Three-frequency signal generation system and generation method based on integrated optoelectronic oscillator

Abstract

The invention discloses a three-frequency signal generation system and generation method based on an integrated photoelectric oscillator, the system comprises a laser, a first optical coupler, a loop I, a loop II, a second optical coupler and a third photoelectric detector, and the loop I and the loop II comprise two upload and download type micro-ring resonators. According to the system, two optoelectronic oscillator loops are constructed through a laser, a first optical coupler, a loop I and a loop II to generate first and second microwave signals with different frequencies, two paths of optical signals filtered out by downloading ends of two micro-ring resonators are combined through a second optical coupler and output to a third photoelectric detector for beat frequency, and a third microwave signal is generated; the frequency of the third microwave signal is the sum or difference of the frequencies of the first and second microwave signals. According to the invention, high-quality frequency-tunable three-frequency signals can be generated, miniaturization and integration of the photoelectric oscillator are realized, the size and weight of the photoelectric oscillator system are reduced, the system cost is reduced, and the photoelectric oscillator is suitable for more application scenes.

Description

Technical Field

[0001] The present invention belongs to the field of microwave photon technology, and in particular relates to a triple-frequency signal generating system and a generating method based on an integrated optoelectronic oscillator. Background Art

[0002] High-quality microwave oscillators are the basis of all microwave systems and have a wide range of application scenarios. With the continuous development of modern electronic systems, microwave signals of a single frequency can no longer meet the needs of various application scenarios. For example, in wireless communications, global positioning systems (GPS), and multi-function radar systems, multiple frequency signals are required, so multi-frequency signal generators have been widely studied. In the early days, people used electronic methods to generate multi-frequency signals. The system usually consisted of a large number of phase-locked loops and voltage-controlled oscillators. The extensive use of phase-locked loops and voltage-controlled oscillators will lead to increased system cost and complexity. At the same time, the use of electronic methods usually generates high-frequency signals through multiple frequency multiplication, which will lead to the deterioration of signal phase noise.

[0003] At present, optoelectronic oscillators combined with photonic technology can generate microwave signals with higher frequency bands and lower signal noise, and have very good development prospects. At present, most multi-frequency signal generators based on optoelectronic oscillators are built based on discrete systems. The system is large in size, heavy in weight, and high in cost. It often requires the use of long optical fibers as energy storage elements to achieve low phase noise. However, the use of long optical fibers will reduce the stability of the system, resulting in unstable signal frequency, which is not conducive to practical applications. Summary of the invention

[0004] Technical purpose: In view of the above technical problems, the present invention proposes a three-frequency signal generating system and method based on an integrated optoelectronic oscillator, which can generate high-quality frequency-tunable three-frequency signals and can tune the signal frequency by tuning the output wavelength of the laser or the resonant wavelength of the microring resonator.

[0005] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution:

[0006] A triple-frequency signal generation system based on an integrated optoelectronic oscillator includes a laser, a first optical coupler, a loop one, a loop two, a second optical coupler and a third photodetector;

[0007] The laser is used to generate a frequency f c The optical signal;

[0008] The input end of the first optical coupler is connected to the output end of the laser, and is used to receive the optical signal output by the laser, and divide it into two paths and input them into loop one and loop two respectively;

[0009] The loop circuit 1 includes a first phase modulator, a first up-download type micro-ring resonator, a first photodetector, a first electric amplifier and a first electric power divider which are sequentially connected to form a loop structure;

[0010] In the loop 1,

[0011] The first phase modulator is used to receive an optical signal output by the first optical coupler and perform phase modulation, and the output optical signal frequency is the optical carrier f c 、+1-order sideband f c +f1, -1 order sideband f c -f1;

[0012] The optical input end of the first microring resonator is connected to the output end of the first phase modulator, and the through end outputs the optical carrier f c and an optical signal of one sideband, and the download end outputs an optical signal of another sideband;

[0013] The first photodetector is used to perform photoelectric detection on the optical signal output from the through-end of the first microring resonator to generate a first microwave signal with a frequency of f1;

[0014] The first electrical power divider is used to receive the electrical signal amplified by the first electrical amplifier and divide it into at least two paths, one of which is used for the photoelectric closed loop and the other is used as the output of the first microwave signal;

