CN105115436B

CN105115436B - The method of sensing device and monitor stress and temperature

Info

Publication number: CN105115436B
Application number: CN201510471900.9A
Authority: CN
Inventors: 姚晓天
Original assignee: Beijing China Light Technology Co ltd; General Optoelectronic Technology Beijing Co ltd; SUZHOU OPTORING TECHNOLOGY CO LTD
Current assignee: Yueshen Innovation Co.,Ltd.
Priority date: 2015-08-04
Filing date: 2015-08-04
Publication date: 2017-11-17
Anticipated expiration: 2035-08-04
Also published as: CN105115436A

Abstract

The present invention relates to a kind of sensing device and the method for monitor stress and temperature, the device includes：Sensing baseplate, optical birefringence medium, light source, the linear optics polarizer, interferometer, processor, the apparatus and method change to obtain the temperature change of the optical birefringence medium according to the spacing between polarization interference peak, and stress and/or the strain of the optical birefringence medium are obtained according to the peak value at polarization interference peak.So stress, strain and the monitoring of temperature can be carried out come measuring targets using same optical birefringence medium, and will not be influenced each other between stress, strain and temperature change.

Description

The method of sensing device and monitor stress and temperature

Technical field

The present invention relates to monitoring field, more particularly to a kind of sensing device and monitor stress, the method for strain and temperature.

Background technology

Temperature, stress and strain be optical fiber sensing technology application in very important physical quantity, large bridge, tunnel, The safety monitoring such as dam field, it is necessary to be monitored to parameters such as temperature, stress and strains.Stress refer to monitored object by Power caused by the external force arrived or inside, strain and refer to because monitored object is stressed caused deformation, such as expand, Bending or displacement, etc..Current existing optical fiber sensing technology, is to use discrete measurement system to temperature, stress and strain System measures respectively, such as fiber grating measuring system, is each point or measurement temperature by being measured point by point to testee Degree, or measurement stress or strain, system cost is high and can not realize that overall distribution formula measures.Existing polarization interference principle point Cloth Fibre Optical Sensor e measurement technology, simply stress (such as ambient pressure) is parsed, without for straining and temperature Analytic method, specifically how the strain of testee is changed into the stress that medium is detected for polarization interference, so as to produce The crosstalk measured value of reaction strain does not have concrete scheme and measure.

The content of the invention

Based on this, this programme offer is a kind of to monitor strain, stress and temperature by way of polarization interference measurement Method and device.

A kind of method of monitor stress and temperature, it comprises the following steps：The linearly polarized light of coupling wideband band enters optics Birefringent medium, two orthogonal polarization modes transmission of the linearly polarized light along the optical birefringence medium, the optics are two-fold Penetrate medium output optical output signal；The optical output signal is guided by the linear optics polarizer, the polarizer is by institute Two orthogonal polarization modes for stating optical output signal are mutually mixed；Linearly polarized light caused by the optical polariser is guided to enter interference Instrument, so as to obtain the interference between two orthogonal polarization modes, to produce polarization interference peak；According to the spacing between polarization interference peak Change obtains the optical birefringence to obtain the temperature change of the optical birefringence medium, according to the peak value at polarization interference peak The stress of medium and/or strain.

In one of the embodiments, the optical birefringence medium is provided with default polarization interference.

In one of the embodiments, the optical birefringence medium includes polarization maintaining optical fibre.

In one of the embodiments, in addition to step：The optical output signal of the optical birefringence medium output enters Enter optical delay, make to produce delay between two orthogonal polarization modes.

In one of the embodiments, the optical birefringence medium is attached on object under test, to monitor described treat Survey stress, strain and the temperature of object.

In one of the embodiments, the optical birefringence medium is arranged on sensing baseplate, the sensing baseplate patch It is attached on object under test, to monitor the stress of the object under test, strain and temperature.

In one of the embodiments, the optical birefringence medium one-dimensional space or two dimension on the sensing baseplate is empty Between be distributed, to monitor the stress of the object under test, strain and the spatial distribution of temperature.

In one of the embodiments, default polarization is applied to the optical birefringence medium by the sensing baseplate Crosstalk.

A kind of sensing device, to the temperature change of monitoring object, strain and/or stress, it includes：Optical birefringence is situated between Matter, for perceiving the temperature change of object under test, stress and/or strain；Light source, to produce wide band linearly polarized light, institute Two orthogonal polarization modes transmission of the linearly polarized light along the optical birefringence medium is stated, the optical birefringence medium exports optics Output signal；The linear optics polarizer, to receive the optical output signal, and it is orthogonal by the two of the optical output signal Polarization mode is mutually mixed；Interferometer, to receive the light through the linear optics polarizer, and obtain two orthogonal polarization modes Between interference, to produce polarization interference peak；Processor, changed according to the spacing between polarization interference peak to obtain the optics The temperature change of birefringent medium, the stress of the optical birefringence medium is obtained according to the peak value at polarization interference peak and/or answered Become.

In one of the embodiments, it also includes：Optical delay, to receive the optical birefringence medium output Optical output signal, make to produce delay between two orthogonal polarization modes, and be transferred to the linear optics polarizer.

In one of the embodiments, the sensing device also includes sensing baseplate, described to be connected with object under test Optical birefringence medium is in a manner of linear array or face array way is arranged on the sensing baseplate.

In one of the embodiments, raised or groove, and the raised or groove are provided with the sensing baseplate Contacted with the optical birefringence medium so that the optical birefringence medium has default polarization interference.

In one of the embodiments, multiple through holes are offered on the sensing baseplate, the optical birefringence medium is worn The through hole is crossed, the optical birefringence dielectric distribution is in the both sides of the sensing baseplate so that the optical birefringence medium With default polarization interference.

In one of the embodiments, multiple through holes pair, the optical birefringence medium are offered on the sensing baseplate Through the through hole pair, the optical birefringence dielectric distribution is in the side of the sensing baseplate so that the optical birefringence Medium has default polarization interference.

In one of the embodiments, Z-shaped passage is offered on the sensing baseplate, the optical birefringence medium is set Put in the Z-shaped passage so that the optical birefringence medium has default polarization interference.

In one of the embodiments, the polarization axis direction of the optical birefringence medium and the normal direction of sensing baseplate It is at 45 °.

The above method and device can be same using the peak value and spacing at caused polarization interference peak in optical birefringence medium When obtain stress, strain and temperature, same optical birefringence medium can be utilized to carry out stress come measuring targets, strain and The monitoring of temperature change.

Brief description of the drawings

Fig. 1 is the structural representation of sensing device；

Fig. 2A is the structural representation of polarization interference analyzer, and Fig. 2 B are optical linear light polarizer relative to polarization maintaining optical fibre The orientation of optical axis, the situation shown in Fig. 2 C are that stress is to be present in multiple positions along polarization maintaining optical fibre to produce the polarization-maintaining light Crosstalk between two fine orthogonal polarization modes；

Fig. 3 is shown installs optical delay device additional tested between optical fiber and optical interdferometer, two-fold to measure optics The exemplary means of the polarization interference of medium (such as polarization maintaining optical fibre) are penetrated, and further illustrate the operation of the device；

Fig. 4 illustrates optical birefringence medium polarization interference analyzer of the measurement based on the application of birefringence dispersion compensation function Structural representation；

Fig. 5 shows an example of the polarization interference curve of polarization-maintaining fiber coil.The output of fiber optic loop is shown in both ends With the crosstalk envelope amplitude and width of input interface, and (solid line) and afterwards is shown before the intermediate region of fiber optic loop The birefringence dispersion compensation of (dotted line)；

The width of Fig. 6 A demonstration measurement envelopes, the width is the multiple diverse location strings of polarization maintaining optical fibre sample in Fig. 4 systems Peak is disturbed by stress induced, Fig. 6 B give the measurement of the input connector of the different polarization maintaining optical fibre length of exemplary six kinds Value D crosstalks.

