Emission isolation microwave photon receiving system and method based on parallel electro-optical modulator

Abstract

The invention provides an emission isolation microwave photon receiving system and method based on a parallel electro-optical modulator. Relates to the photoelectric technology field and the modern radar field. Comprising a first continuous wave laser, a second continuous wave laser, a first optical coupler, an antenna, a first Mach-Zehnder modulator, a second Mach-Zehnder modulator, a third Mach-Zehnder modulator, a first power divider, a second power divider, a first variable optical attenuator, a first variable optical delay line, a second variable optical attenuator and a second variable optical delay line. The second optical coupler is used for balancing the photoelectric detector; according to the invention, broadband isolation of signals transmitted at the same time and at the same frequency based on a single antenna and an optical self-interference elimination technology based on a parallel electro-optical modulation structure can be realized, and reflection self-interference signals caused by impedance mismatching of radio frequency connection ports and self-interference signals remaining in opposite transmission modulation can be eliminated at the same time; the isolation degree of the emission isolation microwave photon receiver is improved, the working bandwidth is large, and the isolation degree is high.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic technology and modern radar, and in particular to a transmission isolation microwave photon receiving system and method based on a parallel electro-optical modulator. Background Art

[0002] Simultaneous transmit and receive (STAR) systems have important applications in broadband wireless communications and modern radar detection. In wireless communication systems, full-duplex systems with simultaneous transmit and receive functions can improve the utilization of time and spectrum resources; in radar detection systems, simultaneous transmit and receive can solve the blind spot problem of traditional radar detection. Isolation is one of the key parameters of the simultaneous transmit and receive system, which is used to characterize the degree of isolation of the system's transmitted signal from the crosstalk of the received signal. The simultaneous transmit and receive system based on long-distance dual antennas can significantly improve the isolation of the system. In comparison, the simultaneous transmit and receive system based on a single antenna is more compact and has potential applications in airborne and shipborne radars, small communication base stations and other application scenarios. However, due to the lack of efficient physical isolation of single antenna transmission and reception, the transmission isolation is low. Therefore, a high-isolation simultaneous transmit and receive system based on a single antenna is urgently needed for extremely challenging applications.

[0003] The traditional single-antenna simultaneous co-frequency transceiver system uses an electrical circulator to achieve isolation between the transmit link and the receive link. However, ferrite circulators are limited by electronic bottlenecks and have problems such as low isolation, limited operating bandwidth, and difficulty in operating across octaves. The microwave photon-based transmit isolation receiver can significantly improve the operating bandwidth by leveraging the broadband characteristics of photonic technology. At the same time, by utilizing the effect of the electro-optical modulator that the optical carrier and the modulated signal have high modulation efficiency when transmitted in the same direction and low modulation efficiency when transmitted in the opposite direction, the receiving end can effectively isolate the transmit signal (Po Dong, "Travelling-wave Mach-Zehnder modulators functioning as optical isolators," Optics Express, 23(8), 10498–10505(2015).). In order to further improve the isolation, the electro-optic modulator electrodes with non-uniform spacing can be designed to increase the mismatch between the opposite modulation signal and the optical carrier speed, reduce the opposite modulation efficiency, and thus improve the receiver isolation (C. Cox and E. Ackerman, "TIPRx: a transmit-isolating photonic receiver," Journal of Lightwave Technology, 32(20), 3630-3636(2014).). In addition, two 90° bridges are used to realize single sideband modulation of the co-directional modulated receiving signal and the opposite modulated transmitting signal, and the modulation sidebands of the two are symmetrical relative to the optical carrier. Therefore, the residual modulation sideband of the transmitting signal can be filtered out by an optical filter before photoelectric detection to improve the isolation (Edward I. Ackerman, Charles H. Cox, Harold V. Rousse, and Preetpaul S. Devgan "Broadband simultaneous transmit and receive from a single antenna using improved photonic architecture" in IEEE / MTT-S International Microwave Symposium, 778-781, 2019.). However, since the edge of the spectrum response curve of the optical filter is not steep enough, this method significantly reduces the isolation of the low-frequency transmitting signal, and the isolation performance is affected by the output wavelength drift of the laser, which puts high demands on the output wavelength stability of the laser. Judging from the current research progress, the isolation of existing microwave photonic receivers based on bidirectional electro-optical modulation transmission isolation still needs to be improved, and the existing solutions have not considered the impact of reflected self-interference signals generated by impedance mismatch at the RF connection port on the isolation of the receiver. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a transmission-isolated microwave photon receiving system based on parallel electro-optic modulators.

