A wideband optical multi-beam system based on phase modulation and implementation method

Abstract

The application discloses a kind of wideband optical multi-beam systems and implementation methods based on phase modulation, belong to wideband radio frequency signal processing technical field, the system includes optical multi-beam forming unit, N photoelectric conversion unit and M including radio frequency signal input end electro-optic phase conversion unit;The method includes that M radio frequency signals are respectively input to M electro-optic phase conversion unit, obtain M phase-modulated light signals;M phase-modulated light signals are input to optical multi-beam forming unit, obtain N synthesis optical signals;N synthesis optical signals are respectively input to N photoelectric conversion unit, obtain N different direction beam signals.The application can significantly expand the technical approach and ability of existing optical multi-beam system, with large instantaneous bandwidth, wide spatial coverage, high signal gain, small noise effect, small nonlinear effect, good beam consistency, simple system architecture and other advantages.

Description

Technical Field

[0001] This invention belongs to the field of broadband radio frequency signal processing technology, specifically relating to a broadband optical multi-beam system based on phase modulation and its implementation method. Background Technology

[0002] Electronic warfare, radio spectrum surveillance, and communication equipment must receive and process radio frequency signals from the outside world to perform their functions. To achieve high sensitivity and omnidirectional interception of space signals, electronic information equipment needs to receive and process broadband radio frequency signals over a large airspace; therefore, the equipment must have strong beam coverage capabilities. Multi-beam systems can simultaneously achieve multiple beams within a certain airspace, ensuring the detection and direction finding of weak signals under wide airspace conditions. Multi-beam systems constructed using optical methods have advantages such as high sensitivity, large instantaneous bandwidth, wide airspace coverage, and good beam consistency, and can be applied to various platforms including ground, aircraft, and satellites.

[0003] Traditional optical multi-beamforming methods mainly employ time-delay weighting of amplitude-modulated optical waves from multiple radio frequency signals to obtain beam signals in different directions (refer to patents CN114217293A, entitled "Optically Controlled Multi-Beamforming Network Chip and Network," and CN113452451A, entitled "Beamforming and Channelization Realized by Microwave Photonics"). However, amplitude-modulated optical multi-beam systems suffer from low signal gain, high noise levels, severe nonlinear effects, and stringent requirements for laser wavelength spacing and accuracy, posing pressing technical challenges for those skilled in the art.

[0004] Therefore, this invention proposes a broadband optical multi-beam system based on phase modulation and its implementation method to at least solve some of the above-mentioned technical problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a broadband optical multi-beam system based on phase modulation and a method for implementing it, so as to at least solve some of the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A broadband optical multi-beam system based on phase modulation includes an optical multi-beamforming unit, N photoelectric conversion units, and M electro-optic phase conversion units including radio frequency signal input terminals. The M electro-optic phase conversion units are respectively input with radio frequency signals. The M electro-optic phase conversion units are all connected to the optical multi-beamforming unit. The optical multi-beamforming unit has N composite optical signal output ports, and each composite optical signal output port is connected to a photoelectric conversion unit.

[0008] Furthermore, the electro-optic phase conversion unit includes a laser and an optical phase modulator connected to the laser's emission port. The optical phase modulator includes an radio frequency signal input terminal for inputting radio frequency signals.

[0009] Furthermore, the optical multi-beamforming unit includes M 1×N optical couplers, N optical wavelength division multiplexers, and N optical interferometers connected to each 1×N optical coupler. The input end of each 1×N optical coupler is connected to the output end of a corresponding optical phase modulator. Each 1×N optical coupler includes N output ends. The input ends of the N optical interferometers are connected one-to-one to the N output ends. The output end of the nth optical interferometer connected to each 1×N optical coupler is connected to the input end of the corresponding nth optical wavelength division multiplexer, where n = 1, 2, 3, ..., N.

[0010] Furthermore, the optical interferometer includes a 1×2 optical coupler A, an optical delay line, and a 1×2 optical coupler B. The input end of the 1×2 optical coupler A is connected to the output end of the corresponding 1×N optical coupler. The 1×2 optical coupler A includes a first output end and a second output end. The first output end is connected to the input end of the optical delay line, and the second output end and the output end of the optical delay line are respectively connected to the input end of the 1×2 optical coupler B.