[0015] The second loop includes a second phase modulator, a second up-downloading micro-ring resonator, a second photodetector, a second electric amplifier and a second electric power divider which are sequentially connected to form a loop structure;

[0016] In the second loop,

[0017] The second phase modulator is used to receive the two optical signals output by the second optical coupler and perform phase modulation. The output optical signal frequency is the optical carrier f c 、+1-order sideband f c +f2, -1 order sideband f c -f2;

[0018] The optical input end of the second microring resonator is connected to the output end of the second phase modulator, and the through end outputs the optical carrier f c and an optical signal of one sideband, and the download end outputs an optical signal of another sideband;

[0019] The second photodetector is used to perform photoelectric detection on the optical signal output from the through-end of the second microring resonator to generate a second microwave signal with a frequency of f2;

[0020] The second electric power divider is used to receive the electric signal amplified by the second electric amplifier and divide it into at least two paths, one of which is used for the photoelectric closed loop and the other is used as the output of the second microwave signal;

[0021] The second optical coupler is connected to the download end of the microring resonator of loop one and loop two. The second optical coupler and the third photodetector are used to couple and photodetect the received optical signal to generate a third microwave signal with a frequency of f1+f2 or f1-f2.

[0022] Preferably, the output end of the third photodetector is provided with a third electric power divider, loop one further includes a first electric mixer and a first electric coupler, and loop two further includes a second electric mixer and a second electric coupler;

[0023] The third electric power divider is used to receive the electric signal generated by the third photodetector and divide it into three paths, one path is used as the output of the third microwave signal, and the other two paths are respectively input into the first electric mixer and the second electric mixer;

[0024] In the loop 1, the first electric mixer is used to receive the electric signals output by the second electric power divider and the third electric power divider, and obtain the electric signal with a frequency of f1 after mixing and input it into the first electric coupler; the first electric coupler is used to receive the electric signals output by the first electric mixer and the first electric power divider and inject them into the first phase modulator, so as to form injection locking of the first microwave signal;

[0025] In the second loop, the second electrical mixer is used to receive the electrical signals output by the first electrical power divider and the third electrical power divider, and after mixing processing, an electrical signal with a frequency of f2 is obtained and input into the second electrical coupler; the second electrical coupler is used to receive the electrical signals output by the second electrical mixer and the second electrical power divider and inject them into the second phase modulator, thereby forming injection locking of the second microwave signal.

[0026] Preferably, the triple-frequency signal generating system is composed of an optical system and an electrical system, the optical system is composed of a laser, a first optical coupler, a first phase modulator, a second phase modulator, a first microring resonator, a second microring resonator, a second optical coupler, a first photodetector, a second photodetector, a third photodetector and optical connection components, and the electrical system is composed of a first electrical amplifier, a second electrical amplifier, a first electrical power divider, a second electrical power divider and electrical connection components.

[0027] Preferably, all or part of the devices in the optical system are integrated on the same chip through photonic integration technology, and the photonic integration technology includes but is not limited to photonic monolithic integration technology, photonic heterogeneous integration technology, photonic heterogeneous integration technology, and micro-assembly process; the electrical system is composed of discrete devices, or the electrical chips are integrated on the same substrate.

[0028] Preferably, in the optical system, the laser is integrated on an indium phosphide-based chip, the optical coupler, phase modulator, and microring resonator are integrated on an indium phosphide-based, silicon-based, thin-film lithium niobate-based, or thin-film lithium tantalate-based chip, and the photodetector is integrated on an indium phosphide-based or silicon-based chip.

[0029] Preferably, some photonic devices in the optical system are integrated on a chip, and input and output coupling ports are provided on the chip.

[0030] Preferably, the partial photonic device integrated chip is optically connected with other optical devices through optical coupling technology, and the optical coupling technology includes but is not limited to optical fiber connection, photonic wire bonding connection, and lens coupling.

[0031] Preferably, the optical system and the electrical system are assembled in the same tube shell by a microassembly process, and the electrical signal interconnection between the optical system and the electrical system is achieved by microstrip lines or gold wire leads.