[0005] An emission-isolated microwave photon receiving system based on a parallel electro-optical modulator comprises a first continuous wave laser, a second continuous wave laser, a first optical coupler, an antenna, a first Mach-Zehnder modulator, a second Mach-Zehnder modulator, a third Mach-Zehnder modulator, a first power divider, a second power divider, a first adjustable optical attenuator, a first adjustable optical delay line, a second adjustable optical attenuator, a second adjustable optical delay line, a second optical coupler, and a balanced photodetector;

[0006] The first continuous wave laser and the second continuous wave laser are both used to output an optical carrier; the first Mach-Zehnder modulator, the second Mach-Zehnder modulator and the third Mach-Zehnder modulator are used to modulate the optical carrier output by the laser;

[0007] The first continuous wave laser is connected to the first Mach-Zehnder modulator; the second continuous wave laser is connected to the first optical coupler, and the first optical coupler is used to split the optical carrier into two, one of which is input into the second Mach-Zehnder modulator, and the other is input into the third Mach-Zehnder modulator; the reference signal of the reflected self-interference signal output by the second Mach-Zehnder modulator passes through the first adjustable optical attenuator and the first adjustable optical delay line in sequence; the reference signal of the opposite modulation signal output by the third Mach-Zehnder modulator passes through the second adjustable optical attenuator and the second adjustable optical delay line in sequence;

[0008] The second optical coupler is used for combining the output of the first adjustable optical delay line and the output of the first Mach-Zehnder modulator and inputting the combined signal into a balanced photodetector;

[0009] The balanced photodetector is used to perform photoelectric conversion on the output signal of the second optical coupler and the output signal of the second adjustable optical delay line;

[0010] The antenna is connected to the first Mach-Zehnder modulator for transmitting and receiving signals;

[0011] The first power divider is connected to the signal source and is used to split the RF signal into two, one of which is connected to the opposite RF port of the first Mach-Zehnder modulator, and the other is connected to the second power divider. Output one of the second power divider is connected to the same-direction RF port of the second Mach-Zehnder modulator, and output two of the second power divider is connected to the opposite RF port of the third Mach-Zehnder modulator.

[0012] The first continuous wave laser and the second continuous wave laser are both distributed feedback lasers with a central wavelength located in the C band, O band or L band. As long as the continuous lasers are located in these bands, there are corresponding photodetectors, and the wavelength difference is large enough so that the difference frequency signal is not detected by the photodetector, the method of the present invention can be implemented.

[0013] Specifically, the optical carrier frequency difference between the first continuous wave laser and the second continuous wave laser is much larger than the bandwidth of the balanced photodetector.

[0014] Specifically, the first Mach-Zehnder modulator operates at a linear bias point on a rising edge.

[0015] Specifically, the second Mach-Zehnder modulator operates at a linear bias point on a falling edge.

[0016] Specifically, the third Mach-Zehnder modulator operates at a linear bias point on a rising edge.

[0017] After photoelectric conversion, the reference signal output by the second Mach-Zehnder modulator has the same amplitude and opposite phase as the reflected self-interference signal in the signal output by the first Mach-Zehnder modulator after photoelectric conversion; after photoelectric conversion, the reference signal output by the third Mach-Zehnder modulator has the same amplitude and opposite phase as the opposite modulation signal in the signal output by the second Mach-Zehnder modulator after photoelectric conversion.

[0018] At the same time, the present invention also provides a transmission isolation photon receiving method based on a parallel electro-optic modulator, which is implemented by using the above-mentioned transmission isolation microwave photon receiving system based on a parallel electro-optic modulator.

[0019] After adopting the above scheme, the beneficial effects of the present invention are as follows:

[0020] The present invention utilizes the efficiency difference between the co-directional transmission modulation and the counter-directional transmission modulation of the optical carrier and the modulation signal in the bidirectional electro-optical modulation to realize the broadband isolation of the signal transmitted simultaneously at the same frequency by a single antenna, and utilizes the optical self-interference elimination technology based on the parallel electro-optical modulation structure to simultaneously eliminate the reflected self-interference signal and the self-interference signal of the counter-directional transmission modulation caused by the impedance mismatch of the antenna RF connection port, thereby improving the isolation of the transmission isolation microwave photon receiver. The entire transmission isolation receiving system has a large working bandwidth, high isolation, compact structure, and can be integrated on chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0022] Figure 2 This is an output spectrum diagram of a balanced photodetector when the transmission signal frequency range is 3 GHz to 6 GHz in the embodiment;

