CN114414528A - Double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signal - Google Patents
Double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signal Download PDFInfo
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Abstract
The invention provides a double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals, which comprises the steps of obtaining wireless signals from the air, carrying out electro-optical modulation on the wireless signals to obtain input optical signals, outputting the input optical signals to a first port of an optical circulator, outputting the input optical signals to a salinity sensor by the optical circulator through a second port, and soaking at least one part of the salinity sensor in seawater to be detected; and after the return light signal output by the salinity sensor is input from the second port of the optical circulator and is output to the photoelectric detector through the third port of the optical circulator, the photoelectric detector performs photoelectric conversion on the return light signal to obtain a measurement electric signal, the measurement electric signal is output to the electronic spectrum analyzer, the frequency of the measurement electric signal is analyzed by the electronic spectrum analyzer, and the salinity of the seawater to be detected is calculated according to the analysis result of the frequency spectrum. The invention can conveniently detect the salinity of the seawater.
Description
Technical Field
The invention relates to the field of salinity detection of seawater, in particular to a double-optical-fiber end surface interference salinity detection method based on 5G microwave photon signals.
Background
The seawater salinity in different regions is often different, and the change of the seawater salinity often has great influence on the marine ecology, therefore, the seawater salinity needs to be monitored, for example, the seawater salinity in some specific regions needs to be detected periodically. The existing system (SDS) for detecting the salinity of the seawater is often provided with a device for detecting the salinity of the seawater.
Referring to fig. 1, the existing seawater salinity detecting device comprises an erbium-doped fiber amplifier 11, an electro-optical modulator 12, a salinity sensor 13, an optical circulator 14, a photoelectric converter 15 and an electronic spectrum analyzer 16. Erbium doped fiber amplifier 11 outputs optical signals to electro-optic modulator 12, and electro-optic modulator 12 also receives radio frequency signals, for example, connects to a Radio Frequency (RF) signal source and receives RF signals. It can be seen that the existing seawater salinity detecting device uses the amplified spontaneous emission signal (ASE) emitted by the erbium-doped fiber amplifier 11, and then is electro-optically modulated by the electro-optical modulator 12 by using the electrical signal generated by the radio frequency signal source, and the modulated optical signal is then sent to the first port 141 of the optical circulator 14 and enters the salinity sensor 13 through the second port 142. During detection, a part of the salinity sensor 13 is immersed in seawater to be detected, and since the frequency of the optical signal changes after the optical signal passes through seawater with different salinity, the changed optical signal is transmitted to the third port 143 through the second port 142 of the optical circulator 14, and is incident to the photoelectric converter 15 through the third port 143.
The photoelectric converter 15 performs photoelectric modulation on the optical signal passing through the salinity sensor 13, converts the optical signal into an electrical signal, outputs the obtained electrical signal to the electronic spectrum analyzer 16, and performs spectrum analysis on the photoelectrically converted signal by the electronic spectrum analyzer, thereby calculating the salinity of the seawater.
However, because the erbium-doped fiber amplifier 11 is expensive and has a large volume, the existing device for detecting seawater salinity has a high production cost, and is inconvenient to detect seawater salinity outdoors due to the large volume, and often needs to acquire a certain amount of seawater from the sea area to be detected and detect the salinity in a laboratory, which results in low efficiency of detecting seawater salinity, and cannot realize detection outdoors anytime and anywhere, and the convenience of detecting seawater salinity is not high.
Disclosure of Invention
The invention aims to provide a double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals, which can conveniently detect seawater salinity outdoors.
In order to achieve the purpose, the method for detecting the end surface interference salinity of the double optical fibers based on the 5G microwave photon signals comprises the following steps: acquiring a wireless signal from the air, electro-optically modulating the wireless signal to obtain an input optical signal, outputting the input optical signal to a first port of an optical circulator, outputting the input optical signal to a salinity sensor by the optical circulator through a second port of the optical circulator, and soaking at least one part of the salinity sensor in seawater to be detected; and after the return light signal output by the salinity sensor is input from the second port of the optical circulator and is output to the photoelectric detector through the third port of the optical circulator, the photoelectric detector performs photoelectric conversion on the return light signal to obtain a measurement electric signal, the measurement electric signal is output to the electronic spectrum analyzer, the frequency of the measurement electric signal is analyzed by the electronic spectrum analyzer, and the salinity of the seawater to be detected is calculated according to the analysis result of the frequency spectrum.
