Multi-modulation-format vector signal modulator based on microwave photonics

Abstract

The invention discloses a multi-modulation-format vector signal modulator based on microwave photonics, and relates to the field of microwave photonics. Comprising an IQ quadrature modulation module, a continuous wave laser, a first power optical splitter, an optical carrier frequency generation module, a polarization beam combiner, an optical amplifier, a polarization beam splitter and a photoelectric balance detector module, the IQ quadrature modulation module comprises a double-parallel Mach-Zehnder modulator, a first forming filter, a second forming filter, a first attenuator, a second attenuator, a first direct current voltage stabilization source and a second direct current voltage stabilization source. According to the invention, the formed and filtered IQ baseband signal is input into the double-parallel Mach-Zehnder modulator for quadrature modulation, the IQ baseband signal and the other path of optical carrier signal subjected to differential MZM frequency multiplication are subjected to polarization beam combination, and then the signal is converted into a radio frequency signal through PD, so that the generation of a high-frequency-band and multi-modulation-format vector signal is realized, and the high-frequency-band multi-modulation-format vector signal is suitable for the fields of high-speed communication, photon radar and the like.

Description

Technical Field

[0001] The present invention relates to the field of microwave photonics, and particularly to a multi - modulation - format vector signal modulator based on microwave photonics. Background Art

[0002] With the rapid development of radar technology, communication systems, and radio systems, higher requirements are put forward for the generation of high - frequency vector signals. Traditional electronic devices face problems such as limited bandwidth, increased power consumption, and nonlinear distortion in the high - frequency band. Especially in the process of generating complex multi - modulation - format vector signals, they are easily affected by noise, signal distortion, and frequency drift, making it difficult to ensure the reliability and stability of the system.

[0003] Vector signals are key signal forms in radar and communication systems. Especially in high - speed communication and high - resolution radar, generating high - quality vector signals is crucial for system performance. Traditional vector signal generation methods mostly use electronic modulation techniques. However, as the frequency increases, the response frequency of electronic devices is limited, making it difficult to achieve the generation of high - quality vector signals with wide bandwidth and high frequency. In addition, the generation of multi - modulation - format vector signals, especially in complex environments, requires the modulator to be able to flexibly support multiple modulation formats and maintain high signal quality.

[0004] In summary, there are problems in the prior art such as limited bandwidth, poor frequency response, and unstable signal quality in vector signal generation at high frequencies. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a multi - modulation - format vector signal modulator based on microwave photonics. The present invention uses microwave photonics technology to modulate baseband signals and radio - frequency signals through an electro - optic modulator to achieve the generation of wide - band high - frequency vector signals, and can support multiple modulation formats, such as QAM (Quadrature Amplitude Modulation), PSK (Phase - Shift Keying), FSK (Frequency - Shift Keying), APSK (Amplitude - Phase Shift Keying), etc., and is suitable for high - performance applications in fields such as radar and communication systems.

[0006] The present invention adopts the following technical solutions to solve the above - mentioned technical problems:

[0007] A multi - modulation - format vector signal modulator based on microwave photonics according to the present invention includes: an IQ quadrature modulation module, a continuous - wave laser, a first power splitter, an optical carrier frequency generation module, a polarization beam combiner, an optical amplifier, a polarization beam splitter, and a photoelectric balanced detector module, wherein,

[0008] The IQ quadrature modulation module includes a dual parallel Mach-Zehnder modulator (DP-MZM), a first shaping filter, a second shaping filter, a first attenuator, a second attenuator, a first DC voltage stabilizer, and a second DC voltage stabilizer. The dual parallel Mach-Zehnder modulator includes a first differential Mach-Zehnder modulator and a second differential Mach-Zehnder modulator. The optical carrier frequency generation module includes a third differential Mach-Zehnder modulator. Among them,

[0009] The first DC voltage stabilizer and the second DC voltage stabilizer are used to make the DP-MZM work at the quadrature point;

[0010] The first shaping filter and the second shaping filter are used to perform pulse shaping on the received baseband IQ two-path signals, and output the shaped two-path IQ signals to the first attenuator and the second attenuator respectively;

[0011] The first attenuator and the second attenuator are used to regulate the amplitudes of the shaped two-path IQ signals respectively, and output the shaped and filtered IQ baseband signals to the DP-MZM;

