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

Abstract

The application discloses a three-frequency signal generation system and method based on an integrated optoelectronic oscillator, which comprises a laser, a first optical coupler, a loop one, a loop two, a second optical coupler and a third photoelectric detector, and two uploading and downloading type micro-ring resonators are contained in the loop one and the loop two. The system generates two microwave signals with different frequencies through the laser, the first optical coupler, the loop one and the loop two, and combines two light signals filtered out from the downloading ends of the two micro-ring resonators through the second optical coupler and outputs the combined light signal to the third photoelectric detector for frequency beating to generate a third microwave signal, and the frequency of the third microwave signal is the sum or difference of the frequencies of the first and second microwave signals. The application can generate a high-quality three-frequency signal with adjustable frequency, realizes the miniaturization and integration of the optoelectronic oscillator, reduces the volume and weight of the optoelectronic oscillator system, lowers the system cost and is suitable for more application scenarios.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave photonics, and particularly relates to a three-frequency signal generation system and method based on an integrated optoelectronic oscillator. BACKGROUND

[0002] High-quality microwave oscillators are the basis of all microwave systems and have a relatively wide range of application scenarios. With the continuous development of modern electronic systems, microwave signals of a single frequency cannot meet the needs of various application scenarios, such as wireless communication, global positioning system (GPS), and multi-functional radar systems, which all require signals of multiple frequencies. Therefore, multi-frequency signal generators have been widely studied. In the early days, people used electronic methods to generate multi-frequency signals, and the system was usually composed of a large number of phase-locked loops and voltage-controlled oscillators. The large number of phase-locked loops and voltage-controlled oscillators used would lead to an increase in system cost and complexity. At the same time, the use of electronic methods usually involves multiple frequency multiplication to generate high-frequency signals, which would cause the deterioration of signal phase noise.

[0003] At present, optoelectronic oscillators combined with photonics technology can generate microwave signals of 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, which have large system volume, heavy weight, high cost, and often need to use long optical fibers as energy storage elements to achieve low phase noise. However, the use of long optical fibers would reduce the stability of the system, leading to unstable signal frequency and being not conducive to practical application. SUMMARY

[0004] Technical purpose: In view of the above technical problems, the application provides a three-frequency signal generation system and method based on an integrated optoelectronic oscillator, which can generate high-quality frequency-tunable three-frequency signals, and the signal frequency can be tuned by tuning the output wavelength of the laser or the resonant wavelength of the micro-ring resonator.

[0005] Technical scheme: To achieve the above technical purpose, the application adopts the following technical scheme:

[0006] The three-frequency signal generation system based on the integrated optoelectronic oscillator comprises a laser, a first optical coupler, a loop one, a loop two, a second optical coupler, and a third optoelectronic detector.

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

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

[0009] The loop one comprises a first phase modulator, a first micro-ring resonator of upload-download type, a first photoelectric detector, a first electric amplifier and a first electric power divider connected in sequence to form a loop structure;

[0010] In the loop one,

[0011] The first phase modulator is configured to receive a light signal output by a first optical coupler and perform phase modulation, and output light signals with frequencies of optical carrier f c , +1 order sideband f c +f1, -1 order sideband f c -f1;

[0012] The light input end of the first micro-ring resonator is connected to the output end of the first phase modulator, and the through end outputs light signals of optical carrier f c and one sideband, and the download end outputs light signals of another sideband;

[0013] The first photoelectric detector is configured to perform photoelectric detection on the light signals output by the through end of the first micro-ring resonator, and realize generation of a first microwave signal with a frequency of f1;

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

[0015] The loop two comprises a second phase modulator, a second micro-ring resonator of upload-download type, a second photoelectric detector, a second electric amplifier and a second electric power divider connected in sequence to form a loop structure;

[0016] In the loop two,

[0017] The second phase modulator is configured to receive two light signals output by a second optical coupler and perform phase modulation, and output light signals with frequencies of optical carrier f c , +1 order sideband f c +f2, -1 order sideband f c -f2;