It can be seen from the above-mentioned scheme that, in the present invention, a wireless signal is obtained from the air, and an input optical signal is obtained after electro-optical modulation is performed on the wireless signal, for example, a wireless signal transceiver module is used to obtain a wireless signal of mobile communication from the air as an electro-optical modulated signal. Because the wireless signal transceiver module's low in production cost, and small, can reduce the manufacturing cost of sea water salinity detection device by a wide margin to reduce the volume of whole equipment, can conveniently carry out the detection of sea water salinity in the open air, improve the convenience that the sea water salinity detected.
In a preferred aspect, acquiring wireless signals from the air comprises: and acquiring a wireless signal from the air by using the wireless signal transceiving module.
Further, the wireless signal acquired by the wireless signal transceiver module is a mobile communication wireless signal.
Because a large amount of wireless signals of mobile communication exist in the air, for example, when people use mobile phones to communicate, a large amount of radio signals exist in the air, the radio signals in the air are obtained and used as basic input electric signals, and the electric signals are used for modulating a direct modulation type electro-optical modulator, so that the convenience of seawater salinity detection can be improved.
In a further aspect, the wireless signal transceiver module includes a band pass filter, and the band pass filter filters and outputs the wireless signal with a predetermined frequency.
Therefore, according to the actual situation of the wireless signals in the air, the wireless signals in the specific frequency band are selected from the air as the input basic electric signals, for example, the wireless signals in the specific frequency band with higher intensity are used, and the accuracy of seawater salinity detection can be improved.
The further proposal is that after acquiring wireless signals from the air, the wireless signals are amplified and then electro-optically modulated; wherein electro-optically modulating the signal comprises: and directly modulating the voltage or the current of the light source by using the amplified signal to obtain an input optical signal.
Therefore, the optical signal generated by the erbium-doped optical fiber amplifier can be avoided by directly modulating, the cost of seawater salinity detection can be greatly reduced, the size of the seawater salinity detection device is correspondingly reduced, and the seawater salinity detection on the outdoor site can be realized.
In a further embodiment, the salinity sensor is a salinity sensor with an APC joint. Preferably, the salinity sensor comprises two sections of physical contact optical fibers and a section of single-mode optical fiber, and a reference solution with preset salinity is arranged between the APC joint and the first end face of the first section of physical contact optical fiber; the single-mode optical fiber is positioned between the first section of physical contact optical fiber and the second section of physical contact optical fiber, and the second end face of the second section of physical contact optical fiber is soaked in seawater to be detected.
It can be seen that when the input optical signal passes through the reference solution after passing through the APC splice and forms a reflected optical signal on the first end face of the first segment of physical contact fiber, the reflected optical signal is transmitted to the second port of the optical circulator. In addition, a portion of the optical signal will pass through the first end face of the first segment of physical contact fiber and continue along the single mode fiber, reflecting upon reaching the second end face of the second segment of physical contact fiber. Thus, the two reflected signals pass through the second port and the third port of the optical circulator in sequence, and form a microwave photonic filter at the third port due to interference, and only optical signals with specific wavelengths can pass through the third port to enter the photoelectric converter. Therefore, the signals after photoelectric conversion are analyzed on an electronic spectrum analyzer, and the electronic spectrum analyzer determines the salinity of the seawater to be detected according to the frequency band of the optical signals output by the optical circulator.
Still further, the length of the single mode optical fiber is greater than the length of the first segment of physical contact optical fiber, and the length of the single mode optical fiber is greater than the length of the second segment of physical contact optical fiber.
Therefore, by arranging the longer single-mode optical fiber, the two beams of optical signals have larger time delay, the requirement of interference is met, and the accuracy of seawater salinity detection is improved.
In a further aspect, the optical signal reflected by the first end surface of the first segment of physical contact light and the optical signal reflected by the second end surface of the second segment of physical contact light sequentially pass through the third port of the optical circulator.
Because the optical signals reflected on the two end faces of the two sections of physical contact light successively pass through the third port of the optical circulator, the microwave photonic filter is formed, only the optical signals with specific wavelength can pass through the third port to enter the photoelectric converter, the signal quantity received by the electronic spectrum analyzer is limited, and the salinity of the seawater can be accurately calculated.
Further, after acquiring the wireless signal from the air, judging whether the power of the acquired wireless signal meets the preset requirement, and if not, acquiring a new wireless signal again.
It can be seen that if the power of the acquired wireless signal is low, the wireless signal is abandoned, and a new wireless signal is acquired again, so as to ensure that the power of the wireless signal subjected to electro-optical modulation is high, and thus the accuracy of the seawater salinity detection is ensured.