[0023] Figure 3 This is an output spectrum diagram of a balanced photodetector when the transmission signal frequency range is 6 GHz to 12 GHz in the embodiment;

[0024] Figure 4 This is an output spectrum diagram of a balanced photodetector when the transmission signal frequency range is 12 GHz to 24 GHz in the embodiment;

[0025] 1-first continuous wave laser, 2-second continuous wave laser, 3-first optical coupler, 4-antenna, 5-first Mach Zehnder modulator, 6-second MZM, 7-third MZM, 8-signal source, 9-first power divider, 10-second power divider, 11-first adjustable optical attenuator, 12-first adjustable optical delay line, 13-second VOA, 14-second OTDL, 15-second OC, 16-balanced photodetector;

[0026] In the figure, due to the limitation of image space, some devices are represented in reduced size in English. MZM stands for Mach Zehnder modulator, VOA stands for adjustable optical attenuator, OTDL stands for adjustable optical delay line, and OC stands for optical coupler. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] The following is combined with Figures 1 to 4 The present invention is described in detail with reference to the accompanying drawings and examples.

[0029] like Figure 1 As shown, the transmission isolation microwave photon receiving system based on the parallel electro-optical modulator of the present specific implementation includes a first continuous wave laser 1, a second continuous wave laser 2, a first optical coupler 3, an antenna 4, a first Mach-Zehnder modulator 5, a second Mach-Zehnder modulator, a third Mach-Zehnder modulator, a first power divider 9, a second power divider 10, a first adjustable optical attenuator 11, a first adjustable optical delay line 12, a second adjustable optical attenuator, a second adjustable optical delay line, a second optical coupler, and a balanced photodetector 16;

[0030] The first continuous wave laser 1 and the second continuous wave laser 2 are both used to output an optical carrier; the first Mach-Zehnder modulator 5, the second Mach-Zehnder modulator and the third Mach-Zehnder modulator are used to modulate the optical carrier output by the laser;

[0031] The first continuous wave laser 1 is connected to the first Mach-Zehnder modulator 5; the second continuous wave laser 2 is connected to the first optical coupler 3, and the first optical coupler 3 is used to split the optical carrier into two, one of which is input into the second Mach-Zehnder modulator, and the other is input into the third Mach-Zehnder modulator; the reference signal of the reflected self-interference signal output by the second Mach-Zehnder modulator passes through the first adjustable optical attenuator 11 and the first adjustable optical delay line 12 in sequence; the reference signal of the opposite modulation signal output by the third Mach-Zehnder modulator passes through the second adjustable optical attenuator and the second adjustable optical delay line in sequence;

[0032] The second optical coupler is used to combine the output of the first adjustable optical delay line 12 and the output of the first Mach-Zehnder modulator 5 and input the combined signal into the balanced photodetector 16;

[0033] The balanced photodetector 16 is used for performing photoelectric conversion on the output signal of the second optical coupler and the output signal of the second adjustable optical delay line;

[0034] The antenna 4 is connected to the first Mach-Zehnder modulator 5 for transmitting and receiving signals;

[0035] The signal source 8 is used to generate a radio frequency signal; the first power divider 9 is connected to the signal source 8, and is used to split the radio frequency signal into two, one of which is connected to the opposite radio frequency port of the first Mach-Zehnder modulator 5, and the other is connected to the second power divider 10, the output one of the second power divider 10 is connected to the same direction radio frequency port of the second Mach-Zehnder modulator, and the output two of the second power divider 10 is connected to the opposite radio frequency port of the third Mach-Zehnder modulator.

[0036] After photoelectric conversion, the reference signal output by the second Mach-Zehnder modulator has the same amplitude and opposite phase as the reflected self-interference signal in the signal output by the first Mach-Zehnder modulator 5 after photoelectric conversion; after photoelectric conversion, the reference signal output by the third Mach-Zehnder modulator has the same amplitude and opposite phase as the opposite modulation signal in the signal output by the second Mach-Zehnder modulator after photoelectric conversion.

