CN115015630B - An ultra-weak frequency offset signal detection system and method based on a photoelectric oscillator - Google Patents

Abstract

The invention discloses an ultra-weak frequency offset signal detection system and method based on a photoelectric oscillator, comprising the following steps: the device comprises a laser emitting module, a photoelectric oscillator module, a phase-locked loop module and an ultra-weak frequency deviation signal detection module; the laser emission module is used for emitting laser and generating a first optical signal and a second optical signal; the photoelectric oscillator module is used for generating a starting mode of the photoelectric oscillator and outputting a first electric signal; the phase-locked loop module is used for stabilizing the starting frequency of the starting mode of the photoelectric oscillator; the ultra-weak frequency deviation signal detection module is used for acquiring an ultra-weak frequency deviation optical signal to be detected and a second optical signal, generating a beat frequency signal, and feeding back to the photoelectric oscillator module with frequency deviation information; the phase-locked loop module moves the first electric signal after the phase and the beat frequency signal output by the ultra-weak frequency deviation signal detection module are coupled to the photoelectric oscillator module to obtain ultra-weak frequency deviation signal information. The method realizes the detection of the ultra-weak frequency offset signals with high refresh rate, high resolution and high sensitivity, and has strong electromagnetic interference resistance.

Description

An ultra-weak frequency offset signal detection system and method based on a photoelectric oscillator

technical field

The invention relates to the field of ultra-weak frequency offset signal detection, in particular to a photoelectric oscillator-based ultra-weak frequency offset signal detection system and method.

Background technique

With the rapid development of communication technology, more and more fields have paid more attention to frequency offset signal detection technology. Since the frequency offset between signals carries a lot of information, frequency offset signal detection is particularly important. In addition, due to power limitations, there is an urgent need for ultra-weak frequency offset signal detection technology in some fields, such as radar, medical treatment, Internet of Things, precision instrument control, and microphysics. Therefore, it is of great scientific significance and practical demand to carry out the research on ultra-weak frequency offset signal detection technology. Solving this problem will effectively promote the development of various fields and contribute to the development of the national economy.

Contents of the invention

In order to solve the problems existing in the above-mentioned prior art, the present invention provides an ultra-weak frequency offset signal detection system and method based on an optoelectronic oscillator, including a laser emitting module, an optoelectronic oscillator module, a phase-locked loop module, an ultra-weak Frequency deviation signal detection module. It realizes the detection of ultra-weak frequency offset signals with high refresh rate, high resolution and high sensitivity; it has the ability to respond to ultra-weak signals; it can detect a larger frequency offset range; it has lower requirements on the output power and line width of the laser, It provides richer methods and more flexible spectrum data analysis options for the detection of ultra-weak frequency offset signals.

In order to achieve the above technical purpose, the present invention provides a photoelectric oscillator-based ultra-weak frequency deviation signal detection system, including: a laser emission module, a photoelectric oscillator module, a phase-locked loop module and an ultra-weak frequency deviation signal detection module;

The laser emitting module is used to emit laser light to generate a first optical signal and a second optical signal;

The photoelectric oscillator module is used to obtain the first optical signal, obtain the starting mode of the photoelectric oscillator, and output the first electrical signal at the same time;

The phase-locked loop module is used to stabilize the start-up frequency of the start-up mode of the photoelectric oscillator;

The ultra-weak frequency offset signal detection module is used to obtain the ultra-weak frequency offset light signal to be detected and the second optical signal, generate a beat frequency signal, and feed back the photoelectric oscillator module with frequency offset information;

The phase-shifted first electrical signal of the phase-locked loop module and the beat frequency signal output by the ultra-weak frequency offset signal detection module are coupled to the photoelectric oscillator module to obtain an ultra-weak frequency offset signal information.

Optionally, the laser emitting module includes: a laser and an optical fiber beam splitter;

The laser is connected to the optical fiber beam splitter;

The laser is used to emit laser light;

The optical fiber beam splitter is used to split the laser light to obtain the first optical signal and the second optical signal.

