Large-bandwidth tunable microwave frequency hopping signal system based on coherent multiple optical combs and working method thereof

Abstract

The invention provides a large-bandwidth tunable microwave frequency hopping signal system based on multiple coherent optical combs and a working method thereof, the system comprises a wavelength division multiplexer, the output end of the wavelength division multiplexer is connected with an optical switch array, and the optical switch array outputs signals to a photoelectric detector; the tunable microwave frequency hopping signal system further comprises a digital baseband signal generator, digital baseband signals generated by the digital baseband signal generator are output to the quadrature amplitude modulator after being subjected to serial-parallel conversion, and the quadrature amplitude modulator outputs signals to the two first Mach-Zehnder modulators. The plurality of first Mach-Zehnder modulators receive initial laser signals output by the semiconductor laser, the first Mach-Zehnder modulators modulate the initial laser signals by using signals output by the quadrature amplitude modulator, and the obtained first modulated signals are output to the second Mach-Zehnder modulator. The invention further provides a working method of the system. According to the invention, the frequency of the frequency hopping signal can be flexibly adjusted.

Description

Technical Field

[0001] The invention relates to the technical field of microwave photon communication, in particular to a large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs and a working method of the system. Background Art

[0002] With the rapid development of information and 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. 5G communication technology uses frequency bands below 6GHz and millimeter wave, and it still faces many challenges. Two challenges are often encountered in the application of wireless communication: external interference and multipath fading. External interference usually comes from co-channel interference between devices in the public frequency band. In addition, the reflection of wireless signals caused by obstacles such as trees, forests, buildings and human activities makes it difficult for the device to accurately receive these mixed signals and leads to multipath fading that cannot be decoded. At present, the key technology to solve external interference and multipath fading in wireless communication is to use "frequency hopping communication" technology, the working principle of which is that the carrier frequency of the transmission signal between the transmitter and the receiver changes discretely according to a predetermined rule. In civil communication systems, frequency hopping signals have anti-attenuation and anti-interference characteristics, which can improve the transmission capacity of the system; in radar systems, narrow pulse and large bandwidth frequency hopping signals can improve the detection accuracy of radar; in electronic countermeasure systems, the hopping of signal frequency can resist reconnaissance and implement confidential communication. Therefore, the use of frequency hopping communication can effectively improve signal fading and greatly improve communication quality, especially in special information transmission scenarios such as military, aviation, and aerospace. Frequency hopping communication can effectively improve the confidentiality and anti-interference of communication.

[0003] The invention patent application with the publication number CN118826897A discloses a microwave photon frequency hopping transmission and receiving system, which has a dual-band dual-frequency cascade 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. In the frequency hopping transmission part, the communication signal is loaded onto the optical carrier through carrier suppressed single sideband modulation, and the optical carrier and the optical comb tooth beat frequency selected by the optical switch generate a radio frequency transmission signal carrying the communication signal, and the switching of the transmission carrier frequency point is realized through the rapid switching of the optical switch.

[0004] However, the scheme uses an electro-optical frequency comb generator to generate two sets of optical frequency comb signals located in band I and band Q with the same comb tooth frequency interval, and the optical comb tooth frequency interval has specific requirements, that is, it needs to be equal to the required frequency hopping frequency interval. Therefore, the frequency interval of the optical signal in the optical comb signal generated by the electro-optical frequency comb generator is fixed, so that after the subsequent frequency beating, the frequency interval of the obtained frequency hopping signal is also fixed. Therefore, the frequency interval of the frequency hopping signal generated by the existing microwave photon-based frequency hopping signal system is fixed and cannot be adjusted, which makes the frequency hopping signal system insufficiently flexible and cannot meet the higher performance requirements of the frequency hopping signal system. Summary of the invention

[0005] The first object of the present invention is to provide a large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical combs which can flexibly adjust the interval frequency of the frequency hopping signal.

[0006] The second object of the present invention is to provide a working method for the above-mentioned large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs.