Drawings
Fig. 1 is a block diagram of a conventional seawater salinity detecting apparatus.
FIG. 2 is a block diagram of a seawater salinity detection apparatus used in an embodiment of the dual-fiber end-face interference salinity detection method based on 5G microwave photon signals.
FIG. 3 is a block diagram of the structure of a salinity sensor in a seawater salinity detection device used in the embodiment of the dual-fiber end surface interference salinity detection method based on 5G microwave photon signals.
FIG. 4 is a flowchart of an embodiment of a double-fiber end surface interference salinity detection method based on 5G microwave photon signals.
FIG. 5 is a flow chart of calculating the final seawater salinity value in the embodiment of the dual-fiber end-face interference salinity detection method based on 5G microwave photon signals.
The invention is further explained with reference to the drawings and the embodiments.
Detailed Description
The invention relates to a double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals, which is a method for detecting seawater salinity, and particularly, a wireless signal transceiver module with low production cost and small volume is used for acquiring aerial wireless signals, such as mobile communication wireless signals, and the voltage or current of a laser is directly modulated by using the wireless signals, so that the production cost and the volume of a seawater salinity detection device are reduced by using an erbium-doped optical fiber amplifier, and the seawater salinity detection is conveniently carried out outdoors.
The method of the embodiment uses the seawater salinity detection device shown in fig. 2 to detect the salinity of the seawater, and the seawater salinity detection device comprises a wireless signal transceiver module 20, a salinity sensor 23, an optical circulator 24, a photoelectric converter 25 and an electronic spectrum analyzer 26. The wireless signal transceiver module 20 includes a band-pass filter 21, a signal amplifier 22 and an optical-electrical demodulator 28, preferably, the number of the band-pass filters 21 may be one or more, and if a plurality of band-pass filters 21 are provided, signals output by the plurality of band-pass filters 21 are all received by the signal amplifier 22.
The wireless signal transceiver module 20 may acquire wireless signals from the air, for example, acquire wireless signals of a specific frequency band from the air. Specifically, the band pass filter 21 allows only the radio signal of the specific frequency band to pass through, and therefore, the radio signal of the specific frequency band can be acquired from the air by sampling the band pass filter 21 of the specific frequency. The signal amplifier 22 amplifies the wireless signal obtained by the band-pass filter 21, and the amplified signal is output to the optical-electrical demodulator 28.
Preferably, after the wireless signal is acquired by the band-pass filter 21, the wireless signal transceiver module 20 further detects the power of the acquired wireless signal, determines whether the power of the wireless signal meets a preset requirement, for example, whether the power of the wireless signal is higher than the preset power, and if the power of the wireless signal does not meet the preset requirement, abandons the wireless signal and reacquires a new wireless signal. In this way, it can be ensured that the power of the wireless signal input to the signal amplifier 22 has a high power, thereby ensuring the quality of the electro-optical modulation and thus the accuracy of the seawater salinity detection.
The optical-electrical modulator 28 receives the amplified wireless signal, and a light source is disposed in the optical-electrical modulator 28 to generate an optical signal, for example, a light emitting diode or a laser, and the optical signal is generated by the light emitting diode or the laser. The photoelectric modulator 28 uses the amplified wireless signal to directly modulate the voltage or current of the light source, and since the wireless signal received by the band-pass filter 21 from the air is a wireless rf signal, the voltage or current of the light source can be directly modulated by the wireless rf signal to change the frequency of the output optical signal, so that the difficulty of the electro-optical modulation can be reduced by using the photoelectric direct modulation method. In addition, because the optical signal is modulated by an optical-electrical direct modulation mode, an erbium-doped fiber amplifier is not required to be arranged.
Preferably, the wireless signal transceiver module 20 may be implemented by a mobile communication wireless signal transceiver module, for example, a 5G signal transceiver module. For example, the 5G signal transceiver module may be a 5G base station, so that the volume of the wireless signal transceiver module 20 can be made small and the production cost is low, compared with the case of using an erbium-doped fiber amplifier, the embodiment can greatly reduce the production cost of the seawater salinity detecting apparatus and the volume of the seawater salinity detecting apparatus. In addition, since the 5G transceiver module can generally be adapted to a severe environment, the wireless transceiver module 20 can be installed near the seaside and can be maintained for a long time.
