CN201628592U - Parallel multi-point fiber optic temperature sensor - Google Patents

Abstract

The utility model discloses a parallel multiple-point optical temperature sensor comprising a broadband light source, an optical fiber coupler A, coupler arrays O1-On, optical fiber sensing heads S1-Sn, an array waveguide grating AWG, array photodiode probes P1-Pn, a transmission optical fiber and a circuit processing unit; and the parallel multiple-point temperature measuring of high resolution ratio can be realized through the combination of the array waveguide grating and the optical fiber sensing heads packaged by epoxy resin. The sensor has the capability of real-time on-line and remote monitoring, wide measuring range, high sensitivity, strong stability, simple structure, convenient operation and low cost.

Description

The parallel multi-point type optical fiber temperature sensor

Technical field

The utility model relates to a kind of temperature sensor, especially relates to a kind of parallel multi-point type optical fiber temperature sensor based on Fresnel reflection.

Background technology

Temperature is the basic physical parameter of very paying close attention in engineering and the scientific research, and it can reflect material substance internal physical character and chemical property.To the measurement and the monitoring of temperature, in biochemistry, environmental protection, medical treatment and food processing field and modern industry production run, crucial meaning is arranged.Therefore, thermometry is always in continuous research and development, and traditional has all brought into play great function with usefulness electric signal such as thermistor, leucoscopes as the temperature sensor of working foundation in national economy, national defense construction, space technology and scientific research.But for some special industry environment (as inflammable and explosive, high voltage, big electric current, the interference of forceful electric power flow field etc.), these are that the temperature sensor of working foundation is then powerless with the electric signal.At this shortcoming of conventional temperature sensor, various optical fiber temperature sensor technologies also grow up in succession, more typically have based on silica-base film, Fabry Perot interference and multimode interference principle etc.This type of technology structure and signal Processing relative complex, operation are also inconvenient.Yet in application of practical project, measurand often is not a point, but presents the field that certain space distributes, and in order to obtain the more complete information of this class measurand, needs to adopt the temperature-sensing system of multipoint mode modulation.At present, for the physical quantity of multipoint mode, it is clumsy or very uneconomical that the multipoint mode sensor that can provide seems.And be used for the fibre optic temperature sensor of mainly containing of the monitoring temperature that can realize multipoint mode of optical fiber and measurement based on principles such as fiber grating, Raman scattering and Brillouin scatterings, but the signal demodulating system of these optical fiber sensing technologies all more complicated, response time slow and cost an arm and a leg.Therefore, be designed for simple in structure, the cheap multi-point type optical fiber temperature-sensing system of Important Project monitoring temperature, significance arranged for the control of engineering safety accident.

The utility model content

The purpose of this utility model be to provide a kind of reliable accurately, parallel multi-point type optical fiber temperature sensor real-time, survey when can be used for Fibre Optical Sensor and multi-point temp.

Above-mentioned purpose can realize by following technical measures: a kind of parallel multi-point type optical fiber temperature sensor comprises: wideband light source, fiber coupler A, array waveguide grating AWG, fibre coupler arrays O ₁～O _n, a n optical fiber sensing probe S ₁～S _n, array photodiode probe P ₁～P _n, Transmission Fibers and processing of circuit unit;

Described wideband light source is connected with coupling mechanism A by Transmission Fibers; One of them output port of coupling mechanism A by Transmission Fibers be connected with array waveguide grating AWG, among the array waveguide grating AWG light of each passage by Transmission Fibers and coupler array O ₁～O _nCorresponding connection, coupler array O ₁～O _nIn the optical fiber sensing probe S of wherein an array delivery outlet and identical numbering ₁～S _nThe back output that connects one to one successively (is O ₁Corresponding S ₁, O ₂Corresponding S ₂... O _nCorresponding S _n); Optical fiber sensing probe S ₁～S _nThe reflection of every road is surveyed light again through coupler array O ₁～O _n, survey optical delivery fiber and array photodiode probe P by reflection ₁～P _nConnect array photodiode probe P ₁～P _nElectric signal output after the conversion is electrically connected with the processing of circuit unit respectively.During measurement, optical fiber sensing probe S ₁～S _nPlace environment to be measured (as temperature control system).

In the utility model, the value of n determines that according to the spectral range of wideband light source and the port number of array waveguide grating scope is wide more, and passage is many more, and the n value is big more, and in the utility model, the scope of n is taken as 2～500 (2≤n≤500).