[0037] For the transmission isolation microwave photon receiving system based on parallel electro-optic modulator of this embodiment, the optical carrier output by the first continuous wave laser 1 is input into the first Mach-Zehnder modulator. The optical carrier output by the second continuous wave laser 2 is divided into two by the first optical coupler 3, one of which is input into the second Mach-Zehnder modulator, and the other is input into the third Mach-Zehnder modulator. Among them, the optical carrier frequency difference between the first continuous wave laser 1 and the second continuous wave laser 2 is greater than the bandwidth of the balanced photodetector 16. The radio frequency signal output by the signal source 8 is divided into two by the first power divider 9, one of which enters from the opposite radio frequency port (the radio frequency drive port near the optical output end) of the first Mach-Zehnder modulator 5, passes through the electrode of the first Mach-Zehnder modulator 5, and then outputs from the same direction radio frequency port (the radio frequency drive port near the optical input end of the modulator) to the antenna 4, and finally transmits through the antenna 4. Among them, the first Mach-Zehnder modulator 5 operates at the linear bias point of the rising edge. Another RF signal output by the first power divider 9 is divided into two paths by the second power divider 10: one path enters from the co-directional RF port of the second Mach-Zehnder modulator, and modulates the optical carrier in the same direction to generate a reference signal for eliminating the reflected self-interference signal; the other path enters from the opposite RF port of the third Mach-Zehnder modulator, and modulates the optical carrier in the opposite direction to generate a reference signal for eliminating the opposite modulation signal. Among them, the second Mach-Zehnder modulator operates at the linear bias point of the falling edge, and the third Mach-Zehnder modulator operates at the linear bias point of the rising edge. Then, the reference signal of the reflected self-interference signal output by the second Mach-Zehnder modulator passes through the first adjustable optical attenuator 11 (adjustable optical attenuator) and the first adjustable optical delay line 12 (adjustable optical delay line) in sequence, and the reference signal of the residual opposite modulation signal output by the third Mach-Zehnder modulator passes through the second adjustable optical attenuator and the second adjustable optical delay line in sequence. Finally, the outputs of the first adjustable optical delay line 12 and the first Mach-Zehnder modulator 5 are combined through the second optical coupler and input to the balanced photodetector 16 for photoelectric conversion, and the output of the second adjustable optical delay line is input to the other port of the balanced photodetector 16 for photoelectric conversion, and then the differential characteristics of the balanced detector are used to achieve the elimination of the reflected self-interference signal and the opposite residual modulation signal in the electrical domain. In order to eliminate the reflected self-interference signal, the first adjustable optical attenuator 11 and the first adjustable optical delay line 12 are adjusted respectively, so that the reference signal output by the second Mach-Zehnder modulator has the same amplitude and opposite phase as the reflected self-interference signal in the signal output by the first Mach-Zehnder modulator 5 after photoelectric conversion; in order to eliminate the opposite modulation signal, the second adjustable optical attenuator and the second adjustable optical delay line are adjusted respectively, so that the reference signal output by the third Mach-Zehnder modulator has the same amplitude and opposite phase as the opposite modulation signal in the signal output by the second Mach-Zehnder modulator after photoelectric conversion.

