CN100541175C - Quasi-distributed optical fiber concentration sensor - Google Patents

Abstract

A kind of quasi-distributed optical fiber concentration sensor is by wideband A SE light source, fiber coupler, deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _n, optical fiber sensor head G ₁～G _n, array waveguide grating, photodiode probe, array photodiode probe T ₁～T _n, Transmission Fibers and processing of circuit unit connect and compose jointly.This sensor can be realized distributed measurement of concetration, has the ability of real-time online and remote detection, and measurement range is big, highly sensitive, stability is strong, easy to operate.

Description

Quasi-distributed optical fiber concentration sensor

(1) technical field

The present invention relates to a kind of quasi-distributed optical fiber concentration sensor, be specially a kind of quasi-distributed optical fiber concentration sensor system, belong to the novel optical fiber sensing technology based on Fresnel reflection.

(2) background technology

The concentration of solution is one of main parameters that characterizes solution properties, in biochemistry, environmental protection, medical treatment and food processing field, measurement to solution concentration has crucial effect with control to the industrial production run of modernization, and it is the important technical that guarantees and improve the quality of products.Therefore, the method for many measurement solution concentrations is arisen at the historic moment.Traditional surveying instrument comprises commercial projection polariscope, colorimeter, Abbe refractometer etc., also have measuring methods such as wide band absorption spectroscopic methodology, titrimetry and photoluminescence quenching, but these methods of great majority all are confined to visible-range and all are the methods of sampling, can not carry out real-time monitoring.Subsequently, some new technologies such as optoacoustic, fiber grating, spr sensor and Raman spectrum occur in succession, but these methods cost an arm and a leg and be not easy to operate.Current optical fiber concentration method for sensing mostly is non-selectivity greatly or optical fiber does not have the sensing effect and just as passing the light means, the continuous detecting of especially online solution concentration and control aspect also are in relatively backward state. and above-mentioned method all is difficult to the distributed real-time measurement of realization.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 optical fiber sensing system that distributes and modulate.For this reason, based on having corresponding relation between the concentration of solution and its refractive index, the present invention proposes quasi-distributed sensing scheme based on the measurement solution concentration of the intensity modulation type of Fresnel reflection principle.Having utilized the fundamental characteristics of deielectric-coating optical filtering type wavelength division multiplexer (TFF type DWDM) is to show as a reflective optical filter, the a plurality of TFF of serial connection in an optical fiber, the arrowband ripple of TFF reflection is that the light at center enters into solution to be measured and surveys, and has used array waveguide grating (AWG) to realize the distributed optical fiber concentration sensing as demodulating unit.By the collection of single passage realization to a plurality of test signals, the great advantage of this technology has been to reduce the required number of channels of test data collection equipment, thereby has reduced testing cost, and can realize the measurement to the accurate distribution field value of solution concentration to be measured.Since this sensor-based system detection efficiency height, and be easy to form sensing network, for wide prospect has been opened up in its practical application.

(3) summary of the invention

The object of the present invention is to provide a kind of reliable accurately, quasi-distributed optical fiber concentration sensing device real-time.Compared with prior art, the present invention has the ability of real-time online and remote detection, can be used for Fibre Optical Sensor, absorbs the measurement of opaque wave band (or medium) by force, and can be used for surveying the space distribution of refractive index or concentration.In addition, have also that measurement range is big, sensitivity is higher and characteristics such as easy to operate.

Specifically, quasi-distributed optical fiber concentration sensor of the present invention is by wideband A SE light source, fiber coupler, a n deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _n(use B respectively ₁, B ₂... B _nExpression), a n optical fiber sensor head G ₁～G _n(use G respectively ₁, G ₂... G _nExpression), array waveguide grating AWG, photodiode probe, array photodiode probe T ₁～T _n(use T respectively ₁, T ₂... T _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 by Transmission Fibers; Coupling mechanism is by Transmission Fibers and deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _n, photodiode probe is connected with array waveguide grating AWG; Deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _nOptical fiber sensor head G with identical numbering ₁～G _nConnect one to one successively (is B ₁Corresponding G ₁, B ₂Corresponding G ₂... B _nCorresponding G _n); Array waveguide grating AWG is by Transmission Fibers and array photodiode probe T ₁～T _nConnect; Array photodiode probe T ₁～T _nBe electrically connected with the processing of circuit unit respectively.When measuring, optical fiber sensor head G ₁～G _nInsert in the testing liquid.

