CN100588913C - Simplifying type multiplexing white light interference optical fiber sensing demodulating equipment - Google Patents

Abstract

The invention provides a simplified multiplexing white light interference fiber sensing demodulating device, which comprises a single-fiber two-way optical transmitting/receiving module, an optical fiber resonant cavity, a single-mode transmission fiber, and an optical fiber sensing array, wherein the single-fiber two-way optical transmitting/receiving module is composed of a semiconductor light source as the transmitting terminal, a semiconductor photodetector as the receiving terminal and related devices packaged together; and an optical fiber annular cavity is composed of an optical fiber coupler, an optical fiber self-focusing lens and a movable corner reflector. The device can achieve enquiry and measurement of a plurality of optical fiber sensors by embedding the single-fiber two-wayoptical transmitting/receiving module and the optical fiber resonant cavity in the single-mode optical fiber, and has the advantages of simple structure, easy implementation, no length restriction ofthe transmission cable, no influence caused by the external environment, and good stability and reliability. The device can be used for the measurement of physical quantities such as distributed deformation, strain and temperature, and can be used for multi-task sensing, multi-element sensing, local strain sensing, large-scale deformation sensing, etc.

Description

A kind of simplifying type multiplexing white light interference optical fiber sensing demodulating equipment

(1) technical field

What the present invention relates to is a kind of measurement mechanism, specifically a kind of fiber array sensor of sensing and demodulating of simplifying type multiplexing white light fibre optic interferometer.

(2) background technology

Adopt the fibre optic interferometer of the light source of low relevant, broad band to be commonly called the white light fibre optic interferometer.Typical optical fiber white light interference instrument as shown in Figure 1, its structural group becomes utilizes optical fiber to build Micheslon formula interferometer, and adopt wide spectrum light source LED or ASE that interferometer is driven, for it provides luminous energy, survey the measurement of white-light fringe realization to measured physical quantity by detector.Its principle of work is as follows, after the wide range light that is sent by wide spectrum light source 11 enters single-mode fiber, be divided into two bundles by 3dB single-mode fiber 2 * 2 coupling mechanisms 13, a branch of light enters the single-mode fiber 14 that is used as gage beam, optical reflection face 15 reflection backs by its rear end are returned along former road, arrive photodetector 12 through single-mode fiber 14, coupling mechanism 13, this Shu Guang is called measuring-signal light; Send light by light source 11 and be coupled device 13 other a branch of light along separate routes, enter as single mode and connect optical fiber 16, GRIN Lens 17 with reference to arm, arrive photodetector 12 through returning along former road equally after the reflection of mobile mirror 18, this Shu Guang is called as reference signal light.Measuring-signal light and reference signal light are in detector surface generation coherence stack, because the coherent length of wide spectrum light source is very short, be approximately several microns to tens microns, have only when reference signal light and measuring-signal optical path difference during less than the coherent length of light source, just can produce coherence stack, output white light interference pattern (referring to accompanying drawing 2).

As shown in Figure 2, the feature of white-light fringe is that a principal maximum is arranged, and is called the center striped, and it is corresponding for it with zero optical path difference, during promptly corresponding to reference beam and measuring beam equivalent optical path, is called reference beam and measuring beam and has the light path matching relationship.By changing the retardation of fibre delay line, the light path of reference signal is changed, can obtain the center interference fringe.The position of center striped provides a reliable absolute position reference for measurement, when measuring beam because during the influencing light path and change of extraneous measured physical quantity, only need to scan the change in location of the white-light fringe that obtains, can obtain the absolute value of measured physics amount by the reference arm light path.Compare with other fibre optic interferometers, except having advantages such as high sensitivity, essential safety, anti-electromagnetic field interference, maximum characteristics are to carry out absolute measurement to pressure, strain, temperature etc. are to be measured.Therefore the white light interference fibre optic interferometer is widely used in the measurement of physical quantity, mechanical quantity, environment parameter, chemistry amount, biomedical amount.

In order to solve the multiplexed problem of fibre optic interferometer, people have carried out many-sided research, and the multiplexing technique that has developed has: time-division multiplex technology (TDM), frequency multiplexing technique (FDM or FMCW), wavelength-division multiplex technique (WDM) and empty multiplex technique (SDM).