[0007] To achieve the above-mentioned first purpose, the present invention provides a large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs, including a wavelength division multiplexer, wherein the output end of the wavelength division multiplexer is connected to an optical switch array, wherein a plurality of optical switches are arranged in the optical switch array, wherein each output end of the wavelength division multiplexer is respectively connected to an optical switch, and the optical switch array outputs a signal to a photodetector; the tunable microwave frequency-hopping signal system also includes a digital baseband signal generator, wherein the digital baseband signal generated by the digital baseband signal generator is output to more than two orthogonal amplitude modulators after serial-to-parallel conversion, wherein each orthogonal amplitude modulator outputs a signal to two first Mach-Zehnder modulators, and wherein the plurality of first Mach-Zehnder modulators output a signal to the first Mach-Zehnder modulators. Both receive an initial laser signal output by a semiconductor laser, the first Mach-Zehnder modulator uses a signal output from the orthogonal amplitude modulator to modulate the initial laser signal, and outputs the obtained first modulated signal to the second Mach-Zehnder modulator; the second Mach-Zehnder modulator also receives an adjustable radio frequency signal, uses the adjustable radio frequency signal to modulate the first modulated signal to obtain an optical comb signal, and sends the optical comb signal to a wavelength division multiplexer; the wavelength division multiplexer also receives an initial laser signal output by a semiconductor laser, the initial laser signal is phase-synchronized with each second modulated signal of the optical comb signal, and the photodetector uses the initial laser signal to beat with one second modulated signal to obtain a frequency hopping signal.

[0008] It can be seen from the above scheme that the optical comb signal of the present invention is obtained by modulating the first modulation signal by the second Mach-Zehnder modulator using an adjustable radio frequency signal. Since the second Mach-Zehnder modulator uses an adjustable radio frequency signal for modulation, and the frequency of the adjustable radio frequency signal itself can be adjusted, the frequency interval between the multiple second modulation signals obtained after modulation by the second Mach-Zehnder modulator can also be adjusted. Therefore, the frequency interval between the obtained optical comb signals can be adjusted.

[0009] Since the photodetector uses the initial laser signal to beat the second modulation signal to obtain the frequency hopping signal, and since the frequency of the initial laser signal is fixed, the frequency intervals of the multiple frequency hopping signals obtained are changed according to the frequency intervals between the second modulation signals. When the frequency intervals between the second modulation signals are adjustable, the intervals between the multiple frequency hopping signals formed by the frequency hopping signal system can also be adjusted. In this way, the frequency hopping signal system can flexibly adjust the frequency intervals between the frequency hopping signals to meet the requirements of different usage scenarios and higher performance conditions.

[0010] A preferred solution is that the number of channels of the wavelength division multiplexer is the sum of the number of second modulation signals of the optical comb signal and the number of initial laser signals.

[0011] It can be seen that by setting a reasonable number of channels of the wavelength division multiplexer, the requirements of the photodetector for receiving the initial laser signal and multiple second modulated signals can be met, thereby meeting the requirements for generating a frequency hopping signal.

[0012] A further solution is that the optical switch array receives a control signal output by the controller, and controls the working state of each optical switch according to the control signal.

[0013] It can be seen that the controller can adjust the working state of each optical switch according to whether the current frequency hopping signal is interfered or the length of time the current frequency hopping signal is used, so as to meet the switching requirements of the frequency hopping signal.

[0014] A further solution is that the output end of the optical switch array is connected to an optical amplifier array, the optical amplifier array is provided with a plurality of optical amplifiers, and the optical amplifiers are used to amplify the optical power of the second modulation signal and / or the initial laser signal.

[0015] It can be seen that by amplifying the optical power of the second modulation signal and / or the initial laser signal through the optical amplifier, the photodetector can more accurately beat the second modulation signal and the initial laser signal, thereby obtaining a frequency hopping signal with a more accurate frequency.

[0016] A further solution is that the output end of the photodetector is connected to a filter amplifier, and the filter amplifier is used to filter the frequency hopping signal output by the photodetector.

[0017] It can be seen that the frequency hopping signal output by the photodetector is filtered and amplified before being transmitted, making the transmitted frequency hopping signal purer.

[0018] A further solution is that the output end of the filter amplifier is connected to a frequency hopping signal transmitter.

[0019] To achieve the above-mentioned second purpose, the working method of the large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs provided by the present invention includes: the optical switch array obtains the control signal output by the controller, and determines the optical switch that needs to be turned on according to the control signal; after the optical switch is turned on, the wavelength division multiplexer passes one of the second modulation signals and the initial laser signal through two optical switches respectively and outputs them to the photodetector, and the photodetector performs beat frequency based on the second modulation signal and the initial laser signal and obtains a frequency-hopping signal.