[0011] Furthermore, the photoelectric conversion unit includes a photodetector, and the input end of each photodetector is connected to the output end of the corresponding optical wavelength division multiplexer.

[0012] A method for implementing a broadband optical multibeam system based on phase modulation includes the following steps:

[0013] Step 1: M radio frequency signals are input to M electro-optic phase conversion units respectively to obtain M phase-modulated optical signals;

[0014] Step 2: M phase-modulated optical signals are input into the optical multi-beamforming unit to obtain N composite optical signals;

[0015] Step 3: The N synthesized optical signals are input into the N photoelectric conversion units respectively to obtain N beam signals in different directions.

[0016] Furthermore, the lasers of the M electro-optic phase conversion units emit M lasers of different wavelengths and input them into the corresponding optical phase modulators. At the same time, M radio frequency signals enter the corresponding optical phase modulators and are output as M phase-modulated optical signals after being modulated by the optical phase modulators.

[0017] Furthermore, the M phase-modulated optical signals are input to M 1×N optical couplers, and each 1×N optical coupler outputs N split optical signals with equal power, resulting in M×N parallel split optical signals CS.m,n ; Split optical signal CS m,n The input is fed into the corresponding optical interferometers m and n, and after processing, the processed optical signal PS is output. m,n M optical signals processed by PS 1,n PS 2,n PS m,n Simultaneously, the input is sent to the corresponding wavelength division multiplexer n, and then the synthesized optical signal n is output, where m = 1, 2, 3, ..., M; n = 1, 2, 3, ..., N.

[0018] Furthermore, the split optical signal CS m,n The input signal is fed into the 1×2 optical coupler A corresponding to the optical interferometers m and n, and split into two paths. One path is directly output to the 1×2 optical coupler B, and the other path is output to the 1×2 optical coupler B via an optical delay line. Finally, the 1×2 optical coupler B outputs the processed optical signal PS. m,n .

[0019] Furthermore, the synthesized light signal n is input to the photodetector of the corresponding photoelectric conversion unit n to obtain a pointing angle of θ. n The beam signal.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention obtains corresponding phase-modulated optical signals by modulating multiple broadband radio frequency signals onto corresponding optical wave phases. Then, optical techniques are used to simultaneously perform coherent delay demodulation and synthesis of the multiple phase-modulated optical signals. Finally, photoelectric conversion is used to simultaneously obtain multiple beam signals in different directions. This invention significantly expands the technical approaches and capabilities of existing optical multi-beam systems, possessing advantages such as large instantaneous bandwidth, wide spatial coverage, high signal gain, low noise impact, low nonlinear effect impact, good beam consistency, and simple system architecture. It has significant application value in space broadband radio frequency signal reception in electronic warfare, radio spectrum surveillance, and communication equipment. Attached Figure Description

[0022] Figure 1 This is a block diagram illustrating the implementation of the system of the present invention.

[0023] Figure 2 This is a block diagram illustrating the implementation of the electro-optic phase conversion unit of the present invention.

[0024] Figure 3 This is a block diagram illustrating the implementation of the optical multi-beamforming unit of the present invention.

[0025] Figure 4 This is a block diagram illustrating the implementation of the optical interferometer of the present invention.

[0026] Figure 5 This is a block diagram illustrating the implementation of the photoelectric conversion unit of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] In the description of this invention, it should be noted that the terms "first", "second", "A", "B", etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] like Figure 1 The present invention provides a broadband optical multi-beam system based on phase modulation, comprising an optical multi-beamforming unit, N photoelectric conversion units, and M electro-optic phase conversion units including radio frequency signal input terminals. The M electro-optic phase conversion units are respectively input with radio frequency signals. The M electro-optic phase conversion units are all connected to the optical multi-beamforming unit. The optical multi-beamforming unit has N composite optical signal output ports, and each composite optical signal output port is connected to a photoelectric conversion unit.

[0030] This invention also provides a method for implementing a broadband optical multi-beam system based on phase modulation, comprising the following steps:

[0031] Step 1: M radio frequency signals are input to M electro-optic phase conversion units respectively to obtain M phase-modulated optical signals;

[0032] Step 2: M phase-modulated optical signals are input into the optical multi-beamforming unit to obtain N composite optical signals;

[0033] Step 3: The N synthesized optical signals are input into the N photoelectric conversion units respectively to obtain N beam signals in different directions.

