Method and device for acquiring optoelectronic oscillation microwave signal with space-time symmetry

Abstract

The invention provides a method and a device for acquiring a space-time symmetric photoelectric oscillation microwave signal, and relates to the technical field of microwave signals, and the method comprises the steps: modulating a microwave signal to an optical carrier wave through an electro-optical modulator, and obtaining a modulation signal; wherein the modulation signal comprises an upper sideband signal, a lower sideband signal and a carrier component; carrying out overall amplification and single-side-band sag peak suppression filtering processing on the modulation signal to obtain a filtering signal; respectively acting the upper sideband signal and the lower sideband signal with the carrier component, and respectively obtaining a gain signal, a corresponding gain coefficient, an attenuation signal and a corresponding attenuation coefficient through calculation; and when the coupling coefficient between the gain signal and the attenuation signal is fixed to be 1, adjusting the gain coefficient and the attenuation coefficient by using the amplification processing and the recess peak suppression filtering to obtain a target photoelectric oscillation microwave signal. According to the invention, the problems of large phase noise and low stability of oscillation microwave signals are solved.

Description

Technical Field

[0001] The present invention relates to the field of microwave signal technology, and in particular to a method and device for acquiring a parity-time symmetric photoelectric oscillation microwave signal. Background Art

[0002] Microwave signals are widely used in radar, wireless communication, high-precision measurement and other fields. With the continuous development of information technology, higher requirements are placed on the frequency and phase noise of microwave signals. Traditional electronic technology often uses frequency doubling to generate high-frequency microwave signals, but this will seriously deteriorate the phase noise performance of the signal. The hybrid resonant cavity containing optical path and circuit, optoelectronic oscillator, has emerged in the field of microwave signal generation due to its extremely low phase noise and good frequency expansion. However, the long-distance optical fiber inside the optoelectronic oscillator greatly shortens the interval between oscillation modes, making single-mode oscillation difficult. In recent years, the parity-time (PT) symmetry and PT symmetry breaking mechanism in optoelectronic systems have demonstrated their unique mode selection characteristics. Therefore, the mode selection of optoelectronic oscillators using the PT symmetry mechanism has gradually become a research hotspot. In order to realize PT symmetric optoelectronic oscillators, people have successively proposed optoelectronic oscillator structures based on space division multiplexing, wavelength division multiplexing and polarization multiplexing to achieve the gain and loss of the oscillation signal through different physical loops, wavelengths and polarizations. However, the system performance will inevitably be affected by these parameters, thereby reducing the phase noise and stability of the oscillation signal. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method and device for acquiring a parity-time symmetric optoelectronic oscillation microwave signal, which solves the problems of large phase noise and low stability of the oscillation microwave signal.

[0004] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a method for acquiring a parity-time symmetric photoelectric oscillation microwave signal, comprising:

[0005] S1: using an electro-optical modulator, modulating a microwave signal onto an optical carrier to obtain a modulated signal; wherein the modulated signal includes an upper sideband signal, a lower sideband signal and a carrier component;

[0006] S2: Obtain a filtered signal by performing overall amplification and single-sideband notch peak suppression filtering on the modulated signal;

[0007] S3: The upper sideband signal and the lower sideband signal act on the carrier component respectively, and obtain a gain signal, a corresponding gain coefficient, an attenuation signal and a corresponding attenuation coefficient respectively through calculation;

[0008] S4: When the coupling coefficient between the gain signal and the attenuation signal is fixed to 1, the gain coefficient and the attenuation coefficient are adjusted by using the amplification process and the notch peak suppression filter to obtain a target photoelectric oscillation microwave signal.

[0009] Furthermore, the expression of the modulation signal is:

[0010]

[0011] Among them, E EOM represents the modulated signal, t represents the time, α1 represents the loss introduced by the electro-optic modulator, E c represents the optical carrier amplitude, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, and f c represents the optical carrier frequency, J1 represents the first-order coefficient of the first-kind Bessel function, f m Represents the frequency of the photoelectric oscillation microwave signal, cos(2πf c t) represents the carrier component, cos[2π(f c +f m )t] represents the upper sideband signal, cos[2π(f c -f m )t] represents the lower sideband signal.