[0032] The method for generating a triple-frequency signal based on an integrated optoelectronic oscillator is applied in the system and includes the following steps:

[0033] The laser generates a frequency of f c The optical signal is divided into two paths by the first optical coupler and input into loop 1 and loop 2 respectively;

[0034] The first phase modulator in loop 1 receives an optical signal output by the first optical coupler and performs phase modulation. The frequency of the output optical signal is the optical carrier f c 、+1-order sideband f c +f1, -1 order sideband f c -f1; the optical input end of the first microring resonator receives the optical signal output by the first phase modulator, and the through end outputs the optical carrier f c and an optical signal of one sideband, and the download end outputs an optical signal of another sideband; the first photodetector performs photoelectric detection on the optical signal output by the through end of the first microring resonator to realize the generation of a first microwave signal with a frequency of f1; the first microwave signal with a frequency of f1 is amplified by the first electrical amplifier and then input into the first electrical power divider, and the first electrical power divider divides the first microwave signal into at least two paths, one of which is used for a photoelectric closed loop, and the other is used as the output of the first microwave signal;

[0035] The second phase modulator in loop 2 receives another optical signal output by the first optical coupler and performs phase modulation. The output optical signal frequency is the optical carrier f c 、+1-order sideband f c +f2, -1 order sideband f c -f2; the optical input end of the second microring resonator receives the optical signal output by the second phase modulator, and the through end outputs the optical carrier fc and an optical signal of one sideband, and the download end outputs an optical signal of another sideband; the second photodetector performs photoelectric detection on the optical signal output by the through end of the second microring resonator to realize the generation of a second microwave signal with a frequency of f2; the second microwave signal with a frequency of f2 is amplified by the second electric amplifier and then input into the second electric power divider, and the second electric power divider divides it into at least two paths, one of which is used for the photoelectric closed loop, and the other is used as the output of the second microwave signal;

[0036] The input end of the second optical coupler receives the optical signal output by the first microring resonator and the download end of the second microring resonator, and the third photodetector performs photoelectric detection on the optical signal output by the second optical coupler to generate and output a third microwave signal with a frequency of f1+f2 or f1-f2;

[0037] The frequency of the microwave signal is tuned by adjusting the output wavelength of the laser or the resonant wavelengths of the two microring resonators; at the same time, the frequency of the generated third microwave signal is changed by changing the relative position of the laser output wavelength and the resonant wavelengths of the two microring resonators. When the corresponding resonant wavelengths of the two microring resonators are on one side of the laser output wavelength, the frequency of the generated third microwave signal is f1-f2; when the corresponding resonant wavelengths of the two microring resonators are on both sides of the laser output wavelength, the frequency of the generated third microwave signal is f1+f2.

[0038] Preferably, the output end of the third photodetector is provided with a third electric power divider, loop one further includes a first electric mixer and a first electric coupler, and loop two further includes a second electric mixer and a second electric coupler;

[0039] The triple-frequency signal generating method further comprises the steps of:

[0040] The third microwave signal with a frequency of f1+f2 or f1-f2 generated by the third photodetector is input into the third electric power divider and divided into three paths, one of which is used as the output of the third microwave signal, and the other two paths are respectively input into the first electric mixer and the second electric mixer;

[0041] The first electric mixer in loop one receives the electric signals sent by the second electric power divider and the third electric power divider, obtains the electric signal with a frequency of f1 after frequency mixing and inputs it into the first electric coupler; the first electric coupler receives the electric signals output by the first electric mixer and the first electric power divider and injects them into the first phase modulator to realize injection locking of the first microwave signal and improve the frequency stability and side mode suppression ratio of the signal;

[0042] The second electric mixer in loop two receives the electric signals emitted by the first electric power divider and the third electric power divider, obtains an electric signal with a frequency of f2 after mixing processing and inputs it into the second electric coupler; the second electric coupler receives the signals output by the second electric mixer and the second electric power divider and injects them into the second phase modulator to realize injection locking of the second microwave signal and improve the frequency stability and side mode suppression ratio of the signal.

