CN109029776A - A kind of temperature sensor based on your interference structure of Mach Zehnder - Google Patents
A kind of temperature sensor based on your interference structure of Mach Zehnder Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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Abstract
A kind of your temperature sensor of interference structure based on Mach Zehnder of the invention belongs to fiber optic sensor technology field.Its primary structure has pumping source (1), light wavelength division multiplexing (2), Er-doped fiber (3) etc..The present invention uses sinusoidal signal as modulated signal, will not generate High-frequency Interference, has the characteristics that work is more reliable, sensing accuracy is high, has a wide range of application.
Description
Technical field
The invention belongs to the technical field of fibre optical sensor, in particular to a kind of temperature based on your interference structure of Mach Zehnder
Spend sensor.
Background technique
Electromagnetism interference, resistant to chemical etching, transmission loss is small, weight small in size because having for bragg grating (FBG)
Gently, convenient for large-scale production the advantages that, and it is widely used in field of sensing technologies.Currently, temperature sensor is in safety in production
Play a significant role, especially such as mine Different high risk sites, it is most important to the monitoring of temperature.But traditional temperature sensor is most
It is all the variation realization by electric signal, and the temperature sensor based on change in electric is in practical applications by very big limit
System, the use of one side electric signal can cause additional security risk to certain environment (such as coal mine), on the other hand in severe ring
Interference when using under border by environment is larger and transmission is inconvenient.And bragg grating makes its composition due to its above-mentioned advantage
Temperature sensor compared to other sensors have higher reliability, the use being also more suitable under mal-condition.
It is the master thesis " distribution type fiber-optic of Dalian University of Technology Li Hong with the immediate prior art of the present invention
The research of Bragg grating sensor demodulation techniques ", the document provides a kind of based on non-equilibrium Mach Zehnder that interferometry demodulation
The bragg grating stress sensing system (referring to Fig. 1 .4 of page 5 of the document) of technology, the optical fiber sensing system use horse
He Ze Dare principle of interference is changed using the modulated signal that piezoelectric ceramics (PZT) is provided on the wherein arm in interferometer two-arm
Become the length of the arm, to change interferometer output intensity, interferometer output intensity is in cosine letter with the variation of PZT modulated signal
Number rule, if the modulated signal using ideal sawtooth wave as PZT, the output of optical fiber sensing system is directly cosine wave.
Optical fiber sensing system perceives the variation (principle is similar when measurement temperature) of measurement point stress by Bragg grating, and is reflected as
The variation of the variation of reflectance spectrum central wavelength, central wavelength is presented as output cosine after your interferometer of above-mentioned Mach Zehnder
The phase of cosine wave is finally compared with the phase of sawtooth wave, can reflect bragg grating by the variation of wave phase
The variation of reflectance spectrum central wavelength, to realize the variation of measurement extraneous stress (or temperature).
In above-mentioned sensor-based system, existing greatest problem is that sawtooth wave can not accomplish absolute idealization, preferably
Sawtooth wave failing edge is vertical, and the failing edge of actual sawtooth wave always has certain gradient, so that rear class can be made defeated
There are a high dithers for cosine wave out, generally necessary in grade demodulator circuit behind in order to eliminate the high-frequency jitter signal
Using bandpass filter (BPF), DC component and high fdrequency component are filtered out.But on the one hand the high fdrequency component inherently can be to remaining
The phase-detection of string wave impacts (zero crossing change in location)；On the other hand the frequency of the high-frequency jitter signal is driven by PZT
(electrical characteristics of PZT are equivalent to capacitor to the lagging characteristics of circuit performance, PZT itself, and both end voltage cannot jump, therefore
The failing edge of sawtooth wave be do not accomplish it is unlimited short) and the factors such as optical fiber elasticity itself influence, frequency size is indefinite, very
Difficulty filters out completely；Moreover, when using filter, it, can also be simultaneously other than it can be had an impact to the amplitude-frequency characteristic of output signal
The phase-frequency characteristic of signal is had an impact, i.e., filtering is that phase will receive influence near cutoff frequency, this is for relying on phase
It is very unfavorable for changing for the fibre optical sensor to measure temperature change.Therefore, existing bragg grating temperature
Sensor also requires further improvement.
Summary of the invention
In order to overcome existing bragg grating answer temperature sensor there are the shortcomings that, the present invention provides a kind of use
A kind of temperature sensor based on Mach Zehnder you interference structure of the sinusoidal signal as PZT driving signal, so as to avoid height
The generation of frequency interference signal, and when handling the signal received without using filter, so as to avoid filtering
The influence that journey generates phase.