[0012] Furthermore, the expression of the filtered signal is:

[0013]

[0014] Among them, E NF represents the filtered signal, α1 represents the loss introduced by the electro-optic modulator (2), G1 represents the gain of the optical amplifier (3), E c represents the optical carrier amplitude, f c represents the optical carrier frequency, t represents the time, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, J1 represents the first-order coefficient of the first-order Bessel function, α2 represents the loss introduced by the notch filter (4) to the lower sideband, and f m represents the frequency of the photoelectric oscillation microwave signal, f c +f m represents the frequency of the upper sideband signal, f c -f m Indicates the frequency of the lower sideband signal.

[0015] Furthermore, the expression of the gain signal and the corresponding gain coefficient is:

[0016]

[0017]

[0018] The expressions of the attenuation signal and the corresponding attenuation coefficient are:

[0019]

[0020]

[0021] Among them, v up represents the gain signal, t represents time, ρ represents the responsivity of the photodetector, R represents the load impedance of the photodetector, α1 represents the loss introduced by the electro-optic modulator, G1 represents the gain of the optical amplifier, E c represents the optical carrier amplitude, f c represents the optical carrier frequency, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, J1 represents the first-order coefficient of the first-order Bessel function, G0 represents the gain coefficient, G2 represents the gain of the microwave amplifier, and f m represents the frequency of the photoelectric oscillation microwave signal, v down represents the attenuation signal, α2 represents the loss introduced by the notch filter to the lower sideband, L0 represents the attenuation coefficient, V m Represents the amplitude of the photoelectric oscillation microwave signal.

[0022] Further, the S4 includes:

[0023] When the coupling coefficient between the gain signal and the attenuation signal is fixed to 1, the gain coefficient and the attenuation coefficient are adjusted by using the amplification process and the notch peak suppression filter to obtain an adjustment result:

[0024] |G0|=|L0|<κ;

[0025] Among them, G0 represents the gain coefficient, L0 represents the attenuation coefficient, and κ represents the coupling coefficient;

[0026] Based on the adjustment result, the gain signal and the attenuation signal are used to feed back the microwave signal, and when the feedback result meets the condition that the oscillation signal satisfies, the target photoelectric oscillation microwave signal is obtained:

[0027] E m (t) = V m cos(2πf m t);

[0028] The expression that the oscillation signal satisfies the condition is:

[0029] 2πfm τ+φ0=2kπ;

[0030] Among them, E m represents the target photoelectric oscillation microwave signal, t represents time, V m represents the amplitude of the photoelectric oscillation microwave signal, f m represents the frequency of the photoelectric oscillator microwave signal, φ0 represents the initial phase of the oscillation signal, k represents a positive integer, τ=nL / c, n represents the effective refractive index of the optical fiber, L represents the loop length of the photoelectric oscillator, and c represents the speed of light in a vacuum.

[0031] The beneficial effects of the present invention are as follows: by combining an optical amplifier and an optical notch filter, the upper modulation sideband obtains gain, while the lower modulation sideband is suppressed, and the gain oscillation signal and the attenuation oscillation signal are obtained by beating with the carrier frequency respectively. (1) When the gain of the amplifier and the amplitude of the notch peak of the filter are adjusted so that the signal gain and the attenuation coefficient are equal and less than the coupling coefficient, the optoelectronic oscillator satisfies the PT symmetry breaking condition and can achieve single longitudinal mode output in a long loop; (2) The mirror symmetry of the double-sideband modulated signal is used to construct two oscillation signals with different gains, without involving the wavelength and polarization characteristics of the optical signal, and using a physical loop, which greatly simplifies the system structure and improves the signal stability and phase noise performance.