[0043] Beneficial effects: Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0044] The present invention can generate high-quality frequency-tunable triple-frequency signals, while achieving miniaturization and integration of optoelectronic oscillators, greatly reducing the volume and weight of the optoelectronic oscillator system, reducing system costs, and facilitating adaptation to more application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the structure of the triple-frequency signal generating system based on the integrated optoelectronic oscillator proposed in Example 1;

[0046] Figure 2 The filter frequency f is the download end of the two microring resonators. c +f RF1 and f c +f RF2 Spectrum diagram of the light signals at points A and B when the light signal is ;

[0047] Figure 3 The filter frequency f is the download end of the two microring resonators. c +f RF1 and f c -f RF2 Spectrum diagram of the light signals at points A and B when the light signal is ;

[0048] Figure 4 For the corresponding Figure 2 The spectrum of the optical signal at point C in the illustrated situation;

[0049] Figure 5 For the corresponding Figure 3 The spectrum of the optical signal at point C in the illustrated situation;

[0050] Figure 6 This is a schematic diagram of the structure of the integrated triple-frequency signal generating system proposed in Example 2;

[0051] Figure 7 Schematic diagram of the structure of an adjustable upload and download type microring resonator. DETAILED DESCRIPTION

[0052] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0053] Embodiment 1

[0054] This embodiment proposes a triple-frequency signal generation system based on an integrated optoelectronic oscillator, such as Figure 1 As shown, it includes: laser LD1, optical coupler OCP1, phase modulators PM1 and PM2, microring resonators MRR1 and MRR2, photodetectors PD1, PD2, PD3, optical coupler OCP2, electric amplifiers EA1 and EA2, electric power dividers PS1 and PS2, PM1, MRR1, PD1, EA1 and PS1 constitute OEO loop LOOP1, PM2, MRR2, PD2, EA2 and PS2 constitute OEO loop LOOP2.

[0055] The principle of generating triple-frequency signals in this system is as follows:

[0056] The frequency emitted from laser LD1 is f c The optical signal is divided into two paths by the optical coupler OCP1 and enters the upper and lower PMs for signal modulation respectively;

[0057] Then PM1 generates a frequency of f c The optical carrier signal and frequency are f c +f RF1 、f c -f RF1 The two sets of ±1-order modulation sidebands are generated by PM2 with a frequency of f c The optical carrier signal and frequency are f c +f RF2 、f c -f RF2 The two groups of ±1-order modulation sidebands are respectively passed through the through-ends of the upper and lower up-down microring resonators MRR1 and MRR2 to filter out the +1-order sideband (or -1-order sideband), thereby breaking the amplitude balance of the modulation signal and completing the phase-to-intensity modulation.

[0058] The optical signals at the two microring resonators are sent to two photodetectors PD1 and PD2 for beat frequency, and the frequency is f RF1 and f RF2 Two electrical signals of

[0059] Electrical signal f RF1 and f RF2 After being amplified by the electric amplifiers EA1 and EA2 respectively, they are input into the electric power dividers PS1 and PS2;

[0060] The power dividers PS1 and PS2 divide the corresponding input signals into two paths, one of which is the system frequency f RF1 / f RF2The RF output signals (RF1 and RF2) are loaded back to the two PMs to form two optoelectronic closed loops, realize OEO oscillation, and generate two signals with different frequencies.

[0061] The frequency of the OEO oscillation signal is determined by the wavelength difference between the optical carrier and the MRR resonant wavelength. Since the two MRRs have different resonant wavelengths, two signals with different frequencies can be output through the two OEO loops.

[0062] Figure 2 and Figure 3 Two situations of the optical signal after passing through the two microring resonators MRR1 and MRR2 directly to the end point A / point B are shown.

[0063] Figure 2 In the figure, the through-port of the microring resonator MRR1 filters out the frequency f c and f c -f RF1 The two optical signals of the microring resonator MRR2 are filtered out at the through end with the frequency f c and f c -f RF2 After the two OEO loops are formed, the optical signals passing through the two PMs will be filtered out at the download end of the microring resonator with the frequency f c +f RF1 and f c +f RF2 The two optical signals are combined into one optical signal through optical coupler OCP2. At this time, the optical signal at point C after the combination is as follows: Figure 4 As shown, the light is coupled out of the chip through the grating coupler and sent to the photodetector PD3 for beat frequency, and the frequency f can be obtained. RF2 -f RF1 signal (RF3), three signals of different frequencies are generated simultaneously through the system.

