optical fiber probe is arranged in a measured temperature field 2-4; the optical fiber probe is used for reflecting the optical signal output by the light source twice, so that the optical signal after twice reflection is interfered to obtain an interfered optical signal;

the optical fiber circulator is used for transmitting the interfered optical signal to the spectrometer;

the spectrometer is used for generating a spectrogram of the interfered optical signal; the spectrogram is used to analyze the temperature change of the measured temperature field.

In addition, the temperature sensor provided by the invention further comprises:

2-3 of an optical fiber clamp;

the fiber clamp is used to secure the transmission fiber.

Fig. 4 is a flowchart of a method for manufacturing an optical fiber probe according to an embodiment of the present invention, and as shown in fig. 4, the present invention further provides a method for manufacturing an optical fiber probe, including:

step 401: performing coating removal treatment on one end of the single mode fiber;

step 402: performing end face cutting on one end of the single-mode optical fiber subjected to coating layer removal treatment, and coating ultraviolet curing glue on the end face;

step 403: the other end of the single-mode optical fiber is respectively connected with a light source and a spectrometer through an optical fiber circulator;

step 404: and starting a light source, moving the single-mode optical fiber by using the optical fiber clamp under an optical microscope to enable the end face of the single-mode optical fiber to be in contact with the first end face of the interference structure, and curing the ultraviolet curing adhesive when an interference spectrum appears on the spectrometer to obtain the optical fiber probe.

Wherein the length of the single mode fiber subjected to coating layer removal treatment is 1.5 cm.

In order to overcome the defects of the prior art, the invention provides an optical fiber probe, which structurally utilizes two end faces of a silicon carbide column (an interference structure) as two parallel plane reflectors, namely plane parallel cavities, also called Fabry-Perot resonant cavities, so that reflected light energy can be coupled back to a single-mode fiber core again, and the transmission loss of the light energy is reduced. In terms of materials, silicon carbide is selected as a material of the Fabry-Perot resonant cavity, the silicon carbide has a high thermo-optic coefficient which is about 6 multiplied by 10 < -5 > K < -1 > and is more than 10 times of the thermo-optic coefficient of a silicon dioxide material, and the sensitivity of a device can be improved. After the incident light is reflected by two parallel planes in sequence, two reflected light beams have a certain phase difference, so that an optical fiber interferometer can be formed.

Fig. 3 is a schematic process diagram of a method for manufacturing an optical fiber probe according to an embodiment of the present invention, and as shown in fig. 3, the process for manufacturing an optical fiber probe includes the following steps:

process (a): a section of single mode fiber is taken, and a coating layer is removed by 1.5cm from the tail part of the fiber.

A process (b): and the tail end face of the optical fiber is cut by using an optical fiber cutter, so that the tail end face of the optical fiber is kept neat and clean.

Process (c): and (b) dipping ultraviolet curing glue on the tail end face of the single-mode optical fiber in the process (b).

Process (d): connecting the single-mode optical fiber in the process (c) with a light source and a spectrometer, and aligning and contacting the end face of the single-mode optical fiber with the end face of the silicon carbide column by using an optical fiber clamp under an optical microscope until the spectrometer generates a clear interference spectrum;

process (e): and (3) placing the sensing structure under an ultraviolet lamp, and curing the ultraviolet curing adhesive between the single-mode optical fiber and the silicon carbide microstructure. An extrinsic fiber fabry-perot temperature sensing probe with a stable structure can be obtained as shown in process (f).

In addition, the invention can change the interference spectrum by adjusting the size of the silicon carbide column, realize the spectrum tracking in different dynamic ranges, and further can enlarge or reduce the measurement range of the temperature. Wherein the diameter of the silicon carbide column is more than 10 μm, and the thickness of the column is 1-500 μm.

The invention adopts a fiber optic circulator to couple sensing signals. As shown in fig. 2, the transmission fiber is held by a fiber clamp to suspend the sensing probe in the water bath (the measured temperature field). The optical signal sent by the light source or the optical fiber laser enters the silicon carbide column from the first port of the optical fiber ring through the second port. The light entering the sensor is reflected by a part of light on the surface A (first end surface) of the silicon carbide column, the rest of light penetrates through the surface A of the silicon carbide column and enters the silicon carbide microcavity to be reflected by the surface B (second end surface) of the silicon carbide column, the two parts of light interfere in the reflection process, the interfered light signal enters the optical fiber spectrometer through the second port of the optical fiber circulator and the third port to be demodulated, an interference characteristic peak appears in an output spectrum, the water temperature is changed through the water bath, and when the measured temperature changes, the effective refractive index of the silicon carbide changes along with the interference characteristic peak, so that the position of the interference characteristic peak moves. Therefore, by monitoring the position of the characteristic peak, the change of the measured temperature can be obtained, and the transmission spectrum can be simply expressed as the process of interference of two modes.

Wherein, I represents the light intensity of the interfered optical signal; i is₁And I₂The light intensity of the two reflected lights, delta is the phase difference between the two reflected lights,n is the refractive index of the silicon carbide column, λ is the typical transmission wavelength, typically 1550nm, and G is the length of the interference structure.

From the above analysis, it can be seen that for a fixed interference path length, the position of the interference peak depends on the effective refractive index of the silicon carbide column. When the measured temperature changes, the effective refractive index of the silicon carbide column changes, and the position of the interference characteristic peak changes. Therefore, it can realize sensing of temperature.

Compared with the prior art, the invention has the following advantages:

1) the extrinsic optical fiber Fabry-Perot temperature sensing probe is simple in manufacturing process and structure and convenient for point type measurement.

2) The Fabry-Perot resonant cavity is made of silicon carbide materials, and due to the fact that the photo-thermal coefficient is high, the sensing sensitivity and the resolution ratio can be effectively improved.

3) The sensing probe is small in size, has a high thermal diffusion coefficient, and can effectively improve the response speed of the sensor.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.