Microwave frequency hopping signal system based on multiple beams of pure optical signals and working method thereof

Abstract

The invention provides a microwave frequency hopping signal system based on multiple beams of pure optical signals and a working method thereof.The system comprises an optical comb signal generating part and a frequency hopping signal selecting part, the frequency hopping signal selecting part comprises a wavelength division multiplexer, the wavelength division multiplexer outputs signals to an optical switch array, a plurality of optical switches are arranged in the optical switch array, and the optical switches are connected with the optical comb signal generating part. The optical switch array outputs a signal to the photoelectric detector; the optical comb signal generation part comprises a pure optical comb signal generation part and a modulated optical signal generation part; the pure optical comb signal generation part is composed of a continuous wave laser, a sinusoidal signal generator, a polarization controller and a first Mach-Zehnder modulator, and a laser signal generated by the continuous wave laser is output to the first Mach-Zehnder modulator through the polarization controller; the first Mach-Zehnder modulator further receives a sine wave signal output by the sine wave signal generator and modulates the laser signal by using the sine wave signal to obtain an optical comb signal containing multiple paths of pure laser signals, and the optical comb signal is output to the wavelength division multiplexer; the modulated optical signal generation part outputs a modulated optical signal to the optical switch array; the photoelectric detector performs beat frequency on one path of pure laser signal in the optical comb signal and the modulated optical signal to form a frequency hopping signal. The invention further provides a working method of the frequency hopping signal system. The frequency hopping signal system is simple in structure and low in production cost.

Description

Technical Field

[0001] The invention relates to the technical field of microwave photon communication, in particular to a microwave frequency hopping signal system based on multiple pure optical signals and a working method of the system. Background Art

[0002] With the development of communication technology, wireless communication technology has developed from the first generation to the fifth generation, and each generation has higher frequencies, larger bandwidths and higher data rates. Frequency hopping technology has been a hot topic in recent years. The application of frequency hopping technology in wireless communication technology can effectively improve the anti-interception and anti-interference capabilities of wireless communication systems, and can greatly improve the communication security of wireless communication systems.

[0003] Microwave photonic technology has the advantages of large bandwidth, instantaneous response, high tuning flexibility, low transmission loss and easy reconstruction, and is believed to be able to provide a higher operating frequency band and a larger operating bandwidth than the traditional electrical domain. The use of microwave photonic technology to generate frequency-hopping microwave signals is believed to be able to provide a higher frequency-hopping speed and frequency-hopping bandwidth than the traditional electrical domain, which is conducive to improving data transmission capabilities and improving data transmission security. Moreover, with the increasing maturity of microwave photonic technology in recent years, it has gradually become popular and provided a good foundation for large-scale applications.

[0004] In recent years, research on the application of microwave photonic technology in frequency hopping signal systems has gradually matured. For example, the invention patent application with publication number CN118826897A discloses a microwave photonic frequency hopping transmission and receiving system, which has a dual-band dual-frequency cascaded optical frequency comb module, a transmission carrier generation and signal modulation module, a radio frequency transmission module, an orthogonal optical sampling clock generation module, an electro-optical sampling and orthogonal demultiplexing module, a radio frequency receiving module, an optoelectronic conversion and digital processing module, and a synchronization and control module.

[0005] However, the overall structure of this solution is very complicated. A wavelength division multiplexer is required in the dual-band dual-frequency cascaded optical frequency comb module, and the entire microwave photon frequency hopping transmission and receiving system has a total of four wavelength division multiplexers. The dual-band dual-frequency cascaded optical frequency comb module also needs to be equipped with multiple devices such as a dual-band optical frequency comb generating device and an electro-optical frequency comb generating device, resulting in high production costs for the microwave photon frequency hopping transmission system and difficulty in popularization and application. Summary of the invention

[0006] The first object of the present invention is to provide a microwave frequency hopping signal system based on multiple pure optical signals with simple structure and low production cost.

