SAR signal acceleration processing method and device based on photonic planar waveguide chip

Abstract

The present invention discloses a SAR signal acceleration processing method and device based on a photon planar waveguide chip, which belongs to the field of optoelectronic technology and signal processing technology. The method includes a signal generator generating a SAR echo signal to be processed, modulating it to coherent laser sources of different wavelengths through multiple intensity modulators to obtain a multi-wavelength modulated signal; combining the multi-wavelength modulated signal into a single beam light signal, and adjusting the polarization direction to obtain a polarization-optimized modulated light signal; inputting the modulated light signal into a photon planar waveguide chip, and coupling the light signal output by the photon planar waveguide chip to a detector array through an on-chip end face coupler array to complete the conversion of the photoelectric signal. The acceleration chip of the present invention has a small size and high integration, and can greatly increase the number of processing channels of the network.

Description

Technical Field

[0001] The present invention belongs to the field of optoelectronic technology and signal processing technology, and in particular relates to a SAR signal acceleration processing method and device based on a photon planar waveguide chip. Background Art

[0002] Microwave synthetic aperture radar (SAR) is a remote sensing technology that uses microwaves to achieve high-resolution imaging. The SAR system transmits electromagnetic waves to the ground or target area and receives reflected signals. After complex data processing and imaging algorithms, it generates images with fine spatial resolution. Its main advantage is its all-weather and all-day working ability, which enables it to accurately collect data even in adverse weather conditions.

[0003] SAR signal imaging processing includes a large number of complex operations such as matched filtering, convolution, motion compensation, transposition, and range motion correction, among which Fourier transform (FT) and convolution account for about 80% of the system's processing power consumption and computing time. The logic unit and storage unit of the processor currently used in electronic computing hardware are discrete von Neumann architectures. Data needs to be transferred back and forth between the processor and the memory. Frequent tidal data reading and writing reduces the computing rate while increasing the power consumption of a single calculation. The resulting bandwidth bottleneck and power consumption bottleneck severely limit the computing energy efficiency of the von Neumann architecture, namely the "memory wall" and "power wall" problems, which make it difficult to meet the needs of large-scale data, low-power processing, and real-time applications of future SAR systems.

[0004] In recent years, photonic technology has shown great potential in the field of signal processing and computing. Compared with traditional electronic processors, photonic computing uses the propagation, interference and diffraction characteristics of light waves to achieve parallel computing, and has extremely high bandwidth and speed advantages. In addition, photonic chips consume much less power than electronic chips and can significantly reduce the heat generated during signal processing. Especially when it comes to computationally intensive operations such as Fourier transforms and matrix multiplications, photonic technology exhibits extremely high computing efficiency and can directly solve the bandwidth bottleneck caused by frequent data reading and writing in the von Neumann architecture.

[0005] Photonic integrated chip technology is one of the core technologies of photonic computing. The integrated optical path realizes high-speed optical signal processing on-chip through a micron-level waveguide system. In recent years, photonic integrated chip technology based on silicon, silicon nitride and indium phosphide has made significant progress and can support larger-scale and more complex photonic circuit integration. Although existing photonic computing technology can effectively improve the performance of certain specific computing tasks, in applications such as SAR signal processing that have high real-time requirements, how to organically combine photonic computing with existing electronic computing architecture and make full use of the advantages of optoelectronic collaborative processing is still a technical difficulty.

[0006] The existing implementation schemes of optical Fourier transform are not suitable for on-chip large-scale Fourier transform processing of SAR echo signals. The scheme based on dispersion and time lens is limited by the picosecond optical pulse length and is not suitable for radar echo signals. In addition, the hardware structure is highly complex and the calculation accuracy remains to be studied. The architecture based on butterfly optical fast Fourier transform unit is not conducive to on-chip integrated design because it requires the integration of large delay units on the chip, and a large number of phase shifters need to be modulated at different positions in the system. The scheme based on star coupler currently still has a relatively small discrete Fourier transform sequence length and does not fully utilize the multiplexing characteristics of light. The scheme based on plasmon primitives to realize Fourier transform requires complex technology to realize the excitation and control of plasmons, and has high requirements on material properties and preparation processes, which restricts the extensiveness of practical applications.

