Large bandwidth tunable microwave photonic frequency hopping communication system

Abstract

The utility model provides a kind of wideband tunable microwave photon frequency hopping communication system, including data transmitting device, data transmitting device includes four Mach-Zehnder modulators, and each Mach-Zehnder modulator receives the signal output by quadrature amplitude modulator;Carrier signal source outputs the carrier signal containing four different wavelengths to first wave division multiplexer, and first wave division multiplexer outputs four carrier signals to first optical switch, and first optical switch outputs four carrier signals to four Mach-Zehnder modulators, and first optical switch also receives the first control signal output by first frequency hopping sequence controller, and Mach-Zehnder modulator uses respective carrier signal to modulate received digital signal and then output;First micro electromechanical device is provided in first optical switch, and first micro electromechanical device has first mirror and can change the rotation angle of first mirror.The utility model can improve the security of data transmission, and production cost is low.

Description

Technical Field

[0001] This utility model relates to the field of information and communication technology, specifically, to a wideband tunable microwave photonic frequency hopping communication system. Background Technology

[0002] With the development of microwave photonics technology, it has been applied in frequency-hopping communication systems to achieve wider bandwidth data communication. Tunable microwave photonics frequency-hopping technology can be applied to radar communication systems and various civilian applications, such as in automotive chips and modules to enable communication between two vehicles. Furthermore, tunable microwave photonics frequency-hopping technology can also be used for communication in autonomous vehicles. For example, control centers can use this technology to send control signals to unmanned aircraft, cars, or ships to control the operation of these vehicles.

[0003] With increasingly stringent security requirements for data transmission, researchers have begun to investigate the data transmission security issues of tunable microwave photonic frequency hopping technology. One existing carrier-suppressed optical frequency hopping communication system uses a band grating and a first optical switch at the transmitter, and a second optical switch at the receiver. It changes the connection between the two input and output ports of the first optical switch by outputting a first frequency hopping sequence. Since both the first and second optical switches used in this system are 2×2 switches (meaning each switch has only two input and two output ports), even changing the connection between the input and output ports only results in two possible connection methods. Therefore, if the transmitted data is intercepted, the data is easily cracked, compromising data transmission security.

[0004] Furthermore, since most traditional 2×2 optical switches are transmissive optical switches, they incorporate birefringent crystals, rotating devices, and other components to alter the beam transmission path, thereby achieving the switch's function. However, increasing the number of ports on the optical switch makes the transmissive optical switch structure extremely complex and bulky, leading to increased production costs for optical frequency-hopping communication systems and hindering their miniaturization. Summary of the Invention

[0005] The purpose of this invention is to provide a wideband tunable microwave photonic frequency hopping communication system with high data transmission security and low production cost.

[0006] To achieve the above objectives, the wideband tunable microwave photonic frequency hopping communication system provided by this utility model includes a data transmitting device, which includes four Mach-Zehnder modulators, each of which receives a signal output from a quadrature amplitude modulator. The data transmitting device also includes a carrier signal source, which outputs a carrier signal containing four different wavelengths to a first wavelength division multiplexer. The first wavelength division multiplexer outputs four carrier signals to a first optical switch. The first optical switch is a 4×4 optical switch, which outputs the four carrier signals to the four Mach-Zehnder modulators. The first optical switch also receives a first control signal output from a first frequency hopping sequence controller. The Mach-Zehnder modulators use their respective carrier signals to modulate the received digital signals and then output them. The first optical switch contains a first microelectromechanical device (MEMS), which has a first reflector. The first MEMS changes the rotation angle of the first reflector according to the first control signal.

[0007] As can be seen from the above scheme, the first optical switch is a 4×4 optical switch, that is, it has four input ports and four output ports. The four input ports receive four carrier signals of different wavelengths respectively. Furthermore, since the first optical switch receives the first control signal output by the first frequency hopping sequence controller, it can change the connection relationship between the four input ports and the four output ports. Because there are 24 possible connection relationships between the four input ports and the four output ports, the first optical switch has 24 different output modes. Even if the data transmitted by the data transmitter is intercepted, the difficulty of cracking the intercepted data is very high, which increases the security of data transmission.

[0008] In addition, since the first optical switch is a reflective optical switch with a first microelectromechanical device, this reflective optical switch does not require a large number of optical components such as birefringent crystals. It only needs to drive the first reflector to rotate through an external voltage to change the connection between the input port and the output port, which can reduce the production cost of the wideband tunable microwave photonic frequency hopping communication system.

[0009] A preferred embodiment is that the first optical switch has four first input ports and four first output ports, each first input port being connected to an output of the first wavelength division multiplexer and receiving a carrier signal of one wavelength, and each output port outputting a carrier signal to a Mach-Zehnder modulator.

