CN114518162B - Optical fiber hydrophone interference signal intensity compensation method and system - Google Patents
Optical fiber hydrophone interference signal intensity compensation method and system Download PDFInfo
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Abstract
The application discloses a method and a system for compensating interference signal intensity of an optical fiber hydrophone, wherein the method comprises the following steps: acquiring an echo pulse signal, and processing the echo pulse signal by using a preset method to obtain an initial interference signal; calculating an intensity attenuation coefficient of the initial interference signal; and performing intensity compensation on the initial interference signal according to the intensity attenuation coefficient to obtain an interference signal after intensity compensation. The method resamples the distorted echo pulse signals by using a preset method, so that the track of each pulse peak value can be positioned more accurately; determining a signal intensity attenuation coefficient by calculating the peak value of the pulse signal; and performing intensity compensation on the signal according to the intensity attenuation coefficient. The invention fundamentally solves the problem of amplitude attenuation of interference signals caused by introducing the circulator, effectively improves the signal-to-noise ratio of the interference signals and improves the stability of signal demodulation.
Description
Technical Field
The invention relates to the technical field of optical fiber sensing, in particular to an optical fiber hydrophone interference signal intensity compensation method, an optical fiber hydrophone interference signal intensity compensation device, a computer readable storage medium and a computer readable storage system.
Background
The optical fiber sensor has been widely studied worldwide due to the advantages of high sensitivity, electromagnetic interference resistance, large-scale multiplexing and the like. In recent years, with the mature application of the online grating etching technology of the wire drawing tower, the weak reflection grating sensing array is greatly developed, and the multiplexing capability of the grating is greatly enhanced. In the field of underwater environment detection, large-scale multiplexing and good resolution are key indexes of an optical fiber hydrophone, and especially for a towed array, the increase of array multiplexing elements can improve array gain, so that the detection distance of a target is enlarged; meanwhile, the detection precision can be further improved by good spatial resolution.
In order to realize high spatial resolution of the quasi-distributed time division multiplexing array, two methods of reducing grating intervals and improving the sampling rate of the system become a preferred solution. The detection precision of weak light pulses is improved, and a stable interference signal demodulation algorithm is selected, so that the system performance is greatly affected. In the prior art, demodulation algorithms based on 3×3 couplers are widely used because of their simple structure; however, in the optical path to which the algorithm is applied, the light intensity of one path of signal is reduced due to the insertion loss of the circulator, and meanwhile, the time when three paths of light pulses reach the detector is inconsistent due to the extension of the optical path, so that the peak point position is extremely likely to be offset, the intensity of an interference signal is greatly reduced due to the fact that the error motion track of the peak value after the offset is recorded, and the asymmetry of three paths of signals is increased. The phase shift demodulation technology based on the Elliptic Fitting Algorithm (EFA) has higher precision and stability for measuring the asymmetric signals, but the algorithm has high complexity, and particularly for a time division multiplexing system, a high-speed data acquisition system is generally required to process massive data, and the method can increase the burden of data processing, thereby being unfavorable for application and popularization.
Therefore, a simple and effective signal preprocessing method is needed to solve the problem of amplitude attenuation of interference signals caused by introducing a single-channel circulator, and meanwhile, the stability of interference signal output and the signal-to-noise ratio of signals are required to be improved, so that convenience is provided for subsequent signal demodulation.
Disclosure of Invention
In view of the foregoing, it is desirable to provide a method, apparatus, computer-readable storage medium and system for compensating the interference signal strength of an optical fiber hydrophone, which are used to solve the problems of the prior art, such as attenuation of the interference signal amplitude, low signal-to-noise ratio of the signal, and poor demodulation stability, caused by the introduction of a circulator.
In order to solve the problems, the invention provides a method for compensating the interference signal intensity of an optical fiber hydrophone, which comprises the following steps:
acquiring an echo pulse signal, and processing the echo pulse signal by using a preset method to obtain an initial interference signal;
calculating an intensity attenuation coefficient of the initial interference signal;
and performing intensity compensation on the initial interference signal according to the intensity attenuation coefficient to obtain an interference signal after intensity compensation.
Further, the preset method is a cubic spline interpolation algorithm.