People such as Jackson [Santos, J.L., Jackson, D.A., Coherence sensing of time-addressedoptical-fiber sensors illuminated by a multimode laser diode Appl.Opti, 30,5068-5076,1991] Fa Zhan time-division multiplex technology (TDM) is an optical path difference of utilizing the sensing unit on same fiber buss, and promptly optical fiber comes the multiplex technique of addressing to the late effect of light wave.Technical scheme is: multimode laser diode send less than the light pulse in transmission time between adjacent sensors on the fiber buss, and during the input end of injection fibre bus, because each sensing unit is different apart from the distance of light pulse transmitting terminal on bus, terminal at fiber buss will receive series of pulses, a sensing unit on the corresponding fiber buss of the information that wherein each light pulse comprised, the address of this sensing unit of time delay size reflection of light pulse distributes.If can in the time of light impulse length, finish continuous light path scanning to the white light sensing unit, can be to obtaining the heat transfer agent of sensor.This method complex structure, multiplexing limited amount, measurement range is little, and measuring accuracy is low.

Wayne V.Sorin, [Multiplexed sensing using optical coherencereflectrometry such as Mountain View, United States Patent, Patent Number 5,557,400,1996], adopt the multiplexed interference technique of white light optical fiber to measure parameters such as tension force, strain, displacement, but used white light source and the photoelectric detection system of its method is separate, and the more complex structure of the used device of its photoelectric detection system.Other similar techniques also has W.Don Morison, waits [Fiber optic sensor usable over wide range of gage lengths, United States Patent, Patent Number6870975,2005]; Ralph Posey, Deng [Integratedfiber optic strain sensing using low-coherence wavelength-encoded addressing, United States Patent, Patent Number6289740,2001] also adopt the multiplexed interference technique of white light optical fiber to measure parameters such as strain, displacement, this method has mainly adopted the method for reconciling optical source wavelength to realize measuring.Domestic literature is as disclosed optical fiber Fizeau strain transducer Frequency Division Multiplexing system and the method (publication number CN1553273A) etc. based on light amplification of, Chinese patent communique.The multichannel multiplexing method of above-mentioned fibre optic interferometer, mainly based on time-division multiplex technology, existing a large amount of technical patent and technical papers published.

The applicant discloses multiplex fibre optic interferometer and nesting constructing method (Chinese patent publication number: CA1963399A) thereof in 2006, having invented can the structure sensor array and full optical fiber interferometer optical fiber and its implementation of network, solves the multiplexed problem of fibre optic interferometer; The applicant in 2007 disclosed low relevant strand turn round formula class Sagnac optical-fiber deformation sensor (Chinese patent publication number: 101074867A), be mainly used to solve the problem of the anti-breaking-up in the fibre optic sensor arra laying process.In above-mentioned application, when particularly white light interferometer was connected with fibre optic sensor arra, the light path of the local demodulated interferential instrument and the sensing interferometer of far-end mates by light path realized inquiring and demodulation of fibre optic sensor arra.The sensing interferometer array can be fully passive like this, and its benefit is that a plurality of interference signals of exporting in the array are insensitive to the variation of the connection fiber lengths between local demodulated interferential instrument and the sensor array, has strengthened measuring stability and reliability.

But in above-mentioned interferometer structure based on space division multiplexing, local demodulated interferential instrument adopts discrete interferometer structures such as Michelson interferometer, Mach-Zehnder interferometer mostly.They have two separate transmission lines usually, are used to realize the tuning and coupling of light path.But because there is not common light channel structure in it, very easily be subjected to the influence of environmental factor (such as temperature and vibration), cause the light path of two light paths to produce inconsistent variation, the demodulation of sensor signal is exerted an influence, reduced the signal demodulation sensitivity of interferometer, make the precise decreasing of measurement, long-term stability and reliability can't guarantee; The structure of interferometer is also comparatively complicated simultaneously, is not used in the practicability of interferometer.

(3) summary of the invention

The objective of the invention is to solve the complex structure of this type of fibre optic interferometer, connect with optical fiber cable relevant with measurement, measure poor reliability, stability problem such as low provides a kind of quantity height simple in structure, multiplexing, measurement range is big, measuring accuracy is high a kind of simplifying type multiplexing white light interference optical fiber sensing demodulating equipment.