[0018] The light input end of the second micro-ring resonator is connected to the output end of the second phase modulator, and the through end outputs light signals of optical carrier f c and one sideband, and the download end outputs light signals of another sideband;

[0019] The second photoelectric detector is configured to perform photoelectric detection on the light signals output by the through end of the second micro-ring resonator, and realize generation of a second microwave signal with a frequency of f2;

[0020] The second electric power divider is used for receiving the electric signal amplified by the second electric amplifier and dividing it into at least two paths, one of which is used for the optoelectronic 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 resonators of the loop one and the loop two, and the second optical coupler and the third photodetector are used for coupling and photodetecting the received optical signal to generate the third microwave signal with the frequency of f1+f2 or f1-f2.

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

[0023] The third electric power divider is used for receiving the electric signal generated by the third photodetector and dividing it into three paths, one of which is used as the output of the third microwave signal, and the other two are respectively input into the first electric mixer and the second electric mixer.

[0024] In the loop one, the first electric mixer is used for receiving the electric signal output by the second electric power divider and the third electric power divider, mixing and processing to obtain the electric signal with the frequency of f1 and inputting it into the first electric coupler; the first electric coupler is used for receiving the electric signal output by the first electric mixer and the first electric power divider and injecting it into the first phase modulator to form the injection locking of the first microwave signal.

[0025] In the loop two, the second electric mixer is used for receiving the electric signal output by the first electric power divider and the third electric power divider, mixing and processing to obtain the electric signal with the frequency of f2 and inputting it into the second electric coupler; the second electric coupler is used for receiving the electric signal output by the second electric mixer and the second electric power divider and injecting it into the second phase modulator to form the injection locking of the second microwave signal.

[0026] Preferably, the three-frequency signal generation system is composed of an optical system and an electric 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 an optical connection component, and the electric system is composed of a first electric amplifier, a second electric amplifier, a first electric power divider, a second electric power divider and an electric connection component.

[0027] Preferably, all or part of the devices in the optical system are integrated on the same chip by a photonic integration technology, which includes but is not limited to photonic monolithic integration technology, photonic heterogeneous integration technology, photonic heterostructure integration technology and micro-assembly process; the electric system is composed of discrete devices, or the electric 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, the phase modulator, and the micro-ring 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, part of the photonic devices in the optical system are integrated on a chip, and input and output coupling ports are arranged on the chip.

[0030] Preferably, the chip on which the part of the photonic devices are integrated is in optical path communication with other optical devices through an optical coupling technology, which includes but is not limited to 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 through a micro-assembly process, and electrical signal interconnection between the optical system and the electrical system is achieved through a microstrip line or a gold wire lead.

[0032] The application discloses a three-frequency signal generation method based on an integrated optoelectronic oscillator.

[0033] The laser generates an optical signal with a frequency of f c , which is divided into two paths through a first optical coupler and then input into loop one and loop two, respectively.

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

[0035] A second phase modulator in loop two receives the other path of the optical signal output by the first optical coupler and performs phase modulation, and outputs an optical signal with a frequency of an optical carrier f c , a +1st-order sideband f c + f2, and a -1st-order sideband f c - f2; an optical input end of a second micro-ring resonator receives the optical signal output by the second phase modulator, a straight-through end outputs an optical signal with a frequency of the optical carrier fc and one sideband optical signal, the other sideband optical signal is outputted by the download end; the second photodetector photoelectrically detects the optical signal outputted by the through end of the second micro-ring resonator, and second microwave signal generation with the frequency f2 is realized; the second microwave signal generation with the frequency f2 is amplified by the second electric amplifier, and then is inputted into the second electric power divider; the second electric power divider divides the second microwave signal generation 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 outputted by the download end of the first micro-ring resonator and the second micro-ring resonator, the third photodetector photoelectrically detects the optical signal outputted by the second optical coupler, and third microwave signal generation with the frequency f1+f2 or f1-f2 is realized and outputted;