[0064] Similarly, Figure 3 In the experiment, the relative position of the laser output wavelength and the resonance wavelengths of the two microring resonators is changed, so that the resonance wavelengths of the two microring resonators are one on the right side of the laser output wavelength and the other on the left side of the laser output wavelength. At this time, the optical signal after passing through PM1 will filter out the wavelength with a frequency of f after passing through the direct end of the microring resonator. c +f RF1 The +1-order sideband of the optical signal after passing through PM2 will be filtered out after passing through the microring resonator through the direct end. c -f RF2 The -1 order sideband, at this time, the two micro-rings will filter out the frequency f c +f RF1 , f c -f RF2The two signals are combined into one signal through the optical coupler OCP2. At this time, the optical signal at point C after the combination is as follows Figure 5 As shown, the frequency f can be obtained by coupling the light out of the chip and passing it through the photodetector PD3. RF1 +f RF2 signal.

[0065] In summary, the integrated three-frequency signal generating system proposed in this embodiment can generate three signals of different frequencies at the same time, wherein two OEO loops are constructed to generate signals of two frequencies, and the frequency of the other signal generated is the difference frequency or the sum frequency of the two signals.

[0066] Embodiment 2

[0067] like Figure 6 As shown, this embodiment proposes an integrated triple-frequency signal generating system, including: laser LD2, optical couplers OCP3 and OCP4, phase modulators PM3 and PM4, microring resonators MRR3 and MRR4, photodetectors PD4, PD5 and PD6, electrical amplifiers EA3 and EA4, electrical power dividers PS3, PS4 and PS5, electrical mixers M1 and M2, and electrical couplers ECP1 and ECP2.

[0068] Among them, the phase modulator PM3, the microring resonator MRR3, the photodetector PD4, the electric amplifier EA3, the electric power divider PS3, the electric mixer M1 and the electric coupler ECP1 form loop 1. The phase modulator PM4, the microring resonator MRR4, the photodetector PD5, the electric amplifier EA4, the electric power divider PS4, the electric mixer M2 and the electric coupler ECP2 form loop 2. The optical coupler OCP4 connects the download ends of the two microring resonators.

[0069] The principle of generating the triple-frequency signal by the system of this embodiment is as follows:

[0070] The laser emits a frequency of f c The optical signal is divided into two paths after passing through the optical coupler OCP3 and input into the phase modulators PM3 and PM4 respectively;

[0071] The phase modulator PM3 generates an optical carrier signal with a frequency of fc and a frequency of f c +f RF1 , f c -f RF1 The ±1st order modulation sidebands are generated by the phase modulator PM4 with a frequency of f c The optical carrier signal and frequency are f c +f RF2 , f c -f RF2±1-order modulation sidebands; the modulated optical signal is respectively filtered out through the through-ports of the two uploading and downloading microring resonators to filter out the +1-order sideband or -1-order sideband, thereby breaking the amplitude balance of the modulation signal and completing the phase-to-intensity modulation;

[0072] The light output from the two microring resonators is sent to the photodetector PD4 / PD5 respectively, and the beat frequency is f RF1 and f RF2 The two signals are then sent to the electric power divider PS3 / PS4 after being provided with gain by two electric amplifiers EA3 / EA4. The signals passing through the electric power divider PS3 / PS4 are output as RF, input to the electric mixer M1 / M2, and input to the corresponding phase modulator PM3 / PM4 after passing through the electric coupler ECP1 / ECP2 to form an optoelectronic oscillator loop. At this time, loop one and loop two respectively obtain frequencies of f RF1 and f RF2 signal;

[0073] At the same time, the download ends of the two upload-download microring resonators can filter out the frequency f c +f RF1 and f c +f RF2 The two optical signals are sent to the photodetector PD6 after passing through the optical coupler OCP4, and the beat frequency can be obtained as f RF2 -f RF1 The third frequency is generated by the electrical signal of loop 1 and loop 2, and the third frequency is generated by outputting it to the electrical power divider PS5, where one path is used as the RF output, and the other two paths are respectively output to the two electrical mixers M1 / M2, and mixed with the electrical signals generated by loop 1 and loop 2, respectively, to obtain a frequency of f RF1 and f RF2 The signal is input into the phase modulator PM3 / PM4 through two electrical couplers ECP1 / ECP2 to achieve injection locking, which will increase the frequency f generated by the two optoelectronic oscillator loops. RF1 and f RF2 The frequency stability and side mode suppression ratio of the two signals; if the download ends of the two upload-download microring resonators filter out frequencies of f c +f RF1 and f c -f RF2 The two optical signals are sent to the photodetector PS5 after passing through the optical coupler OCP4, and the beat frequency can be obtained as f RF1 +f RF2 The electrical signal is used to generate the third frequency.