[0007] The second object of the present invention is to provide a working method of the above-mentioned microwave frequency-hopping signal system based on multiple pure optical signals.

[0008] To achieve the above-mentioned first purpose, the microwave frequency hopping signal system based on multiple pure optical signals provided by the present invention includes an optical comb signal generating part and a frequency hopping signal selecting part, the frequency hopping signal selecting part includes a wavelength division multiplexer, the wavelength division multiplexer outputs a signal to an optical switch array, a plurality of optical switches are arranged in the optical switch array, and the optical switch array outputs a signal to a photodetector; the optical comb signal generating part includes a pure optical comb signal generating part and a modulated optical signal generating part; the pure optical comb signal generating part is composed of a continuous wave laser, a sine signal generator, a polarization controller and a first Mach-Zehnder modulator, the laser signal generated by the continuous wave laser is output to the first Mach-Zehnder modulator through the polarization controller, the first Mach-Zehnder modulator also receives the sine wave signal output by the sine signal generator, and modulates the laser signal using the sine wave signal to obtain an optical comb signal containing multiple pure laser signals, and the optical comb signal is output to the wavelength division multiplexer; the modulated optical signal generating part outputs a modulated optical signal to the optical switch array; the photodetector uses a pure laser signal in the optical comb signal to beat the modulated optical signal to form a frequency hopping signal.

[0009] It can be seen from the above scheme that the pure optical comb signal generating part of the present invention only includes four devices: a continuous wave laser, a sinusoidal signal generator, a polarization controller and a first Mach-Zehnder modulator. The number of devices used is relatively small, which can reduce the number of devices used in the overall microwave frequency hopping signal system based on multiple pure optical signals.

[0010] In addition, the entire microwave frequency hopping signal system based on multiple pure optical signals uses only one wavelength division multiplexer, which can effectively reduce the volume of the microwave frequency hopping signal system and meet the demand for miniaturization of optical equipment. It is precisely because the number of components used in the microwave frequency hopping signal system is reduced and the overall structure submission is also reduced, so the production cost of the microwave frequency hopping signal system can be reduced, which is conducive to the promotion and application of the microwave frequency hopping signal system.

[0011] A preferred solution is that the modulated optical signal generating part includes a second Mach-Zehnder modulator, which receives the signal output by the orthogonal modulator and uses the signal output by the orthogonal modulator to modulate a pure laser signal to generate a modulated optical signal.

[0012] It can be seen that the modulated optical signal generating part uses the second Mach-Zehnder modulator to generate the modulated optical signal, that is, the modulated laser signal comes from a pure laser signal generated by the pure optical comb signal generating part, so that some optical devices can be multiplexed to further reduce the number of devices used.

[0013] A further solution is that one of the pure laser signals output by the wavelength division multiplexer is input into the second Mach-Zehnder modulator after passing through a splitter.

[0014] It can be seen that by using an optical splitter to split a pure laser signal output by the wavelength division multiplexer and modulating the split optical signal, the optical power of the optical signal input to the second Mach-Zehnder modulator can be reduced.

[0015] A further solution is that the second Mach-Zehnder modulator is a dual-port Mach-Zehnder modulator, the first port of the second Mach-Zehnder modulator receives the signal output by the orthogonal modulator, and the second port of the second Mach-Zehnder modulator receives the signal obtained from the signal output by the orthogonal modulator through a signal amplifier.

[0016] A further solution is that the modulated optical signal generating part further includes an orthogonal frequency division multiplexer, and the orthogonal modulator receives the signal output by the orthogonal frequency division multiplexer.

[0017] A further solution is that the signal output by the orthogonal frequency division multiplexer is filtered by a rectangular optical filter and then output to the orthogonal modulator.

[0018] It can be seen that the signal output by the orthogonal frequency division multiplexer can filter out the interference signal in the signal input to the orthogonal modulator after being filtered by the rectangular optical filter, so that the waveform of the modulated optical signal better meets the requirements.

