Incoherent microwave photon beam forming system based on polarization-wavelength multiplexing
By adopting the polarization-wavelength multiplexing method in microwave photon beam synthesis technology, the problem of resource limitation and insufficient anti-interference ability in the prior art is solved, and a larger scale microwave photon array and higher quality beam synthesis are achieved. Suitable for radar, electronic warfare and communication fields.
Patent Information
- Application Number
- CN202410763957.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-14
- Publication Date
- 2024-12-13
AI Technical Summary
The existing microwave photon beam synthesis technology has shortcomings in large bandwidth and environmental interference resistance, especially incoherent optical beam synthesis encounters resource limitations and quality impacts when dealing with extended array size and channel count.
The polarization-wavelength multiplexing method is adopted to increase the number of incoherent optical paths through the combination of two polarization states and different wavelengths, and expand the scale of the microwave photon array to realize incoherent microwave photon beam synthesis.
The scale of microwave photon phased array has been effectively expanded, the anti-electromagnetic interference capability and bandwidth have been improved, and the quality and reliability of microwave photon beam synthesis have been improved.
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Figure CN119135270A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of microwaves, and in particular relates to an incoherent microwave photon beam synthesis system based on polarization-wavelength multiplexing. Background Art
[0002] With the development and progress of electronic information technology, the demand for large bandwidth in electronic information equipment is becoming stronger and stronger, while the difficulties encountered by electronic technology in generating and processing large bandwidth signals are becoming greater and greater. Microwave photonic technology can process electrical signals through optical domain signal processing. It has its own huge bandwidth advantage and reflects the advantages that electronic technology does not have in generating and processing large bandwidth signals. It is gradually playing an important role in the fields of communications and national defense.
[0003] In recent years, due to the development needs of large-bandwidth phased arrays, optically controlled phased arrays based on microwave photonic technology have been studied a lot. In microwave photonic phased arrays, beam synthesis technology in the receiving array is a key technology. There are generally three methods for microwave photon beam synthesis. The first method is to use microwave photonic technology to achieve delay, and then use electronic technology to achieve beam synthesis; the second method is based on incoherent light, directly realizing microwave photon beam synthesis in the optical domain; the third method is based on coherent light, directly realizing microwave photon beam synthesis in the optical domain. In the first method, the bandwidth of the entire microwave photon phased array is still limited by the bandwidth of the electrical beam synthesis part, while there is no such limitation in the second and third methods. The second method requires incoherent optical signals. Currently, wavelength division multiplexing is generally used to realize incoherent optical signals. In this method, in order to ensure that the microwave signal generated by the beat frequency between optical carriers is relatively high and has little effect on the quality of the final synthesized beam, it is generally required that the wavelength interval between optical carriers exceeds the response bandwidth of the photodetector, which leads to a relatively limited number of available wavelengths. In the third method, due to the use of a fully coherent optical path, there is no limit on the number of optical paths. However, since it is a fully coherent optical signal, it has poor resistance to environmental interference. At present, in order to avoid the influence of environmental factors, fully coherent optical beam synthesis can only be achieved in fully integrated microwave photonic links. Due to the problems of process and material compatibility, fully integrated microwave photonic links are still very immature, and microwave photonic beam synthesis in the optical domain still mainly adopts incoherent optical beam synthesis. Limited by the current limited optical carrier resources, incoherent beam synthesis is stretched to its limits when dealing with the ever-expanding array scale and number of channels. Summary of the invention
[0004] In order to overcome the deficiencies in the prior art, the present invention proposes a system that realizes incoherent optical beam synthesis by combining polarization multiplexing and wavelength multiplexing. While using different wavelengths to realize incoherent light, two polarization states are also used to realize incoherent light, increasing the total number of incoherent optical paths, thereby increasing the number of microwave photon arrays for incoherent synthesis. Compared with the method of using only wavelength division multiplexing, this method can double the number of microwave photon arrays for incoherent beam synthesis, effectively expand the scale of microwave photon phased arrays, and promote the development of microwave photon arrays.
[0005] The invention discloses an incoherent microwave photon beam synthesis system based on polarization-wavelength multiplexing, comprising: an antenna subarray, a microwave photon emission module, an optical delay module, a combiner, a polarization rotation combiner and a photoelectric converter.
[0006] There are 2N antenna subarrays in total, which are divided into two groups. Each group includes N antenna subarrays, which are used to receive the electrical signals to be synthesized and output the electrical signals to the microwave photon transmitting module.