The optical circulator 24 has three ports, i.e., a first port 241, a second port 242, and a third port 243, and an optical signal incident on the optical circulator 24 from the first port 241 can be emitted only from the second port 242, and an optical signal incident on the optical circulator 24 from the second port 242 can be emitted only from the third port 243, and cannot be transmitted in the reverse direction.
The optical-electrical straight modulator 28 modulates the optical signal by using a wireless rf signal to obtain an input optical signal, and the output end of the optical-electrical straight modulator 28 is connected to the first port 241 of the optical circulator 24, so that the input optical signal enters from the first port 241 and exits from the second port 242. Salinity sensor 23 is connected to second port 242 of optical circulator 24 so the input optical signal is incident on salinity sensor 23 from second port 242.
Referring to fig. 3, an optical fiber 231, an APC connector 232, a first segment of physical contact optical fiber 235, a single mode optical fiber 236, and a second segment of physical contact optical fiber 237 are disposed in the salinity sensor 23, wherein a first end of the optical fiber 231 is connected to a second port 242 of the optical circulator 24, and the APC connector 232 is disposed at a second end of the optical fiber 23. Wherein, the outer end face of the APC connector 232 forms an inclined plane of 8 °, that is, the outer end face of the APC connector forms an angle of 8 ° with the axis. The first end face 234 of the first segment of physical contact fiber 235 is a conventional PC connector, i.e., a face polished to a micro-sphere, so that the first end face 234 will form a first reflective surface. The second end of the first length of physical contact fiber 235 is an APC splice and is connected to a single mode fiber 236. The second segment of physical contact fiber 237 has a second end face 239, the second end face 239 is a free end of the second segment of physical contact fiber 237, the second end face 239 is also a common PC connector, i.e., an end face polished to a micro-sphere, and thus the second end face 239 will form a second reflecting surface. The other end of the second segment of physical contact fiber 237 is provided with an APC splice that is connected to the single mode fiber 236. In addition, the second end face 239 of the second segment of the physical contact optical fiber 237 extends into the accommodating cavity 238, the accommodating cavity 238 is filled with seawater to be detected, and preferably, the second end face 239 is completely immersed in the seawater to be detected.
In addition, a holding chamber 233 is disposed between the APC connector 232 and a first end face 234 of the first length of physical contact optical fiber 231, and the holding chamber 233 is filled with a reference solution of a preset salinity, for example, seawater of a known salinity. An input optical signal passes through the optical fiber 231, exits from the APC connector 232, and penetrates through the reference solution, and a portion of the optical signal is reflected by the first end face 234 and incident on the optical fiber 231, thereby forming a first reflected signal. Another portion of the input optical signal will pass through the first end face 234 and be incident on the first segment of physical contact fiber 235, then pass through the single-mode fiber 236 to the second segment of physical contact fiber 237, and be reflected on the second end face 239 to form a second reflected signal, which in turn passes through the second segment of physical contact fiber 237, the single-mode fiber 236, the first segment of physical contact fiber 235 and is incident on the optical fiber 231, and then enters the second port 242 of the optical circulator 24. Therefore, the first reflected signal and the second reflected signal actually pass through the optical circulator 24 one after another, and there is a time difference between the first reflected signal and the second reflected signal when passing through the third port 243 of the optical circulator 24. Thus, a microwave photonic filter is formed at the third port 243 of the optical circulator 24.
In this embodiment, the length of the single mode fiber 236 is between 1.5 km and 2.5 km, preferably, the length of the single mode fiber 236 is 2 km, and the lengths of the first segment of the physical contact fiber 235 and the second segment of the physical contact fiber 237 are equal and do not exceed 5 m, preferably, the lengths of the first segment of the physical contact fiber 235 and the second segment of the physical contact fiber 237 are between 2 m and 3 m. It can be seen that the length of the single mode optical fiber 236 is much greater than the length of the first and second lengths of physical contact optical fibers 235, 237.
Thus, within the salinity sensor 23, since the second end face 239 of the second segment of physical contact optical fiber 237 is completely immersed in the seawater to be tested, the seawater having a known salinity between the first end face 234 and the APC connector 232, such that the first reflected signal and the second reflected signal form microwave interference at the third port 243 of the optical circulator 24. According to the principle of microwave interference, only optical signals with specific wavelengths can pass through the microwave interferometer, and therefore, of interference signals formed by the first reflected signal and the second reflected signal, only optical signals with specific wavelengths are output from the third port 243 of the optical circulator 24, the output optical signals are received by the photoelectric converter 25, and the photoelectric converter 25 performs photoelectric conversion on the received optical signals, converts the optical signals into electrical signals, and forms measurement electrical signals. The photoelectric converter 25 outputs the measurement electrical signal to the electronic spectrum analyzer 26, and the electronic spectrum analyzer 26 performs spectrum analysis on the measurement electrical signal subjected to photoelectric conversion, thereby calculating the salinity of the seawater to be detected.
