CN101526474B - Prism SPR (Surface Plasma wave Resonance) high-sensitivity fiber liquid refractive index sensor - Google Patents

Abstract

The invention relates to a prism SPR (Surface Plasma wave Resonance) high-sensitivity fiber liquid refractive index sensor, which is mainly characterized in that a laser light is coupled to a Y-shaped polarization-maintaining fiber coupler by a P-laser polarizer and a polarization-maintaining fiber collimator; the SPR is excited twice by the laser light outgoing from a sensing light branch polarization-maintaining fiber collimator; the reflection light reaches a sensing light branch optical-to-electrical converter after the two times of SPR excitation; a laser light outgoing from a reference light branch fiber collimator is coupled to a reference light branch optical-to-electrical converter; the light signals are converted into electrical signals by the reference light branch optical-to-electrical converter and the sensing light branch optical-to-electrical converter; the electrical signals are transmitted to an amplifier and an A/D converter; and the converted digital signals are transmitted to a data processing device for data processing. The invention has a simple structure, reduces the energy loss of P-laser, improves the signal-to-noise ratio and the sensitivity and allows long-distance application.

Description

A kind of glass prism SPR high sensitivity optical fiber liquid refractive index sensor

Technical field

The invention belongs to the technology of measuring liquid refractivity based on SPR, particularly a kind of intensity modulation type glass prism SPR high sensitivity optical fiber liquid refractive index sensor.

Background technology

Surface plasma wave resonance effects (surface plasmon wave resonance (SPR)) is as a kind of physical optics phenomenon that occurs in metal and dielectric interface, and it is very responsive to the surrounding medium variations in refractive index.At present, sensor construction based on the SPR effect has been widely used in the fluent meterial detection technique, as fields such as biochemistry, environment monitoring, medicine development and food securities, and make substantial progress in detection, biomolecular reaction kinetic determination and the monitoring of industrial waste water waste gas etc. of gene mutation.Prism-type sensor analytical approach based on SPR has 4 kinds:

(1) angular modulation method, i.e. monochromatic light incident changes incident angle, and the normalized intensity of detection of reflected light is with the situation of change of incident angle, and record intensity of reflected light incident angle hour, just resonance angle;

(2) wavelength-modulated method, i.e. polychromatic light incident is fixed into firing angle and catoptrical spectrum is analyzed, and obtains reflectivity with the wavelength change curve, and the record resonant wavelength;

(3) intensity modulated method, promptly the angle of incident light and wavelength are all fixed, by the mutation analysis change of refractive of detection of reflected light intensity;

(4) phase modulation (PM) method, promptly the angle of incident light and wavelength are all fixed, observation incident light and catoptrical phase differential.

In these 4 kinds of methods, the angular modulation method needs expensive accurate angular turn device and control system, and the wavelength-modulated method needs polychromatic light and expensive spectral analysis device, and the phase modulation (PM) method needs a series of high-frequency circuits, and this just makes their application be restricted.The intensity modulated method is because the fluctuation of the intensity of light source and photelectric receiver and amplifying circuit exist dc shift, therefore the precision based on the method measuring samples refractive index of intensity modulation can be very restricted, adopt document 1[Zhang Zhi-wei, Wu Zhi-fang, Wen Ting-dun.Asimple model for measuring refractive index of a liquid based upon Fresnelequations.Chin.Phys.Lett, 2007,24 (11): 3133～3136] method of setting up model of Ti Chuing just is easy to overcome this shortcoming.

Document 2[Ceng Jie, Liang Dakai, Du Yan, Ceng Zhenwu. based on the glass prism SPR sensor of intensity of reflected light detection. photoelectron laser, 2007,18 (2): 159～163] be a kind of novel glass prism SPR method for sensing based on Ke Laiqieman (Kretschmann) structure.Do not adopt polarization maintaining optical fiber collimator and polarization maintaining optical fibre YXing Ouheqi in this method for sensing, the method that therefore cannot adopt document 1 to propose improves precision; Do not adopt total reflection prism to make a branch of measuring light encourage SPR twice yet, thereby can not further improve sensitivity.In a word, document 2 this methods existence deficiency aspect the interference of elimination bias light, elimination intensity of light source influence of fluctuations and raising measurement sensitivity.

Summary of the invention

The objective of the invention is to overcome the deficiency and the technical matters to be solved of the sensor analytical technology of existing prism-type intensity modulated based on SPR, a kind of compact conformation is provided, work is convenient, can grow the intensity modulation type glass prism SPR high sensitivity optical fiber liquid refractive index sensor that distance is used.