[0019] A further solution is that the output end of the wavelength division multiplexer is connected to an erbium-doped fiber amplifier, which amplifies the optical signal output by the wavelength division multiplexer and outputs it to the optical switch array through a long-distance optical fiber.

[0020] It can be seen that the optical signal output by the wavelength division multiplexer is amplified by the erbium-doped fiber amplifier and then transmitted over long distances, and after long-distance transmission, it is beat to obtain a frequency-hopping signal. This method enables the frequency-hopping signal to be generated at a farther distance to meet the requirements of multi-point signal transmission.

[0021] To achieve the above-mentioned second purpose, the working method of the microwave frequency-hopping signal system based on multiple pure optical signals provided by the present invention comprises: a first Mach-Zehnder modulator uses a sine wave signal to modulate a laser signal to obtain an optical comb signal containing multiple pure laser signals, and outputs the optical comb signal to a wavelength division multiplexer; a modulated optical signal generating part outputs the modulated optical signal to an optical switch array; the optical switch array selects the corresponding optical switch according to the received control signal, and a photoelectric detector uses a pure laser signal in the optical comb signal to beat the modulated optical signal to form a frequency-hopping signal.

[0022] It can be seen from the above scheme that the number of devices used in the pure optical comb signal generating part of the present invention is small, and it can generate multiple pure laser signals to beat with the modulated optical signal to form a frequency hopping signal, and can realize the generation and transmission of the frequency hopping signal with a small number of devices.

[0023] A preferred solution is that the optical switch array switches the selected optical switch according to the received control signal, thereby switching the pure laser signal output to the photodetector, and further switching the frequency of the frequency hopping signal.

[0024] It can be seen that once the currently used frequency hopping signal is interfered with, the controller changes the currently selected optical switch by sending a control signal, thereby changing the currently used pure laser signal. By replacing the pure laser signal with the modulated optical signal for beat frequency, a frequency hopping signal with a different frequency from the previous one can be obtained, thereby realizing the switching of the frequency hopping signal and meeting the requirements of communication security.

[0025] A further solution is that the phase of the pure laser signal is synchronized with the phase of the modulated optical signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of the first part of an embodiment of a microwave frequency-hopping signal system based on multiple pure optical signals of the present invention.

[0027] Figure 2 It is a spectrum diagram of multiple pure laser signals in an embodiment of a microwave frequency hopping signal system based on multiple pure optical signals of the present invention.

[0028] Figure 3 It is a structural diagram of the second part of an embodiment of a microwave frequency-hopping signal system based on multiple pure optical signals of the present invention.

[0029] Figure 4 It is a flow chart of an embodiment of a working method of a microwave frequency-hopping signal system based on multiple pure optical signals of the present invention.

[0030] Figure 5 The present invention is a flowchart of switching frequency hopping signals in an embodiment of a working method of a microwave frequency hopping signal system based on multiple pure optical signals.

[0031] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0032] The microwave frequency hopping signal system based on multiple pure optical signals of the present invention mainly applies microwave photon technology to generate frequency hopping signals, applies continuous wave to generate multiple pure laser signals, modulates one pure laser signal to generate a modulated optical signal, and applies multiple pure laser signals and modulated optical signals to beat the frequency to generate frequency hopping signals. The microwave frequency hopping signal system of the present invention has a simple structure, uses fewer devices, has the advantage of low production cost, and is conducive to popularization and application.

