Encrypted communication system based on microwave photon frequency hopping signal processing and working method thereof

Abstract

The invention provides an encrypted communication system based on microwave photon frequency hopping signal processing and a working method thereof. The system comprises a data transmitting device and a data receiving device, the data transmitting device is provided with a digital baseband signal generator. A quadrature amplitude modulator outputs a signal to a first Mach-Zehnder modulator. The first wavelength division multiplexer outputs four paths of optical signals to the first optical switch, and the first Mach-Zehnder modulators modulate received digital signals by using respective carrier signals and then output the modulated digital signals; the data receiving device is provided with a second wavelength division multiplexer, receives the optical signal of the data transmitting device and outputs the optical signal to a second optical switch, and the optical signal output by the second optical switch is converted into a digital signal through a demodulation and photoelectric conversion module; the first optical switch receives a first control signal output by the first frequency hopping sequence controller so as to change the connection relation between the four input ports and the four output ports. The invention further provides a working method of the system. According to the invention, the security of data transmission can be improved.

Description

Technical Field

[0001] The present invention relates to the field of information communication technology, and in particular to an encryption communication system based on microwave photon frequency hopping signal processing and a working method of the system. Background Art

[0002] With the rapid development of information and communication technology, wireless communication technology has evolved from the first to the fifth generation, with each generation boasting higher frequencies, greater bandwidths, and higher data rates. Microwave frequency hopping technology can address the problems of external interference and multipath fading in wireless communications. In civilian communication systems, frequency hopping signals are resistant to attenuation and interference, increasing system transmission capacity. In radar systems, narrow pulse, large-bandwidth frequency hopping signals can improve radar detection accuracy. Microwave photon frequency hopping technology can also be applied to connected vehicles. For example, two vehicles equipped with onboard communication chips and modules can transmit data using microwave photon frequency hopping, achieving real-time, high-speed interconnection. Microwave photon frequency hopping can also be used to control unmanned vehicles, such as remotely controlling drones, unmanned ships, or unmanned vehicles.

[0003] Chinese invention patent application publication number CN119766277A discloses a large-bandwidth tunable microwave frequency-hopping signal system based on coherent multi-optical combs. The system uses microwave photon frequency hopping technology to generate coherent multi-optical combs and adjusts the frequency intervals between the optical comb signals through tunable frequency signals.

[0004] On the other hand, with the development of communication technology, communication security has become a widely-concerned issue. An existing Chinese invention patent application, publication number CN116264485A, discloses an optical frequency-hopping communication system based on carrier suppression. The system includes a band grating and a first optical switch at the transmitter, a second optical switch at the receiver, and a first frequency-hopping sequence output to the first optical switch to change the connection between the first switch's two input ports and output ports.

[0005] In the above solution, the first optical switch is a 2×2 optical switch with only two input ports and two output ports. Therefore, the first frequency hopping sequence simply uses high and low levels to represent the connection between the two input ports and the output ports of the first optical switch. This solution achieves encryption of transmitted data by changing the frequency of the carrier signals of the two IQ modulators by switching the connection between the input ports and the output ports of the first optical switch.

[0006] However, because the data transmitted only uses two carrier waves, meaning only two channels, the encryption method is relatively simple and easily cracked. Furthermore, because the two IQ modulators directly receive the data to be adjusted, the data encryption level is insufficient, resulting in low data transmission security. Summary of the Invention

[0007] The first object of the present invention is to provide an encrypted communication system based on microwave photon frequency hopping signal processing with high data transmission security.

[0008] The second object of the present invention is to provide a working method of the above-mentioned encrypted communication system based on microwave photon frequency hopping signal processing.