A kind of glass prism SPR high sensitivity optical fiber liquid refractive index sensor, comprise that the laser beam emitting device, TM (or claiming P) light wave that are made of pulsed laser and pulse signal generator produce and device, excitation SPR device, light wave receiving trap, amplification and the A/D conversion and the data processing equipment of transmission, it is characterized in that: described excitation SPR device is twice excitation of a branch of incident light SPR device; Twice excitation of described a branch of incident light SPR device is made up of Ke Laiqieman structure and total reflection device that isosceles prism, metallic film and liquid medium to be measured constitute; Wherein:

● described TM light wave produces and transmitting device comprises the P light polarizer, TM light wave polarization maintaining optical fiber collimator, Y shape polarization-maintaining fiber coupler, sense light branch road polarization maintaining optical fiber collimator and reference light branch road polarization maintaining optical fiber collimator;

● be connected by the polarization maintaining optical fibre connector between described TM light wave polarization maintaining optical fiber collimator, sense light branch road polarization maintaining optical fiber collimator, reference light branch road polarization maintaining optical fiber collimator and the Y shape polarization-maintaining fiber coupler;

● described light wave receiving trap comprises reference light branch road photoelectric commutator, collects the optical fiber collimator and the sense light branch road photoelectric commutator of light;

● described amplification and A/D conversion and data processing equipment comprise amplifier and A/D converter and data processing equipment;

● the laser beam of being sent by pulsed laser produces the TM light wave through the P light polarizer, the TM light wave is coupled in the Y shape polarization-maintaining fiber coupler by TM light wave polarization maintaining optical fiber collimator, the light that comes out from the sense light branch road polarization maintaining optical fiber collimator of Y shape polarization-maintaining fiber coupler, the workplace on the isosceles prism left side in the vertical Ke Laiqieman structure arrives its bottom, on the metallic film and testing liquid medium interface of bottom, arrive the total reflection device after encouraging for the first time SPR, after twice total reflection of reflected light process total reflection device, the workplace on the isosceles prism the right in the vertical again Ke Laiqieman structure arrives its bottom, and encourages SPR on bottom metallic film and testing liquid medium interface for the second time; Encourage the reflected light behind the SPR twice, arrive sense light branch road photoelectric commutator through the optical fiber collimator coupling of collecting light; From the light that the reference light branch road polarization maintaining optical fiber collimator of Y shape polarization-maintaining fiber coupler comes out, coupling arrives reference light branch road photoelectric commutator.After reference light branch road photoelectric commutator and sense light branch road photoelectric commutator are converted to electric signal with light signal, electric signal is sent into amplifier and A/D converter, amplification is also carried out analog to digital conversion, and the digital signal after the conversion is sent into data processing equipment and carried out data processing.

The present invention compared with prior art, having outstanding substantive distinguishing features with significant effect is: reduced the energy loss of TM light wave, can eliminate the interference and the compensatory light intensity instability of bias light, efficiently utilized the TM light wave, thereby improved sensitivity, and can long distance test.

Description of drawings

Fig. 1 is a kind of principle schematic of glass prism SPR high sensitivity optical fiber liquid refractive index sensor;

Fig. 2 is twice excitation of a branch of incident light SPR apparatus structure synoptic diagram;

Fig. 3 is the light intensity reflectivity of four kinds of variable concentrations liquid and the graph of relation of incident angle;

Fig. 4 is that the isosceles prism in total reflection isosceles right-angle prism and the Ke Laiqieman structure is the structural representation of one;

Fig. 5 is the structural representation that the isosceles prism in total reflection isosceles right-angle prism and the Ke Laiqieman structure is glued together;

Fig. 6 is the structural representation that has certain interval between the isosceles prism in total reflection isosceles right-angle prism and the Ke Laiqieman structure;

Fig. 7 is that the total reflection device is the structural representation of pair of planar catoptron;

Fig. 8 is data processing equipment control and flow chart of data processing figure.

Among the figure: pulsed laser 1, the P light polarizer 2, TM light wave polarization maintaining optical fiber collimator 3, Y shape polarization-maintaining fiber coupler 4, sense light branch road polarization maintaining optical fiber collimator 5, reference light branch road polarization maintaining optical fiber collimator 6, reference light branch road photoelectric commutator 7, pulse signal generator 8, amplifier and A/D converter 9, sense light branch road photoelectric commutator 10, data processing equipment 11, collect the optical fiber collimator 12 of light, by isosceles prism 1301, Ke Laiqieman structure 13 and total reflection device 14 that metallic film 1302 and liquid medium to be measured 1303 constitute.