Further, the echo pulse signal is processed by a preset method to obtain an initial interference signal, which comprises the following steps:
inputting a plurality of interpolation nodes at equal intervals in a preset interval of the echo pulse signal;
substituting the interpolation nodes into a preset cubic spline interpolation function respectively to obtain a cubic spline interpolation function value corresponding to the interpolation nodes;
and determining the cubic spline interpolation function value corresponding to the interpolation node as echo pulse data corresponding to the interpolation node.
Further, the echo pulse signal and the initial interference signal are three signals.
Further, acquiring the echo pulse signal includes:
and acquiring echo pulse signals generated by the sensor arm and the reference arm after interference through the coupler.
Further, the three-path initial interference signal specifically includes:
wherein ,Em Representing the amplitude of the sensor arm, E k The amplitude of the reference arm is indicated,represents the phase change measured due to external impact, < >>The constants representing the initial phases, a and b, respectively, represent the signal peak intensity variation coefficients.
Further, calculating an intensity attenuation coefficient of the initial interference signal includes:
obtaining a first peak-to-peak value according to the maximum intensity value and the minimum intensity value of the first path of interference signals;
obtaining a second peak value according to the maximum intensity value and the minimum intensity value of the second path of interference signals;
and calculating the intensity attenuation coefficient according to the first peak value and the second peak value.
The invention also provides an optical fiber hydrophone interference signal intensity compensation device, which comprises a processor and a memory, wherein the memory is stored with a computer program, and when the computer program is executed by the processor, the optical fiber hydrophone interference signal intensity compensation method according to any one of the technical schemes is realized.
The invention also provides a computer readable storage medium, on which a computer program is stored, which when being executed by a processor, implements a method for compensating the interference signal intensity of an optical fiber hydrophone according to any of the above technical schemes.
The invention also provides an optical fiber hydrophone interference signal intensity compensation system, which comprises the optical fiber hydrophone interference signal intensity compensation device, a light source, a signal generator, an acousto-optic modulator, an erbium-doped optical fiber amplifier, a first optical fiber circulator, a weak reflection grating sensing array, a second circulator, a 3X 3 coupler, a Faraday rotating mirror and a demodulator;
the narrow linewidth continuous light emitted by the light source enters an acousto-optic modulator driven by a signal generator to modulate Cheng Maichong light;
the pulse light enters the weak reflection grating sensing array through the first optical fiber circulator after being amplified by the erbium-doped optical fiber amplifier;
the pulse sequence reflected by the weak reflection grating sensing array enters a 3 multiplied by 3 coupler through a second optical fiber circulator and then passes through a Faraday rotating mirror to obtain an echo pulse signal;
the echo pulse signals enter a 3 multiplied by 3 coupler and are processed by the optical fiber hydrophone interference signal intensity compensation device to obtain compensated interference signals;
and the compensated interference signal enters the demodulator for demodulation processing.
Compared with the prior art, the invention has the beneficial effects that: firstly, acquiring an echo pulse signal, and processing the echo pulse signal by using a preset method to obtain an initial interference signal; secondly, calculating the intensity attenuation coefficient of the initial interference signal; and finally, carrying out intensity compensation on the initial interference signal according to the intensity attenuation coefficient to obtain an interference signal after intensity compensation. According to the invention, the distorted echo pulse signals are resampled by a preset method, and the echo pulse signals are fitted, so that the track of each pulse peak can be more accurately positioned; and determining a signal intensity attenuation coefficient by calculating the peak value of the pulse signal, and performing intensity compensation on the signal according to the intensity attenuation coefficient. The invention fundamentally solves the problem of amplitude attenuation of interference signals caused by introducing the circulator, effectively improves the signal-to-noise ratio of the interference signals and improves the stability of signal demodulation.