[0009] To achieve the above-mentioned first objective, the present invention provides an encrypted communication system based on microwave photon frequency hopping signal processing, comprising a data transmitting device and a data receiving device; the data transmitting device comprises a digital baseband signal generator, the digital baseband signal generated by the digital baseband signal generator is output to two orthogonal amplitude modulators, each of which outputs a signal to two first Mach-Zehnder modulators; the data transmitting device is further provided with a first wavelength division multiplexer, the first wavelength division multiplexer outputs four optical signals to a first optical switch, and the first wavelength division multiplexer outputs optical signals with different frequencies to the four first Mach-Zehnder modulators. The data receiving device comprises a second wavelength division multiplexer, which receives an optical signal from the data transmitting device and outputs the optical signal to the second optical switch. The optical signal output by the second optical switch is converted into a digital signal through demodulation and a photoelectric conversion module. The first optical switch receives a first control signal output by a first frequency hopping sequence controller to change the connection relationship between the four input ports and the four output ports, and the second optical switch receives a second control signal output by the second frequency hopping sequence controller.

[0010] As can be seen from the above scheme, on the one hand, because the first optical switch is a 4×4 optical switch, the first control signal output by the first frequency hopping sequence controller can change the connection relationship between the four input ports and the four output ports of the first optical switch. Therefore, the relationship between the data and the carrier wave of each channel can be different in multiple ways, increasing the difficulty of data decryption. On the other hand, because the first Mach-Zehnder modulator receives the digital signal output by the quadrature amplitude modulator, that is, the digital signal modulated by the first Mach-Zehnder modulator is also obtained by quadrature amplitude modulation, the data encryption level is higher, which can further enhance the security of data transmission.

[0011] A preferred solution is that the data transmitting device is further provided with a second Mach-Zehnder modulator, which receives the adjustable radio frequency signal and outputs an optical signal to the first wavelength division multiplexer.

[0012] It can be seen that the frequencies of the four carrier signals output by the first wavelength division multiplexer can be changed by the adjustable radio frequency signal, so that the frequencies of the carrier signals themselves are not fixed, which can further improve the security of data transmission.

[0013] A further solution is that the second Mach-Zehnder modulator also receives the laser signal output by the semiconductor laser.

[0014] A further solution is that the data receiving device is further provided with a digital signal processor, which receives the digital signal output by the demodulation and photoelectric conversion module.

[0015] It can be seen that the original transmitted digital baseband signal can be obtained by processing the digital signal output by the demodulation and optoelectronic conversion module through the digital signal processor.

[0016] A further solution is that the demodulation and photoelectric conversion module also receives the signal output by the laser oscillator.

[0017] A further solution is that the first control signal is a two-bit binary number; and the second control signal is a two-bit binary number.

[0018] As can be seen, the first control signal is represented by a two-digit binary number, which has four different representations. Therefore, it can enable four different connection modes between the input port and the output port of the first optical switch. Similarly, the input port and the output port of the second optical switch also have four different connection modes, thereby increasing the difficulty of decrypting the encrypted data.

[0019] To achieve the second objective, the present invention provides an operating method for an encrypted communication system based on microwave photon frequency hopping signal processing, comprising: a digital baseband signal generator outputting a baseband digital signal to each quadrature amplitude modulator, each quadrature amplitude modulator outputting a signal to two first Mach-Zehnder modulators; a first wavelength division multiplexer outputting a signal to a first optical switch, and the first optical switch receiving a first control signal output by a first frequency hopping sequence controller to change the connection relationship between four input ports and four output ports; the first wavelength division multiplexer outputting carrier signals having different frequencies to the four first Mach-Zehnder modulators, the four first Mach-Zehnder modulators outputting carrier signals having different frequencies, each first Mach-Zehnder modulator modulating a received digital signal using its own carrier signal and outputting the modulated signal; a second wavelength division multiplexer of a data receiving device receiving an optical signal from a data transmitting device and outputting the optical signal to a second optical switch, the second optical switch receiving a second control signal output by the second frequency hopping sequence controller to change the connection relationship between the four input ports and the four output ports, and the optical signal output by the second optical switch being demodulated and converted into a digital signal by an optoelectronic conversion module.