Embodiment

Below in conjunction with description of drawings specific implementation method of the present invention.

Shown in Figure 1, a kind of glass prism SPR high sensitivity optical fiber of the present invention liquid refractive index sensor, comprise that the laser beam emitting device, the TM light wave that are made of pulsed laser 1 and pulse signal generator 8 produce and the device of transmission, excitation SPR device, light wave receiving trap, amplification and A/D conversion and data processing equipment, it is characterized in that: described excitation SPR device is twice excitation of a branch of incident light SPR device; Twice excitation of described a branch of incident light SPR device is made up of Ke Laiqieman structure 13 and total reflection device 14 that isosceles prism 1301, metallic film 1302 and liquid medium to be measured 1303 constitute; Wherein:

● described TM light wave produces and transmitting device comprises the P light polarizer 2, TM light wave polarization maintaining optical fiber collimator 3, Y shape polarization-maintaining fiber coupler 4, sense light branch road polarization maintaining optical fiber collimator 5 and reference light branch road polarization maintaining optical fiber collimator 6;

● between described TM light wave polarization maintaining optical fiber collimator 3, sense light branch road polarization maintaining optical fiber collimator 5, reference light branch road polarization maintaining optical fiber collimator 6 and the Y shape polarization-maintaining fiber coupler 4, adopt the polarization maintaining optical fibre connector to connect;

● described light wave receiving trap comprises reference light branch road photoelectric commutator 7, collects the optical fiber collimator 12 and sense light branch road photoelectric commutator 10 of light;

● described amplification comprises amplifier and A/D converter 9 and data processing equipment 11 with A/D conversion and data processing equipment.

The transmission course of the photosignal of a kind of glass prism SPR high sensitivity optical fiber of the present invention liquid refractive index sensor is: the laser beam of being sent by pulsed laser 1 produces the TM light wave through the P light polarizer, the TM light wave is coupled in the Y shape polarization-maintaining fiber coupler 4 by TM light wave polarization maintaining optical fiber collimator 3, the light that comes out from the sense light branch road polarization maintaining optical fiber collimator 5 of Y shape polarization-maintaining fiber coupler, the isosceles prism left side workplace of vertical Ke Laiqieman structure 13 arrives its bottom, on bottom metallic film and testing liquid medium interface, arrive total reflection device 14 after encouraging for the first time SPR, after twice total reflection of reflected light process total reflection device, the isosceles prism of vertical Ke Laiqieman structure 13 the right workplace arrives its bottom again, and encourages SPR on metallic film and testing liquid medium interface for the second time; Encourage the reflected light behind the SPR twice, arrive sense light branch road photoelectric commutators 10 through optical fiber collimator 12 couplings of collecting light.From the light that the reference light branch road polarization maintaining optical fiber collimator 6 of Y shape polarization-maintaining fiber coupler 4 comes out, coupling arrives reference light branch road photoelectric commutator 7.After reference light branch road photoelectric commutator 7 and sense light branch road photoelectric commutator 10 are converted to electric signal with light signal, electric signal is sent into amplifier and A/D converter 9, amplification is also carried out analog to digital conversion, and the digital signal after the conversion is sent into data processing equipment 11 and carried out data processing.

The pulse signal of pulsed laser 1 is provided by pulse signal generator 8, and pulse signal generator provides the synchronizing signal of image data simultaneously for data processing equipment 11.One of main computing of data processing equipment 11 deal with data is to try to achieve the reference light branch road to have light and the voltage signal when unglazed poor, and the sense light branch road has the ratio of light and the voltage signal difference when unglazed, promptly

$V_R=\frac{V_m-V_n}{V_k-V_l}$

In the formula, V _RBe the ratio of voltage signal difference, V _mAnd V _kBe respectively the voltage signal that sense light branch road and reference light branch road have the light time, V _nAnd V _lIt is respectively sense light branch road and the reference light branch road voltage signal when unglazed.

Because the splitting ratio of Y shape polarization-maintaining fiber coupler 4 is 1: 1, therefore, through the ratio V of resulting voltage signal difference after this computing _RBasically eliminated the temperature of reference light branch road photoelectric commutator 7 and sense light branch road photoelectric commutator 10 and floated the influence of fluctuating with the pulsed laser intensity of light source, thus the sensitivity that has improved test macro.