[0033] Embodiment of microwave frequency hopping signal system based on multiple pure optical signals: This embodiment mainly includes an optical comb signal generation part and a frequency hopping signal selection part. Figure 1 The optical comb signal generating part of this embodiment includes a pure optical comb signal generating part and a modulated optical signal generating part, wherein the pure optical comb signal generating part is composed of a continuous wave laser 11, a sine signal generator 13, a polarization controller 12 and a first Mach-Zehnder modulator 14. The continuous wave laser 11 is used to generate a continuous laser signal, and the generated laser signal is output to the polarization controller 12, and the polarization controller 12 adjusts the polarization state of the laser signal generated by the continuous wave laser 11. The optical signal output by the polarization controller 12 is output to the first Mach-Zehnder modulator 14, and the first Mach-Zehnder modulator 14 also receives the sine wave signal output by the sine signal generator 13, so that the first Mach-Zehnder modulator 14 uses the received sine wave signal to modulate the laser signal output by the polarization controller 12, thereby obtaining multiple pure laser signals. In this way, the phases of the multiple pure laser signals are the same, but the frequencies are different, and the frequency spacing of the pure laser signals of two adjacent channels is equal. The spectrum of the multi-channel pure laser signal output by the first Mach-Zehnder modulator 14 is as follows: Figure 2 The multiple channels of pure laser signals form optical comb signals, which are output to the wavelength division multiplexer 30 .

[0034] The modulated optical signal generating part includes an orthogonal frequency division multiplexer 21, a rectangular optical filter 22, an orthogonal modulator 23, a signal amplifier 24 and a second Mach-Zehnder modulator, wherein the orthogonal frequency division multiplexer 21 is an orthogonal frequency division multiplexer of orthogonal amplitude modulation, outputs a signal to the rectangular optical filter 22, and the rectangular optical filter 22 filters the received signal to obtain a more regular rectangular wave signal.

[0035] The rectangular optical filter 22 outputs the filtered signal to the orthogonal modulator 23. The orthogonal modulator 23 can output two signals, one of which is directly output to the second Mach-Zehnder modulator 25, and the second signal is output to the signal amplifier 24. The signal amplifier 24 amplifies the signal output by the orthogonal modulator 23 and outputs the amplified signal to the second Mach-Zehnder modulator 25. Therefore, the second Mach-Zehnder modulator 25 is a dual-port Mach-Zehnder modulator, that is, the first port of the second Mach-Zehnder modulator 25 receives the signal directly output by the orthogonal modulator 23, and the second port receives the signal output from the orthogonal modulator 23 after passing through the signal amplifier 24.

[0036] In addition, the second Mach-Zehnder modulator 25 also receives a pure laser signal. Specifically, the pure laser signal output by the wavelength division multiplexer 30 is output to the optical splitter 31. The optical splitter 31 splits the pure laser signal and outputs it to the second Mach-Zehnder modulator. In this way, the second Mach-Zehnder modulator 25 modulates the pure laser signal using the signal output by the orthogonal modulator 23, thereby generating a modulated optical signal. Since the modulated optical signal is obtained by modulating the pure laser signal, the modulated optical signal is synchronized with the phase of the multiple pure laser signals.

[0037] In addition, the other multiple channels of pure laser signals output by the wavelength division multiplexer 30 will be input to the optical combiner 32. For example, the wavelength division multiplexer 30 outputs a total of eight channels of pure laser signals, one of which is output to the second Mach-Zehnder modulator 25 after passing through the optical splitter 31, and the remaining seven channels of pure laser signals are output to the optical combiner 32. The optical combiner 32 combines the multiple channels of pure laser signals and outputs them to the erbium-doped fiber amplifier 33. In addition, the modulated optical signal generated by the second Mach-Zehnder modulator 25 is also output to the erbium-doped fiber amplifier 33, which amplifies the pure laser signal and the modulated optical signal and outputs the amplified signal to the erbium-doped fiber, which is then output to a farther location.

[0038] In this embodiment, the frequency hopping signal selection part is provided with an optical switch array 35, an optical amplifier array 37, a photodetector 40, a filter amplifier 41 and a frequency hopping signal transmitter 42 in addition to the wavelength division multiplexer 31. Figure 3As shown. The pure laser signal and the modulated optical signal amplified by the erbium-doped fiber amplifier 33 are output to the optical switch array. The optical switch array 35 is provided with a plurality of optical switches 36. Preferably, the number of the optical switches 36 of the optical switch array 35 is equal to the number of channels of the wavelength division multiplexer 30, and each optical switch 36 corresponds to a channel of the wavelength division multiplexer 30. In addition, the optical switch array 35 can receive a control signal sent by a controller to control the working state of each optical switch 36, for example, to control each optical switch 36 to be in an on state or a off state. If a certain optical switch 36 is in an on state, the pure laser signal or the modulated optical signal of the corresponding optical channel in the wavelength division multiplexer 30 can pass through the optical switch and be transmitted to the optical amplifier array 37. If the optical switch 36 is in an off state, the corresponding optical signal cannot pass through the optical switch and be transmitted to the optical amplifier array 37.