[0012] The DP-MZM is used to perform quadrature modulation on the shaped and filtered IQ baseband signals. The modulation signal is loaded on the x polarization state, and the modulated x polarization state signal is output to the polarization beam combiner;

[0013] The continuous wave laser is used to output a laser source to the first power splitter;

[0014] The first power splitter is used to split the laser source into a first optical signal and a second optical signal with equal power. The first optical signal enters the IQ quadrature modulation module, and the second optical signal enters the optical carrier frequency generation module. Among them, the first optical signal provides a light source for the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator in the IQ quadrature modulation module, and the second optical signal provides a light source for the third differential Mach-Zehnder modulator;

[0015] The optical carrier frequency generation module is used to generate a frequency-doubled optical carrier signal, rotate the polarization direction of the optical carrier signal by 90°, modulate it on the y polarization state, and output the modulated y polarization state signal to the polarization beam combiner;

[0016] The polarization beam combiner is used to combine the modulated x polarization state signal and the y polarization state signal into a single-path signal, and the single-path signal is output to the optical amplifier;

[0017] The optical amplifier is used to amplify the single-path signal, and output the amplified single-path signal to the polarization beam splitter;

[0018] The polarization beam splitter is used to perform polarization splitting on the amplified single-path signal according to the orthogonal phase, and output two orthogonally polarized lights to the optoelectronic balanced detector module;

[0019] An optoelectronic balanced detector module is used to perform balanced detection on two beams of orthogonally polarized light and then output a radio frequency signal modulated in a high frequency band.

[0020] As a further optimization scheme of a multi-modulation format vector signal modulator based on microwave photonics according to the present invention, the DP-MZM includes a second power splitter, a power combiner, a 90° phase shifter, a first differential Mach-Zehnder modulator, and a second differential Mach-Zehnder modulator; wherein,

[0021] The shaped and filtered IQ baseband signal undergoes quadrature modulation through the first differential Mach-Zehnder modulator, the second differential Mach-Zehnder modulator, the 90° phase shifter, and the power combiner. The modulated signal is loaded on the x polarization state, and the modulated x polarization state signal is output to the polarization beam combiner; the first optical signal entering the IQ quadrature modulation module is split equally into the upper and lower arms of the DP-MZM to provide light sources for the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator. The working voltage interfaces of the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator are respectively connected to the first DC voltage stabilizer and the second DC voltage stabilizer. By adjusting the first DC voltage stabilizer and the second DC voltage stabilizer, the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator work at the minimum point, and the DP-MZM works at the quadrature point.

[0022] As a further optimization scheme of a multi-modulation format vector signal modulator based on microwave photonics according to the present invention, the optical carrier generation module includes an analog signal source, a third differential Mach-Zehnder modulator, a third DC voltage stabilizer, an optical filter, and a polarization rotator; wherein,

[0023] The analog signal source is used to output a radio frequency carrier to the third differential Mach-Zehnder modulator;

[0024] The third differential Mach-Zehnder modulator is used to perform frequency doubling processing on the radio frequency carrier and generate a frequency-doubled optical carrier signal for output to the optical filter;

[0025] The optical filter is used to select a specific frequency from the frequency-doubled optical carrier signal and output the filtered optical carrier signal to the polarization rotator;

[0026] The polarization rotator is used to rotate the polarization direction of the filtered optical carrier signal by 90°, modulate the optical carrier signal on the y polarization state perpendicular to the x polarization state, and output the modulated y polarization state signal to the polarization beam combiner;

[0027] The third DC voltage stabilizer is used to make the third differential Mach-Zehnder modulator work at the minimum point.

[0028] As a further optimization scheme of a multi - modulation - format vector signal modulator based on microwave photonics according to the present invention, the optoelectronic balanced detector module includes a first photodetector, a second photodetector and a subtractor. Among them, two orthogonally polarized light beams are respectively input into the first photodetector and the second photodetector for optoelectronic conversion, and the two obtained electrical signals are subtracted by the subtractor, and finally balanced detection output is realized to obtain a radio - frequency signal modulated in the high - frequency band.