Drawings
FIG. 1 is a schematic flow chart of an embodiment of a method for compensating interference signal intensity of an optical fiber hydrophone;
FIG. 2 is a schematic diagram of an embodiment of an optical fiber hydrophone interference signal strength compensation system according to the present invention;
FIG. 3 is a schematic diagram of an embodiment of an optical fiber hydrophone interference signal strength compensation system according to the present invention;
FIG. 4 is a waveform diagram of an original echo pulse signal of an embodiment of a fiber optic hydrophone interference signal intensity compensation system with a weak reflection grating sensor array of 800 weak reflection fiber optic grating sensor arrays;
FIG. 5 is a waveform comparison chart of an echo pulse signal and an initial interference signal of an embodiment of an optical fiber hydrophone interference signal intensity compensation system provided by the invention;
FIG. 6 is a schematic diagram of an embodiment of an optical fiber hydrophone interference signal intensity compensation method according to the present invention;
fig. 7 is a schematic diagram of a 10Hz demodulation signal obtained by using three different methods according to an embodiment of the method for compensating the interference signal intensity of an optical fiber hydrophone.
Detailed Description
Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and together with the description serve to explain the principles of the invention, and are not intended to limit the scope of the invention.
The invention provides a method, a device, a computer-readable storage medium and a system for compensating the interference signal intensity of an optical fiber hydrophone, which are respectively described in detail below.
The embodiment of the invention provides a method for compensating the interference signal intensity of an optical fiber hydrophone, which is shown in a flow chart in figure 1 and specifically comprises the following steps:
s101, acquiring an echo pulse signal, and processing the echo pulse signal by using a preset method to obtain an initial interference signal;
step S102, calculating the intensity attenuation coefficient of the initial interference signal;
and step 103, performing intensity compensation on the initial interference signal according to the intensity attenuation coefficient to obtain an interference signal after intensity compensation.
Compared with the prior art, the optical fiber hydrophone interference signal intensity compensation method provided by the embodiment comprises the steps of firstly, acquiring an echo pulse signal, and processing the echo pulse signal by using a preset method to obtain an initial interference signal; secondly, calculating the intensity attenuation coefficient of the initial interference signal; and finally, carrying out intensity compensation on the initial interference signal according to the intensity attenuation coefficient to obtain an interference signal after intensity compensation. According to the invention, the distorted echo pulse signals are resampled by a preset method, so that the echo pulse signals are fitted, and the track of each pulse peak value can be more accurately positioned; and determining a signal intensity attenuation coefficient by calculating the peak value of the pulse signal, and performing intensity compensation on the signal according to the intensity attenuation coefficient. The invention fundamentally solves the problem of amplitude attenuation of interference signals caused by introducing the circulator, effectively improves the signal-to-noise ratio of the interference signals and improves the stability of signal demodulation.
As a preferred embodiment, in step S101, the preset method is a cubic spline interpolation algorithm.
As a preferred embodiment, the processing the echo pulse signal by using a preset method to obtain an initial interference signal includes:
inputting a plurality of interpolation nodes at equal intervals in a preset interval of the echo pulse signal;
substituting the interpolation nodes into a preset cubic spline interpolation function respectively to obtain a cubic spline interpolation function value corresponding to the interpolation nodes;
and determining the cubic spline interpolation function value corresponding to the interpolation node as echo pulse data corresponding to the interpolation node.
Since no research has shown that the echo pulse signal can be described by a fixed mathematical expression, a cubic spline interpolation method is introduced to process the echo pulse signal in order to reduce the noise of the echo pulse signal. For echo pulse signals, n+1 discrete sampling points are equidistantly inserted in a section [ p, q ], and the original echo pulse signals are interpolated through constructing a cubic polynomial function s (x) of the section;
let s "(x) i )＝M i (i＝0，1，…，n)，s'(x i )＝m i (i=0, 1, …, n) is valid, we can solve the function value of the above function using known conditions, and can express three types of boundary conditions as:
wherein s' (g) and s "(g) represent the first and second derivatives, respectively, of the polynomial function. Therefore, the cubic spline interpolation algorithm can dynamically fit the echo pulse signals, and is used for processing the echo pulse signals of the optical fiber hydrophone system.
As a preferred embodiment, the echo pulse signal and the initial interference signal are three signals.
As a preferred embodiment, acquiring the echo pulse signal comprises:
and acquiring echo pulse signals generated by the sensor arm and the reference arm after interference through the coupler.
As a preferred embodiment, the initial interference signal specifically includes:
wherein ,Em Representing the amplitude of the sensor arm, E k The amplitude of the reference arm is indicated,represents the phase change measured due to external impact, < >>The constants representing the initial phases, a and b, respectively, represent the signal peak intensity variation coefficients.