[0039] The optical amplifier array 37 is provided with a plurality of optical amplifiers, each of which is used to amplify the optical signal output from the optical switch array 35. Since the optical signal has the problem of optical power attenuation after transmission, in order not to affect the subsequent beat frequency effect, the optical signal is amplified before the photodetector 40 performs the beat frequency, which can ensure the beat frequency effect and make the frequency of the generated frequency hopping signal more accurate.

[0040] Preferably, only two optical amplifiers may be provided in the optical amplifier array 37, for example, one optical amplifier amplifies one pure laser signal, and the other optical amplifier amplifies the modulated optical signal, and outputs the amplified optical signal to the photodetector 40. The photodetector 40 receives one pure laser signal and one modulated optical signal, and performs beat frequency with the pure laser signal and the modulated optical signal to obtain a frequency hopping signal. Since the photodetector 40 only needs to receive one pure laser signal when performing beat frequency, and only one pure laser signal should be output from the wavelength division multiplexer 30 at the same time, the optical amplifier array 37 may use only one optical amplifier to amplify one output pure laser signal.

[0041] Since there are multiple pure laser signals and the frequencies of each pure laser signal are different, the frequencies of the frequency hopping signals obtained by beating different pure laser signals with the modulated optical signal are also different. In this way, by selecting different optical switches 36 by the controller, the frequency of the frequency hopping signal obtained by beating the photodetector 40 can be changed.

[0042] The frequency hopping signal output by the photodetector 40 is filtered and amplified by the filter amplifier 41 and then transmitted through the frequency hopping signal transmitter 42 . The frequency hopping signal receiving end can receive the frequency hopping signal transmitted by the frequency hopping signal transmitter 42 .

[0043] Since the optical comb signal generating part of the present embodiment includes a pure optical comb signal generating part and a modulated optical signal generating part, and the pure optical comb signal generating part only includes a continuous wave laser 11, a sine signal generator 13, a polarization controller 12 and a first Mach-Zehnder modulator 14, the number of devices used in the pure optical comb signal generating part is small, the structure is simple, and the production cost of the optical comb signal generating part can be reduced. In addition, the entire microwave frequency hopping signal system only uses one wavelength division multiplexer, which can greatly reduce the cost of the microwave frequency hopping signal system compared to the situation where a large number of wavelength division multiplexers and other devices are used in the traditional technology.

[0044] In addition, after the optical comb signal and the modulated optical signal are amplified by the erbium-doped fiber amplifier, they are transmitted to a distant location through a long-distance erbium-doped fiber before being processed by frequency beating. Furthermore, the signal output by the erbium-doped fiber amplifier can be divided into multiple paths, each of which includes an optical comb signal and a modulated optical signal, and the multiple signals are transmitted to a distant optical switch array and a photodetector through the erbium-doped fiber, and finally the photodetector performs frequency beating to obtain a frequency hopping signal. In this way, frequency beating can be performed to transmit a frequency hopping signal at a distant location, and frequency hopping signals can be transmitted at multiple different locations, and the frequencies of the frequency hopping signals transmitted at multiple distant locations are the same, thereby meeting the use requirements in special use scenarios and improving the security of data communication.

