阅读说明：本技术 气球形mzi传感器及其制作方法和基于mzi传感器的传感系统 (Gas-ball-shaped MZI sensor, manufacturing method thereof and sensing system based on MZI sensor ) 是由 王图涛 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种气球形光纤MZI传感器,传感器包括单模光纤、光纤球形结构和毛细管,单模光纤构成传感回路且其末端为气球形结构,传感回路的输入端和输出端内置在毛细管中固定,光纤球形结构设置在传感回路的输入端。本发明还涉及一种基于气球形光纤MZI的水流速度传感系统,包括宽带光源、光谱分析仪、单模光纤、气球形光纤MZI传感器、水泵、水管、流速计和阀门,宽带光源和光谱分析仪通过单模光纤分别连接气球形光纤MZI传感器的输入端和输出端,水泵、气球形MZI和流速计通过水管顺次连接,阀门连接水管侧壁。本发明解决了现有技术中光纤容易断裂、干涉条纹可见度不高的问题。(The invention discloses a balloon-shaped optical fiber MZI sensor which comprises a single-mode optical fiber, an optical fiber spherical structure and a capillary tube, wherein the single-mode optical fiber forms a sensing loop, the tail end of the sensing loop is of the balloon-shaped structure, the input end and the output end of the sensing loop are fixedly arranged in the capillary tube, and the optical fiber spherical structure is arranged at the input end of the sensing loop. The invention also relates to a water velocity sensing system based on the balloon-shaped optical fiber MZI, which comprises a broadband light source, a spectrum analyzer, a single-mode optical fiber, a balloon-shaped optical fiber MZI sensor, a water pump, a water pipe, a flow meter and a valve, wherein the broadband light source and the spectrum analyzer are respectively connected with the input end and the output end of the balloon-shaped optical fiber MZI sensor through the single-mode optical fiber, the water pump, the balloon-shaped MZI and the flow meter are sequentially connected through the water pipe, and the valve is connected with the side wall of the water pipe. The invention solves the problems of easy breakage of optical fibers and low visibility of interference fringes in the prior art.)

1. The utility model provides a balloon form optic fibre MZI sensor, its characterized in that includes single mode fiber (3), optic fibre spherical structure (9) and capillary (10), single mode fiber (3) constitute sensing circuit and sensing circuit is the balloon form structure, sensing circuit's input and output are built-in to be fixed in capillary (10), optic fibre spherical structure (9) set up the input at sensing circuit.

2. The air balloon optical fiber MZI sensor of claim 1, wherein said air balloon structure tip is located 20-25 mm from said capillary tube (10).

3. The gas-bulb fiber MZI sensor of claim 1, wherein said fiber-bulb structures (9) are 3 in number.

4. The gas-sphere optical fiber MZI sensor of claim 1, wherein said optical fiber-sphere structure (9) has a diameter of 200 to 220 μm.

5. The balloon-shaped fiber MZI sensor of claim 1, wherein said capillary tube (10) has an inner diameter of 0.4mm and a length of 1.5 cm.

6. The balloon-shaped fiber MZI sensor of claim 1, wherein said single mode fiber (3) is a G.652 single mode fiber (3), having a core diameter of 8.2 μm and a cladding diameter of 125 μm.

7. A water velocity sensing system based on a balloon-shaped optical fiber MZI (Mach-Zehnder interferometer) is characterized by comprising a broadband light source (1), a spectrum analyzer (2), a single-mode optical fiber (3), the balloon-shaped optical fiber MZI sensor (4) of any one of claims 1 to 6, a water pump (5), a water pipe (6), a flow meter (7) and a valve (8), wherein the broadband light source (1) and the spectrum analyzer (2) are respectively connected with the input end and the output end of the balloon-shaped optical fiber MZI sensor (4) through the single-mode optical fiber (3), the water pump (5), the balloon-shaped MZI (4) and the flow meter (7) are sequentially connected through the water pipe (6), and the valve (8) is connected with the side wall of the water pipe (6).

8. A manufacturing method of a balloon-shaped optical fiber MZI sensor is characterized by comprising the following steps:

taking a single-mode optical fiber (3) with the length of 10-15 cm, removing a coating layer at one end of the single-mode optical fiber (3), cleaning the coating layer with alcohol, and cutting the end face of the single-mode optical fiber flat by using an optical fiber cutting machine;

putting the cut and flattened single-mode optical fiber (3) into an optical fiber fusion splicer for discharging for multiple times, so that the optical fiber is contracted into a spherical structure (9);

after a spherical structure (9) is manufactured by the same method, the two spherical structures (9) are welded together, and an optical fiber cutter is used for cutting the optical fiber to ensure that the tail end of the optical fiber has only two spherical structures (9);

and taking one spherical structure (9), repeating the steps, welding to form three spherical structures (9), and inserting two ends of the welded optical fiber into the capillary (10) for fixing.

Technical Field

The invention relates to a balloon MZI sensor, a manufacturing method thereof and a sensing system based on the MZI sensor, and belongs to the technical field of optical fiber sensing.