Specifically, the electronic spectrum P (2 π f) corresponding to the optical signal at the third port 243 of the optical circulator 24 is analyzed by the electronic spectrum analyzer 26m) The following formula is satisfied:
in the formula 1, fmIs the microwave frequency, R1For the reflection coefficient at the first end face 234 of the optical signal after passing through seawater of known salinity between the first end face 234 and the APC joint 232, the reflection coefficient R is known because the salinity of the reference solution is known1Is also a known coefficient. R2Is the reflection coefficient of the optical signal at the second end face 239 of the second segment of physical contact optical fiber 237, which is related to the salinity of the seawater to be detected. And A (λ) represents the output spectrum after passing through the photo-electric collimator 28, so R1A (λ) is the spectrum of light reflected at the first end face 234, A (λ) (1-R)1)α2R2Is the spectrum after passing through the first end face 234 and being transmitted and then reflected by the second end face 239, α is the transmission loss of optical power in the optical fiber, and k is a constant related to the photon-to-electron conversion efficiency of the photoelectric converter 25. τ (λ) is the time between the first reflected signal and the second reflected signalDelay, i.e., the difference between the time the first reflected signal arrives at the third port 234 of the optical circulator 24 and the time the second reflected signal arrives at the third port 234 of the optical circulator 24. Specifically, τ (λ) can be expressed by the following formula:
τ(λ)＝ng(lambda) 2L/c (formula 2)
Wherein n isg(λ) is the spectral range [ λ 1, λ 2]]The inner group velocity profile, L is the fiber length between the first end face 234 and the second end face 239, and c is the speed of light in vacuum. According to the integral mean theorem at [ lambda 1, lambda 2]Can be simplified to the following equation:
where λ 0 is the median of the spectral range λ 1, λ 2.
Due to the first term of equation 1 and the microwave frequency fmIs irrelevant, and is therefore at microwave frequency fmrIf 2 π f is satisfiedmrτ(λ0) When the condition is (2n-1) pi, the electron spectrum P (2 pi f) can be obtainedm) Wherein n is an integer. Combining equation 1 to equation 3, the electron spectrum P (2 π f)m) The minimum of (d) can be expressed as follows:
due to the reflection coefficient R2Is a coefficient related to the salinity of the seawater to be detected, and can be expressed as the following formula according to the Fresnel reflection law:
R2(S)＝(nsilica-nwater(S))2/(nsilica+nwater(S))2(formula 5)
Wherein n issilicaAnd nwaterThe refractive index of the light beam transmitted in the optical fiber and the sea water, respectively, and the refractive index n of the light beam transmitted in the optical fibersilicaThe relationship to salinity S can be expressed as:
nwater(S)＝nwater0+k2s (formula 6)
Wherein k is2Is a predetermined constant, for example, 1.779 × 10-4，nwater0Is the refractive index of the beam transmitted in pure water. Thus, combining equations 4 through 6, one can deduce the frequency f at the microwave frequencymrMinimum R of (C)fThe power is as follows:
wherein,
when the salinity of the seawater to be detected changes, the reflection coefficient R2Corresponding changes can also occur, thereby changing the electronic spectrum
The value of (c). Thus, it is possible to measure the microwave frequency fmrMinimum power R offTo detect changes in seawater salinity. According to the above formulas 7 to 10, the variation of the salinity value of the seawater with the microwave frequency is not linear theoretically, and the key index is the sensing sensitivity Q1And a second order nonlinear term Q1And fitting the measurement result of the original data after noise is added in the experiment. To evaluate the linearity of the salinity detection device, the parameter | Q can be theoretically calculated2/Q1|：
|Q2/Q1|＝k2/(2(nsilica-nwater0) (formula 11)
It can be seen that the electron spectrum P (2 pi f) detected by the electron spectrum analyzer 26 is different for the seawater to be detected with different salinitym) The salinity of the seawater to be detected can be calculated according to the value of the electronic spectrum obtained by the electronic spectrum analyzer 26.