[0020] As can be seen from the above scheme, since the first optical switch is a 4×4 optical switch, the first control signal output by the first frequency hopping sequence controller can change the connection relationship between the four input ports and the four output ports of the first optical switch. Therefore, the relationship between the data and the carrier wave of each channel can be different in multiple ways, increasing the difficulty of data decryption. In addition, since the first Mach-Zehnder modulator receives the digital signal output by the quadrature amplitude modulator, that is, the digital signal modulated by the first Mach-Zehnder modulator is also obtained by quadrature amplitude modulation, the data encryption level is higher, making the data transmission more secure.

[0021] A preferred solution is that the first frequency hopping sequence controller and the second frequency hopping sequence controller synchronously change the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch.

[0022] Thus, by synchronously changing the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch, it is possible to ensure that the data receiving device can correctly decode the received data.

[0023] A further solution is that at the same time, the connection relationship between the four input ports and the four output ports of the first optical switch corresponds to the connection relationship between the four input ports and the four output ports of the second optical switch.

[0024] It can be seen that the connection relationship between the first optical switch and the second optical switch is adjusted synchronously and correspondingly, so that the data receiving device can correctly decode the received data.

[0025] A further solution is that the first frequency hopping sequence controller and the second frequency hopping sequence controller receive the same clock signal, and synchronously change the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch based on the clock signal.

[0026] Thus, the first optical switch and the second optical switch can synchronously adjust the connection relationship based on the same clock signal, thereby ensuring that the first optical switch and the second optical switch can synchronously adjust the connection relationship between each input port and output port. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural block diagram of a data transmitting device in an embodiment of an encryption communication system based on microwave photon frequency hopping signal processing of the present invention.

[0028] Figure 2It is a structural block diagram of a data receiving device in an embodiment of an encryption communication system based on microwave photon frequency hopping signal processing of the present invention.

[0029] Figure 3 It is a flow chart of an embodiment of the working method of the encryption communication system based on microwave photon frequency hopping signal processing of the present invention.

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0031] The present invention's encrypted communication system, based on microwave photon frequency-hopping signal processing, is used in encrypted data transmission scenarios, such as radar communications or on-board chips. It can also be applied to remote control of unmanned vehicles by a control center. This system modulates different data across different channels by altering the connections between the four input and output ports of a 4×4 optical switch, achieving a higher level of data encryption and improving data transmission security.

[0032] Example of an encrypted communication system based on microwave photon frequency hopping signal processing: The encryption communication system based on microwave photon frequency hopping signal processing of this embodiment comprises a data transmitting device and a data receiving device. Figure 1 The data transmitter comprises a digital baseband signal generator 10 and two quadrature amplitude modulators 11 and 12. The digital baseband signal generator 10 is used to generate a digital baseband signal, which can be a pulse signal or a sinusoidal signal. The digital baseband signal generated by the digital baseband signal generator 10 undergoes serial-to-parallel conversion and is then split into two paths and output to the quadrature amplitude modulators 11 and 12, respectively. The quadrature amplitude modulators 11 and 12 perform differential quadrature amplitude modulation on the received signals.

[0033] The quadrature amplitude modulator 11 splits the modulated signal into two paths, which are output to two first Mach-Zehnder modulators 21 and 22, respectively. One of the signals output by the quadrature amplitude modulator 11 to the two first Mach-Zehnder modulators 21 and 22 is an I signal, and the other is a Q signal. The I and Q signals are 90° out of phase with each other. Similarly, the quadrature amplitude modulator 12 splits the modulated signal into two paths, which are output to two first Mach-Zehnder modulators 23 and 24, respectively. The two signals are also an I signal and a Q signal.

[0034] The data transmitter is also equipped with an adjustable RF signal source 31, a semiconductor laser 32, a second Mach-Zehnder modulator 33, a first wavelength division multiplexer 34, and a first optical switch 35. The adjustable RF signal source 31 is used to generate an adjustable RF signal and output it to the second Mach-Zehnder modulator 33. The laser signal generated by the semiconductor laser 32 is also output to the second Mach-Zehnder modulator 33. The second Mach-Zehnder modulator 33 modulates the laser signal with the adjustable RF signal to form carrier signals with four different wavelengths. The four carrier signals are output to the first wavelength division multiplexer 34. The first wavelength division multiplexer 34 splits the optical signal according to wavelength to obtain four optical signals. Figure 1 In the figure, the dotted line represents the electrical signal, while the solid line represents the optical signal.