Fig. 7 A and 7B illustrate to be put on the polarization maintaining optical fibre of every 0.5 meter of length in 1 maintenance polarisation fiber sensor upper stress When crosstalk curve；

Fig. 8 A illustrate the birefringence measurement curve of temperature funtion, and Fig. 8 B are that polarization interference curve shows phase in polarization maintaining optical fibre Delay function is closed, Fig. 8 C further illustrate the extended view of the 48th and 49 positions；

Fig. 9 A are the schematic diagram of the sensing baseplate of one in one embodiment, and Fig. 9 B are the corresponding inclined of Fig. 9 A embodiments Shake the functional arrangement at crosstalk peak, and Fig. 9 C are the schematic diagram of the one-dimensional sensing baseplate in another embodiment, and Fig. 9 D are Fig. 9 C implementations The functional arrangement at the corresponding polarization interference peak of example；

Figure 10 A are the schematic diagram of the two-dimentional sensing baseplate in one embodiment, and Figure 10 B are corresponding polarization interference peak Functional arrangement, Figure 10 C are corresponding stress, the position view of temperature change；

Figure 11 A are the overlooking the structure diagram of the one-dimensional sensing baseplate in another embodiment, and Figure 11 B show for side view structure It is intended to；

Figure 12 A are the overlooking the structure diagram of the one-dimensional sensing baseplate in another embodiment, and Figure 12 B show for side view structure It is intended to；

Figure 13 is the functional arrangement at the corresponding polarization interference peak of structure in Figure 11 and Figure 12；

Figure 14 A are the structural representation of the two-dimentional sensing baseplate in another embodiment, and Figure 14 B are corresponding polarization interference peak Functional arrangement, Figure 14 C be corresponding stress, the position view of temperature change；

Figure 15 is the structural representation of a sensing baseplate of the Z-shaped polarization maintaining optical fibre with one-dimensional distribution；

Figure 16 is the structural representation of an embodiment of the sensing baseplate of the Z-shaped polarization maintaining optical fibre with Two dimensional Distribution；

Figure 17 is the structural representation of another embodiment of the sensing baseplate of the Z-shaped polarization maintaining optical fibre with two dimension respectively；

Figure 18 is the FB(flow block) of the method for measurement stress, strain and temperature.

Embodiment

A kind of sensing device is there is disclosed herein, the device can be to the stress of (or difference) measurement object under test simultaneously (or strain) and temperature.Referring now to Fig. 1, sensing device 10 includes sensing baseplate 11, optical birefringence medium 12, polarization string Disturb analyzer 13 and processor 14.Sensing baseplate 11 can be made by flexible or flexible material, and it can be with treating Object connection is surveyed, to measure the stress of object under test (or strain), temperature.Sensing can be arranged in optical birefringence medium 12 On substrate 11, in the present embodiment, optical birefringence medium 12 can be polarization maintaining optical fibre, and it can also be other forms certainly Optical birefringence medium, such as the birefringece crystal such as Yttrium Orthovanadate, quartz crystal, with prestressed glass, etc..Polarization-maintaining light While fibre is arranged on sensing baseplate 11, sensing baseplate 11 can also be made to be applied with default polarization interference to polarization maintaining optical fibre, These polarization interferences can apply the modes such as stress or the bending of certain rule come in advance by sensing baseplate 11 to polarization maintaining optical fibre Set.In the present embodiment, polarization interference analyzer 13 can include light source, optical delay, the linear optics polarizer, dry Interferometer.Light source is to produce wide band linearly polarized light, two cross-polarizations of the linearly polarized light along optical birefringence medium 12 Mould transmits, and optical birefringence medium 12 exports optical output signal.The output signal is received by optical delay, the optics Delayer makes to produce delay between two orthogonal polarization modes, and is transferred to the linear optics polarizer.The linear optics polarizer is by light Two orthogonal polarization modes for learning output signal are mutually mixed.Interferometer receives the light through the linear optics polarizer, and obtains Interference between two orthogonal polarization modes, to produce polarization interference peak.And processor 14, according to the spacing between polarization interference peak Change obtains answering for optical birefringence medium to obtain the temperature change of optical birefringence medium, according to the peak value at polarization interference peak Force value, so as to the temperature of (or difference) monitoring object under test simultaneously and stress (or strain) value.Also schematically show in Fig. 1 Two weights 20 are gone out on sensing baseplate 11 to be provided with, it is big that the two weights 20 can simulate the stress being applied on object under test It is small.Certainly, the sensing device 10 can not include sensing baseplate 11, and optical birefringence medium can be arranged directly on object under test On.

Illustrate the specific metering system of polarization interference below.In polarization maintaining optical fibre, when incidence light strictly with guarantor , can be due to polarization maintaining optical fibre latent defect or outer between two polarization modes of polarization maintaining optical fibre when the fine fast axle of polarisation or slow axis are aligned Produced in pressure optical coupled.The Mode Coupling of polarization maintaining optical fibre slow axis and fast between centers is referred to as polarization interference.One kind description polarization string The method disturbed is the beam intensity ratio of two polarization modes transmitted respectively in slow axis and fast axle.In a particular application, it is thus necessary to determine that The degree of the position of the generation of polarization interference and polarization interference in polarization maintaining optical fibre.

The interference of the light wave transmitted along polarization maintaining optical fibre slow axis and fast axle can produce one in the position that polarization maintaining optical fibre couples Individual real interference signal and a ghost peak interference signal, this ghost peak interference signal are by the multiple coupling of the light wave between multiple crosstalk points Caused by conjunction.When multiple strong crosstalk points in polarization maintaining optical fibre be present, ghost peak signal can be very strong, so as to cause to crosstalk position and strong The false judgment of degree.

Referring now to Fig. 2A -2C.In fig. 2, the broadband light 101 sent from wideband light source is input in position A110 In polarization maintaining optical fibre.Light 101 has a polarized component being aligned with the slow axis of polarization maintaining optical fibre.Pressure at the B of position causes edge Polarization coupled is produced between two orthogonal polarisation states of polarization maintaining optical fibre fast axle and slow axis, produces a polarized component being aligned with fast axle. Because two polarized components are transmitted in a fiber at different rates, therefore in the output end 111 (position C) of optical fiber, two partially The component that shakes can undergo different delays：

Δ z=n_sz-n_fZ=Δs nz (1)

Wherein n_sAnd n_fIt is the refractive index along slow axis and fast axle respectively, two specific refractivity △ n are birefringences, and z is coupling Distance between chalaza B to output point C.Polarization axle and guarantor if placed at the optical polariser 120 after fiber-optic output 111 The fine slow axis of polarisation is (such as Fig. 2 B) at 45 °, and the luminous power of the respective half of two polarized components by polarizer and has identical line Polarization state, its direction are identical with the polarization axle of optical polariser 120.

Therefore, when being received with interferometer from the light that optical polariser 120 exports, the effect of optical polariser 120 is exactly Make reception light that optical interference occur, wherein receiving the polarized component that light is separately contained in two polarization modes, this optics is done Relate to and can be used for polarization interference measurement.

Here, one Michelson's interferometer of the example as interferometer.Beam splitter 130 is used for receiving from optics The light that inclined device 120 exports, and reception light is divided into the light beam that stationary mirror 140 is transferred to along the first light path 142, and The second beam light of a movable mirror 141 is transferred to along the second light path 143.With a driver control movable mirror 141 position adjusts optical path difference of second light path 143 relative to the first light path 142.Two speculums 140,144 are by two-beam Respectively along first path and the second path reverse transfer to beam splitter 130.The light beam returned from two speculums 140 and 141 exists Space mutually occurs at beam splitter 130 to overlap, produces optical interference output light 132, it includes the interference with periodic disturbances peak Signal, this signal are moved generation by the position of speculum 141.The caused two adjacent interference due to mobile mirror 141 Peak-to-peak distance is △ nz, and therefore, from equation (1), the position of the Coupling point in polarization maintaining optical fibre is：Z=△ z/ △ n.Cause This, can position interference point, while can calculate coupling ratio by interference peaks using interference pattern.