Optionally, the optoelectronic oscillator module includes: an electro-optic modulator, a first photodetector, a first electrical amplifier, an electrical filter, and a second electrical amplifier;

The electro-optic modulator, the first photodetector, the first electrical amplifier and the electrical filter are connected in sequence, and the second electrical amplifier is connected to the electro-optic modulator;

the electro-optic modulator is used to modulate the first optical signal;

The first photodetector is used to convert the modulated first optical signal into an electrical signal to generate a first electrical signal;

The first electrical amplifier and the second electrical amplifier are used to provide gain for the resonant cavity;

The electric filter is used to provide the starting frequency.

Optionally, the phase-locked loop module includes: a voltage-controlled phase shifter, a phase-locked loop circuit and a loop filter circuit;

The voltage-controlled phase shifter is connected to the loop filter circuit, and the phase-locked loop circuit is connected to the loop filter circuit;

The voltage-controlled phase shifter is used to shift the phase of the first electrical signal;

The phase-locked loop circuit is used to analyze the frequency and phase of the first electrical signal;

The loop filter circuit is used to filter the branched electrical signal of the first electrical signal after the phase shift.

Optionally, the ultra-weak frequency deviation signal detection module includes: an optical fiber combiner, a second photodetector and a phase shifter;

The optical fiber combiner, the second photodetector and the phase shifter are sequentially connected;

The optical fiber beam combiner is used to combine the second optical signal and the ultra-weak frequency polarized light signal to be detected to generate a combined optical signal;

The second photodetector is used to convert the beam combining optical signal into an electrical signal to generate the beat frequency signal;

The phase shifter is used to adjust the phase of the beat frequency signal.

Optionally, the phase-locked loop module further stabilizes the oscillation frequency of the oscillation mode of the optoelectronic oscillator by stabilizing the cavity length of the optoelectronic oscillator resonant cavity.

Optionally, a power divider is also included, and the power divider is used to divide the phase-shifted first electrical signal into two outputs.

Optionally, an electric spectrometer is also included, and the electric spectrometer is used to perform frequency offset inversion analysis on the frequency spectrum data of the beat frequency signal to obtain frequency offset information.

The present invention also provides a method for detecting an ultra-weak frequency offset signal based on a photoelectric oscillator, comprising the following steps:

Acquiring the first optical signal, obtaining the start-up mode of the photoelectric oscillator, and simultaneously outputting the first electrical signal;

Obtaining the ultra-weak frequency polarized light signal and the second light signal to be detected, generating a beat frequency signal,

Based on the phase-shifted first electrical signal and the beat frequency signal, spectrum analysis is performed to obtain ultra-weak frequency offset signal information.

Optionally, the calculation expression of each frequency in the spectrum analysis is:

|f ₁ -f ₀ |＝f _OEO

Among them, f ₁ is the frequency of the ultra-weak frequency polarized light signal to be detected, f ₀ is the frequency of the input laser, and f _OEO is the start-up frequency of the optoelectronic oscillator.

Optionally, the formula for calculating the ultra-weak frequency offset signal information is:

f ₁ ＝|f ₀ -f _OEO |

Among them, f ₁ is the frequency of the ultra-weak frequency polarized light signal to be detected, f ₀ is the frequency of the input laser, and f _OEO is the start-up frequency of the optoelectronic oscillator.

The present invention has following technical effect:

1. The invention realizes the detection of ultra-weak frequency offset signals with high refresh rate, high resolution and high sensitivity;

2. Through the amplification effect of the local oscillator mode of the resonator, the present invention has the performance of responding to ultra-weak frequency offset signals, has high detection sensitivity for the detection of ultra-weak frequency offset signals, and even has single-photon detection capabilities;

3. The present invention matches the frequency mismatch between the ultra-weak frequency deviation signal and the laser by flexibly adjusting the start-up frequency of the optoelectronic oscillator (OEO) resonator, thereby improving the frequency shift detection range;

4. The present invention has a very high refresh rate when the frequency of the signal to be tested changes, which simplifies the problem of huge data processing in the middle and later stages of the existing ultra-weak frequency offset signal detection, and the system is stable. The ultra-weak frequency offset signal detection module adopts Optical fiber structure, strong anti-electromagnetic interference ability.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without paying creative labor.