As a preferred embodiment, in step S102, calculating the intensity attenuation coefficient of the initial interference signal includes:
obtaining a first peak-to-peak value according to the maximum intensity value and the minimum intensity value of the first path of interference signals;
obtaining a second peak value according to the maximum intensity value and the minimum intensity value of the second path of interference signals;
and calculating the intensity attenuation coefficient according to the first peak value and the second peak value.
As a specific example, since each pulse in the echo pulse signal represents a grating sensor, the echo pulse signal needs to be segmented according to the sensing distance. For the pulse corresponding to any grating sensor, the echo pulse signal generated by the grating sensor can be recorded, and the variation track of the peak value of the pulse signal can be obtained by using fixed pulse delay. For three initial interference signals obtained through a 3 x 3 coupler:
when (when)When the first path of interference signal I C-1 The maximum signal strength of the first path of interference signal is expressed as:
when (when)When the first path of interference signal I C-1 The minimum signal strength of the first path of interference signal is therefore expressed as:
from this, it can be obtained that the first path of interference signal I C-1 The first peak-to-peak value (vpp) of (a) is:
(I C-1 ) max -(I C-1 ) min ＝4aE m E k
by the same method, a second path of interference signal I can be obtained C-2 The second peak to peak value of (2) is:
(I C-2 ) max -(I C-2 ) min ＝4bE m E k
from this, the interference signal intensity attenuation coefficient due to the pulse delay can be calculated as:
as a specific embodiment, in step S103, performing intensity compensation on the initial interference signal according to the intensity attenuation coefficient to obtain an interference signal after intensity compensation, including:
for intensity decay factorIs a function of the initial interference signal of (a):
the method for performing intensity compensation on the initial interference signal comprises the following steps: the signal peak intensity variation coefficient divided by the intensity attenuation coefficient to compensate the signal intensity attenuation generated by the echo pulse signal passing through the circulator can be expressed as:
as a specific example, a demodulation algorithm based on a 3×3 coupler is used to obtain the processing result of the underwater sound signal.
The embodiment of the invention provides an optical fiber hydrophone interference signal intensity compensation device, which comprises a processor and a memory, wherein the memory is stored with a computer program, and when the computer program is executed by the processor, the optical fiber hydrophone interference signal intensity compensation method according to any technical scheme is realized.
The embodiment of the invention provides a computer readable storage medium, on which a computer program is stored, which when being executed by a processor, realizes the optical fiber hydrophone interference signal intensity compensation method according to any one of the technical schemes.
The computer readable storage medium and the apparatus according to the embodiments of the present invention may be implemented with reference to what is specifically described in the foregoing description of an optical fiber hydrophone interference signal intensity compensation method according to the present invention, and have similar beneficial effects as those of the optical fiber hydrophone interference signal intensity compensation method described above, which are not described herein.
The embodiment of the invention provides an optical fiber hydrophone interference signal intensity compensation system, as shown in fig. 2, fig. 2 is a schematic structural diagram of the optical fiber hydrophone interference signal intensity compensation system, and the system comprises an optical fiber hydrophone interference signal intensity compensation device, a light source, a signal generator, an acousto-optic modulator, an erbium-doped optical fiber amplifier, a first optical fiber circulator, a weak reflection grating sensing array, a second circulator, a 3×3 coupler, a Faraday rotary mirror and a demodulator;
the narrow linewidth continuous light emitted by the light source enters an acousto-optic modulator driven by a signal generator to modulate Cheng Maichong light;
the pulse light enters the weak reflection grating sensing array through the first optical fiber circulator after being amplified by the erbium-doped optical fiber amplifier;
the pulse sequence reflected by the weak reflection grating sensing array enters a 3 multiplied by 3 coupler through a second optical fiber circulator and then passes through a Faraday rotating mirror to obtain an echo pulse signal;
the echo pulse signals enter a 3 multiplied by 3 coupler and are processed by the optical fiber hydrophone interference signal intensity compensation device to obtain compensated interference signals;
and the compensated interference signal enters the demodulator for demodulation processing.
As a specific embodiment, the faraday rotator mirror includes a first faraday rotator mirror and a second faraday rotator mirror with arm length differences equal to the grating spacing.