In the sensor, the span of n is 2～500 (i.e. 2≤n≤500).Concrete number determines that according to the spectral range of wideband light source scope is wide more, and the n value is big more.The cardinal rule of determining the n value is to make the difference of the catoptrical centre wavelength of adjacent two deielectric-coating optical filtering type wavelength division multiplexers be not less than 0.8 nanometer, crosstalks excessive and influences measurement result with what prevent to take place between them.

Described processing of circuit unit is by probe T ₁～T _nPre-amplification circuit is (respectively with array photodiode probe T ₁～T _nConnect), single chip microcomputer circuit and LCD display be electrically connected formation jointly, its interconnected relationship is: probe T ₁～T _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.

Above-mentioned probe T ₁～T _nPre-amplification circuit all the same, each pre-amplification circuit is electrically connected formation by a photodiode, a triode, five resistance and three electric capacity, and (T for example pops one's head in ₁Pre-amplification circuit is electrically connected by photodiode D1, triode Q1, resistance R 1～R5 and capacitor C 1～C3 and constitutes; 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, T4 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 PIC16F876, 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.

In invention, two output port I of fiber coupler, the splitting ratio of II are (10%～90%): (90%～10%) (the deielectric-coating optical filtering type of wherein ining succession wavelength division multiplexer TFF B ₁Output terminal be the I port, the output terminal of the photodiode of ining succession probe is the II port).Transmission Fibers is a general single mode fiber.Optical fiber sensor head is made of vertical fiber end face.Array photodiode probe T ₁～T _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 among the present invention, 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.

Working mechanism and measuring method that the present invention adopts are based on the principle of interface Fresnel reflection light intensity to the refractive index size variation sensitivity of material, adopt deielectric-coating optical filtering type wavelength division multiplexer as the wavelength-modulated element, and use the demodulating unit of array waveguide grating as this invention sensor-based system, connect a plurality of TFF and array waveguide grating to realize distributed solution concentration measurement.

The method of testing that the present invention adopts is: as light source, the laser that sends is coupled device through Transmission Fibers and is divided into two-way with wideband A SE, and wherein one road light continues to enter deielectric-coating optical filtering type wavelength division multiplexer TFF B through Transmission Fibers ₁, another road light enters the photodiode probe as control measurement; Deielectric-coating optical filtering type wavelength division multiplexer TFF B ₁Reflected light through optical fiber sensor head G ₁Connect the interphase that enters optical fiber connector and testing liquid and reflect, reflected light passes through TFF B once more ₁Be coupled device coupling after the reflection and enter array waveguide grating AWG through Transmission Fibers and carry out Wavelength demodulation, enter array photodiode probe T at last ₁, the photovoltage of output is proportional to the echo strength of determinand reflection, and transmitted light enters next deielectric-coating optical filtering type wavelength division multiplexer TFF B by Transmission Fibers ₂Equally, deielectric-coating optical filtering type wavelength division multiplexer TFF B ₂Reflected light through optical fiber sensor head G ₂Connect the interphase that enters optical fiber connector and testing liquid and reflect, reflected light passes through TFF B once more ₂After the reflection through TFF B ₁Be coupled device coupling after the transmission and enter array waveguide grating AWG through Transmission Fibers and carry out Wavelength demodulation, enter array photodiode probe T at last ₂, the photovoltage of output is proportional to the echo strength of determinand reflection, and transmitted light enters next deielectric-coating optical filtering type wavelength division multiplexer TFF B by Transmission Fibers ₃, by that analogy.Array photodiode probe T ₁～T _nValue be input to the processing of circuit unit and carry out data processing.Can obtain needed refractive index value by the Fresnel formula.

Light intensity I _rWith incident intensity I _InThe pass be: $I_r=I_{\mathrm{in}}{\left(\frac{n_f-n_x}{n_f+n_x}\right)}^2,$ N wherein _xAnd n _fBe testing liquid and optical fiber effective refractive index.Total light intensity of supposing light source is P ₀, reflection coefficient and the transmission coefficient of TFF are respectively R _i(λ-λ _i) and T _i(λ-λ _i) (i=1,2～n), the transmitance of each passage of 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.For solutions i to be measured, by i array photodiode probe T _iThe light intensity that detects is