1 is a schematic diagram of an ultra-weak frequency offset signal detection system based on an optoelectronic oscillator according to an embodiment of the present invention;

2 is a flow chart of a method for detecting an ultra-weak frequency offset signal based on an optoelectronic oscillator in Embodiment 2 of the present invention;

3 is a schematic diagram of an ultra-weak frequency offset signal detection system based on an optoelectronic oscillator according to Embodiment 3 of the present invention;

In Fig. 1: 1. laser; 2. fiber beam splitter; 3. electro-optic modulator; 4. first photodetector; 5. first electric amplifier; 6. electric filter; 7. voltage-controlled phase shifter; 8. Power divider; 9. Electric coupler; 10. Second electric amplifier; 11. Phase-locked loop circuit; 12. Loop filter circuit; 13. Fiber combiner; 14. Second photodetector; 15. Phase shifter; 16, electric spectrometer;

In Fig. 3: 1. laser; 2. optical fiber beam splitter; 3. electro-optic modulator; 4. first photodetector; 5. first electric amplifier; 6. electric filter; 7. voltage-controlled phase shifter; 8. Power splitter; 9. Electric coupler; 10. Second electric amplifier; 11. Phase-locked loop circuit; 12. Loop filter circuit; 17. Phase shifter; 18. Electrospectrometer.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiment one

As shown in Figure 1, the present invention discloses an ultra-weak frequency offset signal detection system based on a photoelectric oscillator, including: a laser emitting module, a photoelectric oscillator module, a phase-locked loop module, an ultra-weak frequency offset signal detection module, a power Dividers, electrical couplers and spectrometers;

The laser emitting module includes: a laser 1 and an optical fiber splitter 2, and the laser 1 is connected to the optical fiber splitter 2. The laser 1 is used to emit laser light, and the optical fiber beam splitter 2 is used to split the laser light to obtain a first optical signal and a second optical signal.

The photoelectric oscillator module includes: an electro-optic modulator 3, a first photodetector 4, a first electric amplifier 5, an electric filter 6 and a second electric amplifier 10, the electro-optic modulator 3, the first photodetector 4 , the first electrical amplifier 5 and the electrical filter 6 are connected in sequence, and the second electrical amplifier 10 is connected to the electro-optic modulator 3 . The electro-optic modulator 3 is used to modulate the first optical signal, and the first photodetector 4 is used to convert the modulated first optical signal into an electrical signal to generate a first electrical signal, and the first An electrical amplifier 5 and the second electrical amplifier 10 are used to provide gain for the resonant cavity, and the electrical filter 6 is used to provide an oscillation frequency.

The phase-locked loop module includes: a voltage-controlled phase shifter 7, a phase-locked loop circuit 11 and a loop filter circuit 12, the voltage-controlled phase shifter 7 is connected to the loop filter circuit 12, and the phase-locked The loop circuit 11 is connected to the loop filter circuit. The voltage-controlled phase shifter 7 is used to move the phase of the first electrical signal, the phase-locked loop circuit 11 is used to keep the phase and the start-up frequency of the photoelectric oscillator synchronous with the input signal, and the loop filter circuit uses Filtering the branched electrical signal of the first electrical signal.

The ultra-weak frequency deviation signal detection module includes: an optical fiber combiner 13, a second photodetector 14 and a phase shifter 15, and the optical fiber combiner 13, the second photodetector 14 and the phase shifter Devices 15 are connected in sequence. The optical fiber beam combiner 13 is used to combine the second optical signal and the ultra-weak frequency polarized light signal to be detected to generate a beam combined optical signal, and the second photodetector 14 is used to combine the beam combined light The signal is converted into an electrical signal to generate the beat frequency signal, and the phase shifter 15 is used to adjust the phase of the beat frequency signal.

The power divider 8 is used to divide the phase-shifted first electrical signal into two outputs, and the power divider 8 is connected to the voltage-controlled phase shifter 7 and the phase-locked loop circuit 11 respectively.