The purpose of the present invention is achieved through the following technical solutions:
A kind of temperature sensor based on your interference structure of Mach Zehnder, structure have, pumping source 1 and light wavelength division multiplexing
2 end 980nm is connected, one end phase at the end 1550nm of light wavelength division multiplexing 2 and the optical fiber being wrapped on the first piezoelectric ceramics 12
Even, the other end for the optical fiber being wrapped on the first piezoelectric ceramics 11 is connected with the input terminal of the first optoisolator 10, the first piezoelectricity
The control terminal of ceramics 11 is connected with the output port of the first PZT driving circuit 12, the input terminal and number of the first PZT driving circuit 12
The output port of analog conversion circuit 13 is connected, and the input port of D/A converting circuit 13 is connected with single-chip microcontroller 18；First optical isolation
The output end of device 10 is connected with the light input end of optical filter 9, and the electric control end of optical filter 9 is connected with single-chip microcontroller 18, light filter
The light output end of wave device 9 is connected with the first port of optical circulator 7, second port and the Bragg grating group 8 of optical circulator 7
One end is connected, and the third port of optical circulator 7 is connected with the input terminal of the first photo-coupler 5, and the 90% of the first photo-coupler 5 is defeated
Outlet is connected with the input terminal of the second optoisolator 4, and the output end of the second optoisolator 4 is connected with one end of Er-doped fiber 3, mixes
The other end of erbium optical fiber 3 is connected with the common end of light wavelength division multiplexing 2；The 10% output end output and the of first photo-coupler 5
The input terminal of two photo-couplers 6 is connected, an output end of the second photo-coupler 6 and an input terminal of third photo-coupler 24
It is connected, the another output of the second photo-coupler 6 is connected with the one end for the optical fiber being wrapped on the second piezoelectric ceramics 23, winding
The other end of optical fiber on the second piezoelectric ceramics 23 is connected with another input terminal of third photo-coupler 24, third optical coupling
The output end of device 24 is connected with the input terminal of photoelectric conversion circuit 25；
It is characterized in that, structure in addition, the output end and function translation circuit 26 of photoelectric conversion circuit 25 input terminal phase
Even, the output end of functional transformation circuit 26 is connected with an input terminal of adaptive amplitude normalizing circuit 27, and adaptive amplitude is returned
The output end of one circuit 27 is connected with an input terminal of phase-comparison circuit 28；The input terminal and single-chip microcontroller in controllable frequency source 21
18 are connected, and output end is connected with another input terminal of phase-comparison circuit 28, the output end and monolithic of phase-comparison circuit 28
Machine 18 is connected；The output end in controllable frequency source 21 is also connected with the input terminal of the 2nd PZT driving circuit 22, the 2nd PZT driving electricity
The output end on road 22 is connected with the control terminal of the second piezoelectric ceramics 23；The output end of constant-current source circuit 15 and 16 phase of thermistor
Even, thermistor 16 is connected with the input terminal of analog to digital conversion circuit 17, output end and 18 phase of single-chip microcontroller of analog to digital conversion circuit 17
Even；Single-chip microcontroller 18 is also connected with input key 14, serial communication modular 19, display screen 20 respectively；
The structure of the functional transformation circuit 26 is, one end of capacitor C3 and the pin 12 of trigonometric function converter U1 and
One end of resistance R2 is connected, and input terminal of the other end of capacitor C3 as functional transformation circuit 26 is denoted as port ACOS_in, with
The output end of photoelectric conversion circuit 25 is connected；The other end of resistance R2 is grounded；The pin 2 of trigonometric function converter U1,3,4,5,
8,11,13 ground connection, pin 9,10 are connected with one end of capacitor C2 and -12V power supply, the other end ground connection of capacitor C2；Trigonometric function
The pin 6 of converter U1 is connected with pin 7, and pin 16 is connected with one end of+12V power supply and capacitor C1, the other end of capacitor C1
Ground connection；The pin 1 of trigonometric function converter U1 is connected with the sliding end of slide rheostat W1, one end of slide rheostat W1 and electricity
The one end for hindering R1 is connected, and the other end of resistance R1 is connected with the pin 14 of trigonometric function converter U1, the cunning of slide rheostat W1
Output end of the moved end as functional transformation circuit 26, is denoted as port ACOS_out, the input with adaptive amplitude normalizing circuit 27
End is connected；The model AD639 of the trigonometric function converter U1；
The structure of the adaptive amplitude normalizing circuit 27 is one end of capacitor C9 and one end of resistance R3 and chip U2
Pin 3 be connected, the other end of resistance R3 ground connection, input of the other end of capacitor C9 as adaptive amplitude normalizing circuit 27
End, is denoted as port ADAPT_in, and the port ACOS_out of and function translation circuit 26 is connected；Pin 1, pin 7, the pipe of chip U2
Foot 8, pin 14 are grounded, and pin 2 is connected with+5V power supply with pin 4, and pin 11 is connected and one with capacitor C5 with pin 12
End and+5V power supply are connected, the other end ground connection of capacitor C5；The pin 13 of chip U2 is connected with one end of capacitor C4, capacitor C4's
Other end ground connection；The pin 9 of chip U2 is connected with one end of capacitor C6, the other end ground connection of capacitor C6；The pin 5 of chip U2 with
One end of resistance R12 and resistance R11 are connected, the other end ground connection of resistance R12, the output of the other end and amplifier U4 of resistance R11
End and one end of capacitor C8 are connected, the positive supply termination+5V power supply of amplifier U8, negative power end ground connection；The other end of capacitor C8 with
One end of resistance R10 is connected, and the other end of resistance R10 is connected with the non-inverting input terminal of amplifier U4；The inverting input terminal of amplifier U4
It is connected with the sliding end of sliding variohm W3, one end of slide rheostat W3 is connected with+5V power supply, and slide rheostat W3's is another
One end ground connection；One end of capacitor C7 is connected with the non-inverting input terminal of one end of resistance R9 and amplifier U4, another termination of capacitor C7
The other end on ground, resistance R9 is connected with the output end of one end of resistance R7 and amplifier U3, and the other end of resistance R7 is with amplifier U3's
Inverting input terminal is connected；One end of resistance R8 is connected with the non-inverting input terminal of amplifier U3, other end ground connection；The positive supply of amplifier U3
Termination+5V power supply, negative power end ground connection；Output end of the pin 10 of chip U2 as adaptive amplitude normalizing circuit 27, is denoted as
Port ADAPT_out is connected with an input terminal of phase-comparison circuit 28；The pin 10 of chip U2 and the anode of diode D1
It is connected, the cathode of diode D1 is connected with one end of resistance R4, the other end of resistance R4 and one end of resistance R5 and amplifier U3's
Inverting input terminal is connected, and the other end of resistance R5 is connected with the anode of diode D2, the cathode and slide rheostat of diode D2
The sliding end of W2 is connected；One end of slide rheostat W2 is connected and is grounded with the cathode of diode D3, and slide rheostat W2's is another
One end is connected with the anode of one end of resistance R6 and diode D3, another termination -5V power supply of resistance R6；The chip U2 is
Variable gain amplifier chip, model are AD8367；
The structure of the phase-comparison circuit 28 is one end of capacitor C10 and the non-inverting input terminal and resistance of amplifier U5
One end of R13 is connected, and an input terminal of the other end of capacitor C10 as phase-comparison circuit 28 is denoted as port PHASE_
In1 is connected with the port ADAPT_out of adaptive amplitude normalizing circuit 27；The other end of resistance R13 is grounded；Amplifier U5 is just
Power supply termination+5V power supply, negative power end ground connection, reverse inter-input-ing ending grounding, the end CLK of output termination d type flip flop U6A；D type flip flop
The port D of U6A is grounded；The one end capacitor C11 ground connection, the end PR of another termination d type flip flop U6A；Resistance R14 mono- terminates d type flip flop
The end PR of U6A, the end Q of another termination d type flip flop U6A；CLR termination+5V the power supply of d type flip flop U6A, the Q of d type flip flop U6A are non-
Terminate the end PR of d type flip flop U8A；One end of capacitor C12 is connected with one end of the non-inverting input terminal of amplifier U7 and resistance R15, electricity
Hold another input terminal of the other end of C12 as phase-comparison circuit 28, port PHASE_in2 is denoted as, with controllable frequency source
21 port SineM_out is connected；The other end of resistance R15 is grounded；Positive supply termination+5V the power supply of amplifier U7, negative power end
Ground connection, reverse inter-input-ing ending grounding, the end CLK of output termination d type flip flop U6B；The port D of d type flip flop U6B is grounded；Capacitor C13 mono-
End ground connection, the end PR of another termination d type flip flop U6B；Resistance R16 mono- terminates the end PR of d type flip flop U6B, another termination d type flip flop
The end Q of U6B；CLR termination+5V the power supply of d type flip flop U6B, the end CLR of the Q non-terminated d type flip flop U8A of d type flip flop U6B；D touching
The end D and the end CLK for sending out device U8A are grounded, and output end of the end Q as phase-comparison circuit 28 is denoted as port PHASE_out, with
The input terminal of single-chip microcontroller 18 is connected；
The structure in the controllable frequency source 21 is the one of the output termination C14 of one end and amplifier U9 of thermistor Rt1
End, the inverting input terminal of another termination amplifier U9；The pin 2 of another chip termination U10 of capacitor C14；The termination fortune of resistance R17 mono-
The inverting input terminal of U9, one end of another termination capacitor C16, and the output end as controllable frequency source 21 are put, and is denoted as port
SineM_out；The pin 2 of another chip termination U11 of capacitor C16；The pin 2 of a chip termination U10 of capacitor C15, it is another
The pin 2 of chip termination U11；One end of the homophase input terminating resistor R18 of amplifier U9, positive supply termination+5V power supply, negative supply
Termination -5V power supply；The other end of resistance R18 is grounded；The pin 5 of a chip termination U10 of capacitor C17, other end ground connection；Capacitor
The pin 5 of a chip termination U11 of C18, other end ground connection；The pin 1 and pin 10 of chip U10 connects+5V power supply, pin 3, pipe
Foot 4 and pin 6 are grounded；One end of 9 connecting resistance R19 of pin, one end of 8 connecting resistance R20 of pin, the one of 7 connecting resistance R21 of pin
End；An input port of the other end of resistance R19 as controllable frequency source 21, is denoted as port SineM_in1；Resistance R20's
Another input port of the other end as controllable frequency source 21, is denoted as port SineM_in2；Port SineM_in1 and port
SineM_in2 is connected with the input terminal of single-chip microcontroller 18；Another termination+5V power supply of resistance R21；The pin 1 and pin of chip U11
10 connect+5V power supply, and pin 3, pin 4 and pin 6 are grounded；One end of 9 connecting resistance R22 of pin, one end of 8 connecting resistance R23 of pin,
One end of 7 connecting resistance R24 of pin；Another termination port SineM_in1 of resistance R22；Another termination port of resistance R23
SineM_in2；Another termination+5V power supply of resistance R24.
Described preferred 25 DEG C of negative tempperature coefficient thermistors of 10k Ω@of thermistor 16.
The Bragg grating group 8 is preferably made of 3 Bragg gratings, and the reflectivity of each grating is 90%,
Bandwidth is 0.6nm, and central wavelength is respectively 1550nm, 1560nm and 1630nm.
The utility model has the advantages that
1, the present invention uses sinusoidal signal as modulated signal, compared with the prior art is modulated using sawtooth signal,
High-frequency Interference will not be generated, so that sensor-based system work is more reliable.
2, the present invention uses adaptive amplitude normalizing circuit by the amplitude auto-changing of signal after demodulation at suitable phase ratio
Compared with the size that circuit is compared, so that phase-detection error is smaller, the sensing accuracy of entire sensor-based system is effectively increased.
3, compared with prior art, frequency modulating signal of the invention is adjustable, so that sensor-based system applied field of the invention
It closes wider.
4, the present invention has temperature compensation function, effectively overcomes influence of the environment temperature to parameter sensing.
Detailed description of the invention
Fig. 1 is whole functional block diagram of the invention.
Fig. 2 is the basic circuit diagram for the functional transformation circuit that the present invention uses.
Fig. 3 is the basic circuit diagram for the adaptive amplitude normalizing circuit that the present invention uses.
Fig. 4 is the basic circuit diagram for the phase-comparison circuit that the present invention uses.
Fig. 5 is the basic circuit diagram in the controllable frequency source that the present invention uses.
Specific embodiment
The working principle of the invention is further illustrated with reference to the accompanying drawing, it should be appreciated that the component marked in attached drawing
Parameter is the preferred parameter that following embodiment uses, rather than limiting the scope of the invention.
The overall structure of the invention of embodiment 1
As shown in Figure 1, overall structure of the invention has, pumping source 1 (the LC962U type pumping source of OCLARO company, center
Wavelength 980nm, maximum single-mode output optical power are 750mW) and (the COMCORE company 980/1060nm single mode of light wavelength division multiplexing 2
Optical fibre wavelength division multiplexer) the end 980nm be connected, the end 1550nm of light wavelength division multiplexing 2 and be wrapped in the first piezoelectric ceramics 11 (circle
Cylindricality piezoelectric ceramics, outer diameter 50mm, internal diameter 40mm, high 50mm) on optical fiber one end be connected, be wrapped in the first piezoelectric ceramics 11
On optical fiber the other end and the first optoisolator 10 (THORLABS company IO-H-1064B single mode optoisolator) input terminal
It is connected, the control terminal of the first piezoelectric ceramics 11 with the first PZT driving circuit 12 (be shown in by the homemade device of this seminar, specific structure
Patent ZL200710055865.8) output port be connected, the input terminal of the first PZT driving circuit 12 and D/A converting circuit 13
Output port be connected, the input port of D/A converting circuit 13 is connected with single-chip microcontroller 18 (STC89C51 single-chip microcontroller)；First light
(Micron Optics company produces the output end and optical filter 9 of isolator 10, model FFP-TF-1060-010G0200-
2.0) light input end is connected, and the electric control end of optical filter 9 is connected with single-chip microcontroller 18, the light output end and light of optical filter 9
The first port of circulator 7 (Shanghai Han Yu company PIOC3-15 type optical circulator) is connected, the second port and cloth of optical circulator 7
One end of glug grating group 8 (JH-FGA-A101) is connected, the third port of optical circulator 7 and 5 (OZ- of the first photo-coupler
OPTICS company production, model FUSED-12-1064-7/125-90/10-3U-3mm, splitting ratio 90:10) input terminal
Be connected, 90% output end of the first photo-coupler 5 and the second optoisolator 4 (THORLABS company IO-H-1064B single-mode optics every
From device) input terminal be connected, the output end of the second optoisolator 4 and the (SM- of Nufern company of U.S. production of Er-doped fiber 3
ESF-7/125 Er-doped fiber) one end be connected, the other end of Er-doped fiber 3 is connected with the common end of light wavelength division multiplexing 2.On
State basic luminaire part and the transducing part of structure composition fibre optical sensor.10% output end of the first photo-coupler 5 exports
(the model FUSED-12-1060-7/125-50/50-3U-3mm of OZ-OPTICS company production, divides with the second photo-coupler 6
Light is than 1 × 2 fiber coupler for 50:50) input terminal be connected, an output end of the second photo-coupler 6 and third optocoupler
Clutch 24 (the model FUSED-12-1060-7/125-50/50-3U-3mm of OZ-OPTICS company production, splitting ratio 50:
50 1 × 2 fiber coupler) an input terminal be connected, the another output of the second photo-coupler 6 and be wrapped in the second pressure
One end of optical fiber on electroceramics 23 (cylindrical piezoelectric ceramics, outer diameter 50mm, internal diameter 40mm, high 50mm) is connected, and is wrapped in the
The other end of optical fiber on two piezoelectric ceramics 23 is connected with another input terminal of third photo-coupler 24, third photo-coupler 24
Output end be connected with the input terminal of photoelectric conversion circuit 25.Above-mentioned second photo-coupler 6, third photo-coupler 24 and second
Piezoelectric ceramics 23 collectively constitutes Mach Zehnder that interference structure.
Structure of the invention in addition, the input terminal of the output end and function translation circuit 26 of photoelectric conversion circuit 25 is connected,
The output end of functional transformation circuit 26 is connected with an input terminal of adaptive amplitude normalizing circuit 27, adaptive amplitude normalizing electricity
The output end on road 27 is connected with an input terminal of phase-comparison circuit 28；The input terminal in controllable frequency source 21 and 18 phase of single-chip microcontroller
Even, output end is connected with another input terminal of phase-comparison circuit 28, the output end and single-chip microcontroller 18 of phase-comparison circuit 28
It is connected；The output end in controllable frequency source 21 is also connected with the input terminal of the 2nd PZT driving circuit 22, the 2nd PZT driving circuit 22
Output end be connected with the control terminal of the second piezoelectric ceramics 23.Above structure constitutes the demodulation part of sensor.Constant-current source electricity
The output end and thermistor 16 (25 DEG C of 10k Ω@, negative temperature coefficient) on road 15 are connected, thermistor 16 and analog to digital conversion circuit
17 input terminal is connected, and the output end of analog to digital conversion circuit 17 is connected with single-chip microcontroller 18.Above structure is that the present invention provides temperature
Spend compensation function.Single-chip microcontroller 18 is also connected with input key 14, serial communication modular 19, display screen 20 respectively, for ginseng to be arranged
Number communicates and shows the functions such as information with computer.
2 functional transformation circuit of embodiment
The structure of the functional transformation circuit 26 is, one end of capacitor C3 and the pin 12 of trigonometric function converter U1 and
One end of resistance R2 is connected, and input terminal of the other end of capacitor C3 as functional transformation circuit 26 is denoted as port ACOS_in, with
The output end of photoelectric conversion circuit 25 is connected；The other end of resistance R2 is grounded；The pin 2 of trigonometric function converter U1,3,4,5,
8,11,13 ground connection, pin 9,10 are connected with one end of capacitor C2 and -12V power supply, the other end ground connection of capacitor C2；Trigonometric function
The pin 6 of converter U1 is connected with pin 7, and pin 16 is connected with one end of+12V power supply and capacitor C1, the other end of capacitor C1
Ground connection；The pin 1 of trigonometric function converter U1 is connected with the sliding end of slide rheostat W1, one end of slide rheostat W1 and electricity
The one end for hindering R1 is connected, and the other end of resistance R1 is connected with the pin 14 of trigonometric function converter U1, the cunning of slide rheostat W1
Output end of the moved end as functional transformation circuit 26, is denoted as port ACOS_out, the input with adaptive amplitude normalizing circuit 27
End is connected；The model AD639 of the trigonometric function converter U1；The circuit has the function of anti-cosine transform, photoelectric conversion
The signal that circuit 25 exports carries out anticosine processing.
The adaptive amplitude normalizing circuit of embodiment 3
Since the signal amplitude that functional transformation circuit 26 exports is smaller, and influenced by multiple parameters in optical path and circuit,
Size is indefinite, therefore the present invention devises adaptive amplitude normalizing circuit 27, for the signal for exporting functional transformation circuit 26
Amplitude normalization at best size, to further increase the precision of demodulation.The knot of the adaptive amplitude normalizing circuit 27
Structure is that one end of capacitor C9 is connected with the pin 3 of one end of resistance R3 and chip U2, the other end ground connection of resistance R3, capacitor C9
Input terminal of the other end as adaptive amplitude normalizing circuit 27, be denoted as port ADAPT_in, and function translation circuit 26
Port ACOS_out is connected；Pin 1, pin 7, pin 8, the pin 14 of chip U2 is grounded, and pin 2 and pin 4 are electric with+5V
Source is connected, and pin 11 is connected with pin 12 and is connected with one end of capacitor C5 and+5V power supply, the other end ground connection of capacitor C5；Core
The pin 13 of piece U2 is connected with one end of capacitor C4, the other end ground connection of capacitor C4；The pin 9 of chip U2 and one end of capacitor C6
It is connected, the other end ground connection of capacitor C6；The pin 5 of chip U2 is connected with one end of resistance R12 and resistance R11, and resistance R12's is another
One end ground connection, the other end of resistance R11 are connected with one end of the output end of amplifier U4 and capacitor C8, the positive supply termination of amplifier U8
+ 5V power supply, negative power end ground connection；The other end of capacitor C8 is connected with one end of resistance R10, the other end and amplifier of resistance R10
The non-inverting input terminal of U4 is connected；The inverting input terminal of amplifier U4 is connected with the sliding end of sliding variohm W3, slide rheostat
One end of W3 is connected with+5V power supply, the other end ground connection of slide rheostat W3；One end of capacitor C7 and one end of resistance R9 and fortune
The non-inverting input terminal for putting U4 is connected, the other end ground connection of capacitor C7, the other end of resistance R9 and one end of resistance R7 and amplifier U3
Output end be connected, the other end of resistance R7 is connected with the inverting input terminal of amplifier U3；One end of resistance R8 is same with amplifier U3's
Phase input terminal is connected, other end ground connection；Positive supply termination+5V the power supply of amplifier U3, negative power end ground connection；The pin 10 of chip U2
As the output end of adaptive amplitude normalizing circuit 27, it is denoted as port ADAPT_out, an input with phase-comparison circuit 28
End is connected；The pin 10 of chip U2 is connected with the anode of diode D1, and the cathode of diode D1 is connected with one end of resistance R4, electricity
The other end of resistance R4 is connected with the inverting input terminal of one end of resistance R5 and amplifier U3, and the other end of resistance R5 is with diode D2's
Anode is connected, and the cathode of diode D2 is connected with the sliding end of slide rheostat W2；One end of slide rheostat W2 and diode
The cathode of D3 is connected and is grounded, and the other end of slide rheostat W2 is connected with the anode of one end of resistance R6 and diode D3, electricity
Hinder another termination -5V power supply of R6；The chip U2 is variable gain amplifier chip, and model is AD8367；
4 phase-comparison circuit of embodiment
As shown in figure 4, the structure for the phase-comparison circuit 28 that the present invention uses is one end of capacitor C10 and fortune
One end of the non-inverting input terminal and resistance R13 of putting U5 is connected, and the other end of capacitor C10 is defeated as one of phase-comparison circuit 28
Enter end, is denoted as port PHASE_in1, is connected with the port ADAPT_out of adaptive amplitude normalizing circuit 27；Resistance R13's is another
One end ground connection；Positive supply termination+5V the power supply of amplifier U5, negative power end ground connection, reverse inter-input-ing ending grounding, output termination D triggering
The end CLK of device U6A；The port D of d type flip flop U6A is grounded；The one end capacitor C11 ground connection, the end PR of another termination d type flip flop U6A；
Resistance R14 mono- terminates the end PR of d type flip flop U6A, the end Q of another termination d type flip flop U6A；CLR termination+the 5V of d type flip flop U6A
Power supply, the end PR of the Q non-terminated d type flip flop U8A of d type flip flop U6A；One end of capacitor C12 and the non-inverting input terminal of amplifier U7 and
One end of resistance R15 is connected, another input terminal of the other end of capacitor C12 as phase-comparison circuit 28 is denoted as port
PHASE_in2 is connected with the port SineM_out in controllable frequency source 21；The other end of resistance R15 is grounded；The positive electricity of amplifier U7
Source connects+5V power supply, negative power end ground connection, reverse inter-input-ing ending grounding, the end CLK of output termination d type flip flop U6B；D type flip flop
The port D of U6B is grounded；The one end capacitor C13 ground connection, the end PR of another termination d type flip flop U6B；Resistance R16 mono- terminates d type flip flop
The end PR of U6B, the end Q of another termination d type flip flop U6B；CLR termination+5V the power supply of d type flip flop U6B, the Q of d type flip flop U6B are non-
Terminate the end CLR of d type flip flop U8A；The end D and the end CLK of d type flip flop U8A is grounded, and the end Q is defeated as phase-comparison circuit 28
Outlet is denoted as port PHASE_out, is connected with the input terminal of single-chip microcontroller 18.The standard that the circuit exports controllable frequency source 21
Sine wave (the environment shadow that its phase is detected by Bragg grating group 8 of sine wave and the output of adaptive amplitude normalizing circuit 26
Ring) phase bit comparison is carried out, and comparison result is sent into single-chip microcontroller 18, single-chip microcontroller 18 calculates Prague according to the phase differential
Temperature change at grating group 8.