As a specific embodiment, as shown in fig. 3, fig. 3 is a schematic diagram of a system for compensating interference signal intensity of an optical fiber hydrophone according to the present embodiment, where a weak reflection grating sensing array is a uwFBGs array. The echo pulse signal passing through the 3×3 coupler is divided into three signals of C-1, C-2 and C-3, and in order to meet the condition of the 3×3 demodulation algorithm, a second optical fiber circulator is generally used to transmit the signal of C-1 path. In a specific analysis, the echo pulse signal and the initial interference signal are shown in a dotted line diagram. After passing through the second fiber optic circulator, the pulses of the C-1 signal have a delay compared to the C-2 signal and the C-3 signal. In this case, the peak-to-peak amplitudes of the three interference signals obtained by fixing the abscissa will be different. The intensities of the three signals C-1, C-2 and C-3 can be expressed as:
wherein ,Em Representing the amplitude of the sensor arm, E k The amplitude of the reference arm is indicated,represents the phase change measured due to external impact, < >>The constants representing the initial phases, a and b, respectively, represent the signal peak intensity variation coefficients.
Example 1
As a specific embodiment, in order to meet the interference condition in the optical fiber hydrophone interference signal intensity compensation system, the light source is a narrow linewidth laser (DFB-M-1550-150-F-10-09 MPF-FC/APC), the bandwidth of the laser is 3kHz, and the center wavelength is 1550nm;
an acousto-optic modulator (T-M200-0.1C2J-3-F2S) generates a pulse period of 2kHz and a pulse width of 20 ns;
the echo pulse signal passing through the 3×3 coupler is divided into three signals: the C-2 path signal and the C-3 path signal directly enter the optical fiber hydrophone interference signal intensity compensation device, and the C-1 path signal enters the optical fiber hydrophone interference signal intensity compensation device through the second circulator.
The detection bandwidth of the interference signal intensity compensation device (KG-200M-APR) is 200MHz. To distinguish each narrow pulse of the sensor, the sampling rate of the processor is set to 250MSa/s.
In this embodiment, the weak reflection grating sensor array is a uwFBG TDM array with 800 grating sensors, and the sensing distance is 4km. As shown in fig. 4, the abscissa in the figure is the distance of the sensor, the ordinate is the amplitude of the echo pulse signal, and by amplifying a part of the echo pulse signal, it can be seen that: compared with the C-2 signal and the C-3 signal, the total offset of the C-1 signal is t 0 Thus, the amplitude of the C-1 signal at the same position will be greatly reduced during interference, which verifies the theoretical analysis.
After the echo pulse signal enters the optical fiber hydrophone interference signal intensity compensation device, the echo pulse signal is fitted by utilizing cubic spline interpolation, so that strong noise in the echo pulse signal is reduced. The echo pulse signal and the initial interference signal obtained by interpolation of the echo pulse signal are shown in fig. 5. In fig. 5, (a) is the original echo pulse signal, (b) is the initial interference signal; (a) And (b), the abscissa is time, the ordinate is amplitude value, and compared with the echo pulse signal, the obtained initial interference signal after the cubic spline interpolation processing is more complete, which proves that the cubic spline interpolation algorithm is suitable for processing the pulse signal of the weak reflection fiber grating.
Example 2
As a specific embodiment, as shown in fig. 6, fig. 6 is a schematic diagram of an actual experiment of a fiber optic hydrophone interference signal intensity compensation system; in the embodiment, the underwater sound wave is simulated and generated by adopting a vibration liquid column method. The acoustic pressure field in the liquid column is generated by an excitation stage with a linear power amplifier (VT 500), the voltage sensitivity of the accelerometer being 5.76 pc/m.s -2 . Because the exciter can only generate larger amplitude at low frequency under the limitation of output power, in order to meet the requirement of generating phase change with the amplitude larger than pi, the underwater sound signal with the low frequency range of 5-50Hz is selected for experiment. Meanwhile, in order to obtain a correct standing wave signal, the inner diameter of the circular tube is set to 7.50cm, and the height of the liquid column is set to 18.75cm. The optical fiber hydrophone in the experimental system uses uwFBGs array with the central wavelength of 1550nm, the reflectivity between-40 dB and-50 dB, the spacing between adjacent gratings is 5m, and the data acquisition device adopts NI PXIe 5170RAnd preprocessing the obtained signal by using a data processor to perform cubic spline interpolation and intensity compensation.