The electric spectrometer 16 is used to perform frequency offset inversion analysis on the frequency spectrum data detected in the coupling process to obtain frequency offset information; the electric spectrometer 16 is connected to the second electrical amplifier 10 .

The electrical coupler 9 is used to couple the first electrical signal output by the phase-locked loop module and the beat frequency signal output by the ultra-weak frequency offset signal detection module to the photoelectric oscillator module to obtain Ultra-weak frequency offset signal information; the electrical coupler 9 is connected to the phase shifter 15 , the power divider 8 and the second electrical amplifier 10 respectively.

The laser light emitted by the laser transmitter 1 is modulated by the optical fiber beam splitter 2 and the electro-optical modulator 3 in turn, and after the photoelectric conversion is realized by the first photodetector 4, it enters the first electric amplifier 5, the electric filter 6, and the voltage-controlled displacement The phase device 7, the power divider 8, the electric coupler 9, the second electric amplifier 10, and finally the resonant cavity fed back to the photoelectric oscillator through the electro-optic modulator 3 constitute the photoelectric oscillator.

In this embodiment, the wavelength of the laser light emitted by the laser transmitter 1 is λ ₀ , and the frequency is f ₀ . The laser beam passes through the optical fiber beam splitter 2, and the laser light is decomposed into two paths, that is, the first optical signal and the second optical signal. . The first optical signal enters the electro-optic modulator 3 and is modulated by the electro-optic modulator 3. The modulated first optical signal enters the first photodetector 4, and the modulated first optical signal is converted into a first For electrical signals, the electrical filter 6 determines the start-up frequency of the system, and the first electrical amplifier 5 and the second electrical amplifier 10 provide gain for the resonant cavity. After the first electrical signal passes through the first electrical amplifier 5 and the electrical filter 6 in sequence, it enters the voltage-controlled phase shifter 7 to move the phase of the first electrical signal, and the first electrical signal after the shifted phase enters the power divider 8 , the power divider 8 divides the first electric signal after the shifted phase into two electric signal outputs, wherein one electric signal enters the electric coupler 9, and enters the second electric amplifier 10, and the electric signal output by the second electric amplifier 10 Feedback to the electro-optical modulator 3 to form a photoelectric oscillator structure, adjust the gain of the system, so that the photoelectric oscillator just starts to vibrate, and the starting frequency is _fOEO ; another electrical signal enters the phase-locked loop circuit 11, and the phase-locked loop circuit 11 analyzes The frequency and phase of this road electrical signal, make its phase and the start-up frequency f _OEO of photoelectric oscillator keep synchronous with this road signal of input, the output end of phase-locked loop circuit 11 is connected with loop filter circuit 12, and described loop A filter circuit 12 is used to filter the branched electrical signal of the first electrical signal, and the filtered error electrical signal is fed back to the voltage-controlled phase shifter 7 to complete the control of the length of the resonant cavity of the photoelectric oscillator , the purpose is to stabilize the oscillation frequency f _OEO .

In the ultra-weak frequency deviation signal detection module, the second optical signal split by the laser 1 through the optical fiber beam splitter 2 and the ultra-weak frequency polarization signal to be tested enter the optical fiber combiner 13, and the optical fiber combiner 13 combines the first The two optical signals and the ultra-weak frequency polarized light signal to be detected are combined to generate a beam combined optical signal, and the frequency of the ultra-weak frequency polarized light signal to be detected is unknown, which is set to f ₁ , and the output end of the optical fiber combiner 13 is connected to The input end of the second photodetector 14 is connected to convert the combined optical signal into an electrical signal to obtain a beat frequency signal, and the frequency of the beat frequency signal is f ₀ -f ₁ ; the beat frequency signal passes through a phase shifter 15. Adjust the phase of the beat frequency signal by adjusting the power supply voltage of the phase shifter 15, so that the beat frequency signal passing through the phase shifter is input to the electric coupler 9 with an appropriate phase, and the output terminal of the electric coupler 9 is connected to the electric spectrum The electric spectrometer 16 performs frequency offset inversion analysis on the detected frequency spectrum data of the beat frequency signal to obtain frequency offset information.