[0035] The four-wavelength carrier signals are input to the first optical switch 35, which is a 4×4 optical switch. The first optical switch 35 also receives a first control signal from the first frequency hopping sequence controller 36 and changes the connection relationship between the four input ports and the four output ports based on the received first control signal. For example, the first control signal is a two-bit binary number. The connection relationship between the four input ports and the four output ports is changed by inputting different binary numbers to the first optical switch 35.

[0036] Specifically, the four input ports are D1, D2, D3, and D4, and the four output ports are O1, O2, O3, and O4. When the first control signal is a binary number "00," the four input ports D1, D2, D3, and D4 are connected to the four output ports O1, O2, O3, and O4, respectively. That is, a light beam incident from input port D1 is output from output port O1, a light beam incident from input port D2 is output from output port O2, and so on. When the first control signal is a binary number "01," the four input ports D1, D2, D3, and D4 are connected to the four output ports O2, O3, O4, and O1, respectively. That is, a light beam incident from input port D1 is output from output port O2, a light beam incident from input port D2 is output from output port O3, and so on. When the first control signal is a binary number "10", the four input ports D1, D2, D3, and D4 are connected to the four output ports O3, O4, O1, and O2, respectively. That is, the light beam incident from input port D1 is output from output port O3, the light beam incident from input port D2 is output from output port O4, and so on. When the first control signal is a binary number "11", the four input ports D1, D2, D3, and D4 are connected to the four output ports O4, O1, O2, and O3, respectively. That is, the light beam incident from input port D1 is output from output port O4, the light beam incident from input port D2 is output from output port O1, and so on. The connection relationship between the first control signal and the four input ports and the four output ports is shown in Table 1.

[0037] Table 1

[0038] Of course, the above connection relationship is only illustrative. In actual application, the first control signal can be a three-bit binary number or a four-bit binary number. There are a total of 24 different connection relationships between the four input ports and the four output ports.

[0039] Each of the first Mach-Zehnder modulators 21, 22, 23, and 24 receives a signal from the quadrature amplitude modulator and a carrier signal from the first optical switch 35. For example, the first Mach-Zehnder modulator 21 receives a carrier signal output from the output port O1 of the first optical switch 35, the first Mach-Zehnder modulator 22 receives a carrier signal output from the output port O2 of the first optical switch 35, the first Mach-Zehnder modulator 23 receives a carrier signal output from the output port O3 of the first optical switch 35, and the first Mach-Zehnder modulator 24 receives a carrier signal output from the output port O4 of the first optical switch 35.

[0040] Each first Mach-Zehnder modulator modulates the carrier signal using the signal output by the quadrature amplitude modulator, thereby generating a modulated signal. The four first Mach-Zehnder modulators 21, 22, 23, and 24 couple the generated modulated signals and transmit them to the data receiving device. Therefore, the modulated signal transmitted by the data transmitting device includes multiple signals of different wavelengths.

[0041] See also Figure 2 The data receiving device comprises an erbium-doped fiber amplifier 41, a second wavelength division multiplexer 42, a second optical switch 43, a demodulation and optoelectronic conversion module 44, and a digital signal processor 45. The erbium-doped fiber amplifier 41 is used to receive the modulated signal transmitted by the data transmitting device and output it to the second wavelength division multiplexer 42. The second wavelength division multiplexer 42 splits the optical signal containing multiple wavelengths according to wavelength and outputs it to the second optical switch 43. Therefore, each input port of the second optical switch receives an optical signal of a single wavelength.