Background

In 1966, the first theory of optical signal transmission by optical fiber (optical fiber) was first proposed by the high-roll of the british scientist of the book, and under the guidance of the theory, the first low-loss optical fiber was drawn by the american corning corporation in 1970. Meanwhile, optical fiber communication technology and optical fiber sensing technology are also in use. Fiber optic sensors offer unique advantages over conventional electrical sensors. The optical fiber sensor has the advantages of corrosion resistance, electromagnetic interference resistance, small volume, high sensitivity and the like. Therefore, the physical quantity sensing widely used in various fields generally includes physical quantities such as solution concentration, gas concentration, humidity, ph, and magnetic field. Among many optical fiber sensors, the mach-zehnder interferometer (MZI) sensor has been developed very rapidly due to its unique advantages of simple fabrication, good stability, compact structure, high signal extinction ratio, low insertion loss, etc., and has been applied to the sensing fields of temperature, refractive index, strain, magnetic field, etc. In practical applications, flow rate sensors play a very important role in many professional fields such as industry and biochemistry. Over the last several decades, various fiber optic sensors have been proposed by many researchers to measure the flow rate of a liquid. Fiber vortex flowmeters were first proposed for measurement, and then Fiber Bragg Gratings (FBGs) were also proposed for flow velocity measurement. In recent years, fiber-optic michelson and fabry perot sensors have been shown to measure flow rate. However, these sensors are not only complicated in manufacturing process, but also have a problem that the optical fiber is easily broken and the visibility of interference fringes is not high in the process of practical use. Therefore, practical application of the sensor remains a challenge.

Disclosure of Invention

In order to solve the defects of the prior art, the invention aims to provide a balloon-shaped MZI sensor, a manufacturing method thereof and a sensing system based on the MZI sensor, and solves the problems that an optical fiber is easy to break and the visibility of interference fringes is not high in the prior art.

In order to achieve the above object, the present invention adopts the following technical solutions:

a balloon-shaped optical fiber MZI sensor comprises a single-mode optical fiber, an optical fiber spherical structure and a capillary tube, wherein the single-mode optical fiber forms a sensing loop, the sensing loop is of the balloon-shaped structure, the input end and the output end of the sensing loop are fixed in the capillary tube, and the optical fiber spherical structure is arranged at the input end of the sensing loop.

Further, the distance between the top end of the balloon-shaped structure and the capillary tube is 20-25 mm.

Further, the number of the optical fiber spherical structures is 3.

Further, the diameter of the optical fiber spherical structure is 200 to 220 μm.

Further, the capillary tube had an inner diameter of 0.4mm and a length of 1.5 cm.

Further, the single mode fiber was a G.652 single mode fiber, the core diameter was 8.2 μm, and the cladding diameter was 125 μm.

The utility model provides a water velocity sensing system based on balloon shape optic fibre MZI, includes broadband light source, spectral analysis appearance, single mode fiber, aforementioned balloon shape optic fibre MZI sensor, water pump, water pipe, anemograph and valve, and broadband light source and spectral analysis appearance pass through single mode fiber and connect the input and the output of balloon shape optic fibre MZI sensor respectively, and water pump, balloon shape MZI and anemograph pass through the water pipe and connect in order, and the water pipe lateral wall is connected to the valve.

A manufacturing method of a balloon-shaped optical fiber MZI sensor comprises the following steps:

taking a single-mode optical fiber 3 with the length of 10-15 cm, removing a coating layer at one end of the single-mode optical fiber, cleaning the single-mode optical fiber with alcohol, and cutting the end face of the single-mode optical fiber flat by using an optical fiber cutting machine;

putting the cut and flattened single-mode optical fiber into an optical fiber fusion splicer for discharging for multiple times, so that the optical fiber is contracted into a spherical structure;

after a spherical structure is manufactured by the same method, the two spherical structures are welded together, and an optical fiber cutter is used for cutting the optical fiber to ensure that the tail end of the optical fiber has only two spherical structures;

and taking one spherical structure, repeating the steps, welding to form three spherical structures, and inserting the two ends of the welded optical fiber into the capillary tube for fixing.

The invention achieves the following beneficial effects:

1. due to the existence of the spherical structure, the sensitivity of the sensor can be effectively improved, and the optical fiber MZI with the spherical shape can realize large-range high-sensitivity sensing of the water flow speed.

2. The sensor can be manufactured only by using common materials and equipment such as single-mode fibers, fiber cutting machines, fiber welding machines, capillaries and the like, expensive equipment such as a femtosecond laser or a fiber grating writing device and the like is not needed in the manufacturing process, and the sensor is simple in manufacturing process, low in cost and high in sensitivity.

Drawings

FIG. 1 is a schematic diagram of a water flow velocity sensing system based on a balloon-shaped optical fiber MZI;

FIG. 2 is a schematic diagram of a gas-sphere fiber MZI sensor structure of the present invention;

FIG. 3 is a schematic diagram of the fabrication process of a balloon-shaped fiber MZI sensor of the present invention.