[0038] In this embodiment, the first continuous wave laser 1 adopts a distributed feedback laser with a central wavelength of 1550nm, and the second continuous wave laser 2 adopts a distributed feedback laser with a central wavelength of 1554nm. There is no specific restriction on the wavelengths of the first continuous wave laser 1 and the first continuous wave laser 2, as long as the wavelength difference between the first continuous wave laser and the second continuous wave laser is greater than the bandwidth of the flat photoelectric balance detector. The signal source 8 generates a broadband linear frequency modulation signal with a frequency range of 3GHz to 6GHz, and the reflection coefficient caused by the impedance mismatch of the RF port is 0.1-0.2. The frequency range and reflection coefficient of the signal source 8 are not restricted. This is a specific implementation. In order to distinguish the transmitted signal from the received signal, the target reflected signal is assumed to be a single-tone signal with a frequency of 4.2GHz, and the target distance from the antenna is 200m. The bias voltages of the first Mach-Zehnder modulator 5, the second Mach-Zehnder modulator, and the third Mach-Zehnder modulator are set to be respectively Where V π is the half-wave voltage of the three Mach-Zehnder modulators. The optical carrier output by the first continuous wave laser 1 enters the first Mach-Zehnder modulator 5. The optical carrier output by the second continuous wave laser 2 is divided into two paths through the first coupler 3, one path enters the second Mach-Zehnder modulator, and the other path enters the third Mach-Zehnder modulator. The broadband transmission signal output by the signal source 8 is divided into two after passing through the first power divider 9, one electrical signal drives the opposite RF port of the first Mach-Zehnder modulator 5, and the other path enters the second power divider 10 and is divided into two to drive the same RF port of the second Mach-Zehnder modulator and the opposite RF port of the third Mach-Zehnder modulator respectively. The electrical signal entering the opposite RF port of the first Mach-Zehnder modulator 5 passes through the electrode of the first Mach-Zehnder modulator 5 and is transmitted from the same RF port of the first Mach-Zehnder modulator 5 through the antenna 4. The target signal received by the antenna 4 and the reflected self-interference signal generated by the impedance mismatch of the RF port drive the same RF port of the first Mach-Zehnder modulator 5 together. The optical carrier entering the first Mach-Zehnder modulator 5 is modulated in the same direction by the reflected self-interference signal and the received signal, and is modulated in the opposite direction by the transmitted signal. The optical carrier entering the second Mach-Zehnder modulator is modulated in the same direction by the electrical signal, and the optical carrier entering the third Mach-Zehnder modulator is modulated in the opposite direction by the electrical signal. The output optical signal of the second Mach-Zehnder modulator enters the first adjustable optical attenuator 11 and the first adjustable optical delay line 12 in sequence. The optical signal output by the third Mach-Zehnder modulator enters the second adjustable optical attenuator and the second adjustable optical delay line in sequence. The optical signals output by the first adjustable optical delay line 12 and the first Mach-Zehnder modulator 5 are combined into one optical signal after passing through the second optical coupler. The optical signal output by the second optical coupler enters the balanced photodetector 16 for photoelectric conversion. The optical signal output by the second adjustable optical delay line enters the other port of the balanced photodetector 16 for photoelectric conversion.

[0039] Figure 2 : is a normalized spectrum diagram of the output of the balanced photodetector 16, wherein the dotted line is the output spectrum diagram when the outputs of the first adjustable optical delay line 12 and the second adjustable optical delay line are disconnected, that is, the optical self-interference signal elimination is not performed, and the solid line is the output spectrum diagram after the optical self-interference signal elimination is performed. Figure 2 It can be seen that when optical self-interference signal elimination is not used, the target signal is submerged by the self-interference signal and cannot be identified. When optical self-interference signal elimination is used, the self-interference signal suppression ratio is ≥15dB in the frequency range of 3.65GHz to 4.75GHz; and the self-interference signal suppression ratio is ≥25dB ​​in the frequency range of 4.0GHz to 4.4GHz. It can be seen that the self-interference signal elimination technology achieves an improvement of 15dB isolation in 1.1GHz bandwidth and 25dB isolation in 400MHz bandwidth in the 4GHz frequency band.

[0040] When the transmitted signal frequency is in the range of 6GHz to 12GHz, Figure 3 It is a normalized spectrum diagram of the output of the balanced photodetector 1616. When optical self-interference signal elimination is used, the self-interference signal suppression ratio is ≥15dB in the frequency range of 7.3GHz to 7.9GHz; and the self-interference signal suppression ratio is ≥25dB ​​in the frequency range of 7.55GHz to 7.75GHz. It can be seen that the self-interference signal elimination technology achieves an improvement of 15dB isolation in 600MHz bandwidth and 25dB isolation in 200MHz bandwidth in the 7.5GHz frequency band.

[0041] When the transmitted signal frequency is in the range of 12GHz to 24GHz, Figure 4 It is a normalized spectrum diagram of the output of the balanced photodetector 16. When optical self-interference signal elimination is used, the self-interference signal suppression ratio is ≥15dB in the frequency ranges of 13.9GHz to 15GHz, 17.4GHz to 18.3GHz and 20.9GHz to 21.6GHz; in the frequency range of 17.75GHz to 17.95GHz, the self-interference signal suppression ratio is ≥25dB. It can be seen that the self-interference signal elimination technology achieves a 15dB isolation improvement in the 1.1GHz bandwidth at the 14GHz frequency band, a 15dB isolation improvement in the 900MHz bandwidth and a 25dB isolation improvement in the 200MHz bandwidth at the 17GHz frequency band, and a 15dB isolation improvement in the 700MHz bandwidth at the 21GHz frequency band. It effectively improves the isolation of the transmitted signal and the detection capability of weak targets of the single-antenna simultaneous co-frequency transceiver system.