[0042] The second optical switch 43 also receives a second control signal output by the second frequency hopping sequence controller 47 and changes the connection relationship between the four input ports and the four output ports based on the received second control signal. For example, the second control signal is a two-bit binary number. By inputting different binary numbers into the second optical switch 43, the connection relationship between the four input ports and the four output ports is changed. The method for changing the connection relationship between the four input ports and the four output ports of the second optical switch 43 using the second control signal is similar to the method for changing the connection relationship between the four input ports and the four output ports of the first optical switch 35 using the first control signal, and therefore will not be further described.

[0043] The second optical switch 43 outputs the four optical signals to the demodulation and optoelectronic conversion module 44. The demodulation and optoelectronic conversion module 44 is provided with a coherent demodulator, a photodetector, etc. The demodulation and optoelectronic conversion module 44 also receives the signal output by the local laser oscillator 48. Specifically, the signal output by the local laser oscillator 48 is received by the coherent demodulator, which demodulates the received optical signal. The photodetector is used to perform optoelectronic conversion on the demodulated optical signal to obtain an electrical signal. After passing through the photodetector, the optical signal is converted into an electrical signal and the electrical signal is output to the digital signal processor 45. The digital signal processor 45 demodulates the received signal to obtain a digital baseband signal 46.

[0044] In this embodiment, the first frequency hopping sequence controller 36 and the second frequency hopping sequence controller 47 operate synchronously. That is, the first frequency hopping sequence controller 36 and the second frequency hopping sequence controller 47 synchronously change the connection relationship between the four input ports and the four output ports of the first optical switch 35 and the connection relationship between the four input ports and the four output ports of the second optical switch 43, thereby ensuring that, at the same time, the connection relationship between the four input ports and the four output ports of the first optical switch 35 and the connection relationship between the four input ports and the four output ports of the second optical switch 43 correspond to each other, thereby ensuring that the data receiving device can correctly decode the four optical signals to obtain the original digital baseband signal.

[0045] Working method embodiment of an encryption communication system based on microwave photon frequency hopping signal processing: The following combination Figure 3 The operating method of the aforementioned encrypted communication system based on microwave photon frequency hopping signal processing is described below. First, in step S1, a digital baseband signal generator outputs a baseband digital signal to each quadrature amplitude modulator. Then, in step S2, each quadrature amplitude modulator performs modulation based on the received baseband digital signal and outputs the modulated signal to four first Mach-Zehnder modulators.

[0046] At the same time, the tunable RF signal source generates an tunable RF signal and outputs it to the second Mach-Zehnder modulator. The laser signal generated by the semiconductor laser is also output to the second Mach-Zehnder modulator. The second Mach-Zehnder modulator modulates the laser signal with the tunable RF signal to form carrier signals with four different wavelengths. These four carrier signals are then output to the first wavelength division multiplexer. The first wavelength division multiplexer splits the optical signal according to wavelength, generating four optical beams.

[0047] Then, step S3 is executed. The first wavelength division multiplexer outputs four optical signals to the first optical switch, each of which is input to an input port of the first optical switch. Furthermore, the first optical switch receives a first control signal output by the first frequency hopping sequence controller, thereby changing the connection relationship between the four input ports and the four output ports based on the received first control signal. In this embodiment, the first control signal is a two-bit binary number. The connection relationship between the four input ports and the four output ports is changed by inputting different binary numbers to the first optical switch. The correspondence between the four input ports and the four output ports of the first optical switch under different first control signals has been discussed previously and will not be repeated here.

[0048] Then, step S4 is executed, where the first wavelength division multiplexer outputs carrier signals to the four first Mach-Zehnder modulators. Since the wavelengths of the carrier signals are different, the wavelengths of the carrier signals received by the four first Mach-Zehnder modulators are different.

[0049] Next, step S5 is executed, where each first Mach-Zehnder modulator modulates the carrier signal using the signal output by the quadrature amplitude modulator to generate a modulated signal. Furthermore, the four first Mach-Zehnder modulators couple and transmit the generated modulated signals to the data receiving device.