5 controllable frequency source of embodiment
As shown in figure 5, the structure in controllable frequency source 21 used in the present invention is one end of thermistor Rt1 and amplifier
One end of the output termination C14 of U9, the inverting input terminal of another termination amplifier U9；The pipe of another chip termination U10 of capacitor C14
Foot 2；The inverting input terminal of the termination of resistance R17 mono- amplifier U9, one end of another termination capacitor C16, and as controllable frequency source 21
Output end, and be denoted as port SineM_out；The pin 2 of another chip termination U11 of capacitor C16；A termination of capacitor C15
The pin 2 of chip U10, the pin 2 of another chip termination U11；One end of the homophase input terminating resistor R18 of amplifier U9, positive electricity
Source connects+5V power supply, negative supply termination -5V power supply；The other end of resistance R18 is grounded；A chip termination U10's of capacitor C17
Pin 5, other end ground connection；The pin 5 of a chip termination U11 of capacitor C18, other end ground connection；The pin 1 and pipe of chip U10
Foot 10 connects+5V power supply, and pin 3, pin 4 and pin 6 are grounded；One end of 9 connecting resistance R19 of pin, the one of 8 connecting resistance R20 of pin
End, one end of 7 connecting resistance R21 of pin；An input port of the other end of resistance R19 as controllable frequency source 21, is denoted as end
Mouth SineM_in1；Another input port of the other end of resistance R20 as controllable frequency source 21, is denoted as port SineM_
in2；Port SineM_in1 and port SineM_in2 are connected with the input terminal of single-chip microcontroller 18；Another termination+5V electricity of resistance R21
Source；The pin 1 and pin 10 of chip U11 connects+5V power supply, and pin 3, pin 4 and pin 6 are grounded；The one of 9 connecting resistance R22 of pin
End, one end of 8 connecting resistance R23 of pin, one end of 7 connecting resistance R24 of pin；Another termination port SineM_in1 of resistance R22；
Another termination port SineM_in2 of resistance R23；Another termination+5V power supply of resistance R24.The module output frequency is adjustable
Standard sine wave provides required sinusoidal signal for demodulation part of the invention.
6 the working principle of the invention of embodiment
In conjunction with the various embodiments described above and each attached drawing, illustrate the working principle of the invention.When work, by bragg grating
Group 8 is placed on each position (sensitive position in such as mine) for needing monitoring temperature to change, by Er-doped fiber 3, optoisolator 4
The optical fiber laser annular chamber of equal compositions is that bragg grating group 8 provides wideband light source, each bragg grating meeting
There is a specific reflectance spectrum, the peak wavelength of different gratings, reflectance spectrum is different, when some measurand temperature becomes
When change, the reflectance spectrum peak wavelength of the bragg grating at this can occur to deviate accordingly, and reflected light enters by second
In the Mach Zehnder that interferometer that photo-coupler 6, the second piezoelectric ceramics 23, third photo-coupler 24 are constituted, while controllable frequency
Source 21 provides a control signal sin (ω t) for your interferometer of Mach Zehnder, and the signal is in interferometer by bragg fiber light
The influence of the light of grid reflection, then through photoelectric conversion circuit 25 it is converted into electric signal and by the anti-cosine transform of functional transformation circuit 26
It obtains later sin (ω t+ Δ θ), which is adjusted to one suitable big through adaptive 27 amplitude of amplitude normalizing circuit
Small, compared with controllable frequency source 21 generates sinusoidal signal sin (ω t), phase is changed signal at this time, passes through phase ratio
The phase difference detection of the two comes out to compared with circuit 28 and is sent into single-chip microcontroller 18, the temperature of phase difference real reaction measured point becomes
Change, finally realizes the detection to measured point temperature.The present invention is no during modulation and demodulation to use sawtooth wave, to keep away
Sawtooth wave failing edge bring high-frequency jitter signal is exempted from, also there is no need to use bandpass filter to be filtered in demodulator circuit
Wave is avoided and is had an impact to the amplitude-frequency characteristic and phase-frequency characteristic of output signal.The present invention using standard sine wave signal as
PZT modulated signal dexterously uses functional transformation circuit 26 and adaptive amplitude normalizing when demodulating to modulated signal
Modulated signal is recovered phase is controlled by the Bragg grating group 8 and suitable sinusoidal signal of amplitude by circuit 27, so that
When carrying out phase bit comparison in phase-comparison circuit 28, the phase of controlled signal and original signal can be highly precisely compared
Difference, thus the environmental parameter that accurately reaction sensing head (i.e. Bragg grating group 8) is detected.
Since optical fiber laser annular chamber (is generally sensed with bragg grating group 8 vulnerable to environment temperature at work
Pop one's head in not in same position) influence, therefore temperature compensation function has also been devised in the present invention, by constant-current source circuit 15, temperature-sensitive electricity
Resistance 16, analog to digital conversion circuit 17 are constituted.Thermistor 16 is temperature sensor, can cause its resistance when the environmental temperature is changed
Value generates variation, and since constant-current source circuit 15 provides constant current for it, the variation of 16 resistance value of thermistor can cause it
The variation of voltage caused by both ends, then it is converted into digital signal input single-chip microcontroller 18 through analog to digital conversion circuit 17, for compensating
Measurement result bring error is given in the variation of environment temperature locating for optical fiber laser annular chamber.