Fig. 2 C show that the situation of multiple Coupling points can be included in polarization maintaining optical fibre.In the case, measurement process will more It is complicated.Assuming that (n+1) individual Coupling point (x in polarization maintaining optical fibre be present₀x₁x₂··x_n), along the ripple bag of the linear polarization of slow axis input 112 divide for the wavelet packets of 2n along slow axis transmission and the 2n wavelet packets transmitted along fast axle in the output end 113 of polarization maintaining optical fibre. Therefore, in i-th of Coupling point, two ripple packet sequence P_siAnd P_fiPolarize along slow axis and fast axle, included in it transmits light path respectively 2i ripple bag, their light path can be expressed as：

Wherein P_si, j and P_fi, j is illustrated respectively in sequence P_siAnd P_fiJ-th of ripple bag.Ripple after (i+1) individual Coupling point The light path of packet sequence can be calculated by following formula:

Based on formula (3), can be obtained in the light path of the ripple bag of polarization maintaining optical fibre output end by following formula:

Ripple packet sequence P_snAnd P_fnRespective intensities I_snAnd I_fnIt can be calculated by following formula,

Wherein c_nIt is in Coupling point x_nThe coefficient of coup, and the parameter defined available for crosstalk：Crosstalk=abs (10*logC_n)。

After by 45 ° of optical polarisers 120, the original two ripple packet sequences transmitted along polarization fiber slow axis and fast axle Psn and Psn, a ripple packet sequence will be mutually mixed into and polarized along the transmission direction of optical polariser 120.Along optical polariser The light path P of the ripple packet sequence of 120 polarization directions transmission and corresponding light intensity can be calculated by following formula:

When the second light path speculum 141 moves and changes its position, any two in ripple packet sequence P (referring to formula 7) Pulse can produce an interference signal, while the position of interference fringe is determined by the delay difference between two pulses.N Coupling point The individual peak of a total of 2n (2N-1), wherein there is n peak to show actual Coupling point, remaining is ghost peak.These ghost peaks not only produce Raw false coupled signal, but also the part being likely to form in the true interference peaks as caused by true Coupling point, therefore these Ghost peak will reduce the accuracy of measurement crosstalk distribution and amplitude.

It can be seen that from formula (7) and (8), ripple packet sequence includes two groups, and one group of top half by formula (7) is expressed as P_sn-1, Along slow axis in polarization maintaining optical fibre；Another group is expressed as P for the latter half of formula (7)_fn-1, along fast axle in polarization maintaining optical fibre. P_sn-1The position of the interference pattern of any two pulses and the length (x of polarization maintaining optical fibre final section in group_n-x_n-1) unrelated, they prolong It is poor late to be respectively less than (x_n-1-x₀)△n.The interference pattern position of any two pulses in Pfn-1 groups also with polarization maintaining optical fibre final section Length (x_n-x_n-1) unrelated, their delay difference is respectively less than (x_n-1-x₀)△n.For the first half in ripple bag P and lower half it Between interference, respectively from P_sn-1And P_fn-1Group in any ripple its delay difference be (x_n-1-x₀)△n+(P_sn-1,_j-Pfn-1,_k).If The length x of final section polarization maintaining optical fibre_n-x_n-1Than polarization maintaining optical fibre from 0 to n-1 section resulting lengths it is long in the case of, in this position Interference peaks will be divided into two groups, one group is by P_sn-1Or P_fn-1In interference caused by any two ripple parlors formed；Another group is Respectively by P_sn-1A ripple bag and P for sequence_fn-1One ripple of sequence, which is responsible for a task until it is completed to relate to, to be formed.One section of guarantor with High Extinction Ratio (ER) Inclined fiber link generally indicates that coefficient of coup c1, c2 ... ..ci very littles of polarization maintaining optical fibre, so having relatively in the pulse P1 of formula (7) High power.If produced by the coupling more than secondary, while ignore interference terms more than 3 ranks, at this moment in second group of interference group In only n interference signal, the first light path 142 of the reference arm in corresponding interferometer (Fig. 2A) and interferometer change arm The delay difference of second light path is：

Polarization maintaining optical fibre is wherein accurately corresponded to from 0 to n-1 Coupling point.

To reduce ghost peak, an optical delay can be inserted between polarization maintaining optical fibre and optical polariser 220 there can be choosing Select to introducing an Additional optical delay in one of them in two polarization modes of polarization maintaining optical fibre transmission light.Fig. 3 show one The individual device for being typically used for measuring the polarization interference in optical polarization medium (such as polarization maintaining optical fibre), the device is in polarization-maintaining to be measured An optical delay device is added between optical fiber and interferometer, is specifically described the course of work of the device below.Passing through guarantor to be measured After polarisation fibre 202, incident light 201 is divided into two beam quadrature wave packet sequences, and is polarized respectively along slow axis and fast axle.Delayer 210 exists A delay L is added between two quadrature wave packet sequences, wherein aerial delay L should will grow than △ n × l, wherein △ n are double Refractive index, l are polarization maintaining optical fibre length.In this example, additional delay L is loaded on the light that polarization maintaining optical fibre is polarized along slow-axis direction. After by 45 ° of optical polarisers 220, the two are mixed by additional delay L ripple packet sequence, and have identical Polarization state, this polarization state are determined by optical polariser 220.Interferometer 230 after optical polariser 220 is used for producing a system Interference signal of the row delay between △ n × 1 and (L- △ n × 1).These interference signals are only with polarizing coupling caused by coupling position Real signal caused by conjunction is corresponding, and ghost peak is suppressed or eliminated.The output signal that processor 240 is used to receive interferometer 230 passes through The signal for handling output measures the position of polarization maintaining optical fibre Coupling point and intensity.

Consider the situation in which three Coupling point x be present along polarization maintaining optical fibre₁、x₂、x₃, and the light for inputting polarization maintaining optical fibre is inclined Shake slow axis of the direction along polarization maintaining optical fibre, without fast axis component.In each Coupling point, light not only from the polarization mode coupling of slow axis to In the polarization mode of fast axle, also in the polarization mode from the polarization mode coupling of fast axle to slow axis.It is so coupling as a result, protect The ripple packet sequence of inclined optical fiber output contains the ripple bag of more secondary couplings.

After 45 ° of polarizers, will mutually be mixed along the ripple bag of slow axis and quick shaft direction.If the mixed light is input to In interferometer, when the delay of an arm of interferometer changes, a series of interference peaks can be obtained.Caused interference peaks represent true Real Coupling point and ghost peak, ghost peak is different from true Coupling point, and produces mistake when identifying true Coupling point.Ghost peak may also can It is added in true peak, reduces crosstalk measurement accuracy.

The present invention, can be in the output end of polarization maintaining optical fibre and the input of polarizer to suppress unwanted ghost peak quantity and amplitude One optical delay 210 of end insertion, is shown in Fig. 3.The deferred mount has polarization selectivity, and can be added between fast axle and slow axis Additional delay.Therefore, separated in time in the ripple packet sequence of the fast axle after analyzer and slow axis.If to the dynamic of interferometer Identical postpones between arm and fixed arm, then, when delayer is scanned, zeroth order, second order and higher order time will not be produced Interference signal；Therefore, most of ghost peak can disappear in the measurements.So as to, device shown in Fig. 3 than shown in Fig. 2 based on other The device of interferometer method has the sensitivity of higher measurement accuracy, bigger dynamic range and Geng Gao.

Polarizationselective light optical delay 210 in Fig. 3 can form structure by a variety of, and according to different application needs Select the device in Fig. 3.The light transmitted along two polarization modes of polarization maintaining optical fibre is divided into along two by using polarization beam apparatus Two independent optical signals of independent optical paths transmission, tunable optical delay device can to the two independent optical signals close beam it It is preceding to add adjustable optical delay, two independent optical signals are synthesized by a light by the linear light polarizer after interferometer Signal is further to handle.These devices can be configured to fixed optical delay device, and it produces preferable optical delay △L(>N × 1) or variable delay, it is controllable under above-mentioned preferable light delay △ L.Using appropriate delay, Fig. 3 is seen, ghost peak can It is suppressed.