[0007] There are 2N microwave photon transmitting modules in total, which are divided into two groups. Each group includes N microwave photon transmitting modules, corresponding to the antenna subarray, and is used to modulate the electrical signal to be synthesized received by the corresponding antenna subarray onto an optical carrier and output it to the optical delay module.
[0008] There are 2N optical delay modules in total, which are divided into two groups. Each group includes N optical delay modules, corresponding to the microwave photon emission modules, which are used to delay the modulated optical signal and output the delayed signal to the combiner.
[0009] There are two combiners, each of which corresponds to a group of optical delay modules, which are used to combine N optical signals with the same polarization and different wavelengths in each group into one and output it to the polarization rotation combiner.
[0010] The polarization rotation combiner is used to rotate one of the two input optical signals into a polarization state perpendicular to the original polarization while keeping the wavelength unchanged and the polarization and wavelength of the other signal unchanged, and to combine the two signals with and without polarization rotation into one signal and output it to the photoelectric converter.
[0011] The photoelectric converter is used to convert the optical signal into an electrical signal and output it, thereby completing the incoherent microwave photon beam synthesis.
[0012] The two groups of microwave photon transmitting modules are configured with the same or similar wavelengths, but the wavelengths of the lasers of the microwave photon transmitting modules in each group are different, ensuring that there is no interference between different wavelengths, and the corresponding frequency interval must be larger than the response bandwidth of the photodetector used in optical beam synthesis, ensuring that the optical signals in each group of microwave photon transmitting modules are incoherent, and the electrical signals generated by the beat frequency of optical signals of different wavelengths have little effect on the quality of the final synthesized beam.
[0013] The optical delay module is used to delay the modulated optical signal, and the delay amount can be adjustable or fixed.
[0014] The two combiners combine N optical signals with the same polarization but different wavelengths into one optical signal, and the output optical signal contains N different wavelengths and has the same polarization state.
[0015] The optical signal synthesized by the polarization rotation beam combiner includes the optical signals emitted by all microwave photon emission modules, that is, includes all electrical signals to be synthesized.
[0016] The microwave photon emission module, the optical delay module, the combiner and the polarization rotation combiner are connected by polarization-maintaining optical fiber, and the polarization rotation combiner and the photoelectric converter are connected by ordinary single-mode optical fiber or polarization-maintaining optical fiber.
[0017] The beneficial effects of the present invention are
[0018] By mixing polarization multiplexing and wavelength multiplexing, the influence of microwave signals generated by the beat frequency of optical carrier signals on the quality of the final synthesized beam is eliminated, and the scale of the incoherent microwave photon beam synthesis array is increased. It has the advantages of a large number of channels, large bandwidth and strong resistance to electromagnetic interference. It can play an important application value in the fields of radar, electronic warfare, communication, etc. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a principle block diagram of the present invention. DETAILED DESCRIPTION
[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0021] The incoherent microwave photon beam synthesis system of the present invention is realized by wavelength multiplexing and polarization multiplexing, and its principle block diagram is as follows: Figure 1 As shown, the system includes:
[0022] 101-2N antenna subarrays are equally divided into two groups 101-1 and 101-2 and numbered 101-1-i and 101-2-i (1≤i≤N), with a total of 2N antenna subarrays for receiving the electrical signal to be synthesized. Its output port is connected to the electrical input port of the corresponding microwave photon transmitting module. The antenna subarray can be implemented using various antennas and their array structures. The number of antennas in the subarray can be 1 or other numbers. The received electrical signal can be a microwave signal of any frequency and bandwidth from P band to W band.
[0023] 102-2N microwave photon transmitting modules are also equally divided into two groups 102-1 and 102-2 and numbered, which are numbered 102-1-j and 102-2-j (1≤j≤N), a total of 2N, and are used to modulate the corresponding electrical signals to be synthesized onto the optical carrier. Each microwave photon transmitting module corresponds to an antenna subarray, and each microwave photon transmitting module has an electrical input port and an optical output port. The electrical input port is connected to the output port corresponding to the antenna subarray, and the optical output port is connected to the input port corresponding to the optical delay module. The frequency interval corresponding to the wavelength interval of the optical signal in each group of transmitting modules must be greater than the response bandwidth of the photodetector used in optical beam synthesis to ensure that the microwave signal generated by the beat frequency between optical carriers is not output through photoelectric conversion, and has little effect on the quality of the final synthesized beam. The two groups of transmitting modules use the same wavelength or similar wavelengths. The microwave photon emission module can be implemented using a directly modulated laser or a combination of a laser and a modulator, wherein the laser can be implemented based on InP materials or other materials that can achieve laser generation, and the modulator can be implemented based on materials such as bulk lithium niobate, thin-film lithium niobate, InP, silicon on insulator, or other materials that can achieve electro-optical conversion.