[0037] The tuning of the frequency of the microwave signal is realized by adjusting the output wavelength of the laser and the resonant wavelengths of the two micro-ring resonators; meanwhile, the frequency of the third microwave signal is changed by changing the relative positions of the output wavelength of the laser and the resonant wavelengths of the two micro-ring resonators; when the corresponding resonant wavelengths of the two micro-ring resonators are on one side of the output wavelength of the laser, the frequency of the third microwave signal is f1-f2; when the corresponding resonant wavelengths of the two micro-ring resonators are on both sides of the output wavelength of the laser, the frequency of the 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 comprises a first electric mixer and a first electric coupler, and loop two further comprises a second electric mixer and a second electric coupler;

[0039] The three-frequency signal generation method further comprises the steps of:

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

[0041] The first electric mixer in loop one receives the electric signals outputted by the second electric power divider and the third electric power divider, and obtains the electric signal with the frequency f1 after mixing frequency processing and inputting into the first electric coupler; the first electric coupler receives the electric signals outputted by the first electric mixer and the first electric power divider, and injects the electric signals into the first phase modulator, so as to realize the injection locking of the first microwave signal and improve the frequency stability and the side lobe suppression ratio of the signal;

[0042] The second electrical mixer in loop two receives the electrical signals emitted by the first electrical power divider and the third electrical power divider, obtains an electrical signal with a frequency of f2 after mixing processing, and inputs it into the second electrical coupler; the second electrical coupler receives the signals output by the second electrical mixer and the second electrical power divider and injects them into the second phase modulator to achieve injection locking of the second microwave signal, thereby improving 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, lowering system costs, and facilitating adaptation to more application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0046] Figure 2 The frequency f is filtered out from 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 frequency f is filtered out from 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 To correspond Figure 2 Spectrum of the optical signal at point C in the illustrated situation;

[0049] Figure 5 To correspond Figure 3 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 microring resonator. DETAILED DESCRIPTION

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

[0053] Example 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, electrical amplifiers EA1 and EA2, electrical power dividers PS1 and PS2, PM1, MRR1, PD1, EA1 and PS1 constitute an OEO loop LOOP1, and PM2, MRR2, PD2, EA2 and PS2 constitute an 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 split into two paths by the optical coupler OCP1 and enters the upper and lower PMs respectively for signal modulation;

[0057] Then PM1 generates a frequency of f c The optical carrier signal and frequency is 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 is f c +f RF2 、f c -f RF2 The two groups of ±1-order modulation sidebands are respectively passed through the through-ports of the upper and lower upload-download 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 from the two microring resonators are sent to the two photodetectors PD1 and PD2 respectively for beat frequency, and the frequency f is obtained. RF1 and f RF2 Two electrical signals;

[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 frequency of the system f RF1 / f RF2The RF output signals (RF1 and RF2) are loaded back to the two PMs, forming two optoelectronic closed loops to achieve 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 and directly reaching 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 filter out the frequencies f respectively through the download end of the microring resonator. c +f RF1 and f c +f RF2 The two optical signals are combined into one through the 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 wavelength of the two microring resonators is changed, so that the resonance wavelengths of the two microring resonators are one on the right side and one on the left side of the laser output wavelength. At this time, the optical signal after passing through PM1 will filter out the wavelength of f after passing through the straight-through 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 of the micro-ring will be filtered out at the download end of the two micro-rings. c +f RF1 , f c -f RF2The two signals are combined into one signal through the optical coupler OCP2. 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 triple-frequency signal generation system proposed in this embodiment can simultaneously generate signals of three different frequencies. 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] Example 2

[0067] like Figure 6 As shown, this embodiment proposes an integrated triple-frequency signal generating system, including: a 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] Loop 1 consists of phase modulator PM3, microring resonator MRR3, photodetector PD4, amplifier EA3, power splitter PS3, mixer M1, and coupler ECP1. Loop 2 consists of phase modulator PM4, microring resonator MRR4, photodetector PD5, amplifier EA4, power splitter PS4, mixer M2, and coupler ECP2. Optical coupler OCP4 connects the two microring resonators' output terminals.