The spatial discrimination polarization interference measurement of polarization-maintaining (PM) optical fiber has a variety of applications, such as distributed stress sensing, optical fiber top Solenoid detects, polarization maintaining optical fibre birefringence and beat length measurement, the identification of polarization interference position, and polarization maintaining optical fibre quality examination.Sweep Retouch Michelson white light interferometer and can be used for distributed polarization interference as measurement.But with testing fiber (FUT) length Increase, measured crosstalk peak will be widened due to birefringence dispersion, cause for the polarization maintaining optical fibre more than certain length such as hundreds of Rice, its spatial resolution and measurement accuracy can reduce.

Technology provided herein can be used for the resolution ratio and measurement accuracy for improving distributed polarization interference measurement.In some realities In existing mode, widening for polarization interference peak can be by simply by measurement data and penalty function as caused by birefringence dispersion It is multiplied to recover.Birefringence dispersion variable can obtain by the width for the crosstalk envelope for finding known distance.The technology can have Effect improves the spatial resolution and amplitude accuracy of long polarization maintaining optical fibre spatial discrimination polarization interference measurement.

Following part provides the detail of mathematical compensation birefringence dispersion, and this operation can improve to be polarized in measurement The spatial resolution and measurement accuracy of crosstalk.Birefringence dispersion can be compensated mathematically the influence that polarization interference measures. A kind of white light interferometer based on distributed polarization interference analyzer of described in the text.The device is used to measure along polarization maintaining optical fibre Initial space differentiates polarization interference peak, and the spectral width at crosstalk peak is as position function so as to obtaining birefringence dispersion △ D.This Outside, penalty function can remove the dispersion as caused by crosstalk peak stretching with being multiplied for original measurement cross-talk data.This experiment is using length Carried out for 1.05km polarization-maintaining fiber coil, should be it is demonstrated experimentally that this method can effectively improve spatial resolution and crosstalk measurement essence Degree, and analysis software can be readily incorporated into.Described technology can be used for a variety of applications, as obtain it is long more than hundreds of meters The accurate polarization interference value of polarization-maintaining plain coil, it can also be used to external trigger crosstalk and such crosstalk measurement.

Fig. 4 shows a device for being used to measure polarization-maintaining fiber coil.The device can be integrated into distributed polarization interference analysis Instrument.The master that the light 101 that polarized broadband light sources 301 are sent is coupled to optical birefringence medium (such as polarization maintaining optical fibre) 110 is inclined Shake on axle.Such 301 practicable various configurations of polarized light source, such as the combination of wideband light source and the polarizer.In the example in fig. 4, Polarized broadband light sources 301 employ the polarization superluminescent diode light source (SLED) of a short-phase dry length.Light 101 is in A points Slow-axis direction is directed into, it is that input optical fibre connector is used to connect polarization-maintaining fiber coil 110.Polarization-maintaining fiber coil 110 is exporting Being terminated at connector C, the polarizer 120 forms an angle with two main polarization axles, and such as 45.Reference picture 2B, the polarizer 120 receive polarization-maintaining The part output light of fiber optic loop 110 simultaneously mixes two cross-polarization.

Polarization-maintaining fiber coil is a kind of birefringent medium, and it is provided along two kinds of orthogonal polarization modes of polarization maintaining optical fibre fast axle and slow axis Formula.In input point A, the input polarization of light 101 is aligned with one of the polarization axle of polarization maintaining optical fibre (such as slow axis).Leave fiber birefringence The optical output signal of medium 110 is directed to interferometer 230, obtains the optical interference between two orthogonal polarization modes.Interferometer 230 produce an interference signal 312.Signal 312 is converted into the detector with optical interference information by photodetector 150 to be believed Number.Detector signal is transformed into data by data acquisition device or data collecting card (DAQ) 330；(such as microprocessor of processor 340 Device or computer) it is used to receive above-mentioned data and handle to obtain interference of light information, so as to obtain being polarized between two orthogonal polarization modes The envelope spectral function of crosstalk.It is worth noting that, a kind of compensation function of the processor 340 application programs, can reduce by birefringence The video stretching of envelope spectral function caused by Light in Medium birefringence dispersion, this compensation function are based on the optical birefringence Medium 110 arrives the measured value of envelope spectral function.

As shown in figure 4, interferometer 230 is the interferometer based on optical fiber, including a fiber coupler 310, it has four Fiber port：Port 1 receives the light from polarizer 120 as interferometer input port；Port 2 is interferometer output port, defeated Go out signal 312；Port 3 is used for the first light path for being connected to interferometer 230；Port 4 is used for the second light for being connected to interferometer 230 Road.Light beam from the polarizer 120 is divided into two beams by fiber coupler 310, and the first beam is to the paths of port 3 and first, and Two beam light are to the paths of port 4 and second.First light path includes an optical fiber, and it is at first faraday's speculum 321 Terminate；Faraday's speculum 321 has the function that the polarization of light beam is rotated to 45 °, so can be produced on the polarization of its reflected light One 90 ° of rotation.Similarly, the second light path includes an optical fiber, and it is terminated at second faraday's speculum 322, instead Penetrate the rotation that light polarization produces 90 °.Then, the reflected beams of the first light path and the second light path mix at fiber coupler 310, Because the optical path difference between the two result in interference.This is a Michelson's interferometer.Variable delay device 323 is used to control two Relative delay between path.In figure 3, variable delay element 323 is placed in the first light path regulation and control relative delay, and response comes from The delayed control signal 342 of processor 340, processor can further operate as control device.In operation, variable delay member Part 323 is scanned, to operate the interferometer 230 as scanning Michelson's interferometer.

Example in Fig. 4, in the B points of polarization-maintaining fiber coil, polarization interference is caused by external interference factor, and some light are from polarization-maintaining Initial polarization of the fiber optic loop 110 along slow axis is coupled to along fast axle, and it is coupled with coefficient of coup h=I1/I2, and h represents two polarizations Between intensity ratio or power ratio, wherein I1 and I2 be the power of fast axle and slow axis respectively.In Fig. 4 example, in fiber optic loop 110 B points, external disturbance cause a polarization interference, and some were coupled to soon along the polarised light of slow axis with coefficient of coup h=I1/I2 originally Axle, I1 and I2 are the power of fast axle and slow axis respectively.Because faster than being propagated along slow axis along the light polarization of fast axle, in fiber optic loop 110 output point C, fast light component △ nZ more advanced than slower rays component, wherein △ n are group's birefringences of polarization-maintaining fiber coil 110, and Z is Length between crosstalk point B and fibre end C.Optical polariser 120 is placed on fiber-optic output and slow axis angle at 45 °, is stepped in scanning Interference is produced on Ke Erxun interferometers 230 on the component of two identical polarization directions.Relative optical path is scanned, when polarizer space An Interference Peaks occur during coincidence, when it separates the coherence length Interference Peaks disappearance more than a light source 301.Position B is string Generation point is disturbed, can be calculated by formula Z=△ Z/ △ N, crosstalk amplitude h can be obtained by interference signal amplitude.Fig. 4 is shown in A, B, C tri- A series of signal of individual position, illustrate the polarized component along slow axis and fast axle.

