CN118424349A - Signal demodulation system and method of optical fiber Mach-Zehnder interference sensor - Google Patents
Signal demodulation system and method of optical fiber Mach-Zehnder interference sensor Download PDFInfo
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Abstract
The invention relates to a signal demodulation system and a method of an optical fiber Mach-Zehnder interference sensor, wherein the system comprises: the laser emission module is used for forming an optical signal; the signal adjusting module is used for introducing an optical circulator and a chirped fiber grating according to an optical signal, acquiring optical path changes corresponding to voltage change values between adjacent bright and dark stripes when the Mach-Zehnder interference sensor is started and is free from external parameter influence, and performing coarse adjustment and fine adjustment on the sensor when the sensor is started and is influenced by the external parameter, and acquiring optical path changes corresponding to the moving number of the interference stripes and optical path changes corresponding to voltage change values of the next bright stripes or dark stripes; and the processing and display module is used for calculating the two optical path changes according to the optical path changes corresponding to the voltage change values between the adjacent bright stripes and the adjacent dark stripes to obtain the environment parameter change of the sensor. The invention can realize the accurate signal demodulation of the Mach-Zehnder interference sensor.
Description
Technical Field
The invention relates to the technical field of optical fiber Mach-Zehnder interference sensors and intersections for realizing signal demodulation by using chirped fiber gratings, in particular to a signal demodulation system and a signal demodulation method of the optical fiber Mach-Zehnder interference sensors.
Background
The optical fiber sensor has wide application prospect in the fields of ocean science, civil engineering, petrochemical industry, aerospace and the like, and has the advantages of electric insulation, electromagnetic interference resistance, high sensitivity, high temperature resistance, corrosion resistance, passive sensor end, intrinsic safety, long-distance transmission without signal conversion and an amplifier, small volume, light weight and the like. The optical fiber sensor is divided into two types, namely a functional type sensor and a light transmission type sensor, wherein the two types comprise a phase modulation sensor, a wavelength modulation sensor and the like. The phase modulation type optical fiber sensor generally converts phase change into light intensity change by utilizing light interference to realize detection of external parameters, such as: pressure, tension, temperature, etc., fiber Mach-Zehnder interferometers are typical ones of them; however, accurate demodulation of interferometric sensor signals has long been favored by researchers, trying to find a simple and fast low cost demodulation method.
Disclosure of Invention
The invention aims at solving the defects of the typical application of an optical fiber Mach-Zehnder interferometer, the inaccuracy of a common interference fringe counting method, the blurriness of the moving direction of an interference fringe and the like, and utilizes the fringe counting method as a rough adjustment method to determine the approximate optical path change of a sensing arm affected by the environment, and the initial working point of a sensing system is arranged in the middle position between bright and dark fringes, so that the moving direction of the interference fringe can be judged according to whether the first interference fringe obtained by detection is the bright fringe or the dark fringe, then the optical path change corresponding to the interference fringe is finely demodulated by an optical circulator and a chirped fiber grating which are ingeniously arranged on a reference arm, and finally the change of the environment parameter is accurately demodulated by adjusting the period of the chirped fiber grating.
In order to achieve the above object, the present invention provides the following solutions:
A signal demodulation system for a fiber mach-zehnder interferometric sensor, comprising:
the laser emission module is used for forming an optical signal;
The signal adjusting module is used for introducing an optical circulator and a chirped fiber grating according to the optical signal, acquiring optical path change corresponding to a voltage change value between adjacent bright and dark stripes when the Mach-Zehnder interference sensor is started and is not influenced by external parameters, and performing coarse adjustment and fine adjustment on the Mach-Zehnder interference sensor when the Mach-Zehnder interference sensor is started and is influenced by the external parameters, and acquiring optical path change corresponding to the moving number of interference stripes and optical path change corresponding to a voltage change value of the next bright stripe or dark stripe;
And the processing and display module is used for calculating the optical path change corresponding to the moving number of the interference fringes and the optical path change corresponding to the voltage change value of the next bright fringe or dark fringe according to the optical path change corresponding to the voltage change value between the adjacent bright and dark fringes, and acquiring the environment parameter change of the Mach-Zehnder interference sensor.
Optionally, the signal conditioning module includes: and the first 3dB optical fiber coupler, the second 3dB optical fiber coupler and the optical fibers between the first 3dB optical fiber coupler and the second 3dB optical fiber coupler are used for forming the Mach-Zehnder interference sensor.