In the utility model, described optical fiber sensing probe is made of epoxy encapsulation metal shell in perpendicular end surface (PC) tail optical fiber joint.

As to further improvement of the utility model, another output port at coupling mechanism A connects a photodiode probe B by Transmission Fibers, use the photodiode probe B to monitor in real time, can utilize the method for relative intensity to eliminate that backlight improves the measuring accuracy and the antijamming capability thereof of instrument to the error that influence brought of light source in the instability of light source and the light path like this.

In the utility model, the splitting ratio of two output ports of described fiber coupler A is 95%～5%: 5%～95%.

As to further improvement of the utility model, at coupler array O ₁～O _nIn another array delivery outlet be connected with and twine optical fiber S ₁～S _n, twining optical fiber is that single-mode transmission optical fiber is entwined through spiral.Twine optical fiber and be used for loss coupler array O ₁～O _nIn the light of another array delivery outlet, survey light in order to avoid influence the reflection of optical fiber sensing probe, improve measuring accuracy.

In the utility model, described coupler array O ₁～O _nIn the splitting ratio of two array output end mouths be 50%: 50%.

In the utility model, described array photodiode probe P ₁～P _nLuminous intensity measurement sensitivity be the 10nW magnitude, specifically depend on the sensitivity requirement of instrument, require high more, high more to the requirement of the luminous intensity measurement sensitivity of photodiode probe.Used Transmission Fibers is a general single mode fiber in the utility model.

The unit of processing of circuit described in the utility model is by probe P ₁～P _nPre-amplification circuit is (respectively with array photodiode probe P ₁～P _nConnection, single chip microcomputer circuit and LCD display are electrically connected formation jointly, probe P ₁～P _nThe incoming line of the output line of pre-amplification circuit and single chip microcomputer circuit is electrically connected; The output line of single chip microcomputer circuit and the incoming line of LCD display are electrically connected.

Compared with prior art, a kind of parallel multi-point type optical fiber temperature sensor that the utility model proposes has following advantage:

(1) realized the parallel multi-point type temperature survey.Use array waveguide grating as the wavelength-modulated original paper, a plurality of coupling mechanism in parallel has been realized the parallel multi-point type temperature survey.

(2) adopt the relative echo strength modulation of fiber reflection formula to measure its measuring accuracy height.Relatively the introducing of echo strength parameter has been eliminated different losses cause in the instability of light source and the inner light path of the sensor-based system branch measuring error effectively, has been reduced external environment and change the influence that measurement is brought, improved measuring accuracy, the refractometry precision can be less than 1 * 10 ^-4

(3) be applicable to the new temperature measurement technology of optical fiber.Because optical fiber is insulator, have good remote optical transmission performance, optical loss is extremely low, the non-constant width of transmission band, can under mal-conditions such as strong electromagnetic, High Temperature High Pressure, atomic radiation, chemical corrosion, use, simple in structure, volume is little, in light weight, highly sensitive.

(4) except being used for the monitoring of general environment temperature, can also be used for the monitoring of particular surroundings temperature.

(5) optical fiber sensing probe epoxy encapsulation can reach high-resolution temperature survey.

Description of drawings

Fig. 1 is the structural representation of the utility model parallel multi-point type optical fiber temperature sensor;

Fig. 2 is the structural representation of optical fiber sensing probe in the utility model;

Fig. 3 is the synoptic diagram that optical fiber sensing probe of the present utility model places temperature control system to measure;

Fig. 4 is connection side's block diagram of processing of circuit of the present utility model unit;

Fig. 5 is the circuit theory diagrams of processing of circuit of the present utility model unit;

Fig. 6 is the program flow chart of processing of circuit of the present utility model unit;

Fig. 7 uses the utility model to carry out thermometric data result and linear fit curve map;

Fig. 8 uses the utility model to measure the time dependent stability curve figure of temperature.

Embodiment

Working mechanism of the present utility model is based on the refractive index size variation sensitivity of interface Fresnel reflection light intensity to material, and hot luminescent material refractive index is used the temperature survey of array waveguide grating as the in parallel a plurality of coupling mechanism multipoint mode of wavelength-modulated element to the principle of temperature variation sensitivity.