[0024] 103-2N optical delay modules are also equally divided into two groups 103-1 and 103-2 and numbered, and the numbers are 103-1-m and 103-2-m (1≤m≤N) respectively, with a total of 2N optical delay modules, which are used to delay the modulated optical signal. Each optical delay module corresponds to a microwave photon transmitting module, and its input port is connected to the optical output port of the corresponding microwave photon transmitting module, and its output port is connected to the input port of the corresponding combiner. The optical delay module can be implemented based on the optical path switching method, the dispersion method, or other solutions that can achieve optical delay.
[0025] 104——Two combiners, which are numbered 104-1 and 104-2 respectively. They are used to combine a group of N optical signals with the same polarization but different wavelengths into one. Each combiner has N input ports and 1 output port, and the N input ports are connected to the optical output ports of a group of N optical delay modules. The output ports of the two combiners are respectively connected to the two input ports of the polarization rotation combiner. The combiner can be implemented based on an arrayed waveguide grating (AWG), a cascaded unequal-arm Mach-Zehnder interferometer, or other devices that can combine multiple optical signals with different wavelengths into one.
[0026] 105——A polarization rotation beam combiner, used to rotate the polarization state of one of the two optical signals to be perpendicular to the original polarization while keeping the polarization state of the other unchanged, and to combine the polarization rotated and unrotated signals into one signal. The polarization rotation beam combiner has two input ports and one output port, the two input ports are respectively connected to the output ports of the two combiners, and the output port is connected to the optical input port of the photoelectric converter. The polarization rotation beam combiner can be implemented by using the existing optical fiber polarization rotator and polarization beam combiner, or other devices with polarization rotation beam combining function can be used.
[0027] 106 is a photoelectric converter, which is used to convert the optical signal into an electrical signal and output it to complete the incoherent microwave photon beam synthesis. Its input port is connected to the output port of the polarization rotation beam combiner. The photoelectric converter is implemented by a device with a photoelectric conversion function. It should be noted that the output electrical signal of the photoelectric converter 106 is the electrical signal synthesized by the incoherent microwave photon beam synthesis method.
[0028] The two groups of microwave photon emission modules 102-1 and 102-2 use the same or similar wavelength configuration. The wavelengths of the lasers of the microwave photon emission modules in each group are different, with a total of N wavelengths. The frequency intervals corresponding to different wavelengths must be greater than the response bandwidth of the photodetector used in optical beam synthesis to ensure that the electrical signals generated by the beat frequency of optical signals of different wavelengths are not output through photoelectric conversion, which has almost no effect on the quality of the final synthesized beam. The polarization states of the two groups of microwave photon emission modules are the same.
[0029] The polarization rotation combiner 105 rotates the polarization state of one of the two synthesized optical signals with the same polarization and both containing N wavelengths to be perpendicular to the original polarization while keeping the polarization state of the other signal unchanged, and synthesizes the polarization rotated and unrotated signals into one signal. The synthesized optical signal contains the optical signals emitted by all microwave photon transmitting modules, that is, it contains all the electrical signals to be synthesized.
[0030] The output optical signals of the two combiners both contain N wavelengths and have the same polarization state.
[0031] The multiple microwave photon emission modules 102 , the multiple optical delay modules 103 , the combiner 104 , and the polarization rotation beam splitter 105 are connected by polarization-maintaining optical fibers, and the polarization rotation beam combiner 105 and the photoelectric converter 106 are connected by common single-mode optical fibers.