[0020] As can be seen from the above scheme, the photoelectric detector of the present invention uses the initial laser signal and a second modulation signal to beat the frequency to obtain the frequency hopping signal. Since the frequency of the initial laser signal is fixed, the frequency interval of the obtained multiple frequency hopping signals changes according to the frequency interval between the second modulation signals. When the frequency interval between the second modulation signals is adjustable, the interval between the multiple frequency hopping signals formed by the frequency hopping signal system can also be adjusted. Therefore, the frequency hopping signal system can flexibly adjust the frequency interval between the frequency hopping signals.

[0021] A preferred solution is that the controller receives prompt information that the frequency hopping signal is interfered, and switches the optical switch that needs to be turned on according to the prompt information, thereby switching the center frequency of the frequency hopping signal generated by the photodetector.

[0022] It can be seen that once a certain frequency hopping signal is interfered, the controller can quickly switch the currently used frequency hopping signal by switching the turned-on optical switch, so that the switching of the frequency hopping signal can be realized in a short time.

[0023] A further solution is that the controller switches the optical switch to be turned on according to a preset rule, thereby switching the center frequency of the frequency hopping signal generated by the photodetector.

[0024] A preferred solution is that the preset rule includes: switching the optical switches that need to be turned on at preset time intervals and in a preset order.

[0025] It can be seen that switching the frequency hopping signal according to a preset time interval can avoid using the frequency hopping signal of a certain channel for a long time, which can improve the confidentiality of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of the first part of an embodiment of a large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs of the present invention.

[0027] Figure 2 It is a spectrum diagram of four-path optical comb signal simulated by computer in an embodiment of the large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical combs of the present invention.

[0028] Figure 3 It is a structural diagram of the second part of an embodiment of a large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs of the present invention.

[0029] Figure 4 It is a flow chart of the first embodiment of the working method of the large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical combs of the present invention.

[0030] Figure 5 It is a flow chart of the second embodiment of the working method of the large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical combs of the present invention.

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

[0032] The large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs of the present invention mainly uses microwave photonic technology to generate frequency-hopping signals. Since the frequency-hopping signal is generated by the beat frequency of an initial laser signal with a preset frequency and a first modulation signal obtained through modulation, and the frequency of the adjustable radio frequency signal itself used to generate the first modulation signal can be adjusted, the frequency interval between the frequency-hopping signals generated by the frequency-hopping signal system can also be adjusted to improve the flexibility of the frequency-hopping signal system.

[0033] Embodiment of a large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb: 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 digital baseband signal generator 10 and two orthogonal amplitude modulators 11 and 12. The digital baseband signal generator 10 is used to generate a digital baseband signal. The digital baseband signal can be a pulse signal or a sinusoidal signal. Preferably, the digital baseband signal has a relatively fixed frequency. The digital baseband signal generated by the digital baseband signal generator 10 is divided into two paths after serial-to-parallel conversion and output to the orthogonal amplitude modulators 11 and 12 respectively. The orthogonal amplitude modulators 11 and 12 perform differential orthogonal amplitude modulation on the received signals respectively.

[0034] The quadrature amplitude modulator 11 divides the modulated signal into two paths, which are respectively output to the two first Mach-Zehnder modulators 21 and 22. Among the signals output by the quadrature amplitude modulator 11 to the two first Mach-Zehnder modulators 21 and 22, one signal is an I signal and the other signal is a Q signal. The phase difference between the I signal and the Q signal is 90°. Similarly, the quadrature amplitude modulator 12 divides the modulated signal into two paths, which are respectively output to the two first Mach-Zehnder modulators 23 and 24. The two signals are also an I signal and a Q signal.

[0035] In addition, the optical comb signal generating part is further provided with a semiconductor laser 20, which is used to generate an initial laser signal. Preferably, the frequency of the initial laser signal is a preset fixed frequency. The initial laser signal generated by the semiconductor laser 20 is output to four first Mach-Zehnder modulators 21, 22, 23, and 24. Each of the first Mach-Zehnder modulators 21, 22, 23, and 24 modulates the initial laser signal using a signal output from the orthogonal amplitude modulator, thereby generating a first modulation signal. The first modulation signals generated by the four first Mach-Zehnder modulators 21, 22, 23, and 24 are all output to the second Mach-Zehnder modulator 26. Figure 1 In , the dotted line represents the electrical signal, and the solid line represents the optical signal.