[0010] As can be seen, each output port of the first optical switch outputs a carrier signal to a Mach-Zehnder modulator, so that the wavelengths of the carrier signals received by different Mach-Zehnder modulators are different, thereby enabling the use of different channels to modulate different data and thus achieving data encryption.

[0011] A further option is to have four first microelectromechanical devices, each corresponding to a first input port.

[0012] It can be seen that each microelectromechanical device can reflect the light beam from a first input port, thereby independently controlling the transmission direction of the light beam from each input port.

[0013] A further approach is that each first microelectromechanical device receives a first voltage control signal and controls the rotation angle of the first reflector according to the first voltage control signal.

[0014] A further proposed solution is that the wideband tunable microwave photonic frequency hopping communication system also includes a data receiving device. This data receiving device has an erbium-doped fiber amplifier, which outputs a signal to a second wavelength division multiplexer. The second wavelength division multiplexer outputs a carrier signal to a second optical switch, and the second optical switch receives a second control signal output by a second frequency hopping sequence controller. The second optical switch is equipped with a second microelectromechanical device (MEMS), which has a second mirror. The second MEMS changes the rotation angle of the second mirror according to the second control signal.

[0015] Therefore, the data receiving device is also equipped with a second optical switch, which can also receive the second control signal output by the second frequency hopping sequence controller. Thus, it can demodulate different carrier signals accordingly to obtain the initial digital signal.

[0016] A further embodiment is that the second optical switch has four second input ports and four second output ports. Each second input port is connected to one output of the second wavelength division multiplexer and receives one carrier signal. The number of second microelectromechanical devices is four, and each second microelectromechanical device corresponds to one second input port.

[0017] Therefore, the second optical switch is also a 4×4 optical switch, and it can also adjust the connection relationship between the four input ports and the four output ports. Thus, it can change the connection relationship between its own four input ports and four output ports according to the settings of the first optical switch, thereby realizing the decryption of the signal.

[0018] A further option is that the data receiving device is also equipped with a coherent demodulator, and each second output port of the second optical switch outputs a carrier signal to the coherent demodulator.

[0019] Preferably, the coherent demodulator outputs the demodulated optical signal to the photodetector, which is used to convert the received optical signal into an electrical signal.

[0020] Therefore, it can be seen that a coherent demodulator can demodulate an optical signal, and an optical band detector can convert the demodulated optical signal into an electrical signal to obtain a digital signal.

[0021] A further approach is that each second microelectromechanical device receives a second voltage control signal and controls the rotation angle of the second reflector according to the second voltage control signal.

[0022] A further option is to include a digital signal processor in the data receiving device, which receives the electrical signals output by the photodetector.

[0023] Therefore, it can be seen that a digital signal processor can process the digital signal output by the photodetector to obtain the original baseband digital signal. Attached Figure Description

[0024] Figure 1 This is a structural block diagram of the data transmission device in an embodiment of the wideband tunable microwave photonic frequency hopping communication system of this utility model.

[0025] Figure 2 This is a schematic diagram of the structure of the first optical switch in an embodiment of the wideband tunable microwave photonic frequency hopping communication system of this utility model.

[0026] Figure 3 This is a structural block diagram of the data receiving device in an embodiment of the wideband tunable microwave photonic frequency hopping communication system of this utility model.

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0028] This utility model's wideband tunable microwave photonic frequency hopping communication system is used in scenarios where encrypted data transmission is required, such as in radar communication or vehicle-mounted chips. It can also be used in control centers for remote control of unmanned vehicles.

[0029] The wideband tunable microwave photonic frequency-hopping communication system of this embodiment has a data transmitting device and a data receiving device. See [link to documentation]. Figure 1 The data transmission device has a digital baseband signal generator 10 and two quadrature amplitude modulators 11 and 12. The digital baseband signal generated by the digital baseband signal generator 10 is sent to the two quadrature amplitude modulators 11 and 12. The two quadrature amplitude modulators 11 and 12 perform differential quadrature amplitude modulation on the received signal respectively.

[0030] The quadrature amplitude modulator 11 splits the modulated signal into two paths, which are output to two Mach-Zehnder modulators 21 and 22 respectively, while the quadrature amplitude modulator 12 splits the modulated signal into two paths, which are output to two Mach-Zehnder modulators 23 and 24 respectively.

[0031] The data transmitting device is also equipped with a carrier signal source 33, which generates four carrier signals with different wavelengths. Preferably, the carrier signal source 33 uses a Mach-Zehnder modulator to generate the four different carrier signals. For example, the Mach-Zehnder modulator receives a tunable radio frequency signal and a laser signal, and modulates the laser signal with the tunable radio frequency signal to form four carrier signals with different wavelengths.