[0029] As a further optimization scheme of a multi - modulation - format vector signal modulator based on microwave photonics according to the present invention, by adjusting the first shaping filter, the second shaping filter, the first attenuator and the second attenuator, the input I - channel and Q - channel signals can satisfy the small - signal approximation in the first differential Mach - Zehnder modulator and the second differential Mach - Zehnder modulator.

[0030] As a further optimization scheme of a multi - modulation - format vector signal modulator based on microwave photonics according to the present invention, by adjusting the amplitude of the analog signal source and selecting the modulation index of the third differential Mach - Zehnder modulator, the radio - frequency carrier is expanded by the first - kind Bessel function, and then the required frequency is selected through an optical filter.

[0031] When the present invention adopts the above - mentioned technical solutions compared with the prior art, it has the following technical effects:

[0032] (1) By precisely controlling parameters such as the bias voltage and the amplitude of the radio - frequency signal, this method optimizes the accuracy and stability of signal modulation, overcomes the problems of limited bandwidth and nonlinear distortion in traditional electronic modulation methods, and realizes the generation of broadband, high - frequency - band, and high - quality vector signals;

[0033] (2) The present invention has wide applicability and can be used in fields such as high - speed communication, photonic radar, and spectrum analysis. Description of the Drawings

[0034] Figure 1 is a schematic diagram of a high - quality multi - modulation - format vector signal modulator based on microwave photonics;

[0035] Figure 2 is the continuous - wave laser spectrum;

[0036] Figure 3 is the spectrum of the IQ base - band signal modulated into the optical domain;

[0037] Figure 4 is the optical carrier signal;

[0038] Figure 5 is the radio - frequency signal modulated in the high - frequency band;

[0039] Figure 6It is the evaluation of the quality of vector signal generation; among them, (a) is the reference signal, that is, the digital baseband signal constellation diagram before modulation, and (b) is the signal diagram after downsampling of the constellation trajectory of the generated radio frequency signal entering the vector analyzer. Specific implementation mode

[0040] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Microwave photonics technology provides a new solution for vector signal generation with its broadband, electromagnetic interference resistance and excellent performance in high frequency bands. By utilizing the high-speed modulation characteristics of photonic devices, the bottleneck of traditional electronic modulation in high frequency bands can be broken through. It can not only generate vector signals in high frequency bands, but also support various modulation formats, including common modulation methods such as QAM (Quadrature Amplitude Modulation), PSK (Phase Shift Keying), FSK (Frequency Shift Keying) and composite modulation APSK (Amplitude Phase Shift Keying), etc., thus significantly improving the flexibility and performance stability of the system.

[0042] Therefore, the vector signal generation method based on microwave photonics can effectively solve the challenges in the generation of multi-modulation format signals in current radar and communication systems in high frequency bands, and provides important technical support for future high-speed and high-precision applications.

[0043] The high-quality multi-modulation format vector signal modulator based on microwave photonics mainly includes three parts: IQ quadrature modulation module, optical carrier frequency generation module and optoelectronic balanced detector module.

[0044] Among them, the IQ quadrature modulation module is composed of a second power splitter, a power combiner, a 90° phase shifter, a first differential Mach-Zehnder modulator, a second differential Mach-Zehnder modulator, a first shaping filter, a second shaping filter, a first attenuator, a second attenuator, a first DC voltage stabilizer, and a second DC voltage stabilizer. Among them, the second power splitter, the power combiner, the 90° phase shifter, the first differential Mach-Zehnder modulator, and the second differential Mach-Zehnder modulator form an integrated device, a dual-parallel Mach-Zehnder modulator DP-MZM; the optical carrier frequency generation module is composed of an analog signal source, a third differential Mach-Zehnder modulator, a third DC voltage stabilizer, an optical filter, and a polarization rotator; the optoelectronic balanced detector module is composed of a first photodetector, a second photodetector, and a subtractor.