Realizing above-mentioned computing, mainly is that data processing equipment control and flow chart of data processing software are finished, its data processing equipment control and flow chart of data processing figure, as shown in Figure 8.Described control and flow chart of data processing are:

(1), the beginning that powers on, the measuring system initialization.

(2), judge that the push button signalling of measurement is arranged? do not (N) then return and continues to judge that the push button signalling of measurement is arranged? be (Y), detect the high level of synchronizing signal, start the A/D conversion command, sampling, record V _mAnd V _k

(3), judge that sampling is through with? not (N) then returns the high level that continues to detect synchronizing signal, detect the high level of synchronizing signal after, start the A/D conversion command, sampling, record V _mAnd V _kBe (Y), detect the low level of synchronizing signal, start the A/D conversion command, sampling, record V _nAnd V _l

(4), judge that sampling is through with? not (N) then returns the low level that continues to detect synchronizing signal, detect the low level of synchronizing signal after, start the A/D conversion command, sampling, record V _nAnd V _lBe (Y), do subtraction and division arithmetic: (V _n-V _m)/(V _l-V _k), the ratio V of voltage signal difference after the demonstration computing _RThe result, finish this test.

(5), shutdown finishes.

Shown in Figure 2, twice excitation of a branch of incident light SPR apparatus structure synoptic diagram; In the structure of twice excitation of a branch of incident light SPR, suppose that the refractive index of isosceles prism and fluid to be measured medium is respectively n ₃And n ₁, the complex index of refraction of metal film is D is the thickness of metal film, λ ₀Be light wavelength in a vacuum, θ ₁Be the incident angle of light at isosceles prism and metal film interface, θ ₃Be the refraction angle of light at metal film and measured liquid medium interface, u ₂And v ₂Be actual quantities, so, light intensity total reflectivity R is

In the formula,

${\mathrm{\&rho;}}_{12}^2=\frac{{[{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">n</figure-callout>}}_2^2(1-{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">k</figure-callout>}}_2^2)\cos {\mathrm{\&theta;}}_1-n_1{u}_2]}^2+{[2{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">n</figure-callout>}}_2^2{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\cos {\mathrm{\&theta;}}_1-n_1{v}_2]}^2}{{[{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">n</figure-callout>}}_2^2(1-{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">k</figure-callout>}}_2^2)\cos {\mathrm{\&theta;}}_1+n_1{u}_2]}^2+{[{2\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">n</figure-callout>}}_2^2{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\cos {\mathrm{\&theta;}}_1+n_1{v}_2]}^2}$

${\mathrm{\&rho;}}_{23}^2=\frac{{[{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">n</figure-callout>}}_2^2(1-{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">k</figure-callout>}}_2^2)\cos {\mathrm{\&theta;}}_3-n_3{u}_2]}^2+{[2{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">n</figure-callout>}}_2^2{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\cos {\mathrm{\&theta;}}_3-n_3{v}_2]}^2}{{[{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">n</figure-callout>}}_2^2(1-{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">k</figure-callout>}}_2^2)\cos {\mathrm{\&theta;}}_3+n_3{u}_2]}^2+{[{2\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">n</figure-callout>}}_2^2{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="H200910073960XE00013.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\cos {\mathrm{\&theta;}}_3+n_3{v}_2]}^2}$

η＝2πd/λ ₀

${\hat{n}}_2=n_2(1+i{k}_2)$

${\hat{n}}_2\cos {\mathrm{\&theta;}}_2=u_2+i{v}_2$

In concrete the enforcement, it should be noted that GRIN Lens 501 as sense light branch road polarization maintaining optical fiber collimator 5, at the bonding location of isosceles prism 1301 left side workplaces, should guarantee that the position of twice excitation SPR can not occur in the edge of isosceles prism 1301 bottoms.The angle value at two base angles of isosceles prism 1301 must be the some angle values greater than the cirtical angle of total reflection of the refractive index calculating of the minimum refractive index of measured solution correspondence and isosceles prism 1301, when calculating the cirtical angle of total reflection, as long as it is very little to the absorption of light to measure solution, then can not consider metal film, press Si Nieer (Snell) law, get final product with the refractive index of isosceles prism 1301 and the refractive index calculating of measured liquid medium; The angle value at two base angles of isosceles prism 1301 also can be according to the pairing resonance angle of the selected standard solution of actual measurement environment.Can measuring process be simplified so that two workplace turnover of the vertical isosceles prism 1301 of measuring light make the testing liquid refractive index be in the high sensitivity stage that system detects all the time like this, the method for specifically determining be with reference to figure 3.