[0034] This invention obtains corresponding phase-modulated optical signals by modulating multiple broadband radio frequency signals onto corresponding optical wave phases. Then, optical techniques are used to simultaneously perform coherent delay demodulation and synthesis of the multiple phase-modulated optical signals. Finally, photoelectric conversion is used to simultaneously obtain multiple beam signals in different directions. This invention significantly expands the technical approaches and capabilities of existing optical multi-beam systems, possessing advantages such as large instantaneous bandwidth, wide spatial coverage, high signal gain, low noise impact, low nonlinear effect impact, good beam consistency, and simple system architecture. It has significant application value in space broadband radio frequency signal reception in electronic warfare, radio spectrum surveillance, and communication equipment.

[0035] In some embodiments, such as Figure 2As shown, the electro-optic phase conversion unit includes a laser and an optical phase modulator connected to the laser's emission port. The optical phase modulator includes an radio frequency signal input terminal for inputting radio frequency signals.

[0036] The lasers of the M electro-optic phase conversion units emit M laser beams of different wavelengths, which are then input into the corresponding optical phase modulators. Simultaneously, M radio frequency (RF) signals are input into their respective optical phase modulators, and after modulation, M phase-modulated optical signals are output. The M RF signals are received by an antenna array and input to their respective optical phase modulators.

[0037] In some embodiments, such as Figure 3 As shown, the optical multi-beamforming unit includes M 1×N optical couplers, N optical wavelength division multiplexers, and N optical interferometers connected to each 1×N optical coupler. The input end of each 1×N optical coupler is connected to the output end of a corresponding optical phase modulator. Each 1×N optical coupler includes N output ends. The input ends of the N optical interferometers are connected one by one to the N output ends. The output end of the nth optical interferometer connected to each 1×N optical coupler is connected to the input end of the corresponding nth optical wavelength division multiplexer, where n = 1, 2, 3, ..., N.

[0038] M phase-modulated optical signals are input to M 1×N optical couplers, and each 1×N optical coupler outputs N split optical signals with equal power, resulting in M×N parallel split optical signals CS. m,n ; Split optical signal CS m,n The input is fed into the corresponding optical interferometers m and n, and after processing, the processed optical signal PS is output. m,n M optical signals processed by PS 1,n PS 2,n PS m,n Simultaneously, the signals are input to the corresponding wavelength division multiplexer n, and then the combined optical signal n is output. Wavelength division multiplexer n has M channels, each with one input terminal, processing the optical signal PS. 1,n PS 2,n PS m,n The optical signals are input to their respective channels and processed (PS). 1,n PS 2,n PS m,n The wavelengths are the same as the wavelengths of the corresponding channels, where m = 1, 2, 3, ..., M; n = 1, 2, 3, ..., N.

[0039] In some embodiments, such as Figure 4As shown, the optical interferometer includes a 1×2 optical coupler A, an optical delay line, and a 1×2 optical coupler B. The input end of the 1×2 optical coupler A is connected to the output end of the corresponding 1×N optical coupler. The 1×2 optical coupler A includes a first output end and a second output end. The first output end is connected to the input end of the optical delay line, and the second output end and the output end of the optical delay line are respectively connected to the input end of the 1×2 optical coupler B.

[0040] Split optical signal CS m,n The input signal is fed into the 1×2 optical coupler A of the corresponding optical interferometers m and n, and split into two paths. One path is directly output to the 1×2 optical coupler B, and the other path is output to the 1×2 optical coupler B after passing through an optical delay line. Finally, the 1×2 optical coupler B outputs the amplitude-modulated processed optical signal PS. m,n .

[0041] In some embodiments, such as Figure 5 As shown, the photoelectric conversion unit includes photodetectors, and the input terminal of each photodetector is connected to the output terminal of the corresponding optical wavelength division multiplexer. The synthesized optical signal n is input to the photodetector of the corresponding photoelectric conversion unit n to obtain a pointing angle of θ. n The beam signal.

[0042] For the nth pointing angle θ n The delay times of the beam signal of the optical interferometers m,n (m=1,2,3,…,M; n=1,2,3,…,N) and m+1,n (m=1,2,3,…,M-1; n=1,2,3,…,N) are set to τ. m,n and τ m+1,n , through τ m,n and τ m+1,n The corresponding pointing angle θ can be calculated. n The calculation formula is: Where d is the element spacing of the antenna array, and c is the speed of light.