The envelope at crosstalk peak (interference peaks) is by the spatial distribution of light source 301 and the birefringence dispersion of polarization maintaining optical fibre 110 △ D influence.If SLED301 has a Gauss spectral pattern, crosstalk envelope (degree of coherence) γ birefringence dispersions function △ D and crosstalk point Distance Z is derived：

Wherein,

δ d=(Δ nZ-d) (11)

π c (Δ λ/the λ of ρ=2₀)²Δ DZ=α Δs DZ (12)

Δ D=d τ/d λ=- [ω²/2πc](d²Δβ/dω²)₀ (13)

Aforesaid equation, d are the path imbalances for scanning Michelson's interferometer, and ρ is along the accumulative two-fold of polarization maintaining optical fibre Penetrate dispersion, c is vacuum light speed, △ λ and λ₀It is spectrum width and light source center wavelength respectively, △ β are that the propagation of two polarization eigen modes is normal Number is poor, and w0 is to interfere the 1/e of envelope wide when dispersion ρ is 0.The width is also the coherence length of light source.According to formula (11), parameter δ d It can be adjusted by changing the path length difference d of delay line in interferometer.Optical path difference between path imbalance d compensates two polarization modes △ nZ, it may appear that interference signal.As the unbalance d compensation optical path difference △ nZ of light path, there is interference signal.Formula (11) and formula (13) table Bright, the magnitude and waveform of the crosstalk envelope of measurement are △ D and Z functions.Degraded effects of the birefringence dispersion △ D in crosstalk measurement Fruit is crosstalk envelope amplitude and the linear reduction widened.

It is readily apparent that the influence of birefringence dispersion can be by direct by crosstalk measured value and dispersion compensation function K (ρ) It is multiplied and removes：

Therefore, formula (14) is multiplied with formula (10), original crosstalk envelope can be completely reduced：

To obtain penalty function, need to obtain birefringence dispersion △ D or ρ first.Formula (10) fit envelope line broadening and Relation between birefringence dispersion：

W/W_o=(1+ ρ²)^1/2=(1+ (α Δ D)²Z²)^1/2 (16)

Therefore, by measuring crosstalk envelope in optic fibre input end (Z=L) and output end (Z=0) width, can hold very much Change places and calculate birefringence dispersion △ D.In practical application, to improve △ D precision, string of the polarization maintaining optical fibre in multiple positions need to be measured The width of envelope is disturbed, △ D are obtained by curve matching formula (16).

Fig. 5 is a polarization interference curve by the obtained polarization maintaining optical fibre coils of Fig. 4, and it reflects birefringence dispersion to surveying The influence at crosstalk peak is measured, and how to compensate and removes these influences.Correspond at most left and most right peak by exporting and the company of input Connect crosstalk caused by device A and C.Small peak between the two is the crosstalk caused by stress during Optical Fiber Winding.The reality of right side insertion Line shows that birefringence dispersion produces two adverse effects：(1) the crosstalk acrometron at crosstalk connector A occurs for envelope line broadening (2) The reduction of degree.Dotted line shows that the envelope of crosstalk and amplitude are repaired after dispersion compensation.Especially, dispersion compensating, it is defeated The spectral peak width entered at connector is 34.1um, left side peak width caused by its out connector C with zero dispersion (Z=0) 32.4um is very close.

Fig. 6 shows function of the spectrum width of measurement as distance Z, and various realities have been carried out by using the system shown in Fig. 4 Test.The measurement of multiple polarization interference points has been carried out along testing fiber diverse location.Measured value clearly illustrates, by birefringence dispersion Influence, the quadratic power of spectrum width is directly proportional to distance Z.The characteristic is consistent with formula (16).Under such testing condition, due to two-fold The spatial resolution for the polarization interference measurement that the spectral line broadening for penetrating dispersion causes distance more than 200 meters reduces.

The birefringence dispersion △ D that polarization maintaining optical fibre can be accurately obtained to the data least square fitting of formula (16) are 0.0014ps/(km nm).Bring match value △ D into formulas (14), complete dispersion compensation function.Dispersion compensation function and original Measure cross-talk data to be multiplied, can reach improved cross-talk data, eliminate dependence of the polarization interference to birefringence dispersion △ D.

Fig. 6 A show the envelope line width at crosstalk peak caused by along the pressure of polarization maintaining optical fibre different location.Square in Fig. 6 A The spectrum width after dispersion compensating is represented, round dot represents the spectrum width of non-dispersion compensating.Fig. 6 B are input connector and six differences The crosstalk measured value of length polarization maintaining optical fibre (5m, 205m, 405m, 605m, 805m, 1005m).The crosstalk of input connector is fixed , 5 sections 200 meters of optical fiber is sequentially spliced to the tail end of input connector to increase dispersion.Polarization interference amplitude is due to double Birefringence dispersion reduces with fiber lengths, and is repaired after compensating.

So dispersion compensation technology can effectively slow down the reduction of crosstalk amplitude and the spectral line broadening as caused by dispersion.Equally Ground, wideband light source (such as white light) is used in interferometer based on polarization interference analyzer, this compensation technique can effectively improve string Disturb the spatial resolution and measurement accuracy of amplitude.

For the sensor device device shown in Fig. 4, polarization superluminescent diode (SLED) has short-phase dry length (such as About 25 μm) and it is coupled to polarization maintaining optical fibre to be measured (FUT) (point A) slow axis.Fig. 4 illustrates, in another location point B, polarization interference By disturbing induction outside, it can make some initially slow axis polarization light with coefficient of coup parameter h=I₁/I₂It is coupled to fast axle, I₁And I₂ Fast axle and the light intensity of slow axis are represented respectively.It is defeated in optical fiber because the light ratio polarized along fast axle is along the genuine light propagation of slow axis piece fast Go out end, faster light component △ Z=△ nZ, △ Z more advanced than slower rays component is optical path difference, and △ n are optical fiber group indexs, and Z is string Disturb the fiber lengths between generation point (B) and output point (C).Polarizer is placed on fiber-optic output.The polarizer at 45 ° with slow axis It is placed on optical fiber connector.The polarized component of slow axis and fast axle projects to the equidirectional of polarizer, so as in scanning Michelson The interference pattern of two components is produced on interferometer.Relative optical path is scanned, if two polarized components are spatially overlapping, is interfered Peak；When it separates more than one light source (such as SLED) coherence length, interference peaks disappear.Crosstalk point B position and output point C can Calculated by formula Z=△ Z/ △ n.If there is multiple polarization interference points beyond the B location shown in Fig. 4, it may appear that second order interference peak, This is due to that the light for being coupled to fast axle in crosstalk point can be coupled back into slow axis in follow-up crosstalk point.Such second order coupled can cause Crosstalk ghost peak, and cause white light interference chaotic.Fig. 4 sensor be one without ghost peak distributed polarization interference analyzer, filling Put the internal interference ghost peak removed using a differential group delay (time-delay mechanism) in second order coupled, enabling accurate identification and The a large amount of polarization interferences unambiguously of measurement.

Characteristic based on foregoing description, polarization maintaining optical fibre can be embedded in sensor substrate and make stress sensing element, strain field The polarization interference of polarization maintaining optical fibre can be caused.Crosstalk change can regard an indicator as, reacted and be applied to outside on polarization maintaining optical fibre The change of pressure/strain.Polarization interference is more sensitive to the transverse pressure being applied on polarization maintaining optical fibre, compares, to axial strain or Pressure is less sensitive.Therefore, Fig. 4 sensor can measure transverse strain.But in numerous applications band measurement generally with axial direction Strain/pressure is relevant, such as structure detection.The technology talked about below and device into transverse pressure, make axial strain/pressure transition As the device in Fig. 4 and other sensor devices based on sensor mechanism can detect and monitor axial strain/pressure distribution, so as to Measure axial mechanics parameter.For example, transverse pressure or axial strain can all be surveyed sensor strip/piece disclosed in this document Amount.

Fig. 7 A, 7B illustrate the polarization interference curve that 280 meters of polarization maintaining optical fibres of measurement are wound into and analyzed as polarization interference Instrument internal intervention instrument delay Δ Z function.As shown in Figure 8 A, most left and most right peak is observed, input is corresponded to respectively and output connects The crosstalk sensing of device is connect, slightly has axle dislocation between the polarization and polarization maintaining optical fibre axle of light.Fig. 8 B are shown by every 0.5 meter of polarization-maintaining Optical fiber applies stress so as to induce equidistant periodicity crosstalk peak.