Optionally, the optical fiber includes: the sensing arm is used for being influenced by external parameters, the reference arm is provided with an optical circulator, the optical circulator is provided with a chirped fiber grating, the chirped fiber grating is fixed on a magnetostriction rod and used for coarsely adjusting the Mach-Zehnder interference sensor according to the optical signal when the sensing arm is free from the influence of the external parameters, and finely adjusting the Mach-Zehnder interference sensor when the sensing arm is influenced by the external parameters.
Optionally, the signal conditioning module further comprises: and the photoelectric detector is used for acquiring the optical path change corresponding to the voltage change value between the adjacent bright stripes and the adjacent dark stripes and the optical path change corresponding to the voltage change value of the next bright stripe or the next dark stripe.
Optionally, acquiring the optical path change corresponding to the voltage change value between the adjacent bright and dark stripes includes:
When the Mach-Zehnder interference sensor is started to work and has no external parameter influence, the driving voltage of the magnetostrictive rod is regulated, the first detected bright stripes or dark stripes are used as starting points of voltage recording based on the moving quantity of the interference stripes detected by the photoelectric detector, the times of the bright stripes and the dark stripes are recorded, and the optical path change corresponding to the voltage change value between the adjacent bright stripes and the adjacent dark stripes is obtained according to the times of the bright stripes and the dark stripes.
Optionally, acquiring the optical path change corresponding to the moving number of the interference fringes and the optical path change corresponding to the voltage change value of the next bright fringe or dark fringe includes:
When the Mach-Zehnder interference sensor is started to work and is influenced by external parameters, the driving voltage of the magnetostrictive rod is finely adjusted to obtain voltage change values between adjacent bright stripes and dark stripes, the middle position between the bright stripes and the dark stripes is used as a starting point of work according to the voltage change values between the adjacent bright stripes and the dark stripes, coarse adjustment is performed on the Mach-Zehnder interference sensor based on the photoelectric detector to obtain optical path change corresponding to the moving number of the interference stripes, and fine adjustment is performed on the Mach-Zehnder interference sensor by adjusting the driving voltage of the magnetostrictive rod to enable the interference stripes to change towards the same direction until the photoelectric detector receives the next bright stripe or dark stripe, and the optical path change corresponding to the voltage change value of the next bright stripe or dark stripe is obtained.
Optionally, the method for obtaining the optical path change corresponding to the voltage change value of the next bright stripe or dark stripe includes:
[（V1-V2）/V1]×λ/2；
wherein V1 is the voltage variation value between adjacent bright and dark stripes, V2 is the voltage variation value of the next bright stripe or dark stripe, and lambda is the wavelength.
Optionally, the method for obtaining the environmental parameter change of the mach-zehnder interferometry sensor comprises the following steps:
N×λ/2 +（（V1-V2）/V1）×λ/2 +（V1/2）×λ/2；
wherein, N is the number of interference fringe movements, V1 is the voltage variation value between adjacent bright and dark fringes, V2 is the voltage variation value of the next bright fringe or dark fringe, and lambda is the wavelength.
In order to achieve the above object, the present invention further provides a signal demodulation method of an optical fiber mach-zehnder interferometric sensor, including:
acquiring an optical signal, introducing an optical circulator and a chirped fiber grating according to the optical signal, acquiring optical path change corresponding to a voltage change value between adjacent bright and dark fringes when the Mach-Zehnder interference sensor is started and is not influenced by external parameters, and performing coarse adjustment and fine adjustment on the Mach-Zehnder interference sensor when the Mach-Zehnder interference sensor is started and is influenced by the external parameters to acquire optical path change corresponding to the moving number of interference fringes and optical path change corresponding to a voltage change value of the next bright fringe or dark fringe;
And calculating the optical path change corresponding to the moving number of the interference fringes and the optical path change corresponding to the voltage change value of the next bright fringe or dark fringe according to the optical path change corresponding to the voltage change value between the adjacent bright and dark fringes, and obtaining the environment parameter change of the Mach-Zehnder interference sensor.