Shown in Figure 3, the SPR angular spectrum curve map of liquid a, b, c and the d correspondence of four kinds of variable concentrations that calculate according to formula (1), four kinds of variable concentrations liquid refractive index satisfy n _a＜n _b＜n _c＜n _dAs can be seen from Figure 3, the refractive index along with testing liquid a (figure dotted line), b (solid line among the figure), c (dotted line among the figure) and d (dot-and-dash line among the figure) increases the incident angle θ of excitation SPR incident light successively _a, θ _b, θ _c, θ _dIncrease to 59.4 ° from 56.8 ° successively.Therefore, if with the pairing resonance angle of testing liquid a θ _aAs fixing incident angle, so, four kinds of pairing light intensity reflectivity of liquid increase to 0.76 from 0.01 successively, and its variable quantity is bigger with respect to the change amount of resonance angle, and it is higher to measure sensitivity.

Shown in Figure 4, isosceles prism in total reflection isosceles right-angle prism and the Ke Laiqieman structure is the structural representation of one, the bottom metal-plated membrane 1302 of the isosceles prism 1301 of Ke Laiqieman structure 13, total reflection isosceles right-angle prism 14 is identical with the material of isosceles prism 1301, and is made into one.

Shown in Figure 5, the structural representation that isosceles prism in total reflection isosceles right-angle prism and the Ke Laiqieman structure is glued together, the bottom metal-plated membrane 1302 of the isosceles prism 1301 of Ke Laiqieman structure 13, the workplace on the inclined-plane of total reflection isosceles right-angle prism 14 and isosceles prism 1301 the right is glued together.

Shown in Figure 6, the structural representation that has certain interval between the isosceles prism in total reflection isosceles right-angle prism and the Ke Laiqieman structure, the bottom metal-plated membrane 1302 of the isosceles prism 1301 of Ke Laiqieman structure 13, the workplace on the inclined-plane of total reflection isosceles right-angle prism 14 and isosceles prism 1301 the right keeps certain clearance.

By experimental result as can be known, the reflected light after 14 twice total reflection of TM light wave process total reflection isosceles right-angle prism still is the TM light wave.Therefore, isosceles prism 1301 in the above total reflection isosceles right-angle prism 14 and the Ke Laiqieman structure 13 is except that integrative-structure, for displacement structure, in specific implementation process, all to guarantee the inclined-plane of total reflection isosceles right-angle prism 14 and the workplace keeping parallelism on isosceles prism 1301 the right.Like this, encourage the reflected light behind the SPR first time, still the TM light wave for total reflection isosceles right-angle prism 14, after these light wave process total reflection isosceles right-angle prism 14 twice total reflections, vertically the workplace on isosceles prism 1301 the right arrives its bottom, and on the metallic film and testing liquid medium interface of bottom, encourage SPR for the second time.

Shown in Figure 7, the total reflection device is the structural representation of pair of planar catoptron, and total reflection device 14 can also be a pair of planar catoptron 1401.

By experimental result as can be known, the reflected light after 1,401 twice total reflection of TM light wave process pair of planar catoptron still is the TM light wave.Therefore, in specific implementation process, to guarantee the minute surface of pair of planar catoptron 1401 and the workplace angle at 45 placement on isosceles prism 1301 the right.Like this, encourage the reflected light behind the SPR first time, still the TM light wave for pair of planar catoptron 1401, after these light wave process pair of planar catoptron 1,401 twice total reflections, vertically the workplace on isosceles prism 1301 the right arrives its bottom, and on the metallic film and testing liquid medium interface of bottom, encourage SPR for the second time.

In addition, in concrete enforcement, be also noted that the polarized light direction of vibration of the sense light branch road polarization maintaining optical fiber collimator 5 that is connected with Y shape polarization-maintaining fiber coupler 4, must with the plane of incidence keeping parallelism of isosceles prism 1301 left side workplaces in the Ke Laiqieman structure 13.Like this, could improve the efficient of incident light excitation SPR on the interface of the metallic film 1302 of isosceles prism 1301 bottoms and testing liquid medium 1303, thereby improve the sensitivity of measuring.

A kind of glass prism SPR high sensitivity optical fiber of the present invention liquid refractive index sensor, obtain the pairing light intensity reflectivity of normal fluid by experiment, adopt data processing equipment that survey liquid and the pairing light intensity reflectivity of normal fluid are compared processing, just can obtain the refractive index of fluid to be measured.