[0043] Finally, it should be noted that the above embodiments are merely preferred embodiments of the present invention used to illustrate the technical solutions of the present invention, and are not intended to limit the invention, nor are they intended to limit the patent scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. That is to say, any changes or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but whose technical problems are still consistent with the present invention, should be included within the protection scope of the present invention. In addition, the direct or indirect application of the technical solutions of the present invention to other related technical fields are similarly included within the patent protection scope of the present invention.

Claims

1. A broadband optical multi-beam system based on phase modulation, characterized in that, It includes an optical multibeamforming unit, N photoelectric conversion units, and M electro-optic phase conversion units including radio frequency signal input terminals. The M electro-optic phase conversion units are respectively input with radio frequency signals. The M electro-optic phase conversion units are all connected to the optical multibeamforming unit. The optical multibeamforming unit has N composite light signal output ports, and each composite light signal output port is connected to a photoelectric conversion unit. The electro-optic phase conversion unit includes a laser and an optical phase modulator connected to the laser's emission port. The optical phase modulator includes an radio frequency signal input terminal for inputting radio frequency signals. The optical multi-beamforming unit includes M 1×N optical couplers, N optical wavelength division multiplexers, and N optical interferometers connected to each 1×N optical coupler. The input end of each 1×N optical coupler is connected to the output end of a corresponding optical phase modulator. Each 1×N optical coupler includes N output ends. The input ends of the N optical interferometers are connected one-to-one to the N output ends. The output end of the nth optical interferometer connected to each 1×N optical coupler is connected to the input end of the corresponding nth optical wavelength division multiplexer, where n=1,2,3,…,N; The optical interferometer includes a 1×2 optical coupler A, an optical delay line, and a 1×2 optical coupler B. The input end of the 1×2 optical coupler A is connected to the output end of the corresponding 1×N optical coupler. The 1×2 optical coupler A includes a first output end and a second output end. The first output end is connected to the input end of the optical delay line, and the second output end and the output end of the optical delay line are respectively connected to the input end of the 1×2 optical coupler B.

2. The broadband optical multi-beam system based on phase modulation according to claim 1, characterized in that, The photoelectric conversion unit includes a photodetector, and the input end of each photodetector is connected to the output end of the corresponding optical wavelength division multiplexer.

3. A method for implementing a broadband optical multi-beam system based on phase modulation, characterized in that, Includes the following steps: Step 1: M radio frequency signals are input to M electro-optic phase conversion units respectively to obtain M phase-modulated optical signals; Step 2: M phase-modulated optical signals are input into the optical multi-beamforming unit to obtain N composite optical signals; Step 3: The N synthesized optical signals are respectively input into N photoelectric conversion units to obtain N beam signals in different directions; The lasers of the M electro-optic phase conversion units emit M lasers of different wavelengths and input them into the corresponding optical phase modulators. At the same time, M radio frequency signals enter the corresponding optical phase modulators and are modulated by the optical phase modulators to output M phase-modulated optical signals. M phase-modulated optical signals are input to M 1×N optical couplers, and each 1×N optical coupler outputs N split optical signals with equal power, resulting in M×N parallel split optical signals CS. m,n ; Split optical signal CS m,n The input is fed into the corresponding optical interferometers m and n, and after processing, the processed optical signal PS is output. m,n M optical signals processed by PS 1,n PS 2,n PS m,n Simultaneously, the input is sent to the corresponding wavelength division multiplexer n, and then the synthesized optical signal n is output, where m=1,2,3,…,M; n=1,2,3,…,N; Split optical signal CS m,n The input signal is fed into the 1×2 optical coupler A corresponding to the optical interferometers m and n, and split into two paths. One path is directly output to the 1×2 optical coupler B, and the other path is output to the 1×2 optical coupler B via an optical delay line. Finally, the 1×2 optical coupler B outputs the processed optical signal PS. m,n .

4. The method for implementing a broadband optical multi-beam system based on phase modulation according to claim 3, characterized in that, The synthesized optical signal n is input to the photodetector of the corresponding photoelectric conversion unit n to obtain a pointing angle of q. n The beam signal.

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