[0032] The principle of the present invention is described in detail below:
[0033] The antenna array can receive the electrical signal to be synthesized, and each antenna subarray corresponds to a microwave photon transmitting module. The corresponding electrical signal to be synthesized can be modulated onto the optical carrier through the microwave photon transmitting module. The polarization state of the optical signal emitted by the microwave photon transmitting module is the same, and the optical wavelength of each group of microwave photon transmitting modules is different, and the corresponding frequency interval must be greater than the response bandwidth of the photodetector used in optical beam synthesis, so as to ensure that the optical signals in each group of microwave photon transmitting modules are incoherent, and the electrical signals generated by the beat frequency of optical signals of different wavelengths have little effect on the quality of the final synthesized beam. Since the two groups of microwave photon transmitting modules use the same or similar wavelengths, when the same wavelength is used, when the optical signals in the two groups are combined for optical beam synthesis, the same wavelength will still produce interference effects, which seriously affects the quality of the final microwave photon beam synthesized electrical signal; when similar wavelengths are used, when the optical signals in the two groups are combined for optical beam synthesis, the similar wavelength frequency will cause other electrical signals to beat frequency near the required electrical signal frequency, and it is difficult to filter out by a filter, which also seriously affects the quality of the final microwave photon beam synthesized electrical signal. In order to eliminate the influence of the same or similar wavelengths in the two groups, the two groups of modulated optical signals after delay are respectively synthesized into two optical signals with the same polarization through two combiners, and each optical signal contains N different wavelengths; the two optical signals with the same polarization are synthesized into one through the polarization rotation combiner, and the polarization state of one of the two optical signals is rotated to a state perpendicular to the original polarization, while the other remains unchanged. In this way, the polarization states of the two optical signals with the same original polarization are perpendicular to each other. Although the wavelengths are still the same or similar, no interference will be emitted or unnecessary electrical signals will be generated near the required electrical signals during beam synthesis. At this point, all optical signals are not mutually coherent, and the electrical signals generated during beam synthesis have little effect on the quality of the final synthesized beam. Then the synthesized optical signal containing two polarization states and N wavelengths is input into the photoelectric converter for photoelectric conversion, and beam synthesis is completed.
[0034] The present invention is not limited to the above specific implementations, and the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the above implementations based on the technical essence of the present invention shall be included in the protection scope of the present invention.
Claims
1. An incoherent microwave photon beamforming system based on polarization-wavelength multiplexing, Features: include: Antenna subarrays, microwave photon emission modules, optical delay modules, combiners, polarization rotation combiners, and photoelectric converters; The antenna subarrays are 2N in total and are divided into two groups, each group including N antenna subarrays, for receiving the electrical signal to be synthesized and outputting the electrical signal to the microwave photon transmitting module; The microwave photon transmitting modules are 2N in total and are divided into two groups, each group including N microwave photon transmitting modules, corresponding to the antenna subarrays, and used to modulate the electrical signals to be synthesized received by the corresponding antenna subarrays onto the optical carrier and output them to the optical delay module; The optical delay modules are 2N in total and are divided into two groups, each group including N optical delay modules, corresponding to the microwave photon emission modules, and are used to delay the modulated optical signal and output the delayed signal to the combiner; There are two combiners, each of which corresponds to a group of optical delay modules, for combining N optical signals with the same polarization but different wavelengths in each group into one optical signal and outputting the combined signals to the polarization rotation combiner; The polarization rotation combiner is used to rotate one of the two input optical signals into a polarization state perpendicular to the original polarization while keeping the wavelength unchanged and the polarization and wavelength of the other signal unchanged, and to combine the two signals with and without polarization rotation into one signal and output it to the photoelectric converter; The photoelectric converter is used to convert the optical signal into an electrical signal and output it, thereby completing incoherent microwave photon beam synthesis.
2. The incoherent microwave photon beamforming system based on polarization-wavelength multiplexing according to claim 1, Features: The two groups of microwave photon emission modules are configured with the same or similar wavelengths, but the wavelengths of the lasers of the microwave photon emission modules in each group are different, ensuring that there is no interference between different wavelengths, and the corresponding frequency interval must be greater than the response bandwidth of the photodetector used in optical beam synthesis, ensuring that the optical signals in each group of microwave photon emission modules are incoherent, and the electrical signals generated by the beat frequency of optical signals of different wavelengths have little effect on the quality of the final synthesized beam.
3. The incoherent microwave photon beamforming system based on polarization-wavelength multiplexing according to claim 1, Features: The optical delay module is used to delay the modulated optical signal, and the delay amount can be adjustable or fixed.
4. The incoherent microwave photon beamforming system based on polarization-wavelength multiplexing according to claim 1, Features: The two combiners combine N optical signals with the same polarization but different wavelengths into one optical signal, and the output optical signal contains N different wavelengths and has the same polarization state.
5. The incoherent microwave photon beamforming system based on polarization-wavelength multiplexing according to claim 1, Features: The optical signal synthesized by the polarization rotation beam combiner includes the optical signals emitted by all microwave photon emission modules, that is, includes all electrical signals to be synthesized.
6. The incoherent microwave photon beamforming system based on polarization-wavelength multiplexing according to claim 1, Features: The microwave photon emission module, the optical delay module, the combiner and the polarization rotation combiner are connected by polarization-maintaining optical fiber, and the polarization rotation combiner and the photoelectric converter are connected by ordinary single-mode optical fiber or polarization-maintaining optical fiber.