To Fig. 7 A, the further research of 7B measurement sum, measurement result shows, in the difference that local stress or strain change Position crosstalk peak is induced (to the response of every 0.5 meter of the stress applied).The amplitude at each crosstalk peak represents stress wherein Produce stress or be applied to the amount of corresponding position.Therefore, the amplitude information can be used for measuring stress in polarization maintaining optical fibre or Strain, details is discussed in the previous section of this patent document.It is worth noting that, the spacing between two adjacent crosstalk peaks It is the different index of crosstalk peak indicator, and as explained below, available for measuring local temperature.As taken off in this document Show comprising the peak-to-peak information gap in of amplitude and polarization interference, be by using identical sensor and by using from The identical that sensor receives detects light to temperature and the basis of the dual measurement of stress/strain.

Crosstalk peak-to-peak amplitude and crosstalk are peak-to-peak every with a significant attribute, and the crosstalk curve in Fig. 7 A and 7B is two Orthogonal amount, they are independent of each other, and can individually be obtained.Therefore, the change of the local stress or strain causes The change of crosstalk peak amplitude, it is this change do not interfere with represent local temperature measurement crosstalk it is peak-to-peak every.On the contrary, protected on edge On the fine position of polarisation the change of local temperature crosstalk can be caused peak-to-peak away from change, this change do not influence to represent local to answer The crosstalk acrometron angle value at the crosstalk peak of power/strain level.

The method for the following describing the temperature survey at the interval between crosstalk peak value.In one section of polarization maintaining optical fibre, the group is double Refraction Δ n is the linear function of temperature, and can be expressed as：

Δ n=γ (T₀-T)

Therefore, local temperature change is reflected in the polarization interference of birefringent change as caused by temperature change.

Reference picture 8A, 8B and 8C, Fig. 8 A illustrate the birefringence measurement curve of temperature funtion.When Δ n becomes in local location During change, corresponding change will occur for the position at crosstalk peak or crosstalk peak value.Crosstalk caused by the change in location at the peak is peak-to-peak every it Between change, such as Fig. 8 B, in polarization maintaining optical fibre, polarization interference curve is shown prolongs at 80 DEG C (dotted lines) to 40 DEG C of the related of (solid line) Slow function.Fig. 8 C further illustrate the extended view of the 48th and 49 positions, and the at 80 DEG C (dotted lines) and 40 DEG C (solid line) the 50th Individual crosstalk peak.Therefore, changed by measuring local spacing and local temperature change can determine based on crosstalk it is peak-to-peak away from change. If local stress or strain can also change simultaneously, the crosstalk peak value size of correspondence position can also change.Therefore, survey The peak amplitude at amount peak intervals and detection crosstalk peak can measure to stress and temperature simultaneously.

The temperature survey skill at the interval between the crosstalk peak based on the detection light received using the interferometer in Fig. 4 Art, the change of localised spacer can be used for determining the change in the local temperature of position corresponding to peak corresponding to localised spacer.

Illustrate set-up mode of the polarization maintaining optical fibre on sensing baseplate below.In this polarization maintaining optical fibre in a manner of linear array Or face array way is arranged on the sensing baseplate, the sensing device being distributed in a manner of linear array is one-dimensional (1D) sensor strip Band, its measurable 1D stress and temperature along specific direction；The sensing device being distributed in a manner of the battle array of face is that a two dimension (2D) passes Sensor panel or sheet material, the stress and temperature on its measurable total surface.

Referring now to Fig. 9, the polarization maintaining optical fibre in Fig. 9 is distributed in sensing baseplate in a manner of linear array.Polarization maintaining optical fibre 110 is put On the groove for putting the strip opened up in sensing baseplate 11, the slow axes or fast axis of polarization maintaining optical fibre 11 and the surface normal of strip into 45 degree.The polarization axle orientation of polarization maintaining optical fibre 110 ensure that polarization maintaining optical fibre polarization interference is sensitive to applying stressed change.Generally, Slow axis and fast axle are set to most sensitive to pressure into 45 degree of angles with pressure direction.One kind side that polarization maintaining optical fibre needed for realization is orientated Method, Fig. 9 A are refer to, a groove extended along a length thereof is offered on sensing baseplate 11.Sensing baseplate 11 can by changeability or Elastomeric material is made, so as to which sensing baseplate 11 can deform with the target device engaged.For example sensing baseplate 11 can be modeling Material or the material with certain perfect elasticity, such as nylon and acetal resin material.With the appropriate of polarization axle (slow axis or fast axle) During polarization maintaining optical fibre is routed to band by direction, optional Appropriate method identifies slow axis, such as uses optical magnification device Polarization maintaining optical fibre 110 is checked, and the slower rays that polarization maintaining optical fibre is observed before groove is routed to polarization maintaining optical fibre 110 is orientated with correct optical fiber Axle and fast axis.Fig. 9 B show, in position Z1 and Z2, accordingly to polarize as caused by the pressure being applied to shown in Fig. 9 A on sensor Crosstalk peak.As shown in Figure 9 C, polarization maintaining optical fibre 110 is arranged on sensing baseplate 11, and sensing baseplate 11 is provided with the logical of a strip Groove, polarization maintaining optical fibre 110 are placed on the groove.The slow axes or fast axis of polarization maintaining optical fibre 110 and the normal of sensing baseplate 11 into 45 degree.The polarization axle orientation of polarization maintaining optical fibre 110 ensure that polarization maintaining optical fibre polarization interference is sensitive to applying stressed change.Generally, Slow axis and fast axle are set to most sensitive to pressure into 45 degree of angles with pressure direction.Sensing baseplate 11 can be by changeability or elastic material Material is made, so as to which sensing baseplate 11 can deform with the target device engaged.For example sensing baseplate 11 can be plastics or tool There is the material of certain perfect elasticity, such as nylon and acetal resin material.Be tod with the appropriate direction of polarization axle (slow axis or fast axle) During polarization maintaining optical fibre is routed to band, optional Appropriate method identifies slow axis, is such as protected using optical magnification device inspection Polarisation 110 is fine, and is routed to slow axes and fast axis that polarization maintaining optical fibre is observed before groove optical fiber is orientated with correct optical fiber.This Kind, to ensure the fast and slow axis of polarization maintaining optical fibre and pressure direction method at 45 °, can also be used by setting groove on substrate In Fig. 9 one-dimension optical-fiber laying scheme.Here, transversely groove periodically sets raised or groove on sensing baseplate 11 301, these raised or grooves 301 is apply the fixed position of stress or strain to cause the expected crosstalk in relevant position Peak.The local temperature caused by fire or other thermals source changes, and the localised spacer that crosstalk peak value can vary with temperature produces change Change.Fig. 9 D are shown in position Z₁And Z₂, the corresponding polarization interference peak as caused by the pressure being applied to shown in Fig. 9 C on sensor.Figure 9D is also indicated that, when specific local due to heat at one simultaneously except showing the corresponding polarization interference peak value caused by pressure Source or other influences local temperature are changed, and the interval between corresponding crosstalk peak value can also change.Protected in a place The change of polarisation fibre upper stress can only cause the change along vertical axis crosstalk peak value, not interfere with the local crosstalk peak of temperature survey The change of spacing.

Polarization maintaining optical fibre in Figure 10 is distributed on sensing baseplate in a manner of the battle array of face.Two dimensional Distribution is provided with sensing baseplate 11 Groove, polarization maintaining optical fibre 110 is arranged in the groove.Multiple raised or grooves 301 are equally set on the sensing baseplate 11, whenever When optical fiber is through raised or groove 301, the polarization interference peak of predetermined quantity is produced.As shown in Figure 10 B, what these were pre-loaded into is inclined Crosstalk peak shake as tick lables, wherein polarization interference is position Z function.By external pressure or stress induced polarization interference Figure 10 B are shown at peak, are also presented on Figure 10 C XY figures.As shown in FIG. 10A, in Z₁、Z₂And Z₃Position on have external stress work Used time, corresponding polarization interference peak is shown in fig. 1 ob.Position occurs in corresponding temperature change, corresponding crosstalk peak Spacing is also changed.