[0032] A parity-time symmetric photoelectric oscillation microwave signal acquisition device, comprising:

[0033] A light source, used for outputting an optical carrier;

[0034] An electro-optical modulator, used for modulating the microwave signal onto an optical carrier output by a light source to obtain a modulated signal;

[0035] An optical amplifier, used for amplifying the modulated signal;

[0036] A notch filter, the notch peak of which is located at the sideband of the modulated signal, and is used to suppress any upper sideband signal and lower sideband signal to obtain a filtered signal;

[0037] The optical fiber is used as an energy storage medium of the photoelectric oscillation loop to transmit the filtered signal to the photoelectric detector;

[0038] A photoelectric detector, used for converting the filtered signal into an electrical signal, so that the two sideband signals act on the carrier component to obtain a gain signal and an attenuation signal respectively;

[0039] A microwave amplifier, used for amplifying the gain signal and the attenuation signal;

[0040] A power divider is used to divide the amplified gain signal and attenuation signal into two paths, one path is used as the output target photoelectric oscillation microwave signal, and the other path is reloaded to the radio frequency port of the electro-optic modulator to form a feedback loop of the photoelectric oscillator; wherein the light source, the electro-optic modulator, the optical amplifier, the notch filter, the optical fiber, the photodetector, the microwave amplifier and the power divider are connected in series in sequence, the electro-optic modulator, the optical amplifier and the notch filter belong to a sideband asymmetric modulation module, one end of the power divider is the output end, and the other end of the power divider is connected to the radio frequency port of the electro-optic modulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0042] Figure 1 is an exemplary schematic diagram of a parity-time symmetric optoelectronic oscillation microwave signal acquisition device according to some embodiments of this specification;

[0043] Figure 2 is an exemplary flow chart of a method for acquiring a parity-time symmetric photoelectric oscillation microwave signal according to some embodiments of this specification;

[0044] Among them: 1. light source; 2. electro-optic modulator; 3. optical amplifier; 4. notch filter; 5. optical fiber; 6. photodetector; 7. microwave amplifier; 8. power divider; 9. sideband asymmetric modulation module. DETAILED DESCRIPTION

[0045] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0046] Embodiment 1

[0047] Figure 1 It is a module schematic diagram of a parity-time symmetric optoelectronic oscillation microwave signal acquisition device shown in some embodiments of this specification.

[0048] In some embodiments, the parity-time symmetric optoelectronic oscillation microwave signal acquisition device may include a light source 1, an electro-optical modulator 2, an optical amplifier 3, a notch filter 4, an optical fiber 5, a photodetector 6, a microwave amplifier 7 and a power divider 8; wherein the electro-optical modulator 2, the optical amplifier 3 and the notch filter 4 belong to a sideband asymmetric modulation module 9.

[0049] Light source 1 is used to output an optical carrier.

[0050] The electro-optic modulator 2 is used to modulate the microwave signal onto the optical carrier output by the light source 1 to obtain a modulated signal.

[0051] The optical amplifier 3 is used to amplify the modulated signal.

[0052] The notch peak position of the notch filter 4 is located at the sideband of the modulated signal, and is used to suppress any upper sideband signal and lower sideband signal to obtain a filtered signal.

[0053] The optical fiber 5 is used as an energy storage medium of the photoelectric oscillation loop to transmit the filtered signal to the photodetector 6 .

[0054] By using the optical fiber 5, the quality factor of the optoelectronic oscillation loop can be improved, thereby improving the quality of the acquired optoelectronic oscillation microwave signal.

[0055] The photoelectric detector 6 is used to convert the filtered signal into an electrical signal, so that the two sideband signals act on the carrier component to obtain a gain signal and an attenuation signal respectively.

[0056] The microwave amplifier 7 is used to amplify the gain signal and the attenuation signal.

[0057] The power divider 8 is used to divide the amplified gain signal and attenuation signal into two paths, one of which is used as the output target optoelectronic oscillation microwave signal, and the other is reloaded to the RF port of the electro-optic modulator 2 to form a feedback loop of the optoelectronic oscillator.

[0058] In some embodiments, the light source 1, the electro-optic modulator 2, the optical amplifier 3, the notch filter 4, the optical fiber 5, the photodetector 6, the microwave amplifier 7 and the power divider 8 are connected in series in sequence, the electro-optic modulator 2, the optical amplifier 3 and the notch filter 4 belong to a sideband asymmetric modulation module 9, one end of the power divider 8 is the output end, and the other end of the power divider 8 is connected to the RF port of the electro-optic modulator 2.