[0042] It can be seen from the specific examples that the present invention provides a transmission isolation photon receiver solution based on a parallel electro-optical modulator, which can effectively improve the isolation of the transmission isolation microwave photon receiver within a broadband range.

[0043] The present invention is not limited to the above-mentioned embodiments, and several equivalent variations and substitutions can be made. The laser wavelength is not limited to 1550nm and 1554nm, the emission signal type is not limited to linear frequency modulation signals, and the emission and reception signals are not limited to the range of 3GHz to 24GHz. Various simplifications and modifications within the scope of the principles and methods of the present invention all belong to the protection content of the present invention.

Claims

1. A transmission-isolated microwave photon receiving system based on parallel electro-optic modulator, characterized in that: The invention comprises a first continuous wave laser, a second continuous wave laser, a first optical coupler, an antenna, a first Mach-Zehnder modulator, a second Mach-Zehnder modulator, a third Mach-Zehnder modulator, a first power divider, a second power divider, a first adjustable optical attenuator, a first adjustable optical delay line, a second adjustable optical attenuator, a second adjustable optical delay line, a second optical coupler, and a balanced photodetector; The first continuous wave laser and the second continuous wave laser are both used to output an optical carrier; the first Mach-Zehnder modulator, the second Mach-Zehnder modulator and the third Mach-Zehnder modulator are used to modulate the optical carrier output by the laser; A first continuous wave laser is connected to a first Mach-Zehnder modulator; The second continuous wave laser is connected to the first optical coupler, and the first optical coupler is used to split the optical carrier into two, one of which is input into the second Mach-Zehnder modulator, and the other is input into the third Mach-Zehnder modulator; the reference signal of the reflected self-interference signal output by the second Mach-Zehnder modulator passes through the first adjustable optical attenuator and the first adjustable optical delay line in sequence; the reference signal of the opposite modulation signal output by the third Mach-Zehnder modulator passes through the second adjustable optical attenuator and the second adjustable optical delay line in sequence; The second optical coupler is used for combining the output of the first adjustable optical delay line and the output of the first Mach-Zehnder modulator and inputting the combined signal into a balanced photodetector; The balanced photodetector is used to perform photoelectric conversion on the output signal of the second optical coupler and the output signal of the second adjustable optical delay line; The antenna is connected to the first Mach-Zehnder modulator for transmitting and receiving signals; The first power divider is connected to the signal source and is used to split the RF signal into two, one of which is connected to the opposite RF port of the first Mach-Zehnder modulator, and the other is connected to the second power divider. Output one of the second power divider is connected to the same-direction RF port of the second Mach-Zehnder modulator, and output two of the second power divider is connected to the opposite RF port of the third Mach-Zehnder modulator.

2. The transmission isolation microwave photon receiving system based on parallel electro-optical modulator according to claim 1 is characterized in that: The wavelength difference between the first continuous wave laser and the second continuous wave laser is greater than the bandwidth of the flat photoelectric balance detector.

3. The transmission isolation microwave photon receiving system based on parallel electro-optical modulator according to claim 1, characterized in that: The first continuous wave laser and the second continuous wave laser are both distributed feedback lasers with a central wavelength in the C band, O band or L band.

4. The transmission isolation microwave photon receiving system based on parallel electro-optic modulator according to claim 1, characterized in that: The first Mach-Zehnder modulator operates at a linear bias point on the rising edge.

5. The transmission isolation microwave photon receiving system based on parallel electro-optic modulator according to claim 1, characterized in that: The second Mach-Zehnder modulator operates at a linear bias point on the falling edge.

6. The transmission isolation microwave photon receiving system based on parallel electro-optical modulator according to claim 1, characterized in that: The third Mach-Zehnder modulator operates at a linear bias point on the rising edge.

7. The transmission isolation microwave photon receiving system based on parallel electro-optical modulator according to claim 1, characterized in that: After photoelectric conversion, the reference signal output by the second Mach-Zehnder modulator has the same amplitude and opposite phase as the reflected self-interference signal in the signal output by the first Mach-Zehnder modulator after photoelectric conversion; after photoelectric conversion, the reference signal output by the third Mach-Zehnder modulator has the same amplitude and opposite phase as the opposite modulation signal in the signal output by the second Mach-Zehnder modulator after photoelectric conversion.

8. A method for transmitting isolated microwave photons based on parallel electro-optic modulators, characterized in that: The method is implemented by using a transmission-isolated microwave photon receiving system based on a parallel electro-optical modulator as described in any one of claims 1 to 7.

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