Example 3
In this embodiment, three different methods are used to obtain a 10Hz demodulation signal and calculate the Power Spectral Density (PSD), hereinafter referred to as PSD. The experimental results are shown in fig. 7, in which the abscissa of each waveform is frequency and the ordinate is the amplitude value of the demodulated signal. In fig. 7, the upper square waveform indicates a demodulation result obtained by an echo pulse signal which is not subjected to interpolation and intensity compensation processing, the middle waveform indicates a demodulation result obtained by directly adopting intensity compensation to the echo pulse signal without being subjected to interpolation, and the lower square waveform indicates a demodulation result obtained by performing cubic spline interpolation and intensity compensation on the echo pulse signal; the signal to noise ratios obtained for the three methods were 10.75dB, 23.21dB and 23.31dB, respectively.
It can be seen that the signal-to-noise ratio of the signal without any processing is low, and the attenuation of the interfering signal caused by the pulse delay is a main factor causing signal distortion. After the intensity compensation is carried out by the method of the technical scheme, the demodulation effect is obviously improved.
On the other hand, this example analyzes the average value of the noise PSD at 1rad for reference signals of-36.14 dB, -45.06dB and-46.17 dB, respectively. It can be seen that the noise PSD average value can be reduced by 1.11dB after cubic spline interpolation; the suppression of noise can be further increased by about 8.92dB after the intensity compensation, which also proves to be very effective in the approach proposed in the present application to address the pulse delay problem.
In addition, as shown in Table 1, the present example conducted demodulation experiments at different frequencies for the underwater acoustic signals of 5Hz, 10Hz, 20Hz, 30Hz, 40Hz and 50Hz, respectively, and the results of the qualitative analysis are shown in Table 1. It can be seen that after cubic spline interpolation and intensity compensation, the PSD average value of the signal is greatly improved, and the gain is more than 7dB, which verifies the robustness of the method under different frequencies. Table 1 records the raw and corrected PSD results at different frequencies.
TABLE 1
The invention discloses a method, a device, a computer-readable storage medium and a system for compensating the interference signal intensity of an optical fiber hydrophone. Firstly, acquiring an echo pulse signal, and processing the echo pulse signal by using a preset method to obtain an initial interference signal; secondly, calculating to obtain an intensity attenuation coefficient according to the initial interference signal; and finally, carrying out intensity compensation on the initial interference signal according to the intensity attenuation coefficient to obtain an interference signal after intensity compensation.
According to the invention, the distorted echo pulse signals are resampled by a preset method, so that the echo pulse signals are fitted, and the track of each pulse peak value can be more accurately positioned; and determining a signal intensity attenuation coefficient by calculating the peak value of the pulse signal, and performing intensity compensation on the signal according to the intensity attenuation coefficient. The invention fundamentally solves the problem of amplitude attenuation of interference signals caused by introducing the circulator, effectively improves the signal-to-noise ratio of the interference signals and improves the stability of signal demodulation. From each experimental result, the invention has good effect on treating the pulse delay problem, and the demodulation stability is obviously improved; and has good robustness and practicality, and is suitable for large-scale popularization and use.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.
Claims (7)
1. The optical fiber hydrophone interference signal intensity compensation method is characterized by comprising the following steps:
acquiring an echo pulse signal, and processing the echo pulse signal by using a preset method to obtain an initial interference signal;
calculating an intensity attenuation coefficient of the initial interference signal;
performing intensity compensation on the initial interference signal according to the intensity attenuation coefficient to obtain an interference signal after intensity compensation;
the echo pulse signal and the initial interference signal are three signals;
the three paths of initial interference signals specifically comprise:
wherein ,representing the first path of interference signal->Representing the second path of interference signal, ">Representing a third path of the interference signal,E m representing the amplitude of the sensing arm,E k the amplitude of the reference arm is indicated,φ s (t) Indicating the phase change measured due to external impact,φ 0 a constant representing the initial phase is provided,aandbrespectively representing the signal peak intensity change coefficients;
calculating an intensity attenuation coefficient of the initial interference signal, comprising:
obtaining a first peak-to-peak value according to the difference value between the maximum intensity value and the minimum intensity value of the first path of interference signals;
obtaining a second peak-to-peak value according to the difference value between the maximum intensity value and the minimum intensity value of the second path of interference signals;
and calculating to obtain an intensity attenuation coefficient according to the ratio of the first peak value to the second peak value.