With wideband A SE (ASE-amplified spontaneous emission) as light source, the light that sends is coupled device through Transmission Fibers and is divided into two-way, wherein one road light enters the photodiode probe B as control measurement, and other one road light enters array waveguide grating through Transmission Fibers and is divided into the light of the single wavelength in n road; N road light is through arriving optical fiber sensor head S1～Sn after coupling mechanism C1～Cn, interphase at optical fiber connector and epoxy resin reflects, reflected light passes through coupling mechanism once more after Transmission Fibers enters array photodiode probe P1～Pn, the photovoltage of output is proportional to the echo strength of optical fiber connector and epoxy resin surface reflections, enters winding optical fiber S1～Sn and is depleted and bring out the light of penetrating from each coupling mechanism other.The value of array photodiode probe P1～Pn is input to the processing of circuit unit and carries out data processing.Can obtain needed refractive index value by Fresnel (Fresnel) formula.

Total light intensity of supposing the light that wideband A SE light source sends is I ₀, the transmitance of each passage of array waveguide grating AWG is A _i(λ), the sensitivity of n photodiode is S _i(i=1,2 ... n), splitting ratio k, the k ' of coupling mechanism A, the splitting ratio k of n coupling mechanism _i, k _iFor i optical fiber sensing probe S _iThe refractive index n of epoxy resin _i, by i array photodiode probe P _iThe light intensity that detects is

$P_i={\∫}_{-\∞}^{+\∞}{S}_i{A}_i{\mathrm{kk}}_i{k}_i^{\′}{I}_{0}f\left(\mathrm{\λ}\right){\left(\frac{n_f-n_i}{n_f+n_i}\right)}^2\mathrm{d\λ}$

， (1)

$={\mathrm{kk}}_i{k}_i^{\′}\mathrm{\η}{I}_0{\left(\frac{n_f-n_i}{n_f+n_i}\right)}^2$

Wherein $\mathrm{\η}={\∫}_{-\∞}^{+\∞}{S}_i{A}_{i}f\left(\mathrm{\λ}\right)\mathrm{d\λ}.$ The value of the light source monitoring that this moment, the photodiode probe B recorded is

P _ref＝k′I ₀， (2)

Can obtain relative echo strength by formula (1) and (2) is

$K_i\≡P_i/P_{\mathrm{ref}}=\mathrm{\ξ}{\left(\frac{n_f-n_i}{n_f+n_i}\right)}^2,---\left(3\right)$

Wherein $\mathrm{\ξ}=\frac{{\mathrm{kk}}_i{k}_i^{\′}\mathrm{\η}}{k^{\′}}.$

Because extraneous factors such as temperature, vibration, pressure may influence Optical Fiber Transmission and measurement, binary channels light path intensity variations will be caused simultaneously.Be divided by by two passage echo strengths, i.e. these influences can be most ofly offset in echo strength computing relatively, thereby reduce measuring error, raising apparatus measures stability.Elder generation is with optical fiber sensing probe S before measuring _i(for example room temperature) calibrates in standard temperature, and the relative echo strength that obtains is

$K_{i0}\&equiv;P_{i0}/{\mathrm{<figure-callout\; id="0"\; label="P\; ref"\; filenames="H2009203518939E00052.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{ref}}=\mathrm{\&xi;}{\left(\frac{n_f-n_{i0}}{n_f+n_{i0}}\right)}^2---\left(4\right)$

N wherein _I0Be the refractive index of epoxy resin in standard temperature (for example room temperature).Get by (3) (4):

$K_i/K_{\mathrm{<figure-callout\; id="0"\; label="i"\; filenames="H2009203518939E00052.png"\; state="\{\{state\}\}">i</figure-callout>}0}={\left(\frac{n_f-n_i}{n_f+n_i}\right)}^2{\left(\frac{n_f+n_0}{n_f-n_0}\right)}^2---\left(5\right)$

Just can be regarded as by transformation for mula (5)

$n_i=n_f\&CenterDot;\frac{K_{i0}-\mathrm{\&tau;}\sqrt{K_i}}{K_{i0}+\mathrm{\&tau;}\sqrt{K_i}},---\left(6\right)$

τ=(n wherein _f-n ₀)/(n _f+ n ₀).According to document is λ=1550nm place at wavelength, n _f=1.44961 n ₀=1.0003, so τ=0.1834.For hot luminescent material (as epoxy resin), refractive index and temperature roughly have a linear relationship:

$T={(\&PartialD;n/\&PartialD;T)}^{-1}{n}_i+{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="H2009203518939E00052.png"\; state="\{\{state\}\}">T</figure-callout>}}_0,---\left(7\right)$

Finally just can solve temperature T by (6) (7) formula.Adopt the photodiode probe of higher sensitivity, just can realize the high-acruracy survey of T and monitoring in real time.Therefore, after instrument calibration, draw the value of environment temperature by the big I of measuring relative light intensity.