[0050] After the data receiving device receives the signal output by the data transmitting device, the data receiving device first amplifies the received signal using an erbium-doped fiber amplifier. The amplified signal is then output to the second wavelength division multiplexer. Then, step S6 is executed, where the second wavelength division multiplexer splits the optical signal containing multiple wavelengths according to wavelength and outputs the split signals to the second optical switch, so that each input port of the second optical switch receives an optical signal of a single wavelength.

[0051] Then, in step S7, the second frequency hopping sequence controller sends a second control signal to the second optical switch. The second control signal is a two-bit binary number. Upon receiving the second control signal, the second optical switch changes the connection relationship between the four input ports and the four output ports based on the second control signal. Finally, in step S8, the second optical switch outputs the four optical signals to the demodulation and optoelectronic conversion module. The demodulation and optoelectronic conversion module demodulates the received optical signals to obtain electrical signals, which are then output to the digital signal processor. The digital signal processor processes the received signals to obtain digital baseband signals.

[0052] In this embodiment, the connection relationship between the four input ports and the four output ports of the first optical switch is adjusted by a first control signal output by a first frequency hopping sequence controller, and the connection relationship between the four input ports and the four output ports of the second optical switch is adjusted by a second control signal output by a second frequency hopping sequence controller. This enables encryption of data by a data transmitting device, and decryption of the encrypted data by a data receiving device, thereby achieving secure data transmission.

[0053] Because the data receiving device needs to decrypt the data transmitted by the data transmitting device, to ensure that the data transmitted by the data transmitting device can be correctly decrypted, the first optical switch and the second optical switch need to synchronously adjust the connection relationship between the four input ports and the four output ports. Preferably, the first frequency hopping sequence controller and the second frequency hopping sequence controller are both connected to the same clock signal source and receive the same clock signal. Based on the clock signal, they synchronously change the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch. In this way, the first optical switch and the second optical switch can synchronously adjust the connection relationship between each input port and the output port, so that at the same time, the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch correspond to each other, thereby ensuring that the data receiving device can correctly decode the four optical signals to obtain the original digital baseband signal.

[0054] For example, at the same moment, the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch correspond to each other, which means that at the same moment, the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch are the same. For example, at the first moment, the four input ports D1, D2, D3, and D4 of the first optical switch are connected to the four output ports O1, O2, O3, and O4, respectively. Then, the four input ports D1, D2, D3, and D4 of the second optical switch are also connected to the four output ports O1, O2, O3, and O4, respectively. At the second moment, the four input ports D1, D2, D3, and D4 of the first optical switch are connected to the four output ports O2, O3, O4, and O1, respectively. Then, the four input ports D1, D2, D3, and D4 of the second optical switch are also connected to the four output ports O2, O3, O4, and O1, respectively. In this way, it is possible to ensure that the data receiving device can correctly decode the received data.

[0055] In addition, the first optical switch and the second optical switch can regularly or irregularly update the connection relationship between the four input ports and the four output ports, that is, the first control signal and the second control signal can be updated according to a preset time. In this way, the data transmitting device can actively update the channels of each data, thereby increasing the difficulty of data cracking.

[0056] This invention can be applied in a variety of fields, including radar communications, unmanned vehicles, and vehicle-to-vehicle communications. Using this solution, the first control signal output by the first frequency-hopping sequence controller can change the connection relationship between the four input ports and the four output ports of the first optical switch. This means that the data and carrier waves of each channel can be mapped in a variety of different ways, increasing the difficulty of data decryption. Furthermore, because the first Mach-Zehnder modulator receives the digital signal output by the quadrature amplitude modulator (QAM), the digital signal modulated by the first Mach-Zehnder modulator itself is QAM-modulated. This provides a higher level of data encryption, further enhancing the security of data transmission.