[0059] In some embodiments, a parity-time symmetric optoelectronic oscillation microwave signal acquisition device can be used to perform a parity-time symmetric optoelectronic oscillation microwave signal acquisition method, including S1: using an electro-optical modulator to modulate a microwave signal onto an optical carrier to obtain a modulated signal; wherein the modulated signal includes an upper sideband signal, a lower sideband signal and a carrier component;

[0060] S2: Obtain a filtered signal by performing overall amplification and single-sideband notch peak suppression filtering on the modulated signal;

[0061] S3: The upper sideband signal and the lower sideband signal act on the carrier component respectively, and obtain a gain signal, a corresponding gain coefficient, an attenuation signal and a corresponding attenuation coefficient respectively through calculation;

[0062] S4: When the coupling coefficient between the gain signal and the attenuation signal is fixed to 1, the gain coefficient and the attenuation coefficient are adjusted by using the amplification process and the notch peak suppression filter to obtain a target photoelectric oscillation microwave signal.

[0063] In some embodiments of the present specification, the processor uses a parity-time symmetric optoelectronic oscillation microwave signal acquisition device to perform a parity-time symmetric optoelectronic oscillation microwave signal acquisition method. (1) When the gain of the amplifier and the amplitude of the filter notch peak are adjusted so that the signal gain and the attenuation coefficient are equal and less than the coupling coefficient, the optoelectronic oscillator satisfies the PT symmetry breaking condition and can achieve single longitudinal mode output under a long loop; (2) The mirror symmetry of the double-sideband modulated signal is used to construct two oscillation signals with different gains, without involving the wavelength and polarization characteristics of the optical signal, and using a physical loop, which greatly simplifies the system structure and improves the signal stability and phase noise performance.

[0064] Embodiment 2

[0065] Figure 2 FIG. 1 is an exemplary flow chart of a method for acquiring a parity-time symmetric photoelectric oscillation microwave signal according to some embodiments of this specification. Figure 2 As shown, the process includes the following steps. In some embodiments, the process can be executed by a processor.

[0066] S1: Use an electro-optical modulator to modulate the microwave signal onto an optical carrier to obtain a modulated signal.

[0067] In some embodiments, the processor may modulate the microwave signal onto the optical carrier based on the half-wave voltage of the electro-optical modulator to obtain a modulated signal.

[0068] Half-wave voltage is an important parameter to measure the performance of electro-optic modulator, which represents the voltage required to change the phase of the optical signal by π.

[0069] Microwave signals refer to electromagnetic wave signals with frequencies between 300 MHz and 300 GHz, that is, target photoelectric oscillation microwave signals that need to be generated.

[0070] In some embodiments, the processor may utilize an optoelectronic oscillation acquisition device to obtain a microwave signal.

[0071] An optical carrier is an optical signal used to carry and transmit microwave signals when realizing electrical-optical conversion.

[0072] In some embodiments, the processor can use the light source 1 to output an amplitude of E c , frequency is f c optical carrier.

[0073] The modulated signal is a signal obtained by modulating the optical carrier by the microwave signal. For example, the modulated signal may include a carrier component, an upper sideband signal, and a lower sideband signal.

[0074] In some embodiments, the electro-optic modulator 2 can modulate the microwave signal onto the optical carrier output by the light source to obtain a modulated signal.

[0075] In some embodiments, the expression of the modulation signal may be:

[0076]

[0077] Among them, E EOM represents the modulated signal, t represents the time, α1 represents the loss introduced by the electro-optic modulator, E c represents the optical carrier amplitude, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, and f c represents the optical carrier frequency, J1 represents the first-order coefficient of the first-kind Bessel function, f m Represents the frequency of the photoelectric oscillation microwave signal, cos(2πf c t) represents the carrier component, cos[2π(f c +f m )t] represents the upper sideband signal, cos[2π(f c -f m )t] represents the lower sideband signal.

[0078] In some embodiments, the expression of the modulation index of the signal may be:

[0079]

[0080] Among them, V m Represents the amplitude of the photoelectric oscillation microwave signal, V π Represents the half-wave voltage at the RF port of the electro-optic modulator.

[0081] In some embodiments, the expression of the phase caused by the DC bias voltage can be:

[0082]

[0083] Among them, V dc Represents the voltage applied to the DC bias port of the electro-optic modulator, V πdc Represents the half-wave voltage at the DC bias port of the EO modulator.