The electrical signal output through the power divider 8 and the beat frequency signal carrying the frequency offset information output through the phase shifter 15 enter the electrical coupler 9 at the same time, and are coupled and injected into the resonance of the photoelectric oscillator through the electrical coupler 9 When the signal injected into the resonant cavity of the optoelectronic oscillator reaches the frequency and phase matching conditions with the local oscillation mode of the optoelectronic oscillator, the oscillation frequency of the optoelectronic oscillator is amplified. Adjust the start-up frequency of the system. When the electric spectrometer 16 displays the power of the optoelectronic oscillator start-up frequency f _OEO , it means that the signal injected into the optoelectronic oscillator resonator and the optoelectronic oscillator start-up mode meet the frequency and phase matching conditions , each frequency satisfies the following equation: |f ₁ −f ₀ |=f _OEO .

Obtain the frequency deviation information of the ultra-weak frequency deviation signal to be detected relative to the output laser of the laser device 1, observe and analyze the frequency spectrum by the electrospectrometer 16, and obtain the finally detected ultra-weak frequency deviation signal information, the formula is: f ₁ =|f ₀ -f _OEO | .

Embodiment two

Acquiring the first optical signal, obtaining the start-up mode of the photoelectric oscillator, and simultaneously outputting the first electrical signal;

Obtaining the ultra-weak frequency polarized light signal to be detected and the second light signal to generate a beat frequency signal,

Based on the phase-shifted first electrical signal and the beat frequency signal, spectrum analysis is performed to obtain ultra-weak frequency offset signal information.

Specifically, in the second embodiment

Step 1: The laser light emitted by the laser 1 has a wavelength of λ ₀ and a frequency of f ₀ , and splits it into a first optical signal and a second optical signal through an optical fiber beam splitter 2, wherein the first optical signal is modulated by an electro-optic modulator 3;

Step 2: The modulated first optical signal then enters the first photodetector 4 to convert the modulated first optical signal into an electrical signal to generate a first electrical signal;

Step 3: The first electrical signal passes through the first electrical amplifier 5, the electrical filter 6, the voltage-controlled phase shifter 7, the power divider 8, the electrical coupler 9, and the second electrical amplifier 10 in sequence, wherein the electrical filter 6 Determine the starting frequency of the system, the first electrical amplifier 5 and the second electrical amplifier 10 provide gain for the resonant cavity;

Step 4: The first electrical signal after the shifted phase output by the second electrical amplifier 10 is fed back to the electro-optic modulator 3 to form a photoelectric oscillator structure, and adjust the gain of the system so that OE0 just starts to vibrate, and the start-up frequency is f _OEO ;

Step 5: the photoelectric oscillator is coupled and output from the power divider 8, and the power divider 8 divides the first electrical signal after the phase shift into two paths;

Step 6: One of the electrical signals separated by the power divider 8 enters the phase-locked loop circuit 11, and the frequency and phase of the one of the electrical signals separated by the power divider 8 are analyzed;

Step 7: Transmit one of the electrical signals separated by the power divider 8 to the loop filter circuit 12, and then feed it back to the input end of the voltage-controlled phase shifter 7 to complete the control of the OEO cavity length, the purpose is to stabilize Start-up frequency f _OEO ;

Step 8: The second optical signal and the ultra-weak frequency polarized light signal to be detected with a frequency of f ₁ (unknown frequency) are jointly input to the optical fiber combiner 13 to generate a combined optical signal;

Step 9: Transmit the beam combining optical signal to a second photodetector, convert the beam combining optical signal into an electrical signal, and obtain a beat frequency signal with a frequency of f ₀ -f ₁ ;

Step ten: the beat frequency signal passes through the phase shifter 15, and the power supply voltage of the phase shifter 15 is adjusted, so that the output beat frequency signal is input to the electric coupler 9 with an appropriate phase;

Step eleven: adjust the start-up frequency of the optoelectronic oscillator. When the power of the start-up frequency f _OEO of the optoelectronic oscillator is displayed on the spectrometer 16, it means that the signal injected into the resonant cavity of the optoelectronic oscillator is consistent with the start-up mode of the optoelectronic oscillator Satisfy the frequency and phase matching conditions, and each frequency satisfies the following equation: |f ₁ -f ₀ |=f _OEO ;

Step 12: Obtain the frequency offset information of the ultra-weak frequency polarized light signal to be detected relative to the output laser light of the laser 1, and the calculation formula is: f ₁ =|f ₀ −f _OEO |.