The specific steps of the double-fiber end surface interference salinity detection method based on 5G microwave photon signals are described below with reference to FIG. 4. First, step S1 is executed to acquire a wireless signal, for example, a wireless signal of mobile communication, which may be a 4G signal or a 5G signal, from the air by using the wireless signal transceiver module. Then, step S2 is executed to determine whether the acquired power of the wireless signal meets a preset requirement, for example, whether the power of the wireless signal is greater than a preset power value, if so, step S3 is executed, otherwise, step S8 is executed to discard the currently acquired wireless signal and to re-acquire a new wireless signal, that is, to re-acquire the wireless signal through the band pass filter, and step S2 is executed again.
In step S3, the acquired wireless signal is subjected to amplification processing, for example, a signal amplifier is used to amplify the received wireless signal, and the amplified signal is subjected to direct electro-optical modulation. Preferably, the wireless signal transceiver module is provided with a photo-electric modulator, the photo-electric modulator is provided with a light source, such as a light emitting diode or a laser, and the amplified wireless radio frequency signal is used to directly modulate the voltage or the current of the light source, so as to change the frequency of the optical signal, and the optical signal output by the photo-electric modulator is the input optical signal of this embodiment.
Next, step S4 is executed to send the input optical signal obtained through electro-optical modulation to the first port of the optical circulator, the input optical signal is transmitted from the first port to the second port, and then step S5 is executed, the input optical signal is incident to the salinity sensor from the second port. The input optical signal forms a first reflection signal on a first end face of a first section of physical contact optical fiber of the salinity sensor, and forms a second reflection signal on a second end face of a second section of physical contact optical fiber, and the second reflection signal needs to pass through a long single-mode optical fiber, so that the first reflection signal firstly passes through a second port of the optical circulator and is emitted from a third port, and the second reflection signal is emitted from the second port and the third port of the optical circulator later than the first reflection signal, therefore, microwave interference is formed at the third port of the optical circulator, and the microwave interference is equivalent to forming a microwave photon interferometer.
Then, step S6 is executed, and the return light signal emitted from the third port of the optical circulator is received by the photoelectric converter, and the photoelectric converter performs photoelectric conversion on the return light signal to obtain a measurement electric signal. Finally, step S7 is executed to send the measurement electrical signal to the electronic spectrum analyzer, and the electronic spectrum analyzer calculates the spectrum information of the electrical signal, thereby calculating the salinity value of the seawater to be measured.
In practical application, the resolution of the electronic spectrum analyzer is set, and the frequency scanning range is set to be 3.48GHz to 3.52 GHz. In addition, the salinity of the reference solution disposed between the first end face 234 and the APC connector 232 is a reference value to form a deep trap filter of the microwave photonic filter. Preferably, the depth of the depth-notch filter is greater than 10 dB. The depth of the microwave photonic filter is defined as the difference between the maxima and minima of the radio frequency response curve.
Preferably, for each seawater to be measured, seawater salinity values at a plurality of different frequency bands, for example, salinity values at 5 different frequency bands, may be collected, and an average value of the plurality of salinity values may be calculated as a final calculation result, so as to improve the detection accuracy.
Or, for the wireless signals of the same frequency band, the accuracy of seawater salinity detection can be improved by adopting a mode of measuring for multiple times in a short time. Referring to fig. 5, step S11 is first performed to acquire a plurality of wireless signals scattered in time, for example, a plurality of wireless signals are acquired at preset intervals in a short time, the acquisition time of two adjacent wireless signals is about 1 second, the acquired wireless signals are subjected to photoelectric modulation to obtain an input optical signal, the input optical signal is input to an optical circulator and subjected to photoelectric conversion after passing through a salinity sensor, and a seawater salinity value corresponding to each wireless signal is calculated by using the measured electrical signal, that is, step S12 is performed.
Then, step S13 is executed to determine whether there is significantly abnormal data in the plurality of seawater salinity values, for example, whether there is a seawater salinity value significantly higher than other seawater salinity values or significantly lower than other seawater salinity values, if so, step S14 is executed to remove the significantly abnormal seawater salinity values, and then step S15 is executed. If there is no significantly abnormal seawater salinity value, step S15 is performed. In step S15, the seawater salinity values that are not rejected are subjected to an averaging calculation, and the average obtained by the calculation is taken as a final seawater salinity value. Therefore, the calculation accuracy of the salinity of the seawater can be improved by eliminating the obviously abnormal seawater salinity values and then calculating the average value.