[0045] Working method embodiment of microwave frequency hopping signal system based on multiple pure optical signals: Combine the following Figure 4 The working method of the microwave frequency-hopping signal system based on multiple pure optical signals is introduced. After the frequency-hopping signal system starts working, step S1 is first executed, and the continuous wave laser generates a continuous laser signal. The generated laser signal is output to the polarization controller, and the polarization state of the laser signal is adjusted by the polarization controller. The optical signal output by the polarization controller is output to the first Mach-Zehnder modulator. At the same time, the first Mach-Zehnder modulator also receives the sine wave signal output by the sine signal generator.

[0046] Then, the first Mach-Zehnder modulator performs step S2, modulating the laser signal using the received sine wave signal, thereby generating multiple pure laser signals, the multiple pure laser signals having the same phase but different frequencies. The multiple pure laser signals form an optical comb signal and are output to a wavelength division multiplexer, and one of the pure laser signals output by the wavelength division multiplexer is output to the second Mach-Zehnder modulator of the modulated optical signal generating part.

[0047] Furthermore, step S3 is executed, the second Mach-Zehnder modulator uses a pure laser signal to generate a modulated optical signal. Specifically, the second Mach-Zehnder modulator receives the signal output by the orthogonal modulator, and uses the signal output by the orthogonal modulator to modulate the pure laser signal to generate a modulated optical signal.

[0048] Then, step S4 is executed to amplify the optical comb signal and the modulated optical signal through the erbium-doped fiber amplifier, and then transmit them through the long-distance erbium-doped fiber to the optical switch array set at a remote location. In addition, the optical switch array executes step S5 to receive the control signal output by the controller, and determines the working state of multiple optical switches according to the received control signal, for example, making two optical switches in the on state and making the other optical switches in the off state. After the working state of multiple optical switches is determined, a pure laser signal and a modulated optical signal are output to the corresponding optical amplifier, and the optical amplifier amplifies the optical power of the optical signal and outputs it to the photodetector. The photodetector executes step S6 to beat the pure laser signal and the modulated optical signal to obtain a frequency hopping signal, and the frequency hopping signal is emitted into the air after filtering and amplification.

[0049] In addition, the microwave frequency hopping system also needs to monitor whether the currently used frequency hopping signal is interfered with and switch the frequency hopping signal. Figure 5 When monitoring, firstly, step S11 is executed to determine whether the currently used frequency hopping signal is interfered with. The interference of the frequency hopping signal can be identified by judging whether the frequency hopping signal cannot be received normally by the frequency hopping signal receiving end, or whether the frequency hopping signal received by the frequency hopping signal receiving end is abnormal. Once the currently used frequency hopping signal is interfered with, step S12 is executed to determine the frequency of the new frequency hopping signal, for example, reselect the frequency of the new frequency hopping signal according to a predetermined rule, and determine which optical switch needs to be selected according to the frequency of the new frequency hopping signal, and the controller sends a control signal for reselecting the optical switch to the optical switch array, and then the optical switch array executes step S13 to reselect the corresponding optical switch according to the received control signal. In this way, after the optical switch array receives the new control signal, the optical switch array re-determines the working state of each optical switch, thereby switching the pure laser signal used for the beat frequency.

[0050] Next, step S14 is executed, the photodetector applies the new pure laser signal to beat the modulated optical signal to obtain a new frequency hopping signal, and finally step S15 is executed, the new frequency hopping signal is filtered and amplified and then transmitted to the control by the antenna. Preferably, if multiple photodetectors are provided and arranged in a long-distance distributed manner, the optical switch arrays at multiple different positions will switch the optical switches synchronously, so that the frequency hopping signals transmitted at multiple positions can be switched simultaneously.

[0051] Since the microwave frequency-hopping signal of the present invention uses an erbium-doped fiber amplifier to amplify the pure laser signal and the modulated optical signal through the erbium-doped fiber amplifier and transmit them to a distant location through the erbium-doped fiber, it can meet the signal transmission requirements of multiple different locations and improve the quality of wireless signal communication.