Embodiment three

As shown in Figure 3, the present invention also discloses an ultra-weak frequency bias signal detection system based on a photoelectric oscillator, changing the ultra-weak frequency polarized signal to be detected in Embodiment 1 into an ultra-weak frequency bias signal to be detected , based on the steps of the first embodiment, the ultra-weak frequency offset electrical signal information can be detected.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (8)

1. An ultra-weak frequency offset signal detection system based on an optoelectronic oscillator is characterized by comprising: the device comprises a laser emitting module, a photoelectric oscillator module, a phase-locked loop module and an ultra-weak frequency deviation signal detection module;

the laser emission module is used for emitting laser and generating a first optical signal and a second optical signal;

the photoelectric oscillator module is used for acquiring a first optical signal, obtaining a starting mode of the photoelectric oscillator and outputting a first electric signal at the same time;

the phase-locked loop module is used for stabilizing the starting frequency of the starting mode of the photoelectric oscillator;

the ultra-weak frequency deviation signal detection module is used for acquiring an ultra-weak frequency deviation optical signal to be detected and the second optical signal, generating a beat frequency signal, and feeding back the beat frequency signal to the photoelectric oscillator module along with frequency deviation information;

and the phase-locked loop module is coupled with the beat frequency signal output by the ultra-weak frequency deviation signal detection module and the first electric signal after phase movement and the beat frequency signal are coupled to the photoelectric oscillator module to obtain ultra-weak frequency deviation signal information.

2. The system for detecting an ultra-weak frequency deviation signal based on an optoelectronic oscillator of claim 1, wherein the laser emitting module comprises: a laser and a fiber optic beam splitter;

the laser is connected with the optical fiber beam splitter;

the laser is used for emitting laser;

the optical fiber beam splitter is used for decomposing the laser to obtain a first optical signal and a second optical signal.

3. The system for detecting an ultra-weak frequency deviation signal based on an optoelectronic oscillator of claim 1, wherein the optoelectronic oscillator module comprises: an electro-optic modulator, a first photodetector, a first electrical amplifier, an electrical filter, and a second electrical amplifier;

the electro-optical modulator, the first photoelectric detector, the first electric amplifier and the electric filter are sequentially connected, and the second electric amplifier is connected with the electro-optical modulator;

the electro-optic modulator is used for modulating the first optical signal;

the first photoelectric detector is used for converting the modulated first optical signal into an electric signal to generate a first electric signal;

the first and second electrical amplifiers are configured to provide gain for the resonant cavity;

the electric filter is used for providing a starting frequency.

4. The system for detecting an ultra-weak frequency deviation signal based on an optoelectronic oscillator of claim 1, wherein the phase-locked loop module comprises: a voltage-controlled phase shifter, a phase-locked loop circuit and a loop filter circuit;

the voltage-controlled phase shifter is connected with the loop filter circuit, and the phase-locked loop circuit is connected with the loop filter circuit;

the voltage-controlled phase shifter is used for shifting the phase of the first electric signal;

the phase-locked loop circuit is used for analyzing the frequency and the phase of the first electric signal;

the loop filter circuit is used for filtering the shunt electric signal of the first electric signal after phase shifting.

5. The system for detecting an ultra-weak frequency deviation signal based on an optoelectronic oscillator according to claim 1, wherein the ultra-weak frequency deviation signal detection module comprises: the optical fiber beam combiner, the second photoelectric detector and the phase shifter;

the optical fiber beam combiner, the second photoelectric detector and the phase shifter are sequentially connected;

the optical fiber beam combiner is used for combining the second optical signal and the ultra-weak frequency deviation optical signal to be detected to generate a combined optical signal;

the second photoelectric detector is used for converting the beam-combining optical signal into an electric signal and generating the beat frequency signal;

the phase shifter is used for adjusting the phase of the beat signal.