The first reflection signal and the second reflection signal formed at the end faces of the two sections of physical contact optical fibers of the salinity sensor form microwave photon interference, and the method is actually a double-end-face optical signal interference detection method. Compared with the traditional seawater salinity measuring method based on spectrum measurement, the embodiment can measure the salinity value of the seawater by advancing the minimum value of the radio frequency response curve of microwave photon interference. Experiments show that when the salinity of the seawater is within the range of 30.0-35.5 per mill, the sensitivity of salinity detection is high, and the seawater salinity detection has good linearity and stability.
In addition, since the present embodiment obtains the wireless signal from the air, the frequency of the optical signal is changed by directly modulating the voltage or current of the light source with the wireless signal, so that the optical signal does not need to be generated by using the erbium-doped fiber amplifier. Because the wireless signal transceiver module's low in production cost, and small, can reduce the manufacturing cost of sea water salinity detection device by a wide margin to reduce the volume of whole equipment, can conveniently carry out the detection of sea water salinity in the open air, improve the convenience that the sea water salinity detected.
Finally, it should be emphasized that the above-described preferred embodiments of the present invention are merely examples of implementations, not limitations, and various changes and modifications may be made by those skilled in the art, without departing from the spirit and scope of the invention, and any changes, equivalents, improvements, etc. made within the spirit and scope of the present invention are intended to be embraced therein.
Claims (10)
1. A double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals is characterized by comprising the following steps:
acquiring a wireless signal from the air, electro-optically modulating the wireless signal to obtain an input optical signal, outputting the input optical signal to a first port of an optical circulator, outputting the input optical signal to a salinity sensor by the optical circulator through a second port of the optical circulator, and soaking at least one part of the salinity sensor in seawater to be detected;
and after being input from the second port of the optical circulator, the return light signal output by the salinity sensor is output to a photoelectric detector through the third port of the optical circulator, the photoelectric detector performs photoelectric conversion on the return light signal to obtain a measurement electric signal, the measurement electric signal is output to an electronic spectrum analyzer, the frequency of the measurement electric signal is analyzed by the electronic spectrum analyzer, and the salinity of the seawater to be detected is calculated according to the analysis result of the frequency spectrum.
2. The double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals according to claim 1, characterized in that:
acquiring wireless signals from the air comprises: and acquiring a wireless signal from the air by using the wireless signal transceiving module.
3. The double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals according to claim 2, characterized in that:
the wireless signal acquired by the wireless signal transceiver module is a mobile communication wireless signal.
4. The double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals according to claim 2, characterized in that:
the wireless signal transceiver module comprises a band-pass filter, and the band-pass filter filters and outputs wireless signals with preset frequency.
5. The double-optical-fiber end-face interference salinity test method based on 5G microwave photon signals according to any one of claims 1 to 4, characterized in that:
after acquiring a wireless signal from the air, amplifying the wireless signal and then performing electro-optic modulation;
wherein electro-optically modulating the signal comprises: and directly modulating the voltage or the current of the light source by using the amplified signal to obtain the input optical signal.
6. The double-optical-fiber end-face interference salinity test method based on 5G microwave photon signals according to any one of claims 1 to 4, characterized in that:
the salinity sensor is a salinity sensor with an APC joint.
7. The double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals according to claim 6, characterized in that:
the salinity sensor comprises two sections of physical contact optical fibers and a section of single-mode optical fiber, and a reference solution with preset salinity is arranged between the APC joint and the first end face of the first section of physical contact optical fiber;
the single-mode optical fiber is positioned between the first section of physical contact optical fiber and the second section of physical contact optical fiber, and the second end face of the second section of physical contact optical fiber is soaked in the seawater to be detected.
8. The double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals according to claim 7, characterized in that:
the length of the single mode fiber is greater than the length of the first segment of physical contact fiber, and the length of the single mode fiber is greater than the length of the second segment of physical contact fiber.
9. The double-optical-fiber end-face interference salinity detection method based on 5G microwave photon signals according to claim 8, characterized in that:
and the optical signal reflected by the first end face of the first section of physical contact light and the optical signal reflected by the second end face of the second section of physical contact light sequentially pass through the third port of the optical circulator.