The object of the present invention is achieved like this:

The composition of simplifying type multiplexing white light interference optical fiber sensing demodulating equipment of the present invention comprises single fiber bi-directional optical transceiver module 1, optic fiber ring-shaped cavity 2, single-mode transmission optical fiber 3, fibre optic sensor arra 4; Described single fiber bi-directional optical transceiver module 1 mainly is packaged together as the semiconductor photo detector 103 that receives by a semiconductor light sources 102 as emission, one and forms, semiconductor photo detector 103 is realized the output of light signal and the detection of optical interference signals simultaneously by three electrical pin 109 multiplexing with semiconductor light sources 102; After the wide range light that single fiber bi-directional optical transceiver module 1 sends enters single-mode transmission optical fiber, be divided into two bundles through optic fiber ring-shaped cavity 2, wherein a branch of light, behind single-mode optical-fibre coupler 201 in the optic fiber ring-shaped cavity 2, directly enter the fibre optic sensor arra of forming by single-mode transmission optical fiber 503 and optical reflection face 504 polyphones 4, as measuring beam; A branch of in addition light, reenter single-mode optical-fibre coupler 201 through two GRIN Lens 202 of optic fiber ring-shaped cavity 2 and scanning total reflection prism 203 and be divided into the two-way light beam again, one road light beam continues in optic fiber ring-shaped cavity around loop transmission, and another road light beam enters fibre optic sensor arra 4 transmission as the reference light beam and by getting back to the single fiber bi-directional optical transceiver module after optical reflector 504 reflections; Single fiber bi-directional optical transceiver module 1 is realized the multiplexing white light interference optical fiber sensing demodulation according to the interference signal of measuring beam that returns and reference beam.

The composition of described single fiber bi-directional optical transceiver module 1 comprises that the semiconductor light sources 102 that is encapsulated in the module package housing 101, semiconductor photo detector 103, heat sink 104, optical fiber 105, adhesive epoxy resin 106 and module electrical pin 109 constitute.Semiconductor light sources 102 is solidificated on the semiconductor photo detector 103, and the two is drawn by three electrical pin 109, and wherein an electrical pin is multiplexing by semiconductor light sources 102 and semiconductor photo detector 103.Connect heat sinkly 104 under the semiconductor photo detector 103, connect optical fiber 105, semiconductor light sources 102 outgoing beams 107, semiconductor photo detector 103 receiving beams 108 with adhesive epoxy resin 106 on the semiconductor light sources 102.

After the wide range light that described single fiber bi-directional optical transceiver module 1 sends enters single-mode fiber, be divided into two bundles through optic fiber ring-shaped cavity 2, wherein a branch of light, behind fiber coupler 201 in the optic fiber ring-shaped cavity 2, directly enter be used as sensor 5 by N section single-mould fiber 503 and N the sensor array 4 that opticator reflecting surface 504 is formed, as measuring beam; A branch of in addition light, reenter single-mode optical-fibre coupler 201 through two self-focusing rate lens 202 of optic fiber ring-shaped cavity 2 and scanning total reflection prism 203 and be divided into the two-way light beam again, one road light beam continues in fiber resonance cavity around loop transmission, and another road light beam enters fibre optic sensor arra 4 transmission and by getting back to single fiber bi-directional optical transceiver module 1 after 504 reflections of opticator reverberator.

Described optic fiber ring-shaped cavity 2 is made up of one 2 * 2 single-mode optical-fibre coupler 201, two single mode GRIN Lens 202 and a scanning total reflection prism 203; The splitting ratio of single-mode optical-fibre coupler 201 can be selected in 1%～99% scope.

Described Optical Fiber Sensing Array 4 is made up of several head and the tail Fibre Optical Sensor 5 of serial connection successively.

Described Fibre Optical Sensor 5 is made up of the single-mode fiber 503 that a segment length any two ends has fiber stub 501.

The method of attachment of described fibre optic sensor arra 4 is that Fibre Optical Sensor 5 has the Fibre Optical Sensor 5 of fiber stub 501 by ferrule 502 and other or is connected optical fiber 3 connections.