Polarization maintaining optical fibre in Figure 11 is distributed on sensing baseplate in a manner of linear array.Figure 11 A, Figure 11 B are refer to, Figure 11 A are The top view of the sensing baseplate 11, Figure 11 B are the side views of the sensing baseplate 11.Multiple through holes are offered on sensing baseplate 11 302, polarization maintaining optical fibre 110 produces default polarization interference peak through these through holes 302, and polarization maintaining optical fibre 110 is successively set on sensing base The both sides of plate 11, i.e. polarization maintaining optical fibre 110 reach the second side from the first side of sensing baseplate 11 through first through hole 302, then The first side is returned to by another through hole 302 through a segment distance (being 10cm in some applications).Optical fiber passes through each logical Hole 302, the polarization interference of predetermined quantity can be produced in the position of through hole 302, fibre-optical bending now occurs.In present embodiment In, fiber guiding groove can be added in the both sides of sensor base plate 11 to hide polarization maintaining optical fibre, while polarization maintaining optical fibre can be ensured Fast and slow axis and pressure direction can use the polarization maintaining optical fibre in adhesive or adhesive tape covering groove into 45 degree or so.In this structure, protect One important feature of the fine this Sensor Design of polarisation is local axial strain spirit of the sensor to being applied on sensor strip It is quick, as seen in figs. 11a and 11b, because axial strain can be transformed into lateral stress to produce polarization interference by sensor.Equally , it is applied to when being compressed axially tension force on the band of part, the polarization interference of reduction can occur in the position of fibre-optical bending.At this In embodiment, the interval between through hole 302 is equidistant；These certain spacing can be set according to actual conditions.

Referring now to Figure 12, in the present embodiment, through hole occurs in the form of through hole is to 303, and these through holes 303 are opened It is located on sensing baseplate 11.Figure 12 A and Figure 12 B schematically represent the top view and side view of sensing baseplate.Polarization maintaining optical fibre 110 Crosstalk is initialized through each pair of two holes up and down, as shown in Figure 12 B.Through hole is smaller to the spacing of 303 through hole, and through hole To 303 pairs with to the distance between just it is much bigger, so as to polarization maintaining optical fibre major part it is small in the side of sensing baseplate 11, only one Part polarization maintaining optical fibre is in opposite side.The bending of polarization maintaining optical fibre 110 occurs in polarization maintaining optical fibre 110 through through hole to 303 opening position, light Fibre bending can produce internal polarization interference.Different intervals may be selected in different applications.Can be on the surface of sensor base plate 11 Adhere to one layer tape or adhesive, to cover polarization maintaining optical fibre and protected from potential damage.

It has similar structure for sensing baseplate shown in Figure 11 and Figure 12, and both have similar Z functions.It refer to figure 13 (relative to Figure 12, Figure 13 crosstalk peak will be non-equidistant), when both of which is in Z₁And Z₂, should during with stress There is larger polarization interference peak value in figure, and during local heating, the direct spacing in polarization interference peak also changes.

Polarization maintaining optical fibre 110 in fig. 14 is distributed in a manner of the battle array of face on sensing baseplate 11, and on the way of polarization maintaining optical fibre 110 Through hole 302 is offered on pathway.Shown in Figure 14 A, the through hole for producing predetermined polarisation crosstalk mark is opened up on sensing baseplate 11 302, these indicate transverse pressure or horizontal strain on measurable sensing baseplate 11.Figure 14 A structure application via design is (real Line represents optical fiber in the upper surface of substrate, and dotted line represents that optical fiber is arranged in the lower surface of substrate through through hole), so as to polarization maintaining optical fibre Cause predetermined crosstalk peak through aperture, and by partial lateral transformation for strain into axial stress.In Figure 14 A, X (Z₁Place) and Y (Z₂Place) direction strain can cause apply local train position generation polarization interference.Such as Figure 14 A, in Z=Z₃Place, stress Also crosstalk can be caused.Figure 14 B and 14C are pressure measurement methods.Data can be presented with graphics, wherein X and Y represent pressure/ The position of strain, vertical pivot represent crosstalk/pressure value.And when the spacing at crosstalk peak may determine that local whether be heated.Certainly, exist , can be with through hole to replacing through hole 302 in present embodiment, polarization maintaining optical fibre is arranged on sensing baseplate with face formation formula.

Figure 15 is refer to, in the present embodiment, polarization maintaining optical fibre 110 is distributed in a manner of linear array on sensing baseplate 11.Pass A Z-shaped path is formed on sensillary base plate 11, polarisation fibre 110 is embedded into or is placed in Z-shaped path.Sensor base plate material Can be nylon, acetal resin or other have the material of certain elasticity or mechanical property such as Young's modulus.Turned in Z-shaped path The bending of polarization maintaining optical fibre 110 can cause polarization interference at angle, cause a succession of polarization interference peak with certain amplitude.When an axle It is applied to elongation strain on sensing baseplate 11, produces tension force along polarization maintaining optical fibre 110 and increase the polarization-maintaining light at fibre-optical bending Fine pressure, so as to cause the increase of polarization interference.Likewise, working as one is compressed axially one that strain is applied to sensing baseplate 11 On point, the polarization interference of a reduction occurs at fibre-optical bending.In the present embodiment, the inner groovy of sensing baseplate 11 is carved Into Z-shaped to form Z-shaped path, and change a direction per certain spacing.Thin layer silicon adhesive is other kinds of Coating can be along groove direction application, to guide the direction of empty optical fiber.It is immediately that polarization maintaining optical fibre is embedding after first layer silica gel is coated with Enter into groove.Then, second layer glue covers optical fiber, and adhesive tape can be used for being further ensured that between optical fiber and sensor strip well Bonding.Need it is specifically intended that corner, occurs internal crosstalk peak herein, and obvious become occurs under local train Change, so as to which optical fiber will not be come out due to the perturbation of corner.When glue curing, the adhesive tape before removing, and by another layer Adhesive tape covers whole sensor surface and shielded.It is routed to when polarization maintaining optical fibre 110 in groove, polarization maintaining optical fibre 110 The surface normal of slow axis or fast axle and sensor strip is into 45 degree of angles, to provide maximum measurement sensitivity.Same works as temperature During change, the spacing between polarization interference peak can also change.

Likewise, when polarization maintaining optical fibre is distributed on sensing baseplate in a manner of the battle array of face, the path of polarization maintaining optical fibre can also be set It is set to Z-shaped.Figure 16 is refer to, the path of the polarization maintaining optical fibre 110 set in the sensing baseplate 11 is in Z-shaped, the polarization maintaining optical fibre The change direction in 110 path is in the horizontal plane of sensing baseplate 11.It is provided with present embodiment, on sensing baseplate 11 corresponding Z-shaped groove, polarization maintaining optical fibre 110 is directed with silica gel along groove.The embedded optical fiber of adhesive tape protective layer covering can be used.It is such Sensing baseplate 11 is sensitive to local strain variation, available for detect or identify X, Y-direction local train field change and temperature Change.Please continue to refer to Figure 17, polarization maintaining optical fibre 110 has Z-shaped fiber path in the both sides of sensing baseplate 11, both sides it is identical The path of polarization maintaining optical fibre 110 on position is about vertical.In legend, it is recessed that the both sides of sensing baseplate 11 engrave Yangtze River Delta shape Groove, and direction is orthogonal.Polarization maintaining optical fibre 110 adheres to the other end, then anti-mistake along groove in the side of sensing baseplate 11 by one end To adhere to the opposite side of panel.Polarization maintaining optical fibre 110 is embedded into groove and protected.For example, the width of each big triangle is 8cm, Height 24cm.Because the triangular groove of both sides moves towards orthogonal, this 2D sensor boards are sensitive to the change of pressure or strain, and It can identify and apply stressed direction.Certainly, the distribution of the Z-shaped of the polarization maintaining optical fibre, it is not limited to above-mentioned distribution, this area skill Art personnel when polarization maintaining optical fibre is arranged on sensing baseplate in a word, have pre- it is to be understood that it can also be the distribution of other forms If polarization interference.