The beneficial effects of the invention are as follows:
The invention utilizes the ideas of rough adjustment and fine adjustment, realizes the rough demodulation of the Mach-Zehnder interference sensor by a relatively simple method of fringe counting, and skillfully introduces an optical circulator and a chirped fiber grating into a reference arm so as to further realize the fine demodulation of a sensing signal, and finally obtains the size of a precise environment parameter signal; the method comprises the steps of firstly, adjusting the period size of a chirped fiber grating through a magnetostriction rod, finely adjusting interference fringes of a sensing system to the positions of bright fringes or dark fringes of the interference fringes to serve as working initial points of the sensing system, enabling a subsequent signal demodulation process to be simpler, then demodulating the approximate optical path change quantity of a sensing arm affected by environmental parameters through a fringe counting rough adjustment method, obtaining the specific fringe quantity of the counting method, finally changing the period size of the grating through adjusting the driving voltage of the chirped fiber grating magnetostriction rod, enabling the interference fringes to change towards the same direction until the next interference bright fringes or dark fringes appear, finely demodulating the optical path change corresponding to the optical path change quantity according to the driving voltage change quantity of the magnetostriction rod, and finally accurately demodulating the environmental parameter change of the Mach-Zehnder interference sensor according to coarse adjustment of the fringe count and fine adjustment of the period size of the chirped fiber grating. In addition, the moving direction of the interference fringe can be judged according to the condition that the initial working point is the middle position between the bright fringe and the dark fringe and the 1 st fringe is the bright fringe or the dark fringe when the fringe is counted, so that whether the change of the external environment parameter is increased or decreased is determined, which is not done by the common interference fringe counting method.
The demodulation method only relates to the driving voltage adjustment and the common fringe counting of the magnetostrictive rod, and the demodulation device and the demodulation method are simple, quick and accurate and do not relate to various imported high-precision tip equipment.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a signal demodulation system of an optical fiber mach-zehnder interferometric sensor according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of interference fringes generated by optical signals of a sensor arm and a reference arm according to an embodiment of the present invention;
Fig. 3 is a schematic diagram of a chirped fiber grating reflecting the same wavelength signal at different positions according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
The embodiment discloses a signal demodulation system of an optical fiber Mach-Zehnder interference sensor, comprising:
the laser emission module is used for forming an optical signal;
The signal adjusting module is used for introducing an optical circulator and a chirped fiber grating according to optical signals, acquiring optical path changes corresponding to voltage change values between adjacent bright stripes and dark stripes when the Mach-Zehnder interference sensor is started and is not influenced by external parameters, and performing coarse adjustment and fine adjustment on the Mach-Zehnder interference sensor when the Mach-Zehnder interference sensor is started and is influenced by the external parameters, and acquiring optical path changes corresponding to the moving number of interference stripes and optical path changes corresponding to the voltage change values of the next bright stripes or dark stripes;
The processing and display module is used for calculating the optical path change corresponding to the moving number of the interference fringes and the optical path change corresponding to the voltage change value of the next bright fringe or dark fringe according to the optical path change corresponding to the voltage change value between the adjacent bright and dark fringes, and acquiring the environment parameter change of the Mach-Zehnder interference sensor.
The signal conditioning module includes: the first 3dB optical fiber coupler, the second 3dB optical fiber coupler and the optical fibers between the first 3dB optical fiber coupler and the second 3dB optical fiber coupler are used for forming the Mach-Zehnder interference sensor.
The optical fiber includes: the sensing arm is used for being influenced by external parameters, the optical circulator is arranged on the reference arm, the chirped fiber grating is arranged on the optical circulator and fixed on the magnetostriction rod, the sensing arm is used for carrying out coarse adjustment on the Mach-Zehnder interference sensor according to optical signals when the sensing arm has no external parameter influence, and carrying out fine adjustment on the Mach-Zehnder interference sensor when the sensing arm has external parameter influence.
The signal conditioning module further includes: the photoelectric detector is used for acquiring the optical path change corresponding to the voltage change value between the adjacent bright stripes and the adjacent dark stripes and the optical path change corresponding to the voltage change value of the next bright stripe or the next dark stripe.
The method for acquiring the optical path change corresponding to the voltage change value between the adjacent bright stripes and the adjacent dark stripes comprises the following steps:
When the Mach-Zehnder interference sensor is started and has no external parameter influence before working, the driving voltage of the magnetostrictive rod is regulated, the first detected bright stripes or dark stripes are used as starting points of voltage recording based on the moving quantity of the interference stripes detected by the photoelectric detector, the times of the bright stripes and the dark stripes are recorded, and the optical path change corresponding to the voltage change value between the adjacent bright stripes and the adjacent dark stripes is obtained according to the times of the bright stripes and the dark stripes.