Described optical fibre device all is operated in the single mode state.

The ultimate principle of the inventive method is a white light optical fibre Michelson interferometer principle.

After the wide range light that single fiber bi-directional optical transceiver module 1 sends entered single-mode fiber, single-mode fiber 2 * 2 coupling mechanisms 201 in optic fiber ring-shaped cavity 2 were divided into two bundles, as shown in Figure 4.Wherein a branch of as measuring beam, through behind the fiber coupler 201, directly enter be used as sensor 5 by N section single-mould fiber 503 and N the sensor array 4 that optical reflection face 504 is formed; A branch of in addition light, reenter single-mode optical-fibre coupler 201 through two self-focusing rate lens 202 of optic fiber ring-shaped cavity 2 and scanning total reflection prism 203 and be divided into the two-way light beam again, one road light beam continues in fiber resonance cavity around loop transmission, and another road light beam enters fibre optic sensor arra 4 transmission as the reference light beam and by getting back to single fiber bi-directional optical transceiver module 1 after 504 reflections of opticator reverberator.

The initial length of fiber resonance cavity can be set at L ₀, the length of the Fibre Optical Sensor in the middle of N partial reflection device is L _j(j=1,2,3 ... N), this length and L ₀Near but long a little a bit, and the length of each section Fibre Optical Sensor all has small variation.At this moment, the adjustable interior optical path length of fiber resonance cavity is nL ₀+ 2X, wherein X is the light path between scanning prism and the two gradient-index lens, its value can be regulated by the gated sweep prism.When j Fibre Optical Sensor is subjected to light signal and inquires, be following three kinds of forms by the reference signal that obtains through fiber resonance cavity and j Fibre Optical Sensor left part reverberator:

$(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+(\mathrm{<figure-callout\; id="0"\; label="n\; L"\; filenames="C2008101368260013H2.png"\; state="\{\{state\}\}">n</figure-callout>}{L}_{}{}_0+2X_j)+(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+(\mathrm{<figure-callout\; id="0"\; label="n\; L"\; filenames="C2008101368260013H2.png"\; state="\{\{state\}\}">n</figure-callout>}{L}_{}{}_0+2X_j)---\left(1\right)$

$(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+2(\mathrm{<figure-callout\; id="0"\; label="n\; L"\; filenames="C2008101368260013H2.png"\; state="\{\{state\}\}">n</figure-callout>}{L}_{}{}_0+2X_j)---\left(2\right)$

$(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+2(\mathrm{<figure-callout\; id="0"\; label="n\; L"\; filenames="C2008101368260013H2.png"\; state="\{\{state\}\}">n</figure-callout>}{L}_{}{}_0+2X_j)+(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)---\left(3\right)$

In the formula: n is the refractive index of fiber core, and L is for connecting the length of optical cable.

The measuring-signal that obtains through fiber resonance cavity and j Fibre Optical Sensor right side sub reflector device is following form:

$(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+n{l}_j+n{l}_j+(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)---\left(4\right)$

Comparison reference signal and measuring-signal can obtain:

nL ₀+2X _j＝nl _j，j＝1，2，3...... (5)

Also exist second kind with reference to signal type, promptly at L ₀≈ 2l _SensorUnder the situation:

$(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+(\mathrm{<figure-callout\; id="0"\; label="n\; L"\; filenames="C2008101368260013H2.png"\; state="\{\{state\}\}">n</figure-callout>}{L}_{}{}_0+2X_j)+(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)---\left(6\right)$

$(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+(\mathrm{<figure-callout\; id="0"\; label="n\; L"\; filenames="C2008101368260013H2.png"\; state="\{\{state\}\}">n</figure-callout>}{L}_{}{}_0+2X_j)---\left(7\right)$

Measuring-signal does not change:

$(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)+n{l}_j+n{l}_j+(\mathrm{nL}+n{\mathrm{\&Sigma;}}_{i=1}^{j-1}{l}_i)---\left(8\right)$

Comparison reference signal and measuring-signal can obtain in this case:

nL ₀+2X _j＝2nl _j，j＝1，2，3...... (9)

By formula (5) and formula (9) as can be seen, when measuring-signal light and reference signal light light path coupling, will coherence stack take place at single fiber bi-directional optical transceiver module 1, because the coherent length of wide spectrum light source is very short, be approximately several microns to tens microns, have only when reference signal light and measuring-signal optical path difference during, just can produce coherence stack, output white light interference pattern less than the coherent length of light source.

Also can find out simultaneously from formula (5) and formula (9), light path matching relationship for j Fibre Optical Sensor, all irrelevant with the length l of the length L that is connected optical cable and other Fibre Optical Sensors, the length that promptly connects optical cable is unrestricted, and environment is eliminated the influence that connects optical cable simultaneously.In addition, sensor because the light path relation is separate, does not produce yet and crosstalks each other.

As Fibre Optical Sensor l _jWhen being subjected to extraneous factor effect generation deformation such as stress, strain, regulate the adjustable parameter X in the fiber resonance cavity _j, the light path coupling is made:

$\mathrm{\&Delta;}{X}_j=\mathrm{\&Delta;}\frac{{\mathrm{nl}}_j}{2},j=\mathrm{1,2,3}......---\left(10\right)$

Perhaps Δ X _j=Δ (nl _j), j=1,2,3...... (11)

Suppose Fibre Optical Sensor l ₁Change to l ₁+ Δ l ₁, l ₂Change to l ₂+ Δ l ₂... l _NChange to l _N+ Δ l _N, then can obtain the coefficient of strain of whole sensor

${\mathrm{\&epsiv;}}_1=\frac{\mathrm{\&Delta;}{l}_1}{{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="C2008101368260013H2.png,C2008101368260014H1.png"\; state="\{\{state\}\}">l</figure-callout>}}_1},{\mathrm{\&epsiv;}}_2=\frac{\mathrm{\&Delta;}{l}_2}{{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="C2008101368260014H1.png"\; state="\{\{state\}\}">l</figure-callout>}}_2},......{\mathrm{\&epsiv;}}_N=\frac{\mathrm{\&Delta;}{l}_N}{l_N}---\left(12\right)$

Owing to adopt the interference of the fibre optic interferometer of wide spectrum light source to only occur in the coherent length, corresponding near the several micron the light path matching condition between tens microns, therefore a plurality of fibre optic interferometers can be connected, and make the pairing interference signal of different fiber sensor discrete mutually, distinguish separately, can realize the multiplexed of fibre optic interferometer modulation.Measuring beam is through the different optical light path that different reflecting surface experienced along separate routes, matching relationship one to one can take place with the light path of reference beam, make the white-light fringe of generation separate on the light path scanning space, do not disturb mutually, can realize multiplexed modulation from the light fibre optic interferometer based on above-mentioned thought.

Advantage of the present invention and characteristics are:

(1) the present invention is based on the multiplexing technique of fibre optic interferometer modulation, by embedding a single fiber bi-directional optical transceiver module and a fiber resonance cavity, in an optical fiber, can realize inquiry and measurement to a plurality of optical fibre interferometric sensors, greatly simplified the light channel structure of measuring system, realized easily.

(2) the present invention has adopted two-way light channel structure altogether, make and connect single fiber bi-directional optical transceiver module, fiber resonance cavity, the length of the connection optical cable in Optical Fiber Sensing Array and the array between the Fibre Optical Sensor is unrestricted, also eliminated simultaneously environment to connecting the influence of optical cable, improved antijamming capability, strengthened measuring reliability and stability system.

(3) the simplifying type multiplexing white light fibre optic interferometer of the present invention's structure, by selecting suitable wide spectrum light source of power and suitable fiber section reverberator, can make multiplexing number of sensors reach more or less a hundred, realize the array that Fibre Optical Sensor is laid, greatly simplified the system complex degree, reduce testing expense, guaranteed the real-time of test macro, improved measuring reliability.

(4) fiber optic materials and the device of the present invention's employing are the standard fiber communication device, and cost price is cheap, obtain easily, help promoting.