Below in conjunction with accompanying drawing the utility model content is described in further detail.

As shown in Figure 1, it is the structural representation of the utility model parallel multi-point type optical fiber temperature sensor, wherein, 1 is that wideband A SE light source, 2 is that fiber coupler A, 3 is that photodiode probe B, 4 is that Transmission Fibers, 5 is that array waveguide grating AWG, 6 is fibre coupler arrays O ₁～O _n, 7 be optical fiber sensing probe S ₁～S _n, 8 be array photodiode probe P ₁～P _n, 9 be the processing of circuit unit, 10 for twining optical fiber S ₁～S _n

The parallel multi-point type optical fiber temperature sensor is by wideband A SE light source, fiber coupler A, photodiode probe B, fibre coupler arrays O ₁～O _n(use O respectively ₁, O ₂... O _nExpression), array waveguide grating AWG, a n optical fiber sensing probe S ₁～S _nWith winding optical fiber S ₁～S _n(use S respectively ₁, S ₂... S _nExpression), array photodiode probe P ₁～P _n(use P respectively ₁, P ₂... P _nExpression), Transmission Fibers and processing of circuit unit connect and compose jointly, its interconnected relationship is: wideband A SE light source is connected with coupling mechanism A by Transmission Fibers; Coupling mechanism A is connected with the photodiode probe B by Transmission Fibers; Coupling mechanism A by Transmission Fibers be connected with array waveguide grating, array waveguide grating AWG is by Transmission Fibers and coupler array O ₁～O _nConnection, coupler array O ₁～O _nTwo display output ports respectively with the optical fiber sensing probe S of identical numbering ₁～S _nWith winding optical fiber S ₁～S _nConnect one to one successively (is O ₁Corresponding S ₁, O ₂Corresponding S ₂... O _nCorresponding S _n); Optical fiber sensing probe S ₁～S _nThe reflection of every road is surveyed light again through coupler array O ₁～O _n, survey optical delivery fiber and array photodiode probe P by reflection ₁～P _nConnect array photodiode probe P ₁～P _nBe electrically connected with the processing of circuit unit respectively.During measurement, optical fiber sensing probe S ₁～S _nPlace environment to be measured (as temperature control system).

In the utility model, the splitting ratio of two output port I, the II of fiber coupler A is (95%～5%): (5%～95%), 95%: 5% commonly used, the output terminal of the array waveguide grating AWG that wherein ins succession was the I port, and the output terminal of the photodiode of ining succession probe is the II port; Coupler array O ₁～O _nIn an array delivery outlet optical fiber sensing probe S ₁～S _n, another array delivery outlet is connected with and twines optical fiber S ₁～S _nCoupler array O ₁～O _nIn coupler unit adopt the 2*2 fiber coupler, the splitting ratio of its output port is 50%: 50%.Used Transmission Fibers is general single mode fiber.Optical fiber sensing probe is made of epoxy encapsulation metal shell in PC tail optical fiber joint.Twining optical fiber is that single-mode transmission optical fiber is entwined through spiral.Array photodiode probe P ₁～P _nLuminous intensity measurement sensitivity be the 10nW magnitude, specifically depend on the sensitivity requirement of instrument, require high more, high more to the requirement of the luminous intensity measurement sensitivity of photodiode probe.Use the photodiode probe to monitor in real time in the utility model, purpose is to utilize the method for relative intensity to eliminate that backlight improves the measuring accuracy and the antijamming capability thereof of instrument to the error that influence brought of light source in the instability of light source and the light path.

Fig. 2 is the structural representation of optical fiber sensing probe among Fig. 1,10 expression PC optical fiber pigtail joints, and 11 representative ring epoxy resins, 12 expression betal cans, optical fiber sensing probe are loaded on PC tail optical fiber joint 10 to epoxy resin envelope 11 by metal shell 12 and constitute.Each optical fiber sensing probe S among Fig. 1 ₁～S _nFormation is not always the case.

Fig. 3 is the synoptic diagram that optical fiber sensing probe of the present utility model places temperature control system to measure, the optical fiber sensing probe in 7 presentation graphs 1,13 expression temperature control systems.Before the measurement, optical fiber sensing probe S ₁～S _nPlace under the normal temperature, carry out instrument calibration.During measurement, optical fiber sensing probe S ₁～S _nPlace temperature control system, measurement result converts the value of temperature to be measured to after calculating automatically.