[0084] S2: Obtain a filtered signal by performing overall amplification and single-sideband notch peak suppression filtering on the modulated signal.

[0085] The filtered signal is the modulated signal with one of its sidebands suppressed.

[0086] The upper sideband signal is of frequency f c +f m signal; where f c is the frequency of the optical carrier, f m is the frequency of the microwave signal.

[0087] The lower sideband signal is f c -f m signal.

[0088] In some embodiments, the processor may use the optical amplifier 3 to amplify the modulated signal, and use the notch filter 4 to perform single-sideband suppression on the amplified modulated signal to obtain a filtered signal.

[0089] In some embodiments, the expression of the filtered signal may be:

[0090]

[0091] Among them, E NF represents the filtered signal, α1 represents the loss introduced by the electro-optic modulator (2), G1 represents the gain of the optical amplifier (3), E c represents the optical carrier amplitude, f c represents the optical carrier frequency, t represents the time, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, J1 represents the first-order coefficient of the first-order Bessel function, α2 represents the loss introduced by the notch filter (4) to the lower sideband, and f m represents the frequency of the photoelectric oscillation microwave signal, f c +f m represents the frequency of the upper sideband signal, f c -f m Indicates the frequency of the lower sideband signal.

[0092] S3: The upper sideband signal and the lower sideband signal act on the carrier component respectively, and obtain a gain signal, a corresponding gain coefficient, an attenuation signal and a corresponding attenuation coefficient respectively through calculation.

[0093] The carrier component is the frequency f in the modulated signal. c signal; where f c is the frequency of the optical carrier.

[0094] The gain signal is a microwave signal generated by the interaction of the upper sideband signal and the carrier component.

[0095] The gain coefficient is a coefficient that reflects the gain condition of the gain signal.

[0096] The attenuated signal is a microwave signal generated by the interaction of the lower sideband signal and the carrier component.

[0097] The attenuation coefficient is a coefficient that reflects the attenuation of the attenuation signal.

[0098] In some embodiments, the expression of the gain signal and the corresponding gain coefficient may be:

[0099]

[0100]

[0101] In some embodiments, the expression of the attenuation signal and the corresponding attenuation coefficient may be:

[0102]

[0103]

[0104] Among them, v up represents the gain signal, t represents time, ρ represents the responsivity of the photodetector, R represents the load impedance of the photodetector, α1 represents the loss introduced by the electro-optic modulator, G1 represents the gain of the optical amplifier, E c represents the optical carrier amplitude, f c represents the optical carrier frequency, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, J1 represents the first-order coefficient of the first-order Bessel function, G0 represents the gain coefficient, G2 represents the gain of the microwave amplifier, and f m represents the frequency of the photoelectric oscillation microwave signal, v down represents the attenuation signal, α2 represents the loss introduced by the notch filter to the lower sideband, L0 represents the attenuation coefficient, V m Represents the amplitude of the photoelectric oscillation microwave signal.

[0105] S4: When the coupling coefficient between the gain signal and the attenuation signal is fixed to 1, the gain coefficient and the attenuation coefficient are adjusted by using the amplification process and the notch peak suppression filter to obtain a target photoelectric oscillation microwave signal.

[0106] The coupling coefficient is a coefficient that reflects the coupling between the gain signal and the attenuation signal.

[0107] In some embodiments, the processor may obtain the coupling coefficient by adjusting G0 and L0 to satisfy corresponding conditions.

[0108] The target photoelectric oscillation microwave signal is a stable photoelectric oscillation microwave signal with the highest gain after amplification.

[0109] In some embodiments, the processor can implement S4 based on the following steps: when the coupling coefficient between the gain signal and the attenuation signal is fixed to 1, the gain coefficient and the attenuation coefficient are adjusted by using the amplification processing and the notch peak suppression filter to obtain an adjustment result; based on the adjustment result, the microwave signal is fed back by using the gain signal and the attenuation signal, and when the feedback result meets the oscillation signal satisfying conditions, a target photoelectric oscillation microwave signal is obtained.

[0110] The adjustment result is the gain signal and attenuation signal adjustment result that puts the optoelectronic oscillator in a parity-time symmetry breaking state (PT symmetry breaking state).