The present invention proposes a kind of modulation construction method of simplifying type multiplexing white light fibre optic interferometer, and construct the optical fiber interferometer sensor array thus.Core content of the present invention is to utilize integration thoughts, based on white light interference technique, by embedding bidirectional light receiving and transmitting assembly and optic fiber ring-shaped cavity, be implemented in structure optical fiber white light interference instrument in the simple optical fiber, and Fibre Optical Sensor is multiplexed and demodulation.Particularly, adopt method for packing that light source detects dorsad that white light source and white light interference signal deteching circuit are encapsulated among the single fiber bi-directional optical transceiver module device, realized the multiplexed of white light source and white light interference input; Utilize the light path tuber function of optic fiber ring-shaped cavity, export the different reference optical signal of a plurality of light paths simultaneously, finish demodulation a plurality of Fibre Optical Sensors.

(4) description of drawings

Fig. 1 is typical white light optical fibre Michelson interferometer structural representation.

Fig. 2 is typical white light interference signal schematic representation.

Fig. 3 is a structural representation of the present invention.

Fig. 4 is the optic fiber ring-shaped cavity structural representation.

Fig. 5 is optical fibre sensor structure and attaching method thereof synoptic diagram.

Fig. 6 is the structural representation of single fiber bi-directional optical transceiver module.

(5) embodiment

For example the present invention is done description in more detail below in conjunction with accompanying drawing:

Embodiment one: as shown in Figure 3.The simplifying type multiplexing white light fibre optic interferometer is made up of with optical fiber cable 3, fiber array sensor 4 single fiber bi-directional optical transceiver module 1, fiber resonance cavity 2, connection.

After the wide range light that single fiber bi-directional optical transceiver module 1 sends entered single-mode fiber, single-mode fiber 2 * 2 coupling mechanisms 201 in optic fiber ring-shaped cavity 2 were divided into two bundles, as shown in Figure 4.Wherein a branch of as measuring beam, through behind the fiber coupler 201, directly enter be used as sensor 5 by N section single-mould fiber 503 and N the sensor array 4 that optical reflection face 504 is formed; A branch of in addition light, reenter single-mode optical-fibre coupler 201 through two self-focusing rate lens 202 of optic fiber ring-shaped cavity 2 and scanning total reflection prism 203 and be divided into the two-way light beam again, one road light beam continues in fiber resonance cavity around loop transmission, and another road light beam enters fibre optic sensor arra 4 transmission as the reference light beam and by getting back to single fiber bi-directional optical transceiver module 1 after 504 reflections of opticator reverberator.When scanning total reflection prism 203 carries out light path scanning, make the light signal of sensor front/rear end 504 reflection realize the light path coupling, the sensor of length-specific corresponding in the position of scanning total reflection prism 203 and sensor array or the networking during white light interference peak value that promptly produces.When of the effect of some sensors owing to parameters such as temperature, stress, when producing strain or displacement, the light path scanning position of the appearance white light interference peak value of its correspondence also changes thereupon, and record changes the front-back direction value, according to transformational relation, can carry out the sensing measurement of parameter.

Single fiber bi-directional optical transceiver module 1 is a kind of high performance photoelectric device, and the function of semiconductor light sources 102, semiconductor photo detector 103 is integrated in the standard packaging.As shown in Figure 6, the function of single fiber bi-directional optical transceiver module is integrated in standard 1 * 3 pin package, semiconductor photo detector 103 working methods are detection backlight, promptly, realize the output of light signal and the detection of optical interference signals simultaneously by three electrical pin 109 multiplexing with semiconductor light sources 102.Semiconductor light sources 102 is converted into flashlight with drive current, supplies with interferometer as the luminous energy source; Semiconductor photo detector 103 can convert light signal to electric current, through amplification, filtering, extracts the white light interference signal.Optical fiber of this devices use is realized two-way flash of light preceding an earthquake emission and photodetection function, can improve the utilization ratio of optical fiber.

As shown in Figure 4, two GRIN Lens 202 in the fiber resonance cavity 2, it inserts loss range is 0.5dB, span 3mm-70mm (corresponding) between GRIN Lens and the scanning total reflection mirror with reference to light path scope 6mm-140mm, loss between them is 4～8dB, the optical path length of resonator cavity is chosen in 1990mm, is approximately equal to the Fibre Optical Sensor length of twice.