[0074] The system of this embodiment simultaneously generates three frequency-tunable high-quality RF signals based on an optoelectronic oscillator, meeting the application requirements of various multi-frequency signals, and adopts a mutual injection locking method to improve the frequency stability and side-mode suppression ratio of the signal.

[0075] In the above embodiment, both micro-ring resonators are up-download resonators. Figure 7 As shown, it includes an optical input end, a through end and a download end. The through end is a band-stop filter response, the download end is a band-pass filter response, and has a tunable center frequency, which can play the role of filtering, energy storage and frequency adjustment.

[0076] It can be seen from the above embodiments that in the integrated three-frequency signal generating system designed by the present invention, the frequency of the electrical signals generated by the two loops is determined by the relative position of the optical signal generated by the laser and the resonant wavelength of the microring resonator. The signal frequency can be tuned by tuning the resonant wavelength of the microring resonator. The present invention adopts an integrated approach to achieve the integration and miniaturization of the optoelectronic oscillator, which can effectively reduce the system volume and power consumption. At the same time, the on-chip microring resonator can be used as an energy storage device to replace the long optical fiber and improve the stability of the system.

[0077] In the present invention, the triple-frequency signal generating system is composed of an optical system and an electrical system. The optical system is composed of a laser, an optical coupler, a phase modulator, a phase modulator, a microring resonator, a photodetector and an optical connection component. The electrical system is composed of an electrical amplifier, an electrical power divider and an electrical connection component.

[0078] All or part of the devices in the optical system can be integrated on the same chip through photon integration technology, which includes but is not limited to photon monolithic integration technology, photon heterogeneous integration technology, photon heterogeneous integration technology, and microassembly process; the electrical system can be composed of discrete devices, or the electrical chip can be integrated on the same substrate. The laser can be integrated on an indium phosphide-based chip, the optical coupler, phase modulator, and microring resonator can be integrated on an indium phosphide-based, silicon-based, thin-film lithium niobate-based, or thin-film lithium tantalate-based chip, and the photodetector can be integrated on an indium phosphide-based or silicon-based chip. Or some of the photon devices in the optical system are integrated on the chip, and input and output coupling ports are set on the chip. Some of the photon device integrated chips are connected to other optical devices through optical coupling technology to achieve optical path communication, and the optical coupling technology is not limited to optical fiber connection, photon wire bonding connection, and lens coupling.

[0079] The optical system and the electrical system are assembled in the same tube shell through a microassembly process, and the electrical signal interconnection between the optical system and the electrical system is achieved through microstrip lines or gold wire leads.

[0080] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A three-frequency signal generation system based on an integrated optoelectronic oscillator, characterized in that: It includes a laser, a first optical coupler, a loop 1, a loop 2, a second optical coupler and a third photodetector; The laser is used to generate a frequency f c The optical signal; The input end of the first optical coupler is connected to the output end of the laser, and is used to receive the optical signal output by the laser, and divide it into two paths and input them into loop one and loop two respectively; The loop circuit 1 includes a first phase modulator, a first up-download type micro-ring resonator, a first photodetector, a first electric amplifier and a first electric power divider which are sequentially connected to form a loop structure; In the loop 1, The first phase modulator is used to receive an optical signal output by the first optical coupler and perform phase modulation, and the output optical signal frequency is the optical carrier f c 、+1-order sideband f c +f1, -1 order sideband f c -f1; The optical input end of the first microring resonator is connected to the output end of the first phase modulator, and the through end outputs the optical carrier f c and an optical signal of one sideband, and the download end outputs an optical signal of another sideband; The first photodetector is used to perform photoelectric detection on the optical signal output from the through-end of the first microring resonator to generate a first microwave signal with a frequency of f1; The first electrical power divider is used to receive the electrical signal amplified by the first electrical amplifier and divide it into at least two paths, one of which is used for the photoelectric closed loop and the other is used as the output of the first microwave signal; The second loop includes a second phase modulator, a second up-downloading micro-ring resonator, a second photodetector, a second electric amplifier and a second electric power divider which are sequentially connected to form a loop structure; In the second loop, The second phase modulator is used to receive the two optical signals output by the second optical coupler and perform phase modulation. The output optical signal frequency is the optical carrier f c 、+1-order sideband f c +f2, -1 order sideband f c -f2; The optical input end of the second microring resonator is connected to the output end of the second phase modulator, and the through end outputs the optical carrier f c and an optical signal of one sideband, and the download end outputs an optical signal of another sideband; The second photodetector is used to perform photoelectric detection on the optical signal output from the through-end of the second microring resonator to generate a second microwave signal with a frequency of f2; The second electric power divider is used to receive the electric signal amplified by the second electric amplifier and divide it into at least two paths, one of which is used for the photoelectric closed loop and the other is used as the output of the second microwave signal; The second optical coupler is connected to the download end of the microring resonator of loop one and loop two. The second optical coupler and the third photodetector are used to couple and photodetect the received optical signal to generate a third microwave signal with a frequency of f1+f2 or f1-f2.