A kind of method for measuring stress, strain and temperature is further disclosed herein, refer to Figure 18, this method includes following step Suddenly：

S110：The linearly polarized light of coupling wideband band enters optical birefringence medium, and linearly polarized light is along the optical birefringence Two orthogonal polarization modes transmission of medium, optical birefringence medium output optical output signal.In the present embodiment, optics is double Refractive medium can be arranged directly on object under test or be arranged on sensing baseplate.Optical birefringence medium is also provided with Default polarization interference, optical birefringence medium can include polarization maintaining optical fibre, or such as Yttrium Orthovanadate, quartz crystal birefringence crystalline substance Body, or with prestressed glass etc..When optical birefringence medium is arranged on sensing baseplate, it can be in sensing baseplate The upper one-dimensional space or two-dimensional space distribution, default polarization interference is applied to optical birefringence medium by sensing baseplate, then The sensing baseplate is attached on object under test, so as to monitor the stress of the object under test and temperature.

S130：The optical output signal of optical birefringence medium output enters optical delay, makes two orthogonal polarization modes Between produce delay.

S150：Light will be passed through by the linear optics polarizer, the linear optics polarizer by being directed through the light of optical delay Two orthogonal polarization modes for learning the light of delayer are mutually mixed.

S170：Linearly polarized light caused by linear optical polariser is guided to enter interferometer, so as to obtain two cross-polarizations Interference between mould, to produce polarization interference peak.

S190：According to the spacing between polarization interference peak to obtain the temperature of optical birefringence medium, according to polarization interference The peak value at peak obtains the stress value of optical birefringence medium.

Herein it should be noted that sensing baseplate listed by the present invention, be for convenience in measurement process, be easy to by Birefringent medium and testee are combined layout, in some applications, can also use birefringent medium (such as polarization-maintaining light It is fine) it is directly attached on testee, to experience the stress of testee, strain and temperature, without passing through sensing baseplate.

The present invention presets one of effect of polarization interference point by sensing baseplate, and being can be by the curved of birefringent medium Folding so that the stress variation that can experience sensing baseplate axial direction (i.e. along sensing baseplate in-plane) of birefringent medium； The two of effect be by known default crosstalk point position, judge the crosstalk caused by temperature change it is peak-to-peak away from change, from And judge the change of temperature.In the application, default polarization interference point can not also be set on sensing baseplate, but utilize quilt Survey crosstalk point caused by object self structure --- such as the turning in building structure, gap, crosstalk peak position known to acquisition Put, so as to judge the crosstalk caused by temperature change it is peak-to-peak away from change；Known crosstalk point position can not also be utilized, and That the change that stress or strain occur when testee introduces crosstalk peak, now when temperature changes therewith (such as by In stress or strain caused by testee deformation caused by temperature change), changed by the spacing at these crosstalk peaks, sentenced While disconnected stress or strain, the change of temperature is found.

Each technical characteristic of embodiment described above can be combined arbitrarily, to make description succinct, not to above-mentioned reality Apply all possible combination of each technical characteristic in example to be all described, as long as however, the combination of these technical characteristics is not deposited In contradiction, the scope that this specification is recorded all is considered to be.

Embodiment described above only expresses the several embodiments of the present invention, and its description is more specific and detailed, but simultaneously Can not therefore it be construed as limiting the scope of the patent.It should be pointed out that come for one of ordinary skill in the art Say, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to the protection of the present invention Scope.Therefore, the protection domain of patent of the present invention should be determined by the appended claims.

Claims

1. a kind of method of monitor stress and temperature, it is characterised in that comprise the following steps：

The linearly polarized light of coupling wideband band enters optical birefringence medium, and the linearly polarized light is along the optical birefringence medium Two orthogonal polarization modes transmission, the optical birefringence medium export optical output signal；

The optical output signal is guided by the linear optics polarizer, the polarizer by the two of the optical output signal just Polarization mode is handed over to be mutually mixed；

Linearly polarized light caused by the optical polariser is guided to enter interferometer, it is dry between two orthogonal polarization modes so as to obtain Relate to, to produce polarization interference peak；

Changed according to the spacing between polarization interference peak to obtain the temperature change of the optical birefringence medium, gone here and there according to polarization The peak value for disturbing peak obtains stress and/or the strain of the optical birefringence medium；

The optical birefringence medium is provided with default polarization interference.

2. according to the method for claim 1, it is characterised in that the optical birefringence medium includes polarization maintaining optical fibre.

3. according to the method for claim 1, it is characterised in that also including step：

The optical output signal of the optical birefringence medium output enters optical delay, makes to produce between two orthogonal polarization modes Raw delay.

4. according to the method for claim 1, it is characterised in that the optical birefringence medium is attached on object under test, To monitor the stress of the object under test, strain and temperature.

5. according to the method for claim 1, it is characterised in that the optical birefringence medium is arranged on sensing baseplate, The sensing baseplate is attached on object under test, to monitor the stress of the object under test, strain and temperature.

6. according to the method for claim 5, it is characterised in that the optical birefringence medium is one on the sensing baseplate Dimension space or two-dimensional space distribution, to monitor the stress of the object under test, strain and the spatial distribution of temperature.

7. the method according to claim 5 or 6, it is characterised in that the optical birefringence medium is provided with default polarization Crosstalk, including：Default polarization interference is applied to the optical birefringence medium by the sensing baseplate.

A kind of 8. sensing device, to the temperature change of monitoring object, strain and/or stress, it is characterised in that including：

Optical birefringence medium, the optical birefringence medium is provided with default polarization interference, for perceiving the temperature of object under test Degree change, stress and/or strain；

Light source, to produce wide band linearly polarized light, the linearly polarized light is orthogonal along two of the optical birefringence medium Polarization mode transmits, and the optical birefringence medium exports optical output signal；

The linear optics polarizer, to receive the optical output signal, and by two cross-polarizations of the optical output signal Mould is mutually mixed；

Interferometer, to receive the light through the linear optics polarizer, and the interference between two orthogonal polarization modes is obtained, To produce polarization interference peak；

Processor, changed according to the spacing between polarization interference peak to obtain the temperature change of the optical birefringence medium, root Stress and/or the strain of the optical birefringence medium are obtained according to the peak value at polarization interference peak.

9. device according to claim 8, it is characterised in that the optical birefringence medium includes polarization maintaining optical fibre.

10. device according to claim 8, it is characterised in that also include：

Optical delay, to receive the optical output signal of the optical birefringence medium output, make two orthogonal polarization modes Between produce delay, and be transferred to the linear optics polarizer.

11. device according to claim 8, it is characterised in that the sensing device also includes sensing baseplate, to treating Object connection is surveyed, the optical birefringence medium is in a manner of linear array or face array way is arranged on the sensing baseplate.

12. device according to claim 11, it is characterised in that raised or groove is provided with the sensing baseplate, and And the raised or groove contacts with the optical birefringence medium so that the optical birefringence medium has default polarization Crosstalk.

13. device according to claim 11, it is characterised in that multiple through holes are offered on the sensing baseplate, it is described Optical birefringence medium passes through the through hole, and the optical birefringence dielectric distribution is in the both sides of the sensing baseplate so that institute Stating optical birefringence medium has default polarization interference.

14. device according to claim 11, it is characterised in that multiple through holes pair, institute are offered on the sensing baseplate State optical birefringence medium and pass through the through hole pair, the optical birefringence dielectric distribution makes in the side of the sensing baseplate Obtaining the optical birefringence medium has default polarization interference.

15. device according to claim 11, it is characterised in that Z-shaped passage is offered on the sensing baseplate, it is described Optical birefringence medium is arranged in the Z-shaped passage so that the optical birefringence medium has default polarization interference.

16. device according to claim 11, it is characterised in that the polarization axis direction and biography of the optical birefringence medium The normal direction of sensillary base plate is at 45 °.