[0036] In addition to receiving the first modulation signals outputted from the four first Mach-Zehnder modulators 21, 22, 23, and 24, the second Mach-Zehnder modulator 26 also receives the adjustable RF signal generated by the adjustable RF signal generator 25, and modulates the first modulation signal with the adjustable RF signal. In this way, the second Mach-Zehnder modulator 26 can generate eight second modulation signals, each with a different center frequency, thereby forming an optical comb signal. The simulated spectrum of the four optical comb signals is as follows: Figure 2 As shown, from Figure 2 It can be seen that the frequency intervals between two adjacent optical comb signals are equal. The second Mach-Zehnder modulator 26 outputs the optical comb signal including eight second modulated signals to the frequency hopping signal selection part.

[0037] See also Figure 3 The frequency hopping signal selection part has a wavelength division multiplexer 31, an optical switch array 35, an optical amplifier array 37, a photodetector 40, a filter amplifier 41 and a frequency hopping signal transmitter 42.

[0038] The wavelength division multiplexer 31 is provided with nine channels, eight of which are used to receive eight second modulation signals in the optical comb signal output by the second Mach-Zehnder modulator 26, and the other channel is used to receive the initial laser signal output by the semiconductor laser 20. Therefore, the number of channels of the wavelength division multiplexer is the sum of the number of the second modulation signals of the optical comb signal and the number of the initial laser signals.

[0039] The output end of the wavelength division multiplexer 31 is connected to an optical switch array 35, and 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 31, that is, the number of the optical switches 36 is nine, and each optical switch 36 corresponds to a channel of the wavelength division multiplexer 31. 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 the optical switch 36 to be in an on state or a off state. If the optical switch 36 is in an on state, the second modulation signal of the corresponding optical channel in the wavelength division multiplexer 31 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 second modulation signal of the corresponding optical channel in the wavelength division multiplexer 31 cannot pass through the optical switch and be transmitted to the optical amplifier array 37.

[0040] 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 second modulated signal or the initial laser 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.

[0041] Preferably, one optical amplifier amplifies a second modulation signal, and another optical amplifier amplifies the initial laser signal, and outputs the amplified signal to the photodetector 40. After receiving the second modulation signal, the photodetector 40 applies a second modulation signal to beat the initial laser signal to obtain a frequency hopping signal. In this embodiment, only two optical switches 36 among the multiple optical switches 36 are in the open state at the same time, one optical switch 36 is an optical switch for transmitting a second modulation signal, and the other optical switch 36 is an optical switch for transmitting the initial laser signal, that is, when the frequency hopping signal system is working, the optical switch 36 corresponding to the initial laser signal is always in the open state. Since the frequency of the initial laser signal is fixed, and the center frequencies of the multiple second modulation signals are not the same, the frequency of the frequency hopping signal obtained by selecting different second modulation signals to beat the initial laser signal is also different. In this way, by selecting different optical switches 36 by the controller, the frequency of the frequency hopping signal obtained after the photodetector 40 beats 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 second modulation signal is obtained by modulating the first modulation signal, and the first modulation signal is obtained by modulating the initial laser signal, the phase of the second modulation signal is synchronized with the phase of the initial laser signal, that is, the period of the second modulation signal is the same as that of the initial laser signal, and the phase changes synchronously. In addition, since the frequency intervals between the second modulation signals in the optical comb signal are equal, the frequency intervals between two adjacent frequency hopping signals in the multiple frequency hopping signals obtained by beating different second modulation signals with the initial laser signal are also equal. In addition, since the phase of the second modulation signal is synchronized with the phase of the initial laser signal, the generated frequency hopping signal is very stable.

[0044] In addition, since the frequency of the adjustable RF signal generated by the adjustable RF signal generator 25 is adjustable, that is, the frequency of the adjustable RF signal can be adjusted according to the actual usage situation, once the frequency of the adjustable RF signal is adjusted, the frequency of the generated second modulation signal is also adjusted accordingly, so that the frequency of the frequency hopping signal generated by the frequency hopping signal system also changes accordingly. To this end, in this embodiment, the frequency of the frequency hopping signal finally generated can be flexibly adjusted by changing the frequency of the adjustable RF signal generated by the adjustable RF signal generator 25 according to the actual situation, that is, the frequency of the frequency hopping signal generated by the frequency hopping signal is not fixed, but can be flexibly adjusted according to the actual situation to meet the usage requirements in different usage scenarios.