$P_i=\underset{-\∞}{\overset{\∞}{\∫}}{S}_i{A}_i\left(\mathrm{\λ}\right)R_i^2(\mathrm{\λ}-{\mathrm{\λ}}_i)k{k}^{\′}{I}_s\left(\mathrm{\λ}\right){\left(\frac{n_f-n_{\mathrm{xi}}}{n_f+n_{\mathrm{xi}}}\right)}^2\·\mathrm{d\λ},---\left(1\right)$

N wherein _XiSolution refractive index for i control point in the concentration field.This moment, the value of the light sources monitoring that photodiode probe 3 records was

$P_{\mathrm{ref}}=k^{\&prime;}\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}{I}_s\left(\mathrm{\&lambda;}\right)\&CenterDot;\mathrm{d\&lambda;}=k^{\&prime;}{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="C20071002905800172.png"\; state="\{\{state\}\}">P</figure-callout>}}_0,---\left(2\right)$

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

$K_i=P_i/P_{\mathrm{ref}}=\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}{S}_i{A}_i\left(\mathrm{\&lambda;}\right)R_i^2(\mathrm{\&lambda;}-{\mathrm{\&lambda;}}_i)k{\left(\frac{n_f-n_{\mathrm{xi}}}{n_f+n_{\mathrm{xi}}}\right)}^2\&CenterDot;\mathrm{d\&lambda;},---\left(3\right)$

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 the binary channels echo strength, 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 sensor head G before measuring _iWhen placing air, the relative echo strength that obtains is

$K_i^{\mathrm{air}}=P_i^{\mathrm{air}}/{P_{\mathrm{ref}}}^{\mathrm{air}}=\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}{S}_i{A}_i\left(\mathrm{\&lambda;}\right)R_i^2(\mathrm{\&lambda;}-{\mathrm{\&lambda;}}_i)k{\left(\frac{n_f-n_0}{n_f+n_0}\right)}^2\&CenterDot;\mathrm{d\&lambda;},---\left(4\right)$

N wherein ₀Refractive index for air.Get by (3) (4):

$K_i/K_i^{\mathrm{air}}={\left(\frac{n_f-n_{\mathrm{xi}}}{n_f+n_{\mathrm{xi}}}\right)}^2{\left(\frac{n_f+n_0}{n_f-n_0}\right)}^2,---\left(5\right)$

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

$n_{\mathrm{xi}}=n_f\&CenterDot;\frac{K_i^{\mathrm{air}}-\mathrm{\&tau;}\sqrt{K_i}}{K_i^{\mathrm{air}}+\mathrm{\&tau;}\sqrt{K_i}},---\left(6\right)$

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.Refractive index and concentration for most of solution (for example sugar and salt solusion) roughly have a linear relationship:

$C={(\&PartialD;n/\&PartialD;C)}^{-1}n+{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="C20071002905800172.png"\; state="\{\{state\}\}">C</figure-callout>}}_0.---\left(7\right)$

Finally just can solve the concentration C of solution by (6) (7) formula.Adopt the photodiode probe of higher sensitivity, just can realize the high-acruracy survey of C and monitoring in real time.

The present invention compared with prior art has following advantage:

(1) adopts the relative echo strength modulation of fiber reflection formula measuring method, 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, and has improved measuring accuracy.The refractometry precision can be less than 1 * 10 ^-4

(2) realized distributed measurement of concetration.Adopt deielectric-coating optical filtering type wavelength division multiplexer as the wavelength-modulated element first, and use the demodulating unit of array waveguide grating as this invention sensor-based system, connect a plurality of TFF and array waveguide grating to realize distributed solution concentration measurement.

(3) be applicable to the new refractometry 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 general liquid detection, also can detect trace, dangerous liquid, and the refractometry of carrying out gaseous state or solid matter.

(5) also can be applicable to measure the refractive index of solution and the temperature field or the stress field of measured point by tracer liquid concentration.Because there is relation one to one between concentration, temperature or stress and the refractive index.

(4) description of drawings

Fig. 1 is the structural representation of quasi-distributed optical fiber concentration sensor of the present invention.

Fig. 2 is optical fiber sensor head G of the present invention ₁～G _nIndex path when laser enters the interphase of its fiber end face and test substance.

Fig. 3 is processing of circuit of the present invention unit connection side's block diagram.

Fig. 4 is circuit theory diagrams of the present invention.

Fig. 5 is a processing of circuit unit program block diagram of the present invention.

Fig. 6 uses the present invention to carry out data result and the linear fit curve that the variable concentrations salt solusion is measured.

Fig. 7 uses the present invention to measure the time dependent stability curve of concentration of salt solution.