The step of obtaining the optical path change corresponding to the moving number of the interference fringes and the optical path change corresponding to the voltage change value of the next bright fringe or dark fringe comprises the following steps:
When the Mach-Zehnder interference sensor is started to work and is influenced by external parameters, the driving voltage of the magnetostrictive rod is finely adjusted to obtain voltage variation values between adjacent bright stripes and dark stripes, the middle position between the bright stripes and the dark stripes is used as a starting point of work according to the voltage variation values between the adjacent bright stripes and the dark stripes, coarse adjustment is carried out on the Mach-Zehnder interference sensor based on the photoelectric detector to obtain optical path variation corresponding to the moving number of the interference stripes, and fine adjustment is carried out on the Mach-Zehnder interference sensor by adjusting the driving voltage of the magnetostrictive rod to enable the interference stripes to change towards the same direction until the photoelectric detector receives the next bright stripe or dark stripe, and the optical path variation corresponding to the voltage variation value of the next bright stripe or dark stripe is obtained;
The middle position is used as a starting point of work, namely, the driving voltage of the magnetostrictive rod is finely adjusted, the bright stripes or the dark stripes are found firstly, and then the working point of the magnetostrictive rod is adjusted to be at the middle position between the bright stripes and the dark stripes according to the voltage change value between the adjacent bright stripes and the voltage change value between the adjacent dark stripes.
As shown in fig. 1, this embodiment discloses a signal demodulation system of an optical fiber mach-zehnder interferometric sensor, including: the invention provides a signal demodulation method, which comprises the steps that two 3dB optical fiber couplers and optical fibers between the two optical fiber couplers form a Mach-Zehnder interferometer, wherein one optical fiber is a sensing arm, and the other optical fiber is a reference arm; the chirped fiber grating on the reference arm is fixed on a magnetostrictive rod, and the magnetostrictive rod is controlled by a driver capable of changing the driving voltage, so that the period size of the chirped fiber grating can be changed when the driving voltage is changed, and the same optical wavelength can be reflected at different positions when the same optical wavelength is incident on the chirped fiber grating;
The optical wavelength signal output by the laser is incident to the Mach-Zehnder interferometer, is split by the first 3dB optical fiber coupler and then enters the sensing arm and the reference arm respectively, the optical signal of the sensing arm part is modulated by environment information and then is transmitted to the 2 nd 3dB optical fiber coupler, interference is generated between the optical signal transmitted by the coupling area and the reference arm, the optical signal of the reference arm is input by the 1 port of the optical circulator, is output from the 2 port and then is reflected by the chirped fiber grating, the reflected optical signal returns to the optical circulator from the 2 port, and finally is output from the 3 port of the optical circulator and is transmitted to the 2 nd 3dB optical fiber coupler, and the interference signal of the coupling area is received by the photoelectric detector PD and then is subjected to subsequent fringe counting and signal demodulation by combining with the control of the chirped fiber grating;
The sensing arm and the reference arm generate interference fringes as shown in fig. 2 in the coupling area of the 2 nd 3dB fiber coupler, if the optical path of the sensing arm or the optical path of the reference arm changes, the fringes will move, and the optical path change of the reference arm makes the optical signal reflect at different positions of the chirped fiber grating by adjusting the voltage on the chirped fiber grating magnetostrictive rod, so as to change the optical path size of the optical signal at the reference arm, as shown in fig. 3, namely: the distance of the optical signal in the grating area is shorter or longer by adjusting the driving voltage of the magnetostriction rod, so that the purpose of changing the optical path of the reference arm is achieved; before the sensor is started to work, the sensing arm is kept free from the influence of external environment parameters, then the driving voltage of a magnetostrictive rod on the chirped fiber grating is regulated, the moving quantity of interference fringes is monitored, in the process of regulating the driving voltage, the bright fringes or the dark fringes of the interference fringes are detected to be used as the starting points of voltage recording, the bright-dark-bright fringes are recorded n times (n is more than or equal to 2), and the voltage change value between two adjacent fringes is determined according to the n times, namely: obtaining voltage change V1 of a magnetostriction rod on the chirped fiber grating when the interference fringe is changed once, wherein the optical path change corresponding to the V1 is half wavelength;
when the sensing arm is affected by external parameters, the interference fringes will move, and when the sensing system is started to work, the voltage on the chirped fiber bragg grating magnetostrictive rod is adjusted first so that the photoelectric detector PD receives bright fringes or dark fringes, and when the position of the bright fringes or the dark fringes is well adjusted, the driving voltage and the driving voltage of the magnetostrictive rod are adjusted to be V1/2, namely: the middle position between the bright stripes and the dark stripes is used as a starting point of work, then a sensing system is started, the number N of interference stripe movements is recorded by a stripe counter, finally when an environment parameter is required to be determined, the driving voltage of a magnetostriction rod is regulated until the photoelectric detector PD receives the next bright stripe or dark stripe, the voltage change V2 regulated in the process is recorded, the optical path corresponding to less than one stripe change is ((V1-V2)/V1) x lambda/2, and the environment parameter causes the total optical path change to be Nx lambda/2+ ((V1-V2)/V1) x lambda/2+ (V1/2) x lambda/2), so that the demodulation of the external environment parameter can be completed;
The conventional fringe counting is generally unable to determine the moving direction of the interference fringe, which causes trouble to the detecting method of the fringe counting. According to the invention, the initial working point is determined to be at the middle position between the bright stripes and the dark stripes according to the driving voltage regulation of the magnetostrictive rod, then the direction of the movement of the interference stripes can be judged by determining the 1 st counted stripe to be the bright stripe or the dark stripe according to the subsequent stripe counting, and the change of the external environment parameter can be known to be increased or decreased immediately after the movement direction of the interference stripes is determined.