[0057] 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. An encrypted communication system based on microwave photon frequency hopping signal processing, including a data transmitter and a data receiver; The data transmitting device comprises a digital baseband signal generator, wherein the digital baseband signal generated by the digital baseband signal generator is output to two quadrature amplitude modulators, and each of the quadrature amplitude modulators outputs a signal to two first Mach-Zehnder modulators; Its characteristics are: The data transmitting device is further provided with a first wavelength division multiplexer, which outputs four optical signals to the first optical switch, and the first wavelength division multiplexer outputs carrier signals with different frequencies to the four first Mach-Zehnder modulators, each of which modulates the received digital signal using its own carrier signal and then outputs the modulated digital signal; The data receiving device has a second wavelength division multiplexer, which receives the optical signal from the data transmitting device and outputs it to a second optical switch. The optical signal output by the second optical switch is converted into a digital signal through demodulation and a photoelectric conversion module; The first optical switch receives a first control signal output by a first frequency hopping sequence controller to change the connection relationship between the four input ports and the four output ports, and the second optical switch receives a second control signal output by a second frequency hopping sequence controller.

2. The encrypted communication system based on microwave photon frequency hopping signal processing according to claim 1, characterized in that: The data transmitting device is further provided with a second Mach-Zehnder modulator, which receives an adjustable radio frequency signal and outputs an optical signal to the first wavelength division multiplexer.

3. The encrypted communication system based on microwave photon frequency hopping signal processing according to claim 2, characterized in that: The second Mach-Zehnder modulator also receives a laser signal output by a semiconductor laser.

4. The encrypted communication system based on microwave photon frequency hopping signal processing according to any one of claims 1 to 3, characterized in that: The data receiving device is further provided with a digital signal processor, which receives the digital signal output by the demodulation and photoelectric conversion module.

5. The encrypted communication system based on microwave photon frequency hopping signal processing according to claim 4, characterized in that: The demodulation and photoelectric conversion module also receives the signal output by the laser oscillator.

6. The encrypted communication system based on microwave photon frequency hopping signal processing according to any one of claims 1 to 3, characterized in that: The first control signal is a two-bit binary number; The second control signal is a two-bit binary number.

7. The working method of the encryption communication system based on microwave photon frequency hopping signal processing according to any one of claims 1 to 6, characterized in that: include: The digital baseband signal generator outputs a baseband digital signal to each of the quadrature amplitude modulators, and each of the quadrature amplitude modulators outputs a signal to two first Mach-Zehnder modulators; The first wavelength division multiplexer outputs a signal to the first optical switch, and the first optical switch receives a first control signal output by the first frequency hopping sequence controller to change a connection relationship between four input ports and four output ports; The first wavelength division multiplexer outputs carrier signals with different frequencies to the four first Mach-Zehnder modulators, and the four first Mach-Zehnder modulators output carrier signals with different frequencies. Each of the first Mach-Zehnder modulators modulates a received digital signal using its own carrier signal and then outputs the modulated digital signal. The second wavelength division multiplexer of the data receiving device receives the optical signal from the data transmitting device and outputs it to the second optical switch. The second optical switch receives the second control signal output by the second frequency hopping sequence controller to change the connection relationship between the four input ports and the four output ports. The optical signal output by the second optical switch is converted into a digital signal through demodulation and optoelectronic conversion module.

8. The working method of the encryption communication system based on microwave photon frequency hopping signal processing according to claim 7, characterized in that: include: The first frequency hopping sequence controller and the second frequency hopping sequence controller synchronously change the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch.

9. The operating method of the encryption communication system based on microwave photon frequency hopping signal processing according to claim 8, characterized in that: At the same time, the connection relationship between the four input ports and the four output ports of the first optical switch corresponds to the connection relationship between the four input ports and the four output ports of the second optical switch.

10. The operating method of the encryption communication system based on microwave photon frequency hopping signal processing according to claim 8 or 9, characterized in that: The first frequency hopping sequence controller and the second frequency hopping sequence controller receive the same clock signal and synchronously change the connection relationship between the four input ports and the four output ports of the first optical switch and the connection relationship between the four input ports and the four output ports of the second optical switch based on the clock signal.

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