A kind of glass prism SPR high sensitivity optical fiber of the present invention liquid refractive index sensor also can be realized temperature, the concentration to liquid, the detection of pressure and other parameters.

Claims (4)

1. glass prism SPR high sensitivity optical fiber liquid refractive index sensor, comprise that the laser beam emitting device, the TM light wave that are made of pulsed laser (1) and pulse signal generator (8) produce and the device of transmission, excitation SPR device, light wave receiving trap, amplification and A/D conversion and data processing equipment, it is characterized in that: described excitation SPR device is twice excitation of a branch of incident light SPR device; Twice excitation of described a branch of incident light SPR device is made up of with total reflection device (14) the Ke Laiqieman structure (13) that isosceles prism (1301), metallic film (1302) and liquid medium to be measured (1303) constitute; Wherein:

● described TM light wave produces and transmitting device comprises the P light polarizer (2), TM light wave polarization maintaining optical fiber collimator (3), Y shape polarization-maintaining fiber coupler (4), sense light branch road polarization maintaining optical fiber collimator (5) and reference light branch road polarization maintaining optical fiber collimator (6); Described Y shape polarization-maintaining fiber coupler (4) has a light signal input end and two output terminals, and the splitting ratio of two output terminals is 1: 1;

● between described TM light wave polarization maintaining optical fiber collimator (3), sense light branch road polarization maintaining optical fiber collimator (5), reference light branch road polarization maintaining optical fiber collimator (6) and the Y shape polarization-maintaining fiber coupler (4), adopt the polarization maintaining optical fibre connector to connect;

● described light wave receiving trap comprises reference light branch road photoelectric commutator (7), collects the optical fiber collimator (12) and sense light branch road photoelectric commutator (10) of light;

● described amplification comprises amplifier and A/D converter (9) and data processing equipment (11) with A/D conversion and data processing equipment;

● the laser that is sent by pulsed laser (1) produces the TM light wave through the P light polarizer, the TM light wave is coupled in the Y shape polarization-maintaining fiber coupler (4) by TM light wave polarization maintaining optical fiber collimator (3), the light that comes out from the sense light branch road polarization maintaining optical fiber collimator (5) of Y shape polarization-maintaining fiber coupler, isosceles prism (1301) left side workplace in the vertical Ke Laiqieman structure (13) arrives its bottom, on the metallic film and testing liquid medium interface of bottom, arrive total reflection device (14) after encouraging for the first time SPR, after twice total reflection of reflected light process total reflection device, isosceles prism (1301) the right workplace in the vertical again Ke Laiqieman structure (13) arrives its bottom, and on the metallic film of bottom and testing liquid medium interface the second time encourage SPR; Encourage the reflected light behind the SPR twice, arrive sense light branch road photoelectric commutator (10) through optical fiber collimator (12) coupling of collecting light; From the light that the reference light branch road polarization maintaining optical fiber collimator (6) of Y shape polarization-maintaining fiber coupler comes out, coupling arrives reference light branch road photoelectric commutator (7); After reference light branch road photoelectric commutator and sense light branch road photoelectric commutator are converted to electric signal with light signal, electric signal is sent into amplifier and A/D converter (9), amplification is also carried out analog to digital conversion, and the digital signal after the conversion is sent into data processing equipment (11) and carried out data processing.

Described total reflection device (14) is total reflection isosceles right-angle prism 14 and isosceles prism (1301), and material is identical, and is made into one; Perhaps described total reflection device (14) is pair of planar catoptron (1401).

2. a kind of glass prism SPR high sensitivity optical fiber liquid refractive index sensor according to claim 1 is characterized in that: described total reflection isosceles right-angle prism and isosceles prism (1301) stick with glue knot together.

3. a kind of glass prism SPR high sensitivity optical fiber liquid refractive index sensor according to claim 1 is characterized in that: described total reflection isosceles right-angle prism and isosceles prism (1301) leave the gap between the two.

4. a kind of glass prism SPR high sensitivity optical fiber liquid refractive index sensor according to claim 1 is characterized in that: the GRIN Lens (1201) of the optical fiber collimator (12) of the GRIN Lens (501) of sense light branch road polarization maintaining optical fiber collimator (5), collection light and the workplace on isosceles prism (1301) left side in the Ke Laiqieman structure (13) are to stick with glue knot together.

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