Claims (3)
1. a kind of temperature sensor based on your interference structure of Mach Zehnder, structure have, pumping source (1) and light wavelength division multiplexing
(2) the end 80nm is connected, the end 1550nm of light wavelength division multiplexing (2) and the one of the optical fiber being wrapped on the first piezoelectric ceramics (12)
End is connected, and the other end for the optical fiber being wrapped on the first piezoelectric ceramics (11) is connected with the input terminal of the first optoisolator (10),
The control terminal of first piezoelectric ceramics (11) is connected with the output port of the first PZT driving circuit (12), the first PZT driving circuit
(12) input terminal is connected with the output port of D/A converting circuit (13), the input port and monolithic of D/A converting circuit (13)
Machine (18) is connected；The output end of first optoisolator (10) is connected with the light input end of optical filter (9), optical filter (9)
Electric control end is connected with single-chip microcontroller (18), and the light output end of optical filter (9) is connected with the first port of optical circulator (7), light
The second port of circulator (7) is connected with one end of Bragg grating group (8), the third port and the first light of optical circulator (7)
The input terminal of coupler (5) is connected, the input terminal phase of 90% output end and the second optoisolator (4) of the first photo-coupler (5)
Even, the output end of the second optoisolator (4) is connected with one end of Er-doped fiber (3), the other end and light wave point of Er-doped fiber (3)
The common end of multiplexer (2) is connected；The input of 10% the output end output and the second photo-coupler (6) of first photo-coupler (5)
End is connected, and an output end of the second photo-coupler (6) is connected with an input terminal of third photo-coupler (24), the second optocoupler
The another output of clutch (6) is connected with the one end for the optical fiber being wrapped on the second piezoelectric ceramics (23), is wrapped in the second pressure
The other end of optical fiber on electroceramics (23) is connected with another input terminal of third photo-coupler (24), third photo-coupler
(24) output end is connected with the input terminal of photoelectric conversion circuit (25)；
It is characterized in that, structure in addition, the output end and function translation circuit (26) of photoelectric conversion circuit (25) input terminal phase
Even, the output end of functional transformation circuit (26) is connected with an input terminal of adaptive amplitude normalizing circuit (27), adaptive width
The output end of degree normalizing circuit (27) is connected with an input terminal of phase-comparison circuit (28)；The input in controllable frequency source (21)
End is connected with single-chip microcontroller (18), and output end is connected with another input terminal of phase-comparison circuit (28), phase-comparison circuit
(28) output end is connected with single-chip microcontroller (18)；The output end in controllable frequency source (21) also with the 2nd PZT driving circuit (22)
Input terminal is connected, and the output end of the 2nd PZT driving circuit (22) is connected with the control terminal of the second piezoelectric ceramics (23)；Constant-current source electricity
The output end on road (15) is connected with thermistor (16), and thermistor (16) is connected with the input terminal of analog to digital conversion circuit (17),
The output end of analog to digital conversion circuit (17) is connected with single-chip microcontroller (18)；Single-chip microcontroller (18) also respectively with input key (14), serial ports
Communication module (19), display screen (20) are connected；
The structure of the functional transformation circuit (26) is one end of capacitor C3 and the pin 12 and electricity of trigonometric function converter U1
The one end for hindering R2 is connected, and input terminal of the other end of capacitor C3 as functional transformation circuit (26) is denoted as port ACOS_in, with
The output end of photoelectric conversion circuit (25) is connected；The other end of resistance R2 is grounded；The pin 2 of trigonometric function converter U1,3,4,
5,8,11,13 ground connection, pin 9,10 are connected with one end of capacitor C2 and -12V power supply, the other end ground connection of capacitor C2；Triangle letter
The pin 6 of number converter U1 is connected with pin 7, and pin 16 is connected with one end of+12V power supply and capacitor C1, and capacitor C1's is another
End ground connection；The pin 1 of trigonometric function converter U1 is connected with the sliding end of slide rheostat W1, one end of slide rheostat W1 with
One end of resistance R1 is connected, and the other end of resistance R1 is connected with the pin 14 of trigonometric function converter U1, slide rheostat W1's
Output end of the sliding end as functional transformation circuit (26), is denoted as port ACOS_out, with adaptive amplitude normalizing circuit (27)
Input terminal be connected；The model AD639 of the trigonometric function converter U1；
The structure of the adaptive amplitude normalizing circuit (27) is, one end of capacitor C9 and one end of resistance R3 and chip U2's
Pin 3 is connected, the other end ground connection of resistance R3, input of the other end of capacitor C9 as adaptive amplitude normalizing circuit (27)
End, is denoted as port ADAPT_in, and the port ACOS_out of and function translation circuit (26) is connected；The pin 1 of chip U2, pin 7,
Pin 8, pin 14 are grounded, and pin 2 is connected with+5V power supply with pin 4, and pin 11 is connected with pin 12 and with capacitor C5's
One end and+5V power supply are connected, the other end ground connection of capacitor C5；The pin 13 of chip U2 is connected with one end of capacitor C4, capacitor C4
The other end ground connection；The pin 9 of chip U2 is connected with one end of capacitor C6, the other end ground connection of capacitor C6；The pin 5 of chip U2
It is connected with one end of resistance R12 and resistance R11, the other end of resistance R12 ground connection, the other end of resistance R11 is defeated with amplifier U4's
One end of outlet and capacitor C8 are connected, the positive supply termination+5V power supply of amplifier U8, negative power end ground connection；The other end of capacitor C8
It is connected with one end of resistance R10, the other end of resistance R10 is connected with the non-inverting input terminal of amplifier U4；The anti-phase input of amplifier U4
It holds and is connected with the sliding end of sliding variohm W3, one end of slide rheostat W3 is connected with+5V power supply, slide rheostat W3's
Other end ground connection；One end of capacitor C7 is connected with the non-inverting input terminal of one end of resistance R9 and amplifier U4, the other end of capacitor C7