As shown in Figure 4, be connection side's block diagram of processing of circuit of the present utility model unit.The processing of circuit unit is by the photodiode P that pops one's head in ₁～P _nPre-amplification circuit is (respectively with array photodiode probe P ₁～P _nConnect), single chip microcomputer circuit and LCD display be electrically connected formation jointly, its interconnected relationship is: probe P ₁～P _nThe incoming line of the output line of pre-amplification circuit and single chip microcomputer circuit is electrically connected; The output line of single chip microcomputer circuit and the incoming line of LCD display are electrically connected.

When handling, photodiode probe B and array photodiode linear transducer array T ₁～T _nThe photo-signal of output enters into data processor single chip microcomputer circuit then through pre-amplification circuit, finishes the arithmetical operation of data in the single chip microcomputer circuit, draws end product.Just can determine the variable quantity of corresponding light photodiode current to the detection of prime amplifier output signal by single chip microcomputer.The temperature value that measures send LCD display to be shown by the LCD display module.

As shown in Figure 5, be the circuit theory diagrams of processing of circuit of the present utility model unit.Array photodiode probe P ₁～P _nPre-amplification circuit all the same, each pre-amplification circuit all mainly comprises a photodiode, a triode, five resistance and three electric capacity.Photodiode probe P ₁Pre-amplification circuit is electrically connected by photodiode D1, triode Q1, resistance R 1～R5 and capacitor C 1～C3 and constitutes, the plus earth of described photodiode D2, negative electrode connecting resistance R3 and capacitor C 1 back are in parallel with resistance R 4 and capacitor C 2, this parallel circuit one end ground connection, one termination is gone into the base stage of triode Q1, the base stage of Q1 connects+the 5V power supply by resistance R 2, the emitter of triode Q1 by the parallel circuit of resistance R 5 and capacitor C 3 after ground connection, + 5V power supply is by the collector of resistance R 1 access triode Q1, and the collector of triode Q1 is as output L1.Probe T ₂Pre-amplification circuit is electrically connected by photodiode D2, triode Q2, resistance R 6～R10 and capacitor C 4～C6 and constitutes, wherein D1 is identical with D2, Q1 and Q2, R1 is identical respectively with R10 with R9, R5 with R8, R4 with R6, R2 and R7, R3, and C1 is identical respectively with C6 with C4, C2 and C5, C3.The single chip microcomputer circuit is electrically connected by capacitor C 7～C9,4MHz crystal oscillating circuit, single-chip microcomputer PIC16F876U1, resistance R 11～R15 and button S1～S3 and constitutes; LCD display is electrically connected by LCD display module, resistance R 16～R19 and amplifier Q3 and constitutes.

The annexation of output, incoming line is between each circuit: probe P ₁The L1 output line of pre-amplification circuit and probe P ₂The L2 output line of pre-amplification circuit is electrically connected mutually with the L1 and the L2 pin of single chip microcomputer circuit respectively, two detectable signals carry out data processing through delivering to the single chip microcomputer circuit after amplifying, the LCD_A of LCD display is electrically connected with the corresponding pin of single chip microcomputer circuit respectively mutually with the LCD_E pin, the LCD_RS of LCD display is electrically connected with the corresponding pin of single chip microcomputer circuit respectively mutually with LCD_DB4～LCD_DB7 pin, the INT1 of button circuit S2 and S3 is electrically connected with INT2 mutually with the pin INT1 of INT2 incoming line single chip microcomputer circuit, and end product send LCD display to be shown by the LCD display module.In the drawings, the line that label is identical is connected to each other.Power switch is electrically connected mutually with the control power lead of circuit board.

Showing as Fig. 6, is the program flow chart of processing of circuit of the present utility model unit.After starting instrument, at first initialization is surveyed light and is entered the array photodiode, optical fiber sensing probe S ₁～S _nPlace under the normal temperature, store the luminous power ratio K automatically _I0, and proofread with default value.Carry out the measurement of temperature then, the T that records sends into numerical evaluation and is shown by LCD display.

In order further to check feasibility of the present utility model, the spy carries out following experiment:

Experiment 1:

In experiment, the parallel multi-point type optical fiber temperature sensor of using based on Fresnel reflection places temperature control box, the value of relative light intensity when having measured different temperatures.Experimental result as shown in Figure 7.Positive trigonometric sum inverted triangle is respectively the measured value of temperature rising and decline process among the figure, and solid line is a theoretical curve, and visible measured value can be consistent R well with theoretical value ²Value is greater than 0.99.

Experiment 2:

In this experiment, used based on the parallel multi-point type optical fiber temperature sensor measurement of Fresnel reflection temperature degree situation over time, to estimate the utility model temperature survey stability.In Fig. 8, be to use the utility model to measure the time dependent stability curve of temperature.In the experiment, just measure the size of a temperature, take reading every 2 minutes times.Experimental result shows that the standard deviation of measurement data is ± 0.2 ℃, and the resolution of system is 0.03 ℃.

Structure of the present utility model and principle thereof, method have more than been described.In above exemplary embodiment, use the measurement that this device has carried out different temperatures, experimental result shows that measured temperature all coincide finely with theoretical value, thereby has verified the practicality of this utility model.The optical fiber sensing probe of practical array waveguide grating AWG of the utility model and epoxy encapsulation is realized the real-time online measuring of parallel multi-point type temperature, total system is simple to operate, price is lower, highly sensitive, stability is strong, ability with remote monitoring has the detectivity of three-dimensional refractive index space distribution.

Above-mentioned embodiment is a better embodiment of the present utility model; but the utility model is not limited to above-mentioned concrete embodiment; in the present technique field, accommodation of the present utility model or the identical equivalent replacement of essence are all belonged to protection domain of the present utility model.

Claims (10)

1. A parallel multi-point fiber optic temperature sensor, characterized in that it includes a broadband light source, a fiber coupler A, an arrayed waveguide grating AWG, a fiber coupler array O ₁ ~ _On , n fiber sensing probes S ₁ ~ S _n , array photodiode probes P ₁ -P _n , transmission optical fiber and circuit processing unit; The broadband light source is connected to the coupler A through the transmission fiber; one of the output ports of the coupler A is connected to the arrayed waveguide grating AWG through the transmission fiber, and the light of each channel in the arrayed waveguide grating AWG passes through the transmission fiber and the coupler array O ₁ ～O _n corresponds to the connection, one of the array output ports in the coupler array O ₁ ～O _n is connected with the same number of optical fiber sensing probes S ₁ ～S _n in sequence and then output; the optical fiber sensing probes S ₁ ～S _Each reflection detection light of n passes through the coupler array O ₁ ~ On , and is connected to the array photodiode probe P ₁ ~ _{P n through} the reflection detection light transmission fiber, and the electrical signal output after the conversion of the array photodiode probe P ₁ ~ P _n are respectively electrically connected to the circuit processing unit. 2. A kind of parallel multi-point fiber optic temperature sensor according to claim 1, characterized in that: the value of n is determined according to the spectral range of the broadband light source and the channel number of the arrayed waveguide grating, the wider the range, the more channels, The larger the value of n, the range of n is 2≤n≤500. 3. A parallel multi-point optical fiber temperature sensor according to claim 1, characterized in that: the optical fiber sensing probe is composed of a metal shell and epoxy resin encapsulated in a vertical end face pigtail joint. 4. A parallel multi-point fiber optic temperature sensor according to claim 1, characterized in that: another output port of the coupler A is connected to a photodiode probe B through a transmission fiber. 5. A parallel multi-point optical fiber temperature sensor according to claim 4, characterized in that: the splitting ratio of the two output ports of the optical fiber coupler A is 95%-5%: 5%-95%. 6. A parallel multi-point optical fiber temperature sensor according to claim 1, characterized in that: the output ports of another array in the coupler arrays O _{1 -On} are connected with winding optical fibers S ₁ -S _n , and the winding The optical fiber is a single-mode transmission optical fiber that is helically wound. 7. A parallel multi-point optical fiber temperature sensor according to claim 6, characterized in that: the light splitting ratio of the output ports of the two arrays in the coupler arrays O _{1 -On} is 50%:50%. 8 . The parallel multi-point optical fiber temperature sensor according to claim 1 , wherein the light intensity measurement sensitivity of the array photodiode probes P ₁ -P _n is on the order of 10 nW. 9. A parallel multi-point optical fiber temperature sensor according to claim 1, characterized in that: said transmission optical fibers are common single-mode optical fibers. 10. A parallel multi-point optical fiber temperature sensor according to claim 1, characterized in that: the circuit processing unit includes probes P ₁ to P _n preamplifier circuits, single-chip microcomputer circuits and LCD displays, and the probe P ₁ ~ _Pn The output line of the preamplifier circuit is electrically connected with the input line of the single-chip microcomputer circuit; the output line of the single-chip microcomputer circuit is electrically connected with the input line of the LCD display.

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