[0045] When the present invention starts to work, the laser source emitted from the continuous-wave laser first passes through the first power splitter and is split into two optical signals with equal power. One path enters the IQ quadrature modulation module, and the other path enters the optical carrier frequency generation module. The light source entering the IQ quadrature modulation module is evenly divided into the upper and lower arms of the DP-MZM to provide a light source for the differential Mach-Zehnder modulator MZM. The working voltage interfaces of the differential MZMs 1 and 2 are respectively connected to the first DC voltage stabilizer and the second DC voltage stabilizer, and the RF signal interfaces are respectively connected to the input IQ electrical signals. The two IQ signals are respectively pulse-shaped through the shaping filters, and the attenuators adjust the voltage amplitude range within half of the half-wave voltage of the modulator. By adjusting the DC voltage stabilizer, both the differential MZM 1 and the differential MZM 2 work at the minimum operating point, and the DP-MZM works at the quadrature point. At this time, the two IQ signals are modulated into the optical domain. At the same time, adjust the third DC voltage stabilizer so that the third differential Mach-Zehnder modulator works at the minimum point, adjust the output signal amplitude and frequency of the analog signal source, select an appropriate modulation index to double-frequency the analog single-tone signal into the required optical carrier frequency signal, then filter out the required sideband optical carrier frequency signal through the OBPF, rotate the polarization direction by 90° through the PR, and adjust it to the y polarization state. Then use the polarization beam combiner to combine the x polarization state and the y polarization state into one beam, rotate the central axis by 45° and then orthogonally decompose it into two optical signals, which respectively enter the first photodetector and the second photodetector for photoelectric conversion, and balance detection is achieved after subtraction. Finally, a large-bandwidth and high-quality vector signal modulated in the high-frequency band is output, and multiple modulation formats are supported.

[0046] This embodiment is as Figure 1 shown, and includes a continuous-wave laser LD, a first power splitter, a second power splitter, a power combiner, a 90° phase shifter, a first differential Mach-Zehnder modulator (differential MZM 1), a second differential Mach-Zehnder modulator (differential MZM 2), a third differential Mach-Zehnder modulator (differential MZM 3), a first shaping filter, a second shaping filter, a first attenuator, a second attenuator, an analog signal source, a first DC voltage stabilizer, a second DC voltage stabilizer, a third DC voltage stabilizer, an optical filter OBPF, a polarization rotator PR, a polarization beam combiner PBC, an optical amplifier, a polarization beam splitter PBS, a first photodetector (PD 1), and a second photodetector (PD 2). This method takes the composite modulation format 32APSK as an example.

[0047] After the baseband IQ signals pass through the first shaping filter and the second shaping filter respectively, the amplitudes are respectively regulated by the first attenuator and the second attenuator, and then are respectively input into the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator for quadrature modulation, and the modulation signals are loaded on the x polarization state.

[0048] The second power splitter, power combiner, 90° phase shifter, first differential Mach-Zehnder modulator, second differential Mach-Zehnder modulator, first shaping filter, second shaping filter, first attenuator, second attenuator, first DC voltage stabilizer, and second DC voltage stabilizer constitute an integrated device, a dual-parallel Mach-Zehnder modulator (DP-MZM), which is used for electro-optic modulation of vector signals. By adjusting the first DC voltage stabilizer and the second DC voltage stabilizer, the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator operate at the minimum point, and the DP-MZM operates at the quadrature point. By adjusting the first shaping filter, the second shaping filter, the first attenuator, and the second attenuator, the input electrical signal can satisfy the small-signal approximation within the modulator.

[0049] The third differential Mach-Zehnder modulator performs frequency doubling on the RF carrier input from the analog signal source. The generated optical carrier signal selects a specific frequency through an optical filter, and then the signal is modulated onto the y polarization state perpendicular to the x polarization state through a polarization rotator.

[0050] By adjusting the third DC voltage stabilizer, the third differential Mach-Zehnder modulator operates at the minimum point. By adjusting the amplitude of the analog signal source, a suitable modulation index of the modulator is selected, the RF signal is expanded in terms of the first kind of Bessel function, and then the required frequency is selected through an optical filter.

[0051] The modulated x polarization state and y polarization state signals are combined into a single-path signal through a polarization beam combiner. The output signal power is adjusted through an optical amplifier, and then polarization beam splitting is performed according to the quadrature phase. After balanced detection by the first photodetector and the second photodetector, an RF signal modulated in the high-frequency band is output.

[0052] The specific implementation steps are as follows:

[0053] First, a continuous-wave laser outputs a continuous optical wave with a center frequency of 193.1 THz, an average power of 50 mW, and a line width of 100 kHz (with side modes), as Figure 2 shown. It is split into two beams by the first power splitter and respectively input into the IQ quadrature module and the optical carrier generation module. The optical signal entering the IQ quadrature modulation module is evenly divided by the second power splitter into the upper and lower arms of the differential MZM1 and the differential MZM2, providing light sources for the differential MZM1 and the differential MZM2 respectively.

[0054] The IQ signal adopted by this method is the orthogonal amplitude after 32APSK constellation mapping, with a symbol rate of 4 GBaud. It undergoes pulse shaping through the first shaping filter and the second shaping filter respectively. The first shaping filter and the second shaping filter adopt the root-raised cosine filter with a roll-off factor of 0.18. After shaping filtering, the signal bandwidth becomes 4.72 GHz. The amplitudes of the signals are adjusted by the first attenuator and the second attenuator to make them work within the range of half of the half-wave voltage of the modulator. The DC biases of the differential MZM1 and MZM2 are controlled by the first DC voltage stabilizer and the second DC voltage stabilizer, and the differential MZM1 and MZM2 are adjusted to work at the minimum point, and the DP-MZM as a whole works at the quadrature point. At this time, the baseband IQ signal is quadrature-modulated into the optical domain, and the output signal spectrum of the IQ quadrature module is as Figure 3 shown, and the signal is modulated at the optical center frequency of 193.1 Thz.

[0055] The main function of the optical carrier generation module is to generate the doubled optical carrier signal. Another continuous-wave laser provides the light source for the differential MZM3. The analog signal source outputs an RF signal with a frequency of 24.5 GHz, and the modulation index of the differential MZM3 is controlled to be 4.18 and it works at the minimum operating point to generate a tripled optical carrier signal. Then, the unnecessary sidebands are filtered out by the optical bandpass filter (OBPF), and the doubled optical carrier signal is retained. The polarization rotator (PR) rotates the polarization direction of the optical carrier signal by 90°, and modulates it onto the y polarization state. The optical carrier signal is as Figure 4 shown, which is the 73.5 GHz upper sideband.

[0056] Then, the two optical signals modulated on the x polarization state and the y polarization state are combined into a composite optical signal through the polarization beam combiner (PBC). After combining, the main axis rotates by 45°, and then it is decomposed into two orthogonally polarized optical signals again through the polarization beam splitter (PBS), and are respectively input into the first photodetector (PD1) and the second photodetector (PD2) for photoelectric conversion. The two electrical signals are subtracted by the subtractor, and finally balanced detection output is realized to obtain a large-bandwidth and high-quality vector signal modulated in the high-frequency band. The final RF signal spectrum is as Figure 5 shown.

[0057] The generated RF signal is evaluated by the vector analysis algorithm, and finally the EVM is 2.35%. The comparison result is as Figure 6 shown, Figure 6 where (a) is the reference signal, that is, the constellation diagram of the digital baseband signal before modulation, Figure 6 and (b) in

[0058] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A multi-modulation format vector signal modulator based on microwave photonics, characterized in that: include: IQ orthogonal modulation module, continuous wave laser, first power splitter, optical carrier frequency generation module, polarization beam combiner, optical amplifier, polarization beam splitter and photoelectric balance detector module, wherein, The IQ quadrature modulation module includes a dual parallel Mach-Zehnder modulator DP-MZM, a first shaping filter, a second shaping filter, a first attenuator, a second attenuator, a first DC voltage regulator, and a second DC voltage regulator. The dual parallel Mach-Zehnder modulator includes a first differential Mach-Zehnder modulator and a second differential Mach-Zehnder modulator. The optical carrier frequency generation module includes a third differential Mach-Zehnder modulator. The first DC voltage regulator and the second DC voltage regulator are used to make the DP-MZM work at a quadrature point; The first shaping filter and the second shaping filter are used to perform pulse shaping on the received baseband IQ two-path signals, and output the two shaped IQ signals to the first attenuator and the second attenuator respectively; The first attenuator and the second attenuator are used to adjust the amplitude of the two shaped IQ signals respectively, and output the shaped and filtered IQ baseband signals to the DP-MZM; DP-MZM, used to perform orthogonal modulation on the IQ baseband signal after shaping and filtering, the modulated signal is loaded on the x polarization state, and the modulated x polarization state signal is output to the polarization combiner; A continuous wave laser, used for outputting a laser source to the first power splitter; A first power splitter is used to split the laser source into a first optical signal and a second optical signal of equal power, the first optical signal enters the IQ orthogonal modulation module, and the second optical signal enters the optical carrier frequency generation module; wherein the first optical signal provides a light source for the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator in the IQ orthogonal modulation module, and the second optical signal provides a light source for the third differential Mach-Zehnder modulator; An optical carrier frequency generation module is used to generate a frequency-multiplied optical carrier signal, rotate the polarization direction of the optical carrier signal by 90°, modulate it in the y polarization state, and output the modulated y polarization state signal to the polarization combiner; A polarization beam combiner is used to combine the modulated x-polarization state signal and the y-polarization state signal into a single path signal, and the single path signal is output to the optical amplifier; An optical amplifier, used for amplifying a single path signal and outputting the amplified single path signal to a polarization beam splitter; A polarization beam splitter is used to perform polarization beam splitting on the amplified single path signal according to an orthogonal phase, and output two beams of orthogonal polarized light to a photoelectric balanced detector module; The photoelectric balanced detector module is used to perform balanced detection on two beams of orthogonal polarized light and then output a radio frequency signal modulated in a high frequency band.

2. The multi-modulation format vector signal modulator based on microwave photonics according to claim 1, characterized in that: The DP-MZM includes a second power splitter, a power combiner, a 90° phase shifter, a first differential Mach-Zehnder modulator and a second differential Mach-Zehnder modulator; wherein, The IQ baseband signal after shaping filtering is orthogonally modulated by the first differential Mach-Zehnder modulator, the second differential Mach-Zehnder modulator, the 90° phase shifter, and the power synthesizer. The modulated signal is loaded on the x polarization state, and the modulated x polarization state signal is output to the polarization combiner; the first optical signal entering the IQ orthogonal modulation module is equally divided into the upper and lower arms of the DP-MZM, providing light sources for the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator. The working voltage interfaces of the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator are respectively connected to the first DC stabilized voltage source and the second DC stabilized voltage source. By adjusting the first DC stabilized voltage source and the second DC stabilized voltage source, the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator work at the minimum point, and the DP-MZM works at the orthogonal point.

3. The multi-modulation format vector signal modulator based on microwave photonics according to claim 1, characterized in that: The optical carrier frequency generation module includes an analog signal source, a third differential Mach-Zehnder modulator, a third DC voltage regulator, an optical filter and a polarization rotator; wherein, an analog signal source, for outputting a radio frequency carrier to a third differential Mach-Zehnder modulator; a third differential Mach-Zehnder modulator, used for frequency multiplying the radio frequency carrier, generating a frequency multiplied optical carrier signal and outputting it to the optical filter; An optical filter is used to select a specific frequency from the frequency-multiplied optical carrier signal and output the filtered optical carrier signal to the polarization rotator; A polarization rotator is used to rotate the polarization direction of the filtered optical carrier signal by 90°, modulate the optical carrier signal to a y polarization state perpendicular to the x polarization state, and output the modulated y polarization state signal to the polarization combiner; The third DC regulated voltage source is used to make the third differential Mach-Zehnder modulator operate at a minimum point.

4. The multi-modulation format vector signal modulator based on microwave photonics according to claim 1, characterized in that: The photoelectric balanced detector module includes a first photodetector, a second photodetector and a subtractor, wherein two beams of orthogonal polarized light are respectively input into the first photodetector and the second photodetector for photoelectric conversion, and the two electrical signals obtained are subtracted through the subtractor to finally achieve balanced detection output and obtain a radio frequency signal modulated in the high frequency band.

5. The multi-modulation format vector signal modulator based on microwave photonics according to claim 1, characterized in that: By adjusting the first shaping filter, the second shaping filter, the first attenuator and the second attenuator, the input I-path and Q-path signals can meet the small signal approximation in the first differential Mach-Zehnder modulator and the second differential Mach-Zehnder modulator.

6. The multi-modulation format vector signal modulator based on microwave photonics according to claim 1, characterized in that: By adjusting the amplitude of the analog signal source, the modulation index of the third differential Mach-Zehnder modulator is selected, the first-kind Bessel function of the radio frequency carrier is expanded, and then the required frequency is selected through an optical filter.

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