6. The system of claim 1, wherein the phase-locked loop module stabilizes the oscillation starting frequency of the oscillation starting mode of the optoelectronic oscillator by stabilizing the cavity length of the resonant cavity of the optoelectronic oscillator.

7. The ultra-weak frequency deviation signal detection system based on the photoelectric oscillator according to claim 1, further comprising an electric spectrometer, wherein the electric spectrometer is used for performing frequency deviation inversion analysis on the frequency spectrum data of the beat frequency signal to obtain frequency deviation information.

8. The ultra-weak frequency deviation signal detection method based on the photoelectric oscillator is characterized by comprising the following steps of:

acquiring a first optical signal to obtain a starting mode of the photoelectric oscillator, and outputting a first electric signal at the same time;

obtaining an ultra-weak frequency offset optical signal to be detected and a second optical signal to generate a beat frequency signal,

performing spectrum analysis based on the first electric signal after phase shifting and the beat frequency signal to obtain ultra-weak frequency offset signal information;

the calculation expression of each frequency in the spectrum analysis is as follows:

|f ₁ -f ₀ |＝f _OEO

wherein f ₁ For the frequency f of the ultra-weak frequency offset optical signal to be detected ₀ To input the frequency of the laser, f _OEO The oscillation starting frequency of the photoelectric oscillator;

the calculation formula of the ultra-weak frequency offset signal information is as follows:

f ₁ ＝|f ₀ -f _OEO |

wherein f ₁ For the frequency f of the ultra-weak frequency offset optical signal to be detected ₀ To input the frequency of the laser, f _OEO The oscillation starting frequency of the photoelectric oscillator;

the laser emits laser with wavelength lambda ₀ Frequency f ₀ Dividing the optical fiber into a first optical signal and a second optical signal through an optical fiber beam splitter, wherein the first optical signal is modulated by an electro-optical modulator;

modulating the first optical signal, then entering a first photoelectric detector, converting the modulated first optical signal into an electric signal, and generating a first electric signal;

the first electric signal sequentially passes through a first electric amplifier, an electric filter, a voltage-controlled phase shifter, a power divider, an electric coupler and a second electric amplifier, wherein the electric filter determines the starting frequency of the system, and the first electric amplifier and the second electric amplifier provide gain for the resonant cavity;

the first electric signal after the phase shift output by the second electric amplifier is fed back to the electric light modulator to form an photoelectric oscillator structure, the gain of the regulating system is OEO oscillation, and the oscillation starting frequency is f _OEO ；

The photoelectric oscillator is coupled and output from a power divider, and the power divider divides the first electric signal after phase movement into two paths;

one electric signal separated by the power divider enters a phase-locked loop circuit, and the frequency and the phase of the one electric signal separated by the power divider are analyzed;

transmitting one path of electric signal separated by the power divider to a loop filter circuit, and feeding back to the input end of the voltage-controlled phase shifter to complete the control of the OEO cavity length for stabilizing the oscillation starting frequency f _OEO ；

The second optical signal and the frequency f ₁ The ultra-weak frequency offset optical signals to be detected are input to an optical beam combiner together to generate a combined optical signal;

transmitting the combined light signal to a second photoelectric detector, and converting the combined light signal into an electric signal to obtain a beat signal with the frequency f ₀ -f ₁ ；

The beat frequency signal passes through the phase shifter, and the power supply voltage of the phase shifter is regulated, so that the output beat frequency signal is input to the electric coupler in phase;

adjusting the oscillation starting frequency of the photoelectric oscillator, and when the power of the oscillation starting frequency of the photoelectric oscillator is displayed on the spectrometer to be maximum, enabling the signals injected into the resonant cavity of the photoelectric oscillator and the oscillation starting mode of the photoelectric oscillator to meet the frequency and phase matching conditions, wherein each frequency meets the following conditions: i f ₁ -f ₀ |＝f _OEO ；

Acquiring frequency offset information of an ultra-weak frequency offset optical signal to be detected relative to laser output laser: f (f) ₁ ＝|f ₀ -f _OEO |。

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