[0045] Working method of a large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical combs First embodiment: Combine the following Figure 4 The working method of the above-mentioned large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs is introduced. After the frequency-hopping signal system starts working, the digital baseband signal generator is used to generate a digital baseband signal, and after serial-to-parallel conversion, it is divided into two paths and output to two orthogonal amplitude modulators respectively. The two orthogonal amplitude modulators perform differential orthogonal amplitude modulation on the received signals and output them to four first Mach-Zehnder modulators. Each first Mach-Zehnder modulator uses the signal output from the orthogonal amplitude modulator to modulate the initial laser signal, and outputs the obtained first modulated signal to the second Mach-Zehnder modulator. Subsequently, the second Mach-Zehnder modulator uses an adjustable radio frequency signal to modulate the first modulated signal to obtain an optical comb signal containing multiple second modulated signals, and sends the optical comb signal to the wavelength division multiplexer.

[0046] At this time, the optical switch array executes step S1, receives the control signal output by the controller, and determines the working state of the 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 the multiple optical switches is determined, the second modulation signal and the initial laser signal obtained by wavelength division multiplexing 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 S2, and beats the initial laser signal with the second modulation signal to obtain a frequency hopping signal, and the frequency hopping signal is transmitted into the air after filtering and amplification.

[0047] Then, step S3 is executed, and the frequency hopping signal system needs to determine whether the currently used frequency hopping signal is interfered with, that is, whether the prompt information that the currently used frequency hopping signal is interfered with is received. The interference of the frequency hopping signal can be identified by the frequency hopping signal receiving end determining whether the frequency hopping signal cannot be received normally, or 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 S4 is executed, and the controller sends a control signal for reselecting the optical switch to the optical switch array, and the optical switch array executes step S5, reselects the optical switch for outputting the second modulated signal, and outputs a new control signal to the optical switch array.

[0048] After receiving the new control signal, the optical switch array re-determines the working state of each optical switch, for example, turning off the optical switch that was originally in the working state and turning on an optical switch that was originally in the closed state to achieve the switching of the optical comb signal. Finally, step S6 is executed, and if the frequency of the second modulation signal received by the photodetector changes, the new second modulation signal is applied to beat the initial laser signal to obtain a new frequency hopping signal, and the new frequency hopping signal is transmitted into the air after filtering and amplification.

[0049] The second embodiment of the working method of the large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb: Combine the following Figure 5Another working method of the above-mentioned large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs is introduced. After the frequency-hopping signal system starts working, the digital baseband signal generator is used to generate a digital baseband signal, and after serial-to-parallel conversion, it is divided into two paths and output to two orthogonal amplitude modulators respectively. The two orthogonal amplitude modulators perform differential orthogonal amplitude modulation on the received signals and output them to four first Mach-Zehnder modulators. Each first Mach-Zehnder modulator uses the signal output from the orthogonal amplitude modulator to modulate the initial laser signal, and outputs the obtained first modulated signal to the second Mach-Zehnder modulator. Subsequently, the second Mach-Zehnder modulator uses an adjustable radio frequency signal to modulate the first modulated signal to obtain an optical comb signal containing multiple second modulated signals, and sends the optical comb signal to the wavelength division multiplexer.

[0050] At this time, the optical switch array executes step S11, receives the control signal output by the controller, and determines the working state of the multiple optical switches according to the received control signal. After the working state of the multiple optical switches is determined, the second modulation signal and the initial laser signal obtained by wavelength division multiplexing 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 S12, and beats the initial laser signal with the second modulation signal to obtain a frequency hopping signal, and the frequency hopping signal is transmitted into the air after filtering and amplification.

[0051] Then, step S13 is executed, and the frequency hopping signal system determines whether the current frequency hopping signal usage time reaches a preset duration, such as whether it has been used for 10 hours or 2 days. If the usage reaches the preset duration, step S14 is executed, and the controller sends a control signal for reselecting the optical switch to the optical switch array. In this embodiment, the controller reselects the optical switch according to a preset rule, for example, switching the optical switch to be turned on in a preset order at a preset time interval.