The embodiment also discloses a signal demodulation method of the optical fiber Mach-Zehnder interference sensor, which comprises the following steps:
Acquiring an optical signal, introducing an optical circulator and a chirped fiber grating according to the optical signal, acquiring optical path changes corresponding to voltage change values between adjacent bright and dark fringes when the Mach-Zehnder interference sensor is started and is not influenced by external parameters, and performing coarse adjustment and fine adjustment on the Mach-Zehnder interference sensor when the Mach-Zehnder interference sensor is started and is influenced by the external parameters to acquire the optical path changes corresponding to the moving number of the interference fringes and the optical path changes corresponding to the voltage change values of the next bright or dark fringes;
and calculating the optical path change corresponding to the moving number of the interference fringes and the optical path change corresponding to the voltage change value of the next bright fringe or dark fringe according to the optical path change corresponding to the voltage change value between the adjacent bright and dark fringes, and obtaining the environment parameter change of the Mach-Zehnder interference sensor.
The above embodiments are merely illustrative of the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, but various modifications and improvements made by those skilled in the art to which the present invention pertains are made without departing from the spirit of the present invention, and all modifications and improvements fall within the scope of the present invention as defined in the appended claims.
Claims (9)
1. A signal demodulation system for a mach-zehnder interferometric sensor comprising:
the laser emission module is used for forming an optical signal;
The signal adjusting module is used for introducing an optical circulator and a chirped fiber grating according to the optical signal, acquiring optical path change corresponding to a voltage change value between adjacent bright and dark stripes when the Mach-Zehnder interference sensor is started and is not influenced by external parameters, and performing coarse adjustment and fine adjustment on the Mach-Zehnder interference sensor when the Mach-Zehnder interference sensor is started and is influenced by the external parameters, and acquiring optical path change corresponding to the moving number of interference stripes and optical path change corresponding to a voltage change value of the next bright stripe or dark stripe;
And the processing and display module is used for calculating the optical path change corresponding to the moving number of the interference fringes and the optical path change corresponding to the voltage change value of the next bright fringe or dark fringe according to the optical path change corresponding to the voltage change value between the adjacent bright and dark fringes, and acquiring the environment parameter change of the Mach-Zehnder interference sensor.
2. The system for demodulating a signal from a fiber mach-zehnder interferometric sensor according to claim 1, wherein the signal conditioning module comprises: and the first 3dB optical fiber coupler, the second 3dB optical fiber coupler and the optical fibers between the first 3dB optical fiber coupler and the second 3dB optical fiber coupler are used for forming the Mach-Zehnder interference sensor.
3. The signal demodulation system of a fiber mach-zehnder interferometric sensor of claim 2, wherein the optical fiber comprises: the sensing arm is used for being influenced by external parameters, the reference arm is provided with an optical circulator, the optical circulator is provided with a chirped fiber grating, the chirped fiber grating is fixed on a magnetostriction rod and used for coarsely adjusting the Mach-Zehnder interference sensor according to the optical signal when the sensing arm is free from the influence of the external parameters, and finely adjusting the Mach-Zehnder interference sensor when the sensing arm is influenced by the external parameters.
4. A signal demodulation system for a fibre mach-zehnder interferometric sensor according to claim 3, wherein the signal conditioning module further comprises: and the photoelectric detector is used for acquiring the optical path change corresponding to the voltage change value between the adjacent bright stripes and the adjacent dark stripes and the optical path change corresponding to the voltage change value of the next bright stripe or the next dark stripe.
5. The signal demodulation system of the optical fiber mach-zehnder interferometric sensor of claim 4, wherein obtaining the optical path change corresponding to the voltage change value between the adjacent bright and dark fringes comprises:
When the Mach-Zehnder interference sensor is started to work and has no external parameter influence, the driving voltage of the magnetostrictive rod is regulated, the first detected bright stripes or dark stripes are used as starting points of voltage recording based on the moving quantity of the interference stripes detected by the photoelectric detector, the times of the bright stripes and the dark stripes are recorded, and the optical path change corresponding to the voltage change value between the adjacent bright stripes and the adjacent dark stripes is obtained according to the times of the bright stripes and the dark stripes.
6. The signal demodulation system of the optical fiber mach-zehnder interferometric sensor according to claim 4, wherein obtaining the optical path change corresponding to the number of movements of the interference fringes and the optical path change corresponding to the voltage change value of the next bright or dark fringe comprises:
When the Mach-Zehnder interference sensor is started to work and is influenced by external parameters, the driving voltage of the magnetostrictive rod is finely adjusted to obtain voltage change values between adjacent bright stripes and dark stripes, the middle position between the bright stripes and the dark stripes is used as a starting point of work according to the voltage change values between the adjacent bright stripes and the dark stripes, coarse adjustment is performed on the Mach-Zehnder interference sensor based on the photoelectric detector to obtain optical path change corresponding to the moving number of the interference stripes, and fine adjustment is performed on the Mach-Zehnder interference sensor by adjusting the driving voltage of the magnetostrictive rod to enable the interference stripes to change towards the same direction until the photoelectric detector receives the next bright stripe or dark stripe, and the optical path change corresponding to the voltage change value of the next bright stripe or dark stripe is obtained.
7. The signal demodulation system of the optical fiber mach-zehnder interferometer sensor according to claim 6, wherein the method for obtaining the optical path change corresponding to the voltage change value of the next bright stripe or dark stripe comprises:
[（V1-V2）/V1]×λ/2；
wherein V1 is the voltage variation value between adjacent bright and dark stripes, V2 is the voltage variation value of the next bright stripe or dark stripe, and lambda is the wavelength.
8. The signal demodulation system of an optical fiber mach-zehnder interferometric sensor according to claim 1, wherein the method for obtaining the environmental parameter change of the mach-zehnder interferometric sensor comprises the following steps:
N×λ/2 +（（V1-V2）/V1）×λ/2 +（V1/2）×λ/2；
wherein, N is the number of interference fringe movements, V1 is the voltage variation value between adjacent bright and dark fringes, V2 is the voltage variation value of the next bright fringe or dark fringe, and lambda is the wavelength.
9. A method for demodulating a signal of an optical fiber mach-zehnder interferometric sensor, comprising:
acquiring an optical signal, introducing an optical circulator and a chirped fiber grating according to the optical signal, acquiring optical path change corresponding to a voltage change value between adjacent bright and dark fringes when the Mach-Zehnder interference sensor is started and is not influenced by external parameters, and performing coarse adjustment and fine adjustment on the Mach-Zehnder interference sensor when the Mach-Zehnder interference sensor is started and is influenced by the external parameters to acquire optical path change corresponding to the moving number of interference fringes and optical path change corresponding to a voltage change value of the next bright fringe or dark fringe;
And calculating the optical path change corresponding to the moving number of the interference fringes and the optical path change corresponding to the voltage change value of the next bright fringe or dark fringe according to the optical path change corresponding to the voltage change value between the adjacent bright and dark fringes, and obtaining the environment parameter change of the Mach-Zehnder interference sensor.
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| CN109141487A (en) * | 2018-07-25 | 2019-01-04 | 国网河北省电力有限公司电力科学研究院 | A kind of distributed fiberoptic sensor |
| CN110208967A (en) * | 2019-04-26 | 2019-09-06 | 华东师范大学 | The tunable microwave photon filter device of chirp grating is embedded based on optical fiber MZI |
| CN115112038A (en) * | 2022-07-01 | 2022-09-27 | 西北核技术研究所 | High-precision distributed strain measurement optical system and measurement method |
| CN117991231A (en) * | 2024-03-05 | 2024-05-07 | 哈尔滨工业大学 | Rapid high-precision ranging method and device based on time domain stretching sweep frequency interference |
| CN118050705A (en) * | 2024-03-05 | 2024-05-17 | 哈尔滨工业大学 | Time domain stretching sweep frequency interference ranging range expansion method and device |
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