(5) embodiment

In Fig. 1,1 is that wideband A SE light source, 2 is popped one's head in, 4 is the dense wave division multiplexer DWDM B of TFF type for photodiode for fiber coupler, 3 ₁～B _n, 5 be optical fiber sensor head G ₁～G _n, 6 be that testing liquid, 7 is the array photodiode T that pops one's head in for array waveguide grating AWG, 9 for Transmission Fibers, 8 ₁～T _n, 10 be the processing of circuit unit.

From Fig. 1 as seen, the quasi-distributed optical fiber concentration sensor based on Fresnel reflection of the present invention is by wideband A SE light source, fiber coupler, a n deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _n(use B respectively ₁, B ₂... B _nExpression), a n optical fiber sensor head G ₁～G _n(use G respectively ₁, G ₂... G _nExpression), array waveguide grating AWG, photodiode probe, array photodiode probe T ₁～T _n(use T respectively ₁, T ₂... T _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 by Transmission Fibers; Coupling mechanism is by Transmission Fibers and deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _n, photodiode probe is connected with array waveguide grating AWG; Deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _nOptical fiber sensor head G with identical numbering ₁～G _nConnect one to one successively (is B ₁Corresponding G ₁, B ₂Corresponding G ₂... B _nCorresponding G _n); Array waveguide grating AWG is by Transmission Fibers and array photodiode probe T ₁～T _nConnect; Array photodiode probe T ₁～T _nBe electrically connected with the processing of circuit unit respectively.When measuring, optical fiber sensor head G ₁～G _nInsert in the testing liquid.Wherein the span of n is 2～500 (i.e. 2≤n≤500).

In invention, described wideband A SE optical source wavelength scope is 1525nm-1565nm.The splitting ratio of two output port I, the II of fiber coupler is (10%～90%): (90%～10%), that relatively more commonly used is 50%: 50% (the deielectric-coating optical filtering type of wherein ining succession wavelength division multiplexer TFF B ₁Output terminal be the I port, the output terminal of the photodiode of ining succession probe is the II port).Transmission Fibers is a general single mode fiber.Optical fiber sensor head is made of vertical fiber end face.Photodiode probe T ₁～T _nLuminous intensity measurement sensitivity be the 10nW magnitude, specifically depend on the sensitivity requirement of instrument.Use photodiode probe 3 to monitor in real time among the present invention, purpose is to utilize the method for relative intensity to eliminate in the instability of light source and the light path backlight to the influence of light source.

In Fig. 2, the optical fiber sensor head in 5 presentation graphs 1,6 expressions liquid to be measured, the interphase of 11 expression optical fiber sensor head and determinand.Before the measurement, Fibre Optical Sensor 5 (G ₁～G _n) be placed in the air, carry out instrument calibration.During measurement, optical fiber sensor head 5 (G ₁～G _n) well contact with object under test, measurement result converts the value of refractive index to be measured to after calculating automatically.

As seen from Figure 3, the processing of circuit unit is by probe T ₁～T _nPre-amplification circuit, single chip microcomputer circuit and LCD display are electrically connected formation jointly, and its interconnected relationship is: probe T ₁～T _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 3 and array photodiode probe 9 (T ₁～T _n) photo-signal of output is through pre-amplification circuit, enters into data processor single chip microcomputer circuit then, 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 refractive index value that measures send LCD display to be shown by the LCD display module.

As seen from Figure 4, probe T ₁～T _nPre-amplification circuit all the same, each pre-amplification circuit is electrically connected formation by a photodiode, a triode, five resistance and three electric capacity, and (T for example pops one's head in ₁Pre-amplification circuit is electrically connected by photodiode D1, triode Q1, resistance R 1～R5 and capacitor C 1～C3 and constitutes; 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, T4 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 PIC16F876, 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 T ₁The L1 output line of pre-amplification circuit and probe T 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.

Show that by Fig. 5 behind the startup instrument, the instrument initialization is surveyed light and entered the array photodiode, optical fiber sensor head G ₁～G _nBe placed in the air, store the luminous power ratio K automatically _i ^Air, and proofread with default value.Carry out the measurement of solution refractive index then, the n that records _XiSend into numerical evaluation and show by LCD display.

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

Experiment 1:

In experiment, use the refractive index of having measured the same liquid (salt solusion) of different quality percent concentration based on the quasi-distributed optical fiber concentration sensor of Fresnel reflection.Experimental result is as follows:

In Fig. 6, be to use data result and the linear fit curve that the present invention carries out the refractometry of variable concentrations salt solusion.Label A～I represents the salt solusion of 0～20% variable concentrations respectively.Solid line among the figure is a theoretical curve, and dot is the experiment measuring value, and as seen, measured value can be consistent with theoretical value well, and the R value is greater than 0.99.

Experiment 2:

In this experiment, use the concentration situation over time of having measured the variable concentrations salt solusion based on the distributed optical fiber concentration sensor of Fresnel reflection, to estimate measurement of concetration stability of the present invention.

In Fig. 7, be to use the present invention to measure the time dependent stability curve of concentration of salt solution.In the experiment, just measure the concentration of a salt solusion, take reading every the time of 30s.Experimental result shows, the stability that solution concentration is measured in this invention is 4 * 10 when 0.5-1 ℃ of environment temperature fluctuation ^-4, and can also know that by figure the measuring accuracy of this sensing device is 1 * 10 ^-4

Structure of the present invention and principle thereof, method have more than been described.In above exemplary embodiment, use the measurement of concetration that this device has carried out the salt solusion of variable concentrations, experimental result shows that concentration measurement is all finely identical with theoretical value, thereby has verified the practicality of this invention.Though sensor or device with other also can carry out the measurement of concentration refractive index, but should be first Application based on multilayer dielectric film optical filtering type wavelength division multiplexer (TFF) as modulation device based on distributed optical fiber concentration sensor measuring technology of Fresnel reflection, and use the new distributed optical fiber concentration measuring technique of array waveguide grating AWG as signal demodulation unit.The present invention has realized the real-time online measuring of the distributed solution concentration of multiple spot field, adjacency channel (crosstalking of Δ λ=0.8nm) very low (less than-52dB), total system is simple to operate, price is lower, highly sensitive, stability is strong, ability with remote monitoring, can be applicable to the measurement of opaque wave band or medium, have the detectivity of three-dimensional refractive index space distribution.

The present invention is not limited to above-mentioned embodiment, and accommodation of the present invention or the identical equivalent replacement of essence are all belonged to protection scope of the present invention.

Claims (5)

1, a kind of quasi-distributed optical fiber concentration sensor is characterized in that: it is by wideband A SE light source (1), fiber coupler (2), deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _n(4), optical fiber sensor head G ₁～G _n(5), array waveguide grating (8), photodiode probe (3), array photodiode probe T ₁～T _n(9), Transmission Fibers (7) and processing of circuit unit (10) connect and compose jointly, its interconnected relationship is: wideband A SE light source (1) is connected with coupling mechanism (2) by Transmission Fibers (7); Coupling mechanism (2) is by Transmission Fibers (7) and deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _n(4), photodiode probe (3) is connected with array waveguide grating (8); Deielectric-coating optical filtering type wavelength division multiplexer B ₁～B _n(4) with the optical fiber sensor head G of identical numbering ₁～G _n(5) connect one to one successively; Array waveguide grating (8) is by Transmission Fibers (7) and array photodiode probe T ₁～T _n(9) connect; Array photodiode probe T ₁～T _n(9) be electrically connected with processing of circuit unit (10) respectively; The span of n is 2≤n≤500.

2, sensor as claimed in claim 1 is characterized in that: described processing of circuit unit (10) is by probe T ₁～T _nPre-amplification circuit, single chip microcomputer circuit and LCD display are electrically connected formation jointly, and its interconnected relationship is: probe T ₁～T _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.

3, sensor as claimed in claim 2 is characterized in that: described probe T ₁～T _nPre-amplification circuit is electrically connected by a photodiode, a triode, five resistance and three electric capacity and constitutes; The single chip microcomputer circuit is electrically connected by capacitor C 7～C9,4MHz crystal oscillating circuit, single-chip microcomputer PIC16F876, 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.

4, sensor as claimed in claim 1 is characterized in that: the fiber coupler deielectric-coating optical filtering type wavelength division multiplexer B that ins succession ₁The splitting ratio of output port I and the output port II of the photodiode probe of ining succession be 10%～90%:90%～10%.

5, as the described sensor of the arbitrary claim of claim 1～4, it is characterized in that: described Transmission Fibers is a general single mode fiber; Optical fiber sensor head G ₁～G _nConstitute by vertical fiber end face; Array photodiode probe T ₁～T _nLuminous intensity measurement sensitivity be the 10nW magnitude.

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