[0007] In terms of matrix multiplication photon acceleration chips, current research focuses on realizing optical convolutional neural networks, using simple, small-scale image classification and recognition as the main application verification. There is still a lack of photonic chip solutions suitable for Fourier transform of long-sequence SAR imaging signals. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a SAR signal acceleration processing method and device based on a photonic planar waveguide chip. The advanced integrated photonic technology is used to reduce the dimension of the spatial optical system based on Fresnel diffraction, and a low-loss planar waveguide and a phase shifter array are used as key computing units to realize planar large-scale Fourier transform. At the same time, the insensitivity of the silicon nitride planar waveguide to the incident wavelength under a specific topological structure is utilized, and multiple light sources with different wavelengths are used as carriers to further expand the number of processing channels of the photonic planar waveguide chip.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] A SAR signal acceleration processing method based on a photonic planar waveguide chip, the method comprising:

[0011] Step 1: The signal generator generates a SAR echo signal to be processed, and modulates it to coherent laser sources of different wavelengths through multiple intensity modulators to obtain a multi-wavelength modulated signal;

[0012] Step 2: Combining the multi-wavelength modulated signals into a single optical signal, and adjusting the polarization direction to obtain a polarization-optimized modulated optical signal;

[0013] Step 3, input the modulated optical signal into the photonic planar waveguide chip, and after serial-to-parallel conversion, input the modulated optical signal into the first-stage phase shifter array for wavefront phase modulation, and perform Fourier transform on the signal output by the first-stage phase shifter array through the first planar waveguide; perform a second wavefront phase modulation on the output signal of the first planar waveguide through the second-stage phase shifter array, and then reach the second planar waveguide, and perform inverse Fourier transform on the signal output by the second-stage phase shifter array;

[0014] Step 4: The optical signal output by the photonic planar waveguide chip is coupled to the detector array through the on-chip end face coupler array to complete the conversion of the photoelectric signal.

[0015] On the other hand, the present invention provides a SAR signal acceleration processing device based on a photonic planar waveguide chip, comprising:

[0016] A multi-wavelength modulation signal acquisition unit is used to generate a SAR echo signal to be processed by using a signal generator, and modulate it to coherent laser sources of different wavelengths through multiple intensity modulators to obtain a multi-wavelength modulation signal;

[0017] A modulated optical signal acquisition unit, used for combining the multi-wavelength modulated signals into a single optical signal, and adjusting the polarization direction through a polarization controller to obtain a modulated optical signal after polarization optimization;

[0018] The waveguide chip processing unit is used to input the modulated optical signal into the photonic planar waveguide chip, input the modulated optical signal into the first-stage phase shifter array for wavefront phase modulation after serial-to-parallel conversion, perform Fourier transform on the signal output by the first-stage phase shifter array through the first planar waveguide; perform a second wavefront phase modulation on the output signal of the first planar waveguide through the second-stage phase shifter array and then reach the second planar waveguide, and perform inverse Fourier transform on the signal output by the second-stage phase shifter array;

[0019] The photoelectric signal conversion unit is used to couple the optical signal output by the photonic planar waveguide chip to the detector array through the on-chip end face coupler array to complete the conversion of the photoelectric signal.

[0020] In a third aspect, the present invention provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned SAR signal acceleration processing method based on the photonic planar waveguide chip.

[0021] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned SAR signal acceleration processing method based on a photonic planar waveguide chip.

[0022] The beneficial effects of the present invention are:

[0023] High computing power and high parallelism: Photon acceleration chips can process multiple signals at the same time, greatly improving processing speed. The parallel propagation characteristics of light allow photon chips to handle tasks such as Fourier transform more efficiently than electronic chips.

[0024] Low power consumption: In photonic computing, the propagation of light waves does not produce significant energy loss, so it has lower energy consumption than electronic computing, which helps to be used in power-constrained platforms such as satellites and drones.

[0025] Anti-electromagnetic interference: Since photonic computing does not rely on electrical signal transmission, it is highly immune to electromagnetic interference and is particularly suitable for radar systems that perform tasks in complex environments.

[0026] Real-time: Through the design of optoelectronic collaborative architecture, the present invention realizes real-time processing of SAR signals to meet the requirements of high-resolution imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the derivation diagram of the Fourier transform principle of the planar waveguide;

[0028] Figure 2 The figure is a schematic diagram of a SAR signal acceleration processing device based on a photonic planar waveguide chip according to the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] As mentioned above, in the first aspect, the SAR signal acceleration processing method based on the photonic planar waveguide chip provided by the present invention significantly improves the speed and energy efficiency of SAR signal processing while retaining the imaging accuracy to a certain extent. Photonic acceleration chip technology is adopted to replace the Fourier transform and convolution parts based on the general digital signal processor in the original SAR imaging signal processing with the photonic architecture, thereby improving the Fourier transform computing power while reducing power consumption, breaking through the high-speed and high-resolution processing limitations under rated size and power. Based on the Fresnel diffraction principle and photonic planar waveguide devices, a streamlined photon diffraction calculation model is designed, and a light acceleration chip for long-sequence Fourier transform is realized in combination with wavelength division multiplexing technology, which reduces the requirements for optical devices and chip area, and realizes a topological mechanism in which the chip area and the number of electrically controlled phase shift units grow linearly with the processing scale.