[0052] Finally, it should be emphasized that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A microwave frequency-hopping signal system based on multiple pure optical signals, comprising an optical comb signal generating part and a frequency-hopping signal selecting part, wherein the frequency-hopping signal selecting part comprises a wavelength division multiplexer, wherein the wavelength division multiplexer outputs a signal to an optical switch array, wherein a plurality of optical switches are arranged in the optical switch array, and wherein the optical switch array outputs a signal to a photodetector; Features: The optical comb signal generating part comprises a pure optical comb signal generating part and a modulated optical signal generating part; The pure optical comb signal generating part is composed of a continuous wave laser, a sinusoidal signal generator, a polarization controller and a first Mach-Zehnder modulator. The laser signal generated by the continuous wave laser is output to the first Mach-Zehnder modulator through the polarization controller. The first Mach-Zehnder modulator also receives the sinusoidal signal output by the sinusoidal signal generator, and modulates the laser signal with the sinusoidal signal to obtain an optical comb signal containing multiple channels of pure laser signals. The optical comb signal is output to the wavelength division multiplexer. The modulated optical signal generating section outputs the modulated optical signal to the optical switch array; The photoelectric detector uses one of the pure laser signals in the optical comb signal to beat the modulated optical signal to form a frequency hopping signal.

2. The microwave frequency hopping signal system based on multiple pure optical signals according to claim 1, characterized in that: The modulated optical signal generating part includes a second Mach-Zehnder modulator, which receives the signal output by the orthogonal modulator and uses the signal output by the orthogonal modulator to modulate one channel of the pure laser signal to generate the modulated optical signal.

3. The microwave frequency-hopping signal system based on multiple pure optical signals according to claim 2, characterized in that: One of the pure laser signals output by the wavelength division multiplexer is input into the second Mach-Zehnder modulator after passing through an optical splitter.

4. The microwave frequency-hopping signal system based on multiple pure optical signals according to claim 2, characterized in that: The second Mach-Zehnder modulator is a dual-port Mach-Zehnder modulator, wherein a first port of the second Mach-Zehnder modulator receives a signal output by the orthogonal modulator, and a second port of the second Mach-Zehnder modulator receives a signal obtained by passing the signal output by the orthogonal modulator through a signal amplifier.

5. The microwave frequency hopping signal system based on multiple pure optical signals according to claim 2, characterized in that: The modulated optical signal generating section further includes an orthogonal frequency division multiplexer, and the orthogonal modulator receives the signal output by the orthogonal frequency division multiplexer.

6. The microwave frequency-hopping signal system based on multiple pure optical signals according to claim 5, characterized in that: The signal output by the orthogonal frequency division multiplexer is filtered by a rectangular optical filter and then output to the orthogonal modulator.

7. The microwave frequency-hopping signal system based on multiple pure optical signals according to any one of claims 1 to 6, characterized in that: The output end of the wavelength division multiplexer is connected to an erbium-doped fiber amplifier, which amplifies the optical signal output by the wavelength division multiplexer and then outputs it to the optical switch array through a long-distance optical fiber.

8. The working method of the microwave frequency hopping signal system based on multiple pure optical signals according to any one of claims 1 to 7, characterized in that: include: The first Mach-Zehnder modulator modulates the laser signal using the sine wave signal to obtain an optical comb signal containing multiple channels of pure laser signals, and outputs the optical comb signal to the wavelength division multiplexer; The modulated optical signal generating section outputs the modulated optical signal to the optical switch array; The optical switch array switches on corresponding optical switches according to the received control signal, and the photoelectric detector uses one of the pure laser signals in the optical comb signal to beat the modulated optical signal to form a frequency hopping signal.

9. The working method of the microwave frequency hopping signal system based on multiple pure optical signals according to claim 8, characterized in that: The optical switch array switches the selected optical switch according to the received control signal, thereby switching the pure laser signal output to the photodetector, and further switching the frequency of the frequency hopping signal.

10. The working method of the microwave frequency hopping signal system based on multiple pure optical signals according to claim 8 or 9, characterized in that: The clean laser signal is phase synchronized with the modulated optical signal.

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