The meaning of the reference symbols in the figures: the device comprises a broadband light source 1, a spectrometer 2, a single-mode fiber 3, a fiber MZI sensor 4, a water pump 5, a water pipe 6, a flow rate meter 7, a valve 8, a spherical structure 9 and a capillary tube 10.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

Referring to fig. 2, the balloon-shaped optical fiber MZI sensor 4 includes a single-mode optical fiber 3 and an optical fiber spherical structure 9, the single-mode optical fiber 3 forms a sensing loop, the sensing loop is of a balloon-shaped structure, an input end and an output end of the sensing loop are fixed in a capillary 10, and the optical fiber spherical structure 9 is disposed at the input end of the sensing loop. The distance L from the balloon top end of the balloon-shaped optical fiber MZI sensor 4 to the capillary tube is 20-25 mm, the number of the optical fiber spherical structures 9 on the input side is 3, the diameter of each spherical structure 9 is 200-220 microns, the single-mode optical fiber 3 is a G.652 single-mode optical fiber, the diameter of the fiber core is 8.2 microns, and the diameter of the cladding is 125 microns.

The embodiment discloses a water velocity sensing system based on a balloon-shaped optical fiber MZI, which comprises a broadband light source 1, a spectrum analyzer 2, a single-mode optical fiber 3, a balloon-shaped optical fiber MZI sensor 4, a water pump 5, a water pipe 6, a flow meter 7 and a valve 8, as shown in FIG. 1. The single-mode optical fiber 3 is used for transmitting optical signals, the broadband light source 1, the spectrum analyzer 2 and the balloon-shaped optical fiber MZI sensor 4 are connected through the single-mode optical fiber 3, and the broadband light source 1 and the spectrum analyzer 2 are respectively connected to the input end and the output end of the balloon-shaped optical fiber MZI sensor 4. The balloon-shaped optical fiber MZI sensor 4 is used for the velocity of flow sensing, wherein the water flow direction is perpendicular with the two-dimensional plane that balloon-shaped optical fiber MZI sensor 4 constitutes, water pipe 6 is used for connecting water pump 5, balloon-shaped optical fiber MZI sensor 4 and anemograph 7, broadband light source 1 is used for sending optical signal, spectral analysis appearance 2 is used for gathering the transmission spectrum of sensing signal, water pump 5 and water pipe 6 are used for transmitting rivers, anemograph 7 is used for the detection of actual velocity of water, valve 8 sets up and is used for controlling velocity of water in 6 lateral walls of water pipe.

The manufacturing method of the balloon-shaped optical fiber MZI sensor 4 is shown in FIG. 3:

step S10, taking a single-mode optical fiber 3 with the length of 10-15 cm, removing a coating layer at one end of the single-mode optical fiber 3 for a certain distance, cleaning the coating layer with alcohol, and flattening the end face of the single-mode optical fiber with an optical fiber cutting machine according to the length requirement;

step S20, placing the cut and flattened optical fiber into an optical fiber fusion splicer for multiple discharging, and contracting the fused optical fiber into a spherical structure 9 after repeated discharging under the action of the surface tension of the liquid;

step S30, after a spherical structure 9 is manufactured by the same method, the two spherical structures 9 are welded together, and then an optical fiber cutter is used for cutting the optical fiber to ensure that the tail end of the optical fiber has only two spherical structures 9;

in step S40, three spherical structures 9 are formed by fusion-splicing with one spherical structure 9, and the sensor structure is fixed by inserting the two ends of the fused optical fiber into the capillary 10.

In a specific use process, a broadband light source 1 and a spectrum analyzer 2 are respectively connected with the input end and the output end of a balloon-shaped optical fiber MZI sensor 4. The balloon-shaped optical fiber MZI sensor 4 is inserted into a water tube 6 so that the direction of the water flow is perpendicular to the two-dimensional plane in which the balloon shape lies, the water tube 6 connecting a water pump 5 and a flow meter 7.

The working mode of the embodiment is as follows: the broadband light source 1 generates signal light, the signal light is input to the balloon-shaped optical fiber MZI sensor 4 through the single-mode optical fiber 3, and the signal light is output to the spectrum analyzer 2 after passing through the balloon-shaped optical fiber MZI sensor 4. Meanwhile, different water flow velocities enable the balloon-shaped optical fiber MZI sensor 4 to be bent to different degrees, and then water flow velocity sensing is achieved.

The working principle of the embodiment is as follows: when light is transmitted to the input end spherical structure 9 of the balloon-shaped optical fiber MZI sensor 4 through the single mode fiber 3, because the total reflection condition of light is not satisfied, a part of light can be incident into the cladding from the fiber core, when light is continuously transmitted to the bending part of the output end of the balloon-shaped optical fiber MZI sensor 4, the light inside the cladding can be coupled back to the fiber core, and interfere with the light inside the fiber core, the transmission spectrum can be detected through the optical spectrum analyzer 2, because the water flow can lead to the balloon-shaped optical fiber to be bent, the wavelength of the transmission spectrum is changed, and the change of the water flow speed can be obtained by detecting the wavelength change of the transmission spectrum through the optical spectrum analyzer 2. Meanwhile, the spherical structure can effectively excite the high-order cladding mode, so that the measurement sensitivity of the sensor is enhanced.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.