2. The triple-frequency signal generating system based on an integrated optoelectronic oscillator according to claim 1, characterized in that: The output end of the third photodetector is provided with a third electric power divider, loop one further includes a first electric mixer and a first electric coupler, and loop two further includes a second electric mixer and a second electric coupler; The third electric power divider is used to receive the electric signal generated by the third photodetector and divide it into three paths, one path is used as the output of the third microwave signal, and the other two paths are respectively input into the first electric mixer and the second electric mixer; In the loop 1, the first electric mixer is used to receive the electric signals output by the second electric power divider and the third electric power divider, and obtain the electric signal with a frequency of f1 after mixing and input it into the first electric coupler; the first electric coupler is used to receive the electric signals output by the first electric mixer and the first electric power divider and inject them into the first phase modulator, so as to form injection locking of the first microwave signal; In the second loop, the second electrical mixer is used to receive the electrical signals output by the first electrical power divider and the third electrical power divider, and after mixing processing, an electrical signal with a frequency of f2 is obtained and input into the second electrical coupler; the second electrical coupler is used to receive the electrical signals output by the second electrical mixer and the second electrical power divider and inject them into the second phase modulator, thereby forming injection locking of the second microwave signal.

3. The triple-frequency signal generating system based on an integrated optoelectronic oscillator according to claim 1, characterized in that: The triple-frequency signal generating system is composed of an optical system and an electrical system. The optical system is composed of a laser, a first optical coupler, a first phase modulator, a second phase modulator, a first microring resonator, a second microring resonator, a second optical coupler, a first photodetector, a second photodetector, a third photodetector and optical connection components. The electrical system is composed of a first electrical amplifier, a second electrical amplifier, a first electrical power divider, a second electrical power divider and electrical connection components.

4. The triple-frequency signal generating system based on an integrated optoelectronic oscillator according to claim 3, characterized in that: All or part of the devices in the optical system are integrated on the same chip through photon integration technology, and the photon integration technology includes but is not limited to photon monolithic integration technology, photon heterogeneous integration technology, photon heterogeneous integration technology, and microassembly process; the electrical system is composed of discrete devices, or the electrical chips are integrated on the same substrate.

5. The triple-frequency signal generating system based on an integrated optoelectronic oscillator according to claim 3, characterized in that: In the optical system, the laser is integrated on an indium phosphide-based chip, the optical coupler, the phase modulator, and the microring resonator are integrated on an indium phosphide-based, silicon-based, thin-film lithium niobate-based, or thin-film lithium tantalate-based chip, and the photodetector is integrated on an indium phosphide-based or silicon-based chip.

6. The triple-frequency signal generating system based on an integrated optoelectronic oscillator according to claim 3, characterized in that: Some photonic devices in the optical system are integrated on a chip, and input and output coupling ports are arranged on the chip.

7. The triple-frequency signal generating system based on an integrated optoelectronic oscillator according to claim 6, characterized in that: The partial photonic device integrated chip is optically connected with other optical devices through optical coupling technology, and the optical coupling technology includes but is not limited to optical fiber connection, photonic wire bonding connection, and lens coupling.