10. The double-optical-fiber end-face interference salinity test method based on 5G microwave photon signals according to any one of claims 1 to 4, characterized in that:
after acquiring a wireless signal from the air, judging whether the acquired power of the wireless signal meets a preset requirement, and if not, acquiring a new wireless signal again.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117768018A (en) * | 2023-12-22 | 2024-03-26 | 北京交科公路勘察设计研究院有限公司 | Expressway optical cable digital monitoring and intelligent application system and method |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007524075A (en) * | 2003-06-19 | 2007-08-23 | マサチユセツツ・インスチチユート・オブ・テクノロジイ | Phase measuring system and method |
| CN105891434A (en) * | 2016-06-03 | 2016-08-24 | 深圳职业技术学院 | Seawater salinity online detection method and device |
| US20170030830A1 (en) * | 2013-01-28 | 2017-02-02 | Woods Hole Oceanographic Institution | Submersible n-wavelength interrogation system and method for multiple wavelength interferometers |
| US20170363412A1 (en) * | 2014-12-17 | 2017-12-21 | Pgs Geophysical As | Pressure insensitive interferometer |
| CN109142278A (en) * | 2018-09-14 | 2019-01-04 | 华北电力大学（保定） | A kind of measurement method of seawater salinity |
| CN109831739A (en) * | 2019-03-19 | 2019-05-31 | 王业坤 | A kind of passive SOS calling deliverance apparatus, system and method based on less radio-frequency |
| CN110231631A (en) * | 2019-06-27 | 2019-09-13 | Oppo广东移动通信有限公司 | Localization method, terminal, network access equipment, electronic equipment, storage medium |
| CN111665220A (en) * | 2020-07-16 | 2020-09-15 | 哈尔滨理工大学 | M-Z type refractive index sensor without temperature interference based on peanut structure |
| CN112596024A (en) * | 2020-12-04 | 2021-04-02 | 华中科技大学 | Motion identification method based on environment background wireless radio frequency signal |
| CN112834070A (en) * | 2020-12-30 | 2021-05-25 | 上海第二工业大学 | Method for measuring temperature of optical fiber end face contact gas by using microwave photon filter |
| CN112857609A (en) * | 2020-12-30 | 2021-05-28 | 上海第二工业大学 | Microwave photonic filter system and method for measuring refractive index of contact liquid on end face of optical fiber |
-
2021
- 2021-12-07 CN CN202111486978.XA patent/CN114414528A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007524075A (en) * | 2003-06-19 | 2007-08-23 | マサチユセツツ・インスチチユート・オブ・テクノロジイ | Phase measuring system and method |
| US20170030830A1 (en) * | 2013-01-28 | 2017-02-02 | Woods Hole Oceanographic Institution | Submersible n-wavelength interrogation system and method for multiple wavelength interferometers |
| US20170363412A1 (en) * | 2014-12-17 | 2017-12-21 | Pgs Geophysical As | Pressure insensitive interferometer |
| CN105891434A (en) * | 2016-06-03 | 2016-08-24 | 深圳职业技术学院 | Seawater salinity online detection method and device |
| CN109142278A (en) * | 2018-09-14 | 2019-01-04 | 华北电力大学（保定） | A kind of measurement method of seawater salinity |
| CN109831739A (en) * | 2019-03-19 | 2019-05-31 | 王业坤 | A kind of passive SOS calling deliverance apparatus, system and method based on less radio-frequency |
| CN110231631A (en) * | 2019-06-27 | 2019-09-13 | Oppo广东移动通信有限公司 | Localization method, terminal, network access equipment, electronic equipment, storage medium |
| CN111665220A (en) * | 2020-07-16 | 2020-09-15 | 哈尔滨理工大学 | M-Z type refractive index sensor without temperature interference based on peanut structure |
| CN112596024A (en) * | 2020-12-04 | 2021-04-02 | 华中科技大学 | Motion identification method based on environment background wireless radio frequency signal |
| CN112834070A (en) * | 2020-12-30 | 2021-05-25 | 上海第二工业大学 | Method for measuring temperature of optical fiber end face contact gas by using microwave photon filter |
| CN112857609A (en) * | 2020-12-30 | 2021-05-28 | 上海第二工业大学 | Microwave photonic filter system and method for measuring refractive index of contact liquid on end face of optical fiber |
Non-Patent Citations (2)
| Title |
|---|
| 程虎: "水下环境多参数测量及三维成像的方法研究与系统设计", 中国优秀硕士学位论文全文数据库信息科技辑, no. 3 * |
| 赵鲁梅等: "海水折射率与温度、盐度关系的实验研究", 中国现代教育装备, no. 9 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117768018A (en) * | 2023-12-22 | 2024-03-26 | 北京交科公路勘察设计研究院有限公司 | Expressway optical cable digital monitoring and intelligent application system and method |
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