[0111] In some embodiments, the expression of the adjustment result may be:

[0112] |G0|=|L0|<κ;

[0113] Wherein, G0 represents the gain coefficient, L0 represents the attenuation coefficient, and κ represents the coupling coefficient.

[0114] The feedback result is a result reflecting the oscillation signal data after the gain signal and the attenuation signal are coupled.

[0115] The oscillation signal satisfaction condition is used to screen the feedback results and obtain the satisfaction condition of the target photoelectric oscillation microwave signal.

[0116] In some embodiments, the expression for the oscillation signal to satisfy the condition may be:

[0117] 2πf m t+φ0=2kπ.

[0118] In some embodiments, the expression of the target photoelectric oscillation microwave signal may be:

[0119] 2πf m τ+φ0=2kπ;

[0120] Among them, Em represents the target photoelectric oscillation microwave signal, t represents time, V m represents the amplitude of the photoelectric oscillation microwave signal, f m represents the frequency of the photoelectric oscillator microwave signal, φ0 represents the initial phase of the oscillation signal, k represents a positive integer, τ=nL / c, n represents the effective refractive index of the optical fiber, L represents the loop length of the photoelectric oscillator, and c represents the speed of light in a vacuum.

[0121] In some embodiments of the present specification, the parity-time symmetric optoelectronic oscillation microwave signal acquisition method, by combining an optical amplifier and an optical notch filter, makes the upper modulation sideband gain while the lower modulation sideband is suppressed, and finally obtains a gain oscillation signal and an attenuated oscillation signal by beating with the carrier frequency respectively. (1) When the gain of the amplifier and the amplitude of the notch peak of the filter are adjusted so that the signal gain and the attenuation coefficient are equal and less than the coupling coefficient, the optoelectronic oscillator satisfies the PT symmetry breaking condition and can achieve single longitudinal mode output in a long loop; (2) The mirror symmetry of the double-sideband modulated signal is used to construct two oscillation signals with different gains, without involving the wavelength and polarization characteristics of the optical signal, and using a physical loop, which greatly simplifies the system structure and improves the signal stability and phase noise performance.

Claims

1. A method for acquiring a parity-time symmetric photoelectric oscillation microwave signal, characterized in that: include: S1: using an electro-optical modulator, modulating a microwave signal onto an optical carrier to obtain a modulated signal; wherein the modulated signal includes an upper sideband signal, a lower sideband signal and a carrier component; S2: Obtain a filtered signal by performing overall amplification and single-sideband notch peak suppression filtering on the modulated signal; S3: The upper sideband signal and the lower sideband signal act on the carrier component respectively, and obtain a gain signal, a corresponding gain coefficient, an attenuation signal and a corresponding attenuation coefficient respectively through calculation; S4: When the coupling coefficient between the gain signal and the attenuation signal is fixed to 1, the gain coefficient and the attenuation coefficient are adjusted by using the amplification process and the notch peak suppression filter to obtain a target photoelectric oscillation microwave signal.

2. The method for acquiring parity-time symmetric photoelectric oscillation microwave signals according to claim 1, characterized in that: The expression of the modulation signal is: Among them, E EOM represents the modulated signal, t represents the time, α1 represents the loss introduced by the electro-optic modulator, E c represents the optical carrier amplitude, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, and f c represents the optical carrier frequency, J1 represents the first-order coefficient of the first-kind Bessel function, f m Represents the frequency of the photoelectric oscillation microwave signal, cos(2πf c t) represents the carrier component, cos[2π(f c +f m )t] represents the upper sideband signal, cos[2π(f c -f m )t] represents the lower sideband signal.

3. The method for acquiring parity-time symmetric photoelectric oscillation microwave signals according to claim 1, characterized in that: The expression of the filtered signal is: Among them, E NF represents the filtered signal, α1 represents the loss introduced by the electro-optic modulator (2), G1 represents the gain of the optical amplifier (3), E c represents the optical carrier amplitude, f c represents the optical carrier frequency, t represents the time, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, J1 represents the first-order coefficient of the first-order Bessel function, α2 represents the loss introduced by the notch filter (4) to the lower sideband, and f m represents the frequency of the photoelectric oscillation microwave signal, f c +f m represents the frequency of the upper sideband signal, f c -f m Indicates the frequency of the lower sideband signal.

4. The method for acquiring parity-time symmetric photoelectric oscillation microwave signals according to claim 1, characterized in that: The expression of the gain signal and the corresponding gain coefficient is: The expressions of the attenuation signal and the corresponding attenuation coefficient are: Among them, v up represents the gain signal, t represents time, ρ represents the responsivity of the photodetector, R represents the load impedance of the photodetector, α1 represents the loss introduced by the electro-optic modulator, G1 represents the gain of the optical amplifier, E c represents the optical carrier amplitude, f c represents the optical carrier frequency, represents the phase caused by the DC bias voltage, J0 represents the zero-order coefficient of the first-order Bessel function, m represents the modulation index of the signal, J1 represents the first-order coefficient of the first-order Bessel function, G0 represents the gain coefficient, G2 represents the gain of the microwave amplifier, and f m represents the frequency of the photoelectric oscillation microwave signal, v down represents the attenuation signal, α2 represents the loss introduced by the notch filter to the lower sideband, L0 represents the attenuation coefficient, V m Represents the amplitude of the photoelectric oscillation microwave signal.

5. The method for acquiring parity-time symmetric photoelectric oscillation microwave signals according to claim 1, characterized in that: The S4 includes: When the coupling coefficient between the gain signal and the attenuation signal is fixed to 1, the gain coefficient and the attenuation coefficient are adjusted by using the amplification process and the notch peak suppression filter to obtain an adjustment result: |G0|=|L0|<κ; Among them, G0 represents the gain coefficient, L0 represents the attenuation coefficient, and κ represents the coupling coefficient; Based on the adjustment result, the gain signal and the attenuation signal are used to feed back the microwave signal, and when the feedback result meets the condition that the oscillation signal satisfies, the target photoelectric oscillation microwave signal is obtained: E m (t)=V m cos(2πf m t); The expression that the oscillation signal satisfies the condition is: 2πf m τ+φ0=2kπ; Among them, E m represents the target photoelectric oscillation microwave signal, t represents time, V m represents the amplitude of the photoelectric oscillation microwave signal, f m represents the frequency of the photoelectric oscillator microwave signal, φ0 represents the initial phase of the oscillation signal, k represents a positive integer, τ=nL / c, n represents the effective refractive index of the optical fiber, L represents the loop length of the photoelectric oscillator, and c represents the speed of light in a vacuum.

6. A parity-time symmetric optoelectronic oscillation microwave signal acquisition device, used to execute the parity-time symmetric optoelectronic oscillation microwave signal acquisition method according to any one of claims 1 to 5, characterized in that: include: A light source (1) for outputting an optical carrier; An electro-optical modulator (2) is used to modulate the microwave signal onto an optical carrier output by the light source (1) to obtain a modulated signal; An optical amplifier (3), used for amplifying the modulated signal; A notch filter (4) having a notch peak located at the sideband of the modulated signal and used for suppressing any upper sideband signal and lower sideband signal to obtain a filtered signal; An optical fiber (5) is used as an energy storage medium of a photoelectric oscillation loop to transmit the filtered signal to a photoelectric detector (6); A photoelectric detector (6) is used to convert the filtered signal into an electrical signal, so that the two sideband signals act on the carrier component to obtain a gain signal and an attenuation signal respectively; A microwave amplifier (7), used for amplifying the gain signal and the attenuation signal; A power divider (8) is used to divide the amplified gain signal and attenuation signal into two paths, one path is used as the output target photoelectric oscillation microwave signal, and the other path is reloaded to the radio frequency port of the electro-optic modulator (2) to form a feedback loop of the photoelectric oscillator; wherein the light source (1), the electro-optic modulator (2), the optical amplifier (3), the notch filter (4), the optical fiber (5), the photodetector (6), the microwave amplifier (7) and the power divider (8) are sequentially connected in series, the electro-optic modulator (2), the optical amplifier (3) and the notch filter (4) belong to a sideband asymmetric modulation module (9), one end of the power divider (8) is the output end, and the other end of the power divider (8) is connected to the radio frequency port of the electro-optic modulator (2).

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