[0032] The four carrier signals are output to the first wavelength division multiplexer 34, which splits the optical signals according to their wavelengths to obtain four optical signals. Figure 1 In the diagram, dashed lines represent electrical signals, while solid lines represent optical signals.

[0033] Four carrier signals with different wavelengths are input to the first optical switch 35. In this embodiment, the first optical switch 35 is a 4×4 optical switch, that is, it has four first input ports and four first output ports. In addition, the first optical switch 35 also receives a first control signal output by the first frequency hopping sequence controller 36, and changes the connection relationship between the four first input ports and the four first output ports according to the received first control signal.

[0034] See Figure 2The first optical switch 35 is a reflective optical switch with four first input ports, namely first input ports D1, D2, D3, and D4, and four first output ports, namely first output ports O1, O2, O3, and O4. The four first input ports D1, D2, D3, and D4 are each connected to one output terminal of the first wavelength division multiplexer 34, meaning each receives a carrier signal. Furthermore, four first microelectromechanical devices (MEMS) are disposed within the first optical switch 35, each with a first reflector. For example, the four first reflectors of the four MEMS are first reflectors 61, 62, 63, and 64. In this embodiment, each first MEMS corresponds to one first input port, meaning each first reflector reflects the light beam from one first input port. For example, first reflector 61 reflects the light beam input from first input port D1. By adjusting the rotation angle of first reflector 61, the light beam input from first input port D1 can be emitted to any one of the first output ports O1, O2, O3, and O4. For beams input from the first input ports D2, D3, and D4, the first output port of the beam output can also be changed by adjusting the rotation angle of the first reflectors 62, 63, and 64. Furthermore, at any given time, a first output port only receives beams from one first input port, and will not simultaneously receive beams from two first input ports.

[0035] To change the connection relationship between the four first input ports and the four first output ports, each first microelectromechanical device (MEMS) needs to be controlled individually, meaning the rotation angle of each first reflector 61, 62, 63, and 64 needs to be controlled individually. Therefore, in this embodiment, a first voltage control signal needs to be output to each first MEMS. For example, four voltage controllers 65, 66, 67, and 68 are respectively provided. Voltage controller 65 outputs a first voltage control signal to the first MEMS to change the rotation angle of the first reflector 61; voltage controller 66 controls the rotation angle of the first reflector 62; voltage controller 67 controls the rotation angle of the first reflector 63; and voltage controller 68 controls the rotation angle of the first reflector 64. Thus, the rotation angle of each first reflector 61, 62, 63, and 64 can be controlled individually.

[0036] The four first output ports of the first optical switch 35 output four carrier signals to four Mach-Zehnder modulators 21, 22, 23, and 24, respectively. Therefore, each first output port is connected to one Mach-Zehnder modulator. Since the first optical switch 35 can change the connection relationship between the four first input ports and the four first output ports according to the first control signal, the wavelengths of the carrier signals received by the four Mach-Zehnder modulators 21, 22, 23, and 24 are not fixed. Because there are 24 different connection relationships between the four first input ports and the four first output ports, there are also 24 possible combinations of different carrier signals received by the four Mach-Zehnder modulators 21, 22, 23, and 24.

[0037] Each Mach-Zehnder modulator modulates the carrier signal using the signal output from the quadrature amplitude modulator, thereby generating a modulated signal, which is then transmitted to the data receiving device.

[0038] See Figure 3 The data receiving device includes an erbium-doped fiber amplifier 41, a second wavelength division multiplexer 42, a second optical switch 43, a coherent demodulator 44, a photodetector 45, and a digital signal processor 46. The erbium-doped fiber amplifier 41 receives the modulation signal transmitted by the data transmitting device and outputs 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. In this embodiment, the second optical switch 43 is also a 4×4 optical switch with four second input ports and four second output ports. Furthermore, the second optical switch 43 is also a reflective optical switch, internally equipped with four second microelectromechanical devices (MEMS). Each second MEMS has a second reflector. The second MEMS can receive a second voltage control signal and change the rotation angle of the second reflector according to the received second voltage control signal. Preferably, the structure of the second optical switch 43 is the same as that of the first optical switch 35, and will not be described again.

[0039] 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 second input ports and the four second output ports according to the received second control signal. Preferably, the change in the connection relationship between the four first input ports and the four first output ports of the first optical switch 35 and the change in the connection relationship between the four second input ports and the four second output ports of the second optical switch 43 are performed synchronously, thereby ensuring that the data receiving device can correctly demodulate the received modulated signal to obtain the original digital signal.