[0031] Specifically, a coherent laser is used as a light source, and the polarization of the input light is rotated through a polarization controller to ensure the coupling of the transverse electric fundamental mode light; a thermoelectric controller is used as a substrate under the chip, and a temperature controller can be used to control and stabilize the temperature, which can also further reduce the thermal fluctuations caused by the ambient temperature and the thermal crosstalk within the chip; a multi-channel source meter is used to provide current bias for the phase shifter. After the photon accelerator chip is packaged, the intensity of its output light can be collected by a gain-capable transimpedance amplifier and an analog-to-digital converter. Four coherent laser sources with different wavelengths are used for incident, and the signal is modulated by a four-channel arbitrary waveform generator. After passing through a wavelength division multiplexer, it is input into the polarization controller. At the output end of the inverse Fourier transform, a wavelength division multiplexer is added to obtain the wavelength signals of each channel.

[0032] First, the principle of Fourier transform in photonic planar waveguide is derived, which is used to reduce the dimension of the lens-based Fourier transform system in traditional space optics to a two-dimensional device in integrated photonics, and to design a two-dimensional planar discrete signal processing system based on continuous processing systems such as three-dimensional lenses. Figure 1 As shown, S is the wave source plane, R is the distance between the wave source Q and the observation screen point P, is the incident wavelength, k is the wave vector corresponding to the wavelength, z is the propagation direction, and O is the origin of the wave source plane. According to the Huygens-Fresnel principle, the spherical secondary wave emitted from the secondary wave source Q at any point inside the aperture has a wave perturbation at the observation point P. for:

[0033] ,

[0034] in, is the coordinate of point P, i is the imaginary unit, is the coordinate of the point in the source plane S. When the aperture size is much smaller than the propagation path length, the Fresnel approximation can be used to process the above equation.

[0035] Consider a one-dimensional continuous signal model: After the light field at point Q propagates a distance F along the Z axis, its light field is approximately distributed as follows:

[0036] ,

[0037] Since the light field distribution is independent of the Y axis, it can be excluded from the integral and ignored as a constant term. It is expressed as:

[0038] ,

[0039] That is, the data loaded on the object plane After and The related secondary phase modulation. At this time, the phase plane light field can be expressed as:

[0040] ,

[0041] In summary, after the one-dimensional data to be loaded is multiplied by the quadratic phase, it is approximated by the one-dimensional Fresnel diffraction integral formula and the propagation distance in the plane space is After that, the Fourier transform of the loaded data will be obtained on the object plane. Based on the light field, a one-dimensional phase shifter array is introduced to eliminate Secondary phase modulation term. The output light of the phase shifter continues to propagate forward in the medium. After that, the initial input signal can be restored .

[0042] Based on the above theory, Figure 2 As shown, the SAR signal acceleration processing method based on the photonic planar waveguide chip of the present invention is implemented based on the following system components:

[0043] A coherent laser source is used to generate coherent laser sources of different wavelengths, which are used as carrier waves to transmit SAR echo signals;

[0044] A signal generator, used for generating a SAR echo signal;

[0045] Intensity modulator, used to modulate the SAR echo signal to coherent laser sources of different wavelengths;

[0046] A wavelength division multiplexer, used to combine carrier signals carrying different SAR echo signals;

[0047] A polarization controller is used to control the polarization direction of the combined beam signal and feed it into the photonic planar waveguide chip;

[0048] The photonic planar waveguide chip comprises:

[0049] A delay array, used to convert the input beam-combined signal into a parallel signal;

[0050] The first-stage phase shifter array is used to perform wavefront phase modulation on the input parallel signal;

[0051] A first planar waveguide, used for implementing Fourier transform on the signal output by the first-stage phase shifter array;

[0052] A second-stage phase shifter array is used to perform wavefront phase modulation on the output signal of the first planar waveguide;

[0053] The second planar waveguide is used to implement inverse Fourier transform on the signal output by the second-stage phase shifter array.

[0054] A detector array, used to observe the output signal of the photonic planar waveguide chip, which is also the output signal of the second planar waveguide;

[0055] The digital signal processing unit is used to process and image the signals output by the detector array.

[0056] Specifically, the SAR signal acceleration processing method based on the photonic planar waveguide chip of the present invention comprises the following steps:

[0057] S1, data preprocessing and loading: The signal generator generates the SAR echo signal to be processed. Before loading, the SAR echo signal is low-pass filtered to remove high-frequency noise and quantized to 16 bits to ensure the dynamic range of the signal (not shown in the figure). Subsequently, the SAR echo signal to be processed is modulated to coherent laser sources of different wavelengths through four intensity modulators. The wavelengths are , , and , the modulation rate is , and obtain a multi-wavelength modulated signal.