2. The method for compensating for the interference signal strength of an optical fiber hydrophone according to claim 1, wherein the preset method is a cubic spline interpolation algorithm.
3. The method for compensating the interference signal intensity of the optical fiber hydrophone according to claim 2, wherein the echo pulse signal is processed by a preset method to obtain an initial interference signal, comprising:
inputting a plurality of interpolation nodes at equal intervals in a preset interval of the echo pulse signal;
substituting the interpolation nodes into a preset cubic spline interpolation function respectively to obtain a cubic spline interpolation function value corresponding to the interpolation nodes;
and determining the cubic spline interpolation function value corresponding to the interpolation node as echo pulse data corresponding to the interpolation node.
4. The method of compensating for the intensity of an interference signal of a fiber optic hydrophone as recited in claim 1, wherein acquiring the echo pulse signal comprises:
and acquiring echo pulse signals generated by the sensor arm and the reference arm after interference through the coupler.
5. An optical fiber hydrophone interference signal strength compensation device, comprising a processor and a memory, wherein the memory stores a computer program, which when executed by the processor, implements the optical fiber hydrophone interference signal strength compensation method according to any one of claims 1-4.
6. A computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a method of optical fiber hydrophone interference signal strength compensation according to any of the claims 1-4.
7. An optical fiber hydrophone interference signal intensity compensation system is characterized by comprising the optical fiber hydrophone interference signal intensity compensation device according to claim 5, and further comprising a light source, a signal generator, an acousto-optic modulator, an erbium-doped optical fiber amplifier, a first optical fiber circulator, a weak reflection grating sensing array, a second circulator, a 3×3 coupler, a Faraday rotating mirror and a demodulator;
the narrow linewidth continuous light emitted by the light source enters an acousto-optic modulator driven by a signal generator to modulate Cheng Maichong light;
the pulse light enters the weak reflection grating sensing array through the first optical fiber circulator after being amplified by the erbium-doped optical fiber amplifier;
the pulse sequence reflected by the weak reflection grating sensing array enters a 3 multiplied by 3 coupler through a second optical fiber circulator and then passes through a Faraday rotating mirror to obtain an echo pulse signal;
the echo pulse signals enter a 3 multiplied by 3 coupler and are processed by the optical fiber hydrophone interference signal intensity compensation device to obtain compensated interference signals;
and the compensated interference signal enters the demodulator for demodulation processing.
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| US5457534A (en) * | 1991-10-23 | 1995-10-10 | Phase Metrics | Method and apparatus to calibrate intensity and determine fringe order for interferometric measurement of small spacings |
| JP2008151697A (en) * | 2006-12-19 | 2008-07-03 | Fujifilm Corp | Optical tomographic imaging device |
| CN112097813A (en) * | 2020-09-14 | 2020-12-18 | 中国人民解放军国防科技大学 | 3X3 coupler photoelectric detection method and device based on optical frequency modulation |
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| US7375817B2 (en) * | 2006-05-15 | 2008-05-20 | Shin-Chu Huang | Counting signal processing method for fiber optic interferometric sensor |
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| US5457534A (en) * | 1991-10-23 | 1995-10-10 | Phase Metrics | Method and apparatus to calibrate intensity and determine fringe order for interferometric measurement of small spacings |
| JP2008151697A (en) * | 2006-12-19 | 2008-07-03 | Fujifilm Corp | Optical tomographic imaging device |
| CN112097813A (en) * | 2020-09-14 | 2020-12-18 | 中国人民解放军国防科技大学 | 3X3 coupler photoelectric detection method and device based on optical frequency modulation |
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| 基于拉丝塔光栅阵列的超细线光纤水听器关键技术研究;庞彦东;中国博士学位论文全文数据库基础科学辑(第1期);第48-63页 * |
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