[0052] Next, step S15 is executed, the controller re-selects the optical switch for outputting the second modulation signal, and outputs a new control signal to the optical switch array. Finally, step S16 is executed, if the frequency of the second modulation signal received by the photodetector changes, the new second modulation signal is applied to beat the initial laser signal to obtain a new frequency hopping signal, and the new frequency hopping signal is transmitted into the air after filtering and amplification.

[0053] It can be seen that compared with the passive switching of the frequency hopping signal in the first embodiment, this embodiment adopts the method of actively switching the frequency hopping signal, that is, switching the frequency hopping signal according to a preset time interval, and the switching order of each optical switch is executed in accordance with the preset sequence, so that the frequency change of the switched frequency hopping signal also changes in the preset sequence. Therefore, the frequency hopping signal receiving end only needs to adjust the receiving frequency according to the preset sequence to receive the new frequency hopping signal. In this way, this embodiment can improve the security of wireless communication and meet the use requirements in scenarios where confidential transmission is required.

[0054] 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 large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical combs, including: A wavelength division multiplexer, wherein the output end of the wavelength division multiplexer is connected to an optical switch array, wherein a plurality of optical switches are arranged in the optical switch array, wherein each output end of the wavelength division multiplexer is connected to an optical switch respectively, and the optical switch array outputs a signal to a photodetector; Features: The tunable microwave frequency-hopping signal system further includes a digital baseband signal generator, wherein the digital baseband signal generated by the digital baseband signal generator is output to more than two orthogonal amplitude modulators after serial-to-parallel conversion, each of the orthogonal amplitude modulators outputs a signal to two first Mach-Zehnder modulators, and the plurality of first Mach-Zehnder modulators all receive an initial laser signal output by a semiconductor laser, the first Mach-Zehnder modulator modulates the initial laser signal using a signal output from the orthogonal amplitude modulator, and outputs the obtained first modulated signal to a second Mach-Zehnder modulator; The second Mach-Zehnder modulator also receives an adjustable radio frequency signal, applies the adjustable radio frequency signal to modulate the first modulation signal to obtain an optical comb signal, and sends the optical comb signal to the wavelength division multiplexer; The wavelength division multiplexer also receives an initial laser signal output by the semiconductor laser, the initial laser signal is phase-synchronized with each second modulation signal of the optical comb signal, and the photodetector uses the initial laser signal to beat the second modulation signal to obtain a frequency hopping signal.

2. The large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to claim 1, characterized in that: The number of channels of the wavelength division multiplexer is the sum of the number of the second modulation signals of the optical comb signal and the number of the initial laser signals.

3. The large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to claim 2, characterized in that: The optical switch array receives a control signal output by a controller, and controls the working state of each optical switch according to the control signal.

4. The large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to any one of claims 1 to 3, characterized in that: The output end of the optical switch array is connected to an optical amplifier array, and the optical amplifier array is provided with a plurality of optical amplifiers, and the optical amplifiers are used to amplify the optical power of the second modulation signal and / or the initial laser signal.

5. The large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to any one of claims 1 to 3, characterized in that: The output end of the photodetector is connected to a filter amplifier, and the filter amplifier is used to filter the frequency hopping signal output by the photodetector.

6. The large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to claim 5, characterized in that: The output end of the filter amplifier is connected to a frequency hopping signal transmitter.

7. The working method of the large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to any one of claims 1 to 6, characterized in that: include: The optical switch array obtains a control signal output by the controller, and determines the optical switch to be turned on according to the control signal; After the optical switch is turned on, the wavelength division multiplexer passes one of the second modulation signals and the initial laser signal through two optical switches respectively and outputs them to the photodetector, and the photodetector performs beat frequency based on the second modulation signal and the initial laser signal to obtain a frequency hopping signal.

8. The working method of the large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to claim 7, characterized in that: The controller receives prompt information that the frequency hopping signal is interfered, and switches the optical switch that needs to be turned on according to the prompt information, thereby switching the center frequency of the frequency hopping signal generated by the photoelectric detector.

9. The working method of the large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to claim 7, characterized in that: The controller switches the optical switch that needs to be turned on according to a preset rule, thereby switching the center frequency of the frequency hopping signal generated by the photodetector.

10. The working method of the large bandwidth tunable microwave frequency hopping signal system based on coherent multi-optical comb according to claim 9, characterized in that: The preset rule includes: switching the optical switches that need to be turned on at preset time intervals and in a preset order.

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