[0058] S2, the multi-wavelength modulated signal combines optical carriers of different wavelengths into a single optical signal through a wavelength division multiplexer. The beam is then input into a polarization controller to adjust the polarization direction of the incident light, thereby reducing the coupling loss between the polarization controller and the photonic planar waveguide chip. The signal output by the polarization controller is a modulated optical signal with optimized polarization, which provides a stable input for subsequent optical signal processing.

[0059] S3, input the modulated optical signal into the photonic planar waveguide chip, first convert the input combined beam signal into a parallel signal through the delay array, then perform wavefront phase modulation on the parallel signal through the first-stage phase shifter array, and perform Fourier transform on the signal output by the first-stage phase shifter array through the first planar waveguide; perform wavefront phase modulation on the output signal of the first planar waveguide through the second-stage phase shifter array; and perform inverse Fourier transform on the signal output by the second-stage phase shifter array when it reaches the second planar waveguide. Specifically, the polarization-controlled modulated signal is processed by the on-chip high-precision delay array, and each channel signal introduces a unit delay in turn. , complete the serial-to-parallel conversion operation, ensure the timing consistency and accuracy of the signal, and provide a basis for subsequent parallel signal processing.

[0060] Furthermore, the parallel input signal Enter the first-stage phase shifter array on the chip to control the wavefront phase. The phase shift amount is , where n represents the signal The discrete time index is k, the wave vector, F is the length of the planar waveguide, is the effective refractive index of the planar waveguide. The signal modulated by the phase shifter array can be expressed as:

[0061] ,

[0062] Where N is the size of the planar waveguide input array, is the impulse function, is the input port interval. It is coupled to the first planar waveguide through a tapered waveguide (not shown in the figure), and the output port spacing of the first planar waveguide is , after the signal propagates a specified distance F in the planar waveguide, the signal at the output end can be expressed as:

[0063] ,

[0064] That is, sampling at the output end obtains the input signal The Fourier transform of .

[0065] The output signal of the first planar waveguide is fed into the second-stage phase shifter array on the chip to complete the following operations: a) matching filtering in the frequency domain; b) performing secondary phase compensation to ensure that the second-stage planar waveguide can perform inverse Fourier transform; c) compensating for the phase error introduced by the difference in path length between the two-stage planar waveguides. The phase modulation of the second-stage phase shifter array is:

[0066] ,

[0067] The signal after being regulated by the second-stage phase shifter array is coupled to the second planar waveguide, and the result of the inverse Fourier transform is obtained at the output end of the second planar waveguide according to the Fresnel approximation principle. The parameters of the second planar waveguide are the same as those of the first planar waveguide, and the length of the planar waveguide is , the input port interval is , the effective refractive index of the planar waveguide is , the output port interval is The signal is then output through an on-chip end-face coupler array (not shown in the figure). The phase-modulated optical signal continues to propagate forward in the second planar waveguide region. After that, the output light field can be simplified as:

[0068] ,

[0069] This is the convolution output result.

[0070] S4, output signal processing: The optical signal output by the second planar waveguide is coupled to the detector array (which can be used as a peripheral unit of the chip) through the on-chip end face coupler array to complete the conversion of the photoelectric signal. The converted electrical signal enters the digital signal processing unit for further processing, including amplitude demodulation, phase correction and echo signal reconstruction, to generate the final SAR image or other processing results. For SAR signals with high modulation rates, the processing results can be coupled to external high-speed photodetectors and oscilloscopes through the optical fiber array for real-time testing and monitoring to verify the system performance; for applications with low modulation rates, the detector array can directly output signals to the off-chip CCD array or other acquisition devices for offline analysis and imaging.

[0071] When the above method is applied to point target SAR signal imaging, based on the one-dimensional time series Fourier transform, combined with the sub-aperture cutting algorithm, the simulated echo signals modulated by multiple point targets can be further imaged in two dimensions. The specific process is as follows:

[0072] Reshaping one-dimensional raw echo data: Convert one-dimensional echo data into two-dimensional matrix storage according to different range gates and different azimuth line numbers. The two-dimensional FT order of magnitude is , for a single point target, the number of azimuth lines is reduced to thousands.

[0073] One-dimensional distance Fourier transform: the distance points are The number of FT points of photon acceleration chip is It is difficult to perform a full-resolution range Fourier transform because the SAR data has a one-to-one correspondence between time and frequency. The spectrum of each sub-aperture is part of the full-aperture spectrum. Therefore, the spectrