CN204881905U - Temperature sensor of spherical structure optic fibre - Google Patents

Abstract

The utility model relates to a temperature sensor of spherical structure optic fibre, the system mainly comprises broadband light source, input optic fibre, input spherical structure optic fibre, connection optic fibre, output spherical structure optic fibre, output optical fibre, spectrum appearance, follow smooth after input optic fibre incides input spherical structure optic fibre that broadband light source sent, excited the covering mode sensitive to ambient temperature to with the sandwich layer mode of being connected in the optic fibre a mach special interference once taking place, later go into the output optical fibre through output spherical structure fiber optic coupling, incides on the spectrum appearance, when external environment temperature changes, interfere the wavelength position of attenuation peak can take place corresponding change, interfere the wavelength value of attenuation peak to realize the measurement to ambient temperature through transmitted light on detecting the spectrum appearance. This optical fiber sensor has simple structure, measures advantages such as convenience, sensitivity height.

Description

A kind of temperature sensor of spherical structure optical fiber

Technical field

The utility model relates to temperature detection technology, optical fiber sensing technology, what utilize is the spherical structure optical fiber sensitivity characteristics of temperature variation and the different ambient temperature method that the wavelength value of transmitted light attenuation peak can be made to change to external world, have that structure is simple, volume is little, fast response time, the plurality of advantages such as highly sensitive, safe and reliable, it belongs to optical fiber sensing field.

Background technology

Compared with traditional temperature sensor, there is lot of advantages with current optical fiber temperature sensor, particularly fiber work frequency is wide, and dynamic range is large, is a kind of low loss line, and due to features such as volume are little, quality is light, radiation resistance is good, become the commodity of alternative conventional temperature sensor.Fibre optic temperature sensor, since appearance, has started to be applicable to the fields such as electric system, building, chemical industry, ocean development gradually, and has achieved many practical application achievements.

Such as distributed optical fiber temperature sensor, fiber-optical grating temperature sensor, optical fiber fluorescence temperature sensor, Interference optical-fiber temperature sensors etc., these sensors also need to consider many factors in actual applications simultaneously, the cost of manufacture of such as sensor, the life-span length used, the precision measured, the problems such as the size of photodetector wavelength resolution.

Utility model content

The purpose of this utility model is the problem in order to overcome above-mentioned generation, and meet actual work requirements, propose a kind of optical fiber temperature sensor of spherical structure, this system architecture is simple, reasonable in design, with low cost, directly in real time, result is effectively accurate.

For achieving the above object, the technical solution adopted in the utility model is: a kind of optical fiber temperature sensor of spherical structure, is made up of wideband light source, input optical fibre, input spherical structure optical fiber, connecting fiber, output spherical structure optical fiber, output optical fibre, spectrometer.The light sent from wideband light source incides after input spherical structure optical fiber through input optical fibre, excite temperature sensitive cladding mode to external world, and interfere with the sandwich layer pattern generation Mach in connecting fiber-is once special, entering output optical fibre through exporting spherical structure coupling fiber afterwards, inciding on spectrometer; When ambient temperature changes, can there is corresponding change in the wavelength location of the interference attenuation peak of transmitted light, interferes the wavelength value of attenuation peak to realize the measurement of temperature to external world by detecting transmitted light on spectrometer.

Wherein transmitted light interferes the wavelength variation values Δ λ of attenuation peak and temperature change value Δ T to meet:

$\frac{\mathrm{\Δ}\mathrm{\λ}}{\mathrm{\Δ}T}={\mathrm{\λ}}_{dip}\left(\mathrm{\α}+\frac{{\mathrm{\ζ}}_{core}{n}_{core}-{\mathrm{\ζ}}_{clad}{n}_{clad}}{n_{core}-n_{clad}}\right)$

Wherein, n in above formula _core, n _cladrepresent the effective refractive index of fibre core, covering respectively, ζ _core, ζ _cladrepresent the effective thermo-optical coeffecient of covering, fibre core, λ _diprepresent that transmitted light interferes the wavelength value that attenuation peak is corresponding; α represents the thermal expansivity of optical fiber surface silicon dioxide, and along with the change of ambient temperature, transmitted light interferes attenuation peak wavelength to change, and therefore spherical structure optical fiber has higher temperature sensitive characteristic.

Input spherical structure optical fiber described in the utility model and output spherical structure optical fiber utilize optical fiber splicer to carry out current discharge to fiber end face and make, the spherical diameter of input spherical structure optical fiber is 188.87 μm, the spherical diameter exporting spherical structure optical fiber is 179.98 μm, effectively can pass through transmitted light attenuation peak wavelength value.

Wideband light source described in the utility model is as sending incident light, and spectral range is 650nm-1700nm, can comprise the transmitted light attenuation peak wavelength value that spherical structure optical fiber passes through.

Spectrometer described in the utility model is used as to receive light source, and resolution is 0.01nm, accurately can record the transmitted light attenuation peak wavelength value that spherical structure optical fiber under different temperatures passes through.

Input optical fibre described in the utility model, connecting fiber, output optical fibre are all general single mode fibers, and its cladding diameter is 125 μm, and core diameter is 8 μm.

The feature advantage that the utility model has is: 1. all appts material is all very general, and system architecture is simple; 2. ambient temperature measures and directly detects in real time, and simple to operate; 3. all operations does not all relate to hazardous chemicals, safe and reliable.

Accompanying drawing explanation

Fig. 1 is structural representation of the present utility model

Fig. 2 is the spectrogram under different temperatures of the present utility model

Fig. 3 is experimental result picture of the present utility model

Embodiment

The temperature and humidity conditions that the utility model is suitable for is: > 5 DEG C, 0-90%RH.

As shown in Figure 1, it is a kind of optical fiber temperature sensor of spherical structure.

First with business heat sealing machine, an ordinary optic fibre is made into diameter width and is respectively the input spherical structure optical fiber (3) of 188.87 μm, the output spherical structure optical fiber (5) of 179.98 μm.The end of input optical fibre (3) and output optical fibre (5) is exceeded electrode bar 180 μm, arranging discharge parameter discharge time is 1300ms, strength of discharge is 200bit, input (output) fiber optic tip is softened, become a spheroid, complete the connection with connecting fiber (4) end of input optical fibre (3) and output optical fibre (5) finally by manual mode, form spherical structure Fibre Optical Sensor.Input optical fibre (2), output optical fibre (6) are connected with wideband light source (1) and spectrometer (7) respectively, forms optical fiber sensing system.When carrying out the simulated measurement of different ambient temperature in laboratory, one piece of heating plate is placed in input spherical structure optical fiber (3), connecting fiber (4) with under exporting spherical structure optical fiber (5), the temperature-controllable scope of heating plate is 18 DEG C-150 DEG C, and its accurate temperature value is 0.1 DEG C.By changing the temperature of heating plate, from 18 DEG C to 78 DEG C, spherical structure optical fiber is heated, and observe the attenuation peak wavelength value situation of change of the upper transmitted light of spectrometer (7).The spectral range of wideband light source (1) is 650nm-1700nm, the light sent incides in the middle of input spherical structure optical fiber (3) through input optical fibre (2), by connecting fiber (4), output spherical structure optical fiber (5), output optical fibre (6), incide transmitted light attenuation peak wavelength value corresponding to the upper spherical structure optical fiber that just can read under condition of different temperatures of spectrometer (7), the Fitting Calculation goes out the relation that transmitted light attenuation peak wavelength value and ambient temperature change, thus reaches the object detecting ambient temperature.

As shown in Figure 2, carry out the experimental result picture during simulated measurement of different ambient temperature in laboratory, represent the wavelength value of transmitted light attenuation peak and the oscillogram of extraneous different temperatures value.Can obtain, maximum extinction ratio can reach 18dBm, along with the continuous rising of ambient temperature, obvious Red Shift Phenomena occurs.

As shown in Figure 3, be experimental result picture, represent the wavelength value of transmitted light attenuation peak and the fit linear relationship figure of extraneous different temperatures value.Wavelength value and the extraneous different temperatures of transmitted light attenuation peak are good linear relationship, and fitting coefficient is about 0.9978, and its Sensitirity va1ue is 0.13982nm/ DEG C.According to the wavelength resolution of spectrometer, can obtain detection limit of the present utility model by calculating is 7.15X10 ^-2dEG C, there is higher resolution numerical value.

Know with those skilled in the art know that; according to method of the present utility model; can be implemented in the detection to temperature under some specific environment; the detection etc. of the environment temperatures such as such as chemical industry, generating plant, building, transformer station and fire alarm system; wideband light source, spherical structure optical fiber and spectrometer etc. can carry out new unified collocation; apparatus structure can be optimized design, and protection domain of the present utility model is not limited to above embodiment.

Claims (5)

1. a temperature sensor for spherical structure optical fiber, is characterized in that: be made up of wideband light source (1), input optical fibre (2), input spherical structure optical fiber (3), connecting fiber (4), output spherical structure optical fiber (5), output optical fibre (6), spectrometer (7); The light sent from wideband light source (1) incides after input spherical structure optical fiber (3) through input optical fibre (2), excite temperature sensitive cladding mode to external world, and interfere with the sandwich layer pattern generation Mach in connecting fiber (4)-is once special, being coupled into output optical fibre (6) through exporting spherical structure optical fiber (5) afterwards, inciding on spectrometer (7); When ambient temperature changes, interfering the wavelength location of attenuation peak that corresponding change can occur, interfering the wavelength value of attenuation peak to realize the measurement of temperature to external world by detecting the upper transmitted light of spectrometer (7).

2. the temperature sensor of a kind of spherical structure optical fiber according to claim 1, it is characterized in that: described input spherical structure optical fiber (3) and output spherical structure optical fiber (5) utilize optical fiber splicer to carry out current discharge to fiber end face and makes, the spherical diameter of input spherical structure optical fiber (3) is 188.87 μm, and the spherical diameter exporting spherical structure optical fiber (5) is 179.98 μm.

3. the temperature sensor of a kind of spherical structure optical fiber according to claim 1, it is characterized in that: the spectral range of described wideband light source (1) is 650nm-1700nm, the transmitted light that Mach-once special interference was formed be made up of input spherical structure optical fiber (3), connecting fiber (4) and output spherical structure optical fiber (5) can be comprised and interfere attenuation peak wavelength value.

4. the temperature sensor of a kind of spherical structure optical fiber according to claim 1, is characterized in that: under described spectrometer (7) can record different temperatures, transmitted light interferes attenuation peak wavelength value, and wavelength resolution is 0.01nm.

5. the temperature sensor of a kind of spherical structure optical fiber according to claim 1, it is characterized in that: input optical fibre (2), connecting fiber (4), output optical fibre (6) are all general single mode fibers, its cladding diameter is 125 μm, and core diameter is 8 μm.