[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 modulator PM3 and PM4 respectively;

[0071] The optical carrier signal with a frequency of fc and the optical carrier signal with a frequency of fc are generated by the phase modulator PM3. c +f RF1 , f c -f RF1 ±1 order modulation sidebands are generated by phase modulator PM4 with a frequency of f c The optical carrier signal and frequency is f c +f RF2 , f c -f RF2±1 order modulation sidebands; the modulated optical signals pass through the through ports of the two upload / download type micro-ring resonators respectively to filter out the +1 order sideband or -1 order sideband, break the amplitude balance of the modulation signal and complete the phase-to-intensity modulation;

[0072] The light output from the through ports of the two micro-ring resonators is sent into photodetectors PD4 / PD5 respectively, and beat frequencies to obtain two signals with frequencies of f RF1 and f RF2 The two signals are sent into electrical power splitters PS3 / PS4 respectively after being amplified by two electrical amplifiers EA3 / EA4, and the signals passing through the electrical power splitters PS3 / PS4 are input into electrical mixers M1 / M2 as radio frequency outputs, and are input into corresponding phase modulators PM3 / PM4 after passing through electrical couplers ECP1 / ECP2 to form optoelectronic oscillator loops, at this time, loop one and loop two obtain signals with frequencies of f RF1 and f RF2 ;

[0073] Meanwhile, two optical signals with frequencies of f c +f RF1 and f c +f RF2 can be filtered out from the download ports of the two upload / download type micro-ring resonators respectively, and are sent into a photodetector PD6 after passing through an optical coupler OCP4, and beat frequencies to obtain an electrical signal with a frequency of f RF2 -f RF1 , to realize the generation of a third frequency, which is output into an electrical power splitter PS5 and divided into three paths, one of which is a radio frequency output, and the other two are output into two electrical mixers M1 / M2 respectively to mix with the electrical signals generated by loop one and loop two to obtain signals with frequencies of f RF1 and f RF2 , which are input into phase modulators PM3 / PM4 through two electrical couplers ECP1 / ECP2 respectively to realize injection locking, and improve the frequency stability and side mode suppression ratio of the two signals with frequencies of f RF1 and f RF2 generated by the two optoelectronic oscillator loops; if two optical signals with frequencies of f c +f RF1 and f c -f RF2 are filtered out from the download ports of the two upload / download type micro-ring resonators respectively, beat frequencies to obtain an electrical signal with a frequency of f RF1 +f RF2 can be obtained after the two optical signals pass through an optical coupler OCP4 and are sent into a photodetector PS5, to realize the generation of a third frequency.

[0074] The system of the embodiment simultaneously generates three frequency-tunable high-quality radio frequency signals based on an optoelectronic oscillator, meets the application requirements of multiple frequency signals, and improves the frequency stability and side mode suppression ratio of the signals by using mutual injection locking.

[0075] In the above embodiment, the two micro-ring resonators are upload-download type resonators, as shown in the figure, including an optical input end, a straight-through end and a download end, the straight-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 a role of filtering, energy storage and frequency adjustment. Figure 7

[0076] As can be seen from the above embodiment, in the integrated three-frequency signal generation system designed by the application, the frequencies of the electrical signals generated by the two loops are determined by the relative positions of the optical signals generated by the laser and the resonant wavelengths of the micro-ring resonators, and the tuning of the resonant wavelengths of the micro-ring resonators can realize the tuning of the signal frequency, the application realizes the integration and miniaturization of the optoelectronic oscillator in an integrated manner, which can effectively reduce the system size and power consumption, and at the same time, using the on-chip micro-ring resonator as an energy storage device can replace the long optical fiber to improve the stability of the system.

[0077] In the application, the three-frequency signal generation 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 micro-ring resonator, a photodetector and optical connection components, and the electrical system is composed of an electrical amplifier, an electrical power divider and electrical connection components.