Ground connection, the other end of resistance R9 are connected with the output end of one end of resistance R7 and amplifier U3, the other end and amplifier U3 of resistance R7
Inverting input terminal be connected；One end of resistance R8 is connected with the non-inverting input terminal of amplifier U3, other end ground connection；The positive electricity of amplifier U3
Source connects+5V power supply, negative power end ground connection；Output end of the pin 10 of chip U2 as adaptive amplitude normalizing circuit (27),
It is denoted as port ADAPT_out, is connected with an input terminal of phase-comparison circuit (28)；The pin 10 and diode D1 of chip U2
Anode be connected, the cathode of diode D1 is connected with one end of resistance R4, the other end of resistance R4 and one end of resistance R5 and fortune
The inverting input terminal for putting U3 is connected, and the other end of resistance R5 is connected with the anode of diode D2, the cathode of diode D2 and sliding
The sliding end of rheostat W2 is connected；One end of slide rheostat W2 is connected and is grounded with the cathode of diode D3, slide rheostat
The other end of W2 is connected with the anode of one end of resistance R6 and diode D3, another termination -5V power supply of resistance R6；The core
Piece U2 is variable gain amplifier chip, and model is AD8367；
The structure of the phase-comparison circuit (28) is one end of capacitor C10 and the non-inverting input terminal of amplifier U5 and resistance R13
One end be connected, an input terminal of the other end of capacitor C10 as phase-comparison circuit (28) is denoted as port PHASE_in1,
It is connected with the port ADAPT_out of adaptive amplitude normalizing circuit (27)；The other end of resistance R13 is grounded；The positive electricity of amplifier U5
Source connects+5V power supply, negative power end ground connection, reverse inter-input-ing ending grounding, the end CLK of output termination d type flip flop U6A；D type flip flop
The port D of U6A is grounded；The one end capacitor C11 ground connection, the end PR of another termination d type flip flop U6A；Resistance R14 mono- terminates d type flip flop
The end PR of U6A, the end Q of another termination d type flip flop U6A；CLR termination+5V the power supply of d type flip flop U6A, the Q of d type flip flop U6A are non-
Terminate the end PR of d type flip flop U8A；One end of capacitor C12 is connected with one end of the non-inverting input terminal of amplifier U7 and resistance R15, electricity
Hold another input terminal of the other end of C12 as phase-comparison circuit (28), port PHASE_in2 is denoted as, with controllable frequency
The port SineM_out in source (21) is connected；The other end of resistance R15 is grounded；Positive supply termination+5V the power supply of amplifier U7, negative electricity
Source ground connection, reverse inter-input-ing ending grounding, the end CLK of output termination d type flip flop U6B；The port D of d type flip flop U6B is grounded；Capacitor
The one end C13 ground connection, the end PR of another termination d type flip flop U6B；Resistance R16 mono- terminates the end PR of d type flip flop U6B, another termination D
The end Q of trigger U6B；CLR termination+5V the power supply of d type flip flop U6B, the CLR of the Q non-terminated d type flip flop U8A of d type flip flop U6B
End；The end D and the end CLK of d type flip flop U8A is grounded, and output end of the end Q as phase-comparison circuit (28) is denoted as port
PHASE_out is connected with the input terminal of single-chip microcontroller (18)；
The structure in the controllable frequency source (21) is the one of the output termination C14 of one end and amplifier U9 of thermistor Rt1
End, the inverting input terminal of another termination amplifier U9；The pin 2 of another chip termination U10 of capacitor C14；The termination fortune of resistance R17 mono-
The inverting input terminal of U9, one end of another termination capacitor C16, and the output end as controllable frequency source (21) are put, and is denoted as end
Mouth SineM_out；The pin 2 of another chip termination U11 of capacitor C16；The pin 2 of a chip termination U10 of capacitor C15, separately
The pin 2 of one chip termination U11；One end of the homophase input terminating resistor R18 of amplifier U9, positive supply termination+5V power supply, negative electricity
Source connects -5V power supply；The other end of resistance R18 is grounded；The pin 5 of a chip termination U10 of capacitor C17, other end ground connection；Electricity
Hold the pin 5 of a chip termination U11 of C18, other end ground connection；The pin 1 and pin 10 of chip U10 connects+5V power supply, pin 3,
Pin 4 and pin 6 are grounded；One end of 9 connecting resistance R19 of pin, one end of 8 connecting resistance R20 of pin, the one of 7 connecting resistance R21 of pin
End；An input port of the other end of resistance R19 as controllable frequency source (21), is denoted as port SineM_in1；Resistance R20
Another input port as controllable frequency source (21) of the other end, be denoted as port SineM_in2；Port SineM_in1 and
Port SineM_in2 is connected with the input terminal of single-chip microcontroller (18)；Another termination+5V power supply of resistance R21；The pin 1 of chip U11
+ 5V power supply is connect with pin 10, pin 3, pin 4 and pin 6 are grounded；One end of 9 connecting resistance R22 of pin, 8 connecting resistance R23 of pin
One end, one end of 7 connecting resistance R24 of pin；Another termination port SineM_in1 of resistance R22；Another termination of resistance R23
Port SineM_in2；Another termination+5V power supply of resistance R24.
2. a kind of temperature sensor based on your interference structure of Mach Zehnder according to claim 1, which is characterized in that institute
The thermistor 16 stated is 25 DEG C of negative tempperature coefficient thermistors of 10k Ω@.
3. a kind of temperature sensor based on your interference structure of Mach Zehnder according to claim 1 or 2, the Bradley
Lattice grating group 8 is preferably made of 3 Bragg gratings, and the reflectivity of each grating is 90%, and bandwidth is 0.6nm, center
Wavelength is respectively 1550nm, 1560nm and 1630nm.
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| US20110255078A1 (en) * | 2007-10-23 | 2011-10-20 | Us Sensor Systems, Inc. | Interrogator for a plurality of sensor fiber optic gratings |
| CN102564317A (en) * | 2011-12-23 | 2012-07-11 | 北京交通大学 | High-accuracy remote absolute displacement measurement system based on optical fiber composite interference |
| CN103940361A (en) * | 2014-04-30 | 2014-07-23 | 中国科学院半导体研究所 | Fiber bragg grating low-frequency strain sensing demodulation system |
| CN105656561A (en) * | 2016-03-21 | 2016-06-08 | 吉林大学 | Double-ring feedback gain flattening erbium-doped optical fiber amplifier |
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