[0040] The second optical switch 43 outputs four optical signals to the coherent demodulator 44. The coherent demodulator 44 receives the laser signal output from the local laser oscillator 48, uses this laser signal to demodulate the modulated optical signal, and outputs the demodulated optical signal to the photodetector 45. The photodetector 45 converts the demodulated optical signal into an electrical signal, and outputs the electrical signal to the digital signal processor 45. The digital signal processor 45 demodulates the received signal to obtain a digital baseband signal.

[0041] Because this invention incorporates a first optical switch and a second optical switch, both of which are 4×4 optical switches, by changing the connections between the four first input ports and four first output ports of the first optical switch, it is possible to modulate different data using carrier signals of different wavelengths. Furthermore, there are 24 possible combinations of carrier signals of different wavelengths output from the four first output ports of the first optical switch, thus increasing the difficulty of data cracking. In addition, both the first and second optical switches are reflective optical switches, and both are equipped with microelectromechanical devices (MEMS) to change the angle of the reflector to alter the connection relationship between the four input ports and four output ports, thereby reducing the size of the first and second optical switches and lowering the production cost of the wideband tunable microwave photonic frequency hopping communication system.

[0042] Finally, it should be emphasized that the above are only preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A wideband tunable microwave photonic frequency hopping communication system, comprising a data transmitting device, wherein the data transmitting device comprises four Mach-Zehnder modulators, each of which receives a signal output by a quadrature amplitude modulator; Its features are: The data transmitting device is also equipped with a carrier signal source, which outputs a carrier signal containing four different wavelengths to a first wavelength division multiplexer. The first wavelength division multiplexer outputs four beams of the carrier signal to a first optical switch. The first optical switch is a 4×4 optical switch. The first optical switch outputs the four beams of the carrier signal to four Mach-Zehnder modulators. The first optical switch also receives a first control signal output by a first frequency hopping sequence controller. The Mach-Zehnder modulators use their respective carrier signals to modulate the received digital signal and then output it. The first optical switch contains a first microelectromechanical device (MEMS), which has a first reflector. The first MEMS changes the rotation angle of the first reflector according to the first control signal.

2. The wideband tunable microwave photonic frequency hopping communication system according to claim 1, characterized in that: The first optical switch has four first input ports and four first output ports. Each first input port is connected to an output of the first wavelength division multiplexer and receives a carrier signal of one wavelength. Each output port outputs the carrier signal to a Mach-Zehnder modulator.

3. The wideband tunable microwave photonic frequency hopping communication system according to claim 2, characterized in that: The number of the first microelectromechanical devices is four, and each of the first microelectromechanical devices corresponds to one of the first input ports.

4. The wideband tunable microwave photonic frequency hopping communication system according to claim 3, characterized in that: Each of the first microelectromechanical devices receives a first voltage control signal and controls the rotation angle of the first reflector according to the first voltage control signal.

5. The wideband tunable microwave photonic frequency hopping communication system according to any one of claims 1 to 4, characterized in that: The wideband tunable microwave photonic frequency hopping communication system is also equipped with a data receiving device, which has an erbium-doped fiber amplifier. The erbium-doped fiber amplifier outputs a signal to a second wavelength division multiplexer. The second wavelength division multiplexer outputs the carrier signal to a second optical switch. The second optical switch receives a second control signal output by a second frequency hopping sequence controller. The second optical switch is provided with a second microelectromechanical device (MEMS), which has a second reflector. The second MEMS changes the rotation angle of the second reflector according to the second control signal.

6. The wideband tunable microwave photonic frequency hopping communication system according to claim 5, characterized in that: The second optical switch has four second input ports and four second output ports. Each second input port is connected to one output of the second wavelength division multiplexer and receives one carrier signal. The number of the second microelectromechanical devices is four, and each second microelectromechanical device corresponds to one second input port.

7. The wideband tunable microwave photonic frequency hopping communication system according to claim 6, characterized in that: The data receiving device is further provided with a coherent demodulator, and each of the second output ports of the second optical switch outputs one of the carrier signals to the coherent demodulator.

8. The wideband tunable microwave photonic frequency hopping communication system according to claim 6, characterized in that: Each of the second microelectromechanical devices receives a second voltage control signal and controls the rotation angle of the second reflector according to the second voltage control signal.

9. The wideband tunable microwave photonic frequency hopping communication system according to claim 7, characterized in that: The coherent demodulator outputs the demodulated optical signal to the photodetector, which converts the received optical signal into an electrical signal.

10. The wideband tunable microwave photonic frequency hopping communication system according to claim 9, characterized in that: The data receiving device is also equipped with a digital signal processor, which receives the electrical signals output by the photodetector.

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