[0078] All or part of the devices in the optical system can be integrated on the same chip through photonic integration technology, which includes but is not limited to photonic monolithic integration technology, photonic heterogeneous integration technology, photonic heterostructure integration technology and micro-assembly process; the electrical system can be composed of discrete devices, or the electrical chips can be integrated on the same substrate. The laser can be integrated on an indium phosphide-based chip, the optical coupler, the phase modulator and the micro-ring 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. Alternatively, part of the photonic devices in the optical system are integrated on a chip, and the chip is provided with input and output coupling ports, and the part of the photonic device integrated chip and other optical devices are connected through optical coupling technology to realize optical path communication, and the optical coupling technology includes but is not limited to optical fiber connection, photonic wire bonding connection and lens coupling.

[0079] The optical system and the electrical system are assembled in the same tube shell through a micro-assembly process, and the electrical signals of the optical system and the electrical system are interconnected through microstrip lines or gold wire leads.

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

Claims

1. A triple-frequency signal generation system based on an integrated optoelectronic oscillator, characterized by: The device comprises a laser, a first optical coupler, a first loop, a second loop, a second optical coupler and a third photodetector; The laser is used to generate a frequency f c 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 split it into two paths and input them into loop 1 and loop 2 respectively; The loop circuit 1 includes a first phase modulator, a first up-download microring 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. 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 the other 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 optoelectronic 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-download microring 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 the other sideband; The second photodetector is used to perform photoelectric detection on the optical signal output from the through-port of the second microring resonator to generate a second microwave signal with a frequency of f2; The second electric power splitter is used to receive the electric signal amplified by the second electric amplifier and split it into at least two paths, one of which is used for the optoelectronic 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 photoelectrically detect the received optical signal to generate a third microwave signal with a frequency of f1+f2 or f1-f2.

2. The triple-frequency signal generation 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 electrical power divider is used to receive the electrical 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 input into the first electrical mixer and the second electrical mixer respectively; In the first loop, the first electrical mixer is used to receive the electrical signals output by the second electrical power divider and the third electrical power divider, obtain an electrical signal with a frequency of f1 after frequency mixing, and input it into the first electrical coupler; the first electrical coupler is used to receive the electrical signals output by the first electrical mixer and the first electrical power divider and inject them into the first phase modulator, thereby forming 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, obtain an electrical signal with a frequency of f2 after mixing processing, and input it 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 generation 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 an optical connection component. 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 an electrical connection component.

4. The triple-frequency signal generation 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 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 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, 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.

6. The triple-frequency signal generating system based on an integrated optoelectronic oscillator according to claim 3, characterized in that: Part of the photonic devices in the optical system are integrated on a chip, and input and output coupling ports are provided 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 to 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 generation 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 signals of the optical system and the electrical system are interconnected through microstrip lines or gold wire leads.

9. A method for generating a triple-frequency signal based on an integrated optoelectronic oscillator, applied to 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 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 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 the other sideband; the first photodetector performs photoelectric detection on the optical signal output by the through end of the first microring resonator to generate 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, which 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 the other sideband; the second photodetector performs photoelectric detection on the optical signal output by the through end of the second microring resonator to generate a second microwave signal with a frequency of f2; the second microwave signal with a frequency of f2 is amplified by the second electrical amplifier and then input into the second electrical power divider, which divides the second microwave signal 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 output 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 generated 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 positions 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, wherein: 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 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; The first electrical mixer in loop one receives the electrical signals emitted by the second and third electrical power dividers, obtains an electrical signal with a frequency of f1 after frequency mixing, and inputs it into the first electrical coupler; the first electrical coupler receives the electrical signals output by the first electrical mixer and the first electrical power divider and injects them into the first phase modulator to achieve injection locking of the first microwave signal, thereby improving the frequency stability and side-mode suppression ratio of the signal; The second electrical mixer in loop two receives the electrical signals emitted by the first electrical power divider and the third electrical power divider, obtains an electrical signal with a frequency of f2 after mixing processing, and inputs it into the second electrical coupler; the second electrical coupler receives the signals output by the second electrical mixer and the second electrical power divider and injects them into the second phase modulator to achieve injection locking of the second microwave signal, thereby improving the frequency stability and side mode suppression ratio of the signal.

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