8. The triple-frequency signal generating system based on an integrated optoelectronic oscillator according to claim 3, characterized in that: The optical system and the electrical system are assembled in the same tube shell through a microassembly process, and the electrical signal interconnection between the optical system and the electrical system is achieved through microstrip lines or gold wire leads.

9. A method for generating a triple-frequency signal based on an integrated optoelectronic oscillator, applied in the system of claim 1, characterized in that: The following steps are involved: The laser generates a frequency of f c The optical signal is divided into two paths by the first optical coupler and input into loop 1 and loop 2 respectively; The first phase modulator in loop 1 receives an optical signal output by the first optical coupler and performs phase modulation. The frequency of the output optical signal is the optical carrier f c 、+1-order sideband f c +f1, -1 order sideband f c -f1; the optical input end of the first microring resonator receives the optical signal output by the first phase modulator, and the through end outputs the optical carrier f c and an optical signal of one sideband, and the download end outputs an optical signal of another sideband; the first photodetector performs photoelectric detection on the optical signal output by the through end of the first microring resonator to realize the generation of a first microwave signal with a frequency of f1; the first microwave signal with a frequency of f1 is amplified by the first electrical amplifier and then input into the first electrical power divider, and the first electrical power divider divides the first microwave signal into at least two paths, one of which is used for a photoelectric closed loop, and the other is used as the output of the first microwave signal; The second phase modulator in loop 2 receives another optical signal output by the first optical coupler and performs phase modulation. The output optical signal frequency is the optical carrier f c 、+1-order sideband f c +f2, -1 order sideband f c -f2; the optical input end of the second microring resonator receives the optical signal output by the second phase modulator, and the through end outputs the optical carrier f c and an optical signal of one sideband, and the download end outputs an optical signal of another sideband; the second photodetector performs photoelectric detection on the optical signal output by the through end of the second microring resonator to realize the generation of a second microwave signal with a frequency of f2; the second microwave signal with a frequency of f2 is amplified by the second electric amplifier and then input into the second electric power divider, and the second electric power divider divides it into at least two paths, one of which is used for the photoelectric closed loop, and the other is used as the output of the second microwave signal; The input end of the second optical coupler receives the optical signal output by the first microring resonator and the download end of the second microring resonator, and the third photodetector performs photoelectric detection on the optical signal output by the second optical coupler to generate and output a third microwave signal with a frequency of f1+f2 or f1-f2; The frequency of the microwave signal is tuned by adjusting the output wavelength of the laser or the resonant wavelengths of the two microring resonators; at the same time, the frequency of the generated third microwave signal is changed by changing the relative position of the laser output wavelength and the resonant wavelengths of the two microring resonators. When the corresponding resonant wavelengths of the two microring resonators are on one side of the laser output wavelength, the frequency of the generated third microwave signal is f1-f2; when the corresponding resonant wavelengths of the two microring resonators are on both sides of the laser output wavelength, the frequency of the generated third microwave signal is f1+f2.

10. The method for generating a triple-frequency signal based on an integrated optoelectronic oscillator according to claim 9, characterized in that: The output end of the third photodetector is provided with a third electric power divider, loop one further includes a first electric mixer and a first electric coupler, and loop two further includes a second electric mixer and a second electric coupler; The triple-frequency signal generation method further comprises the steps of: The third microwave signal with a frequency of f1+f2 or f1-f2 generated by the third photodetector is input into the third electric power divider and divided into three paths, one of which is used as the output of the third microwave signal, and the other two paths are respectively input into the first electric mixer and the second electric mixer; The first electric mixer in loop one receives the electric signals sent by the second electric power divider and the third electric power divider, obtains the electric signal with a frequency of f1 after frequency mixing and inputs it into the first electric coupler; the first electric coupler receives the electric signals output by the first electric mixer and the first electric power divider and injects them into the first phase modulator to realize injection locking of the first microwave signal and improve the frequency stability and side mode suppression ratio of the signal; The second electric mixer in loop two receives the electric signals emitted by the first electric power divider and the third electric power divider, obtains an electric signal with a frequency of f2 after mixing processing and inputs it into the second electric coupler; the second electric coupler receives the signals output by the second electric mixer and the second electric power divider and injects them into the second phase modulator to realize injection locking of the second microwave signal and improve the frequency stability and side mode suppression ratio of the signal.

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