Optical Fiber Sensing Array 4 is composed in series successively by 6 Fibre Optical Sensors, 5 head and the tail.Each Fibre Optical Sensor 5 roughly is made of at the single-mode fiber 503 of 1000mm length, and two ends have single-mode fiber lock pin 501.Ferrule 502 is adopted in the method for attachment of Optical Fiber Sensing Array 4, Fibre Optical Sensor 5 and other are had the Fibre Optical Sensor 5 of fiber stub 501 or be connected optical fiber 3 serial connections, then form the optical reflection face 504 of an optical reflectivity 1%～3% between the fiber stub that two are utilized ferrule to connect, as shown in Figure 5.Fiber coupler 201 is chosen as 3dB optical fiber 2 * 2 coupling mechanisms.The principles of modulation and demodulation of its multiplexing white light fibre optic interferometer can be with reference to summary of the invention.This device can be used for the measurement of tension force, displacement, temperature.

Claims (5)

1, a kind of simplifying type multiplexing white light interference optical fiber sensing demodulating equipment, its composition comprise single fiber bi-directional optical transceiver module (1), optic fiber ring-shaped cavity (2), single-mode transmission optical fiber (3), fibre optic sensor arra (4); It is characterized in that: described single fiber bi-directional optical transceiver module (1) mainly is packaged together and is formed by a semiconductor light sources (102) as emission, the semiconductor photo detector (103) as reception, semiconductor photo detector (103) is realized the output of light signal and the detection of optical interference signals simultaneously by three electrical pin (109) multiplexing with semiconductor light sources (102); After the wide range light that single fiber bi-directional optical transceiver module (1) sends enters single-mode transmission optical fiber, be divided into two bundles through optic fiber ring-shaped cavity (2), wherein a branch of light, behind single-mode optical-fibre coupler (201) in the optic fiber ring-shaped cavity (2), directly enter the fibre optic sensor arra of forming by single-mode transmission optical fiber (503) and optical reflection face (504) polyphone (4), as measuring beam; A branch of in addition light, two GRIN Lens (202) of process optic fiber ring-shaped cavity (2) and scanning total reflection prism (203) reenter single-mode optical-fibre coupler (201) and are divided into the two-way light beam again, one road light beam continues in optic fiber ring-shaped cavity around loop transmission, and another road light beam enters fibre optic sensor arra (4) transmission as the reference light beam and by getting back to the single fiber bi-directional optical transceiver module after optical reflection face (504) reflection; Single fiber bi-directional optical transceiver module (1) is realized the multiplexing white light interference optical fiber sensing demodulation according to the interference coherent signal of measuring beam that returns and reference beam.

2, simplifying type multiplexing white light interference optical fiber sensing demodulating equipment according to claim 1 is characterized in that: the composition of described single fiber bi-directional optical transceiver module (1) comprises semiconductor light sources (102), semiconductor photo detector (103), heat sink (104), optical fiber (105), adhesive epoxy resin (106) and the module electrical pin (109) that is encapsulated in the module package housing (101); Semiconductor light sources (102) is solidificated on the semiconductor photo detector (103), and the two is drawn by three electrical pin (109), and wherein an electrical pin is multiplexing by semiconductor light sources (102) and semiconductor photo detector (103); Connect under the semiconductor photo detector (103) heat sink (104), connect optical fiber (105) with adhesive epoxy resin (106) on the semiconductor light sources (102), semiconductor light sources (102) outgoing beam (107), semiconductor photo detector (103) receiving beam (108).

3, simplifying type multiplexing white light interference optical fiber sensing demodulating equipment according to claim 2 is characterized in that: the splitting ratio of described single-mode fiber coupling (201) is selected in 1%～99% scope.

4, simplifying type multiplexing white light interference optical fiber sensing demodulating equipment according to claim 3 is characterized in that: described Fibre Optical Sensor (5) is made up of the single-mode fiber (503) that a segment length any two ends has fiber stub (501).

5, simplifying type multiplexing white light interference optical fiber sensing demodulating equipment according to claim 4 is characterized in that: the syndeton of described fibre optic sensor arra (4) is: Fibre Optical Sensor (5) is connected by Fibre Optical Sensor (5) or the single-mode transmission optical fiber (3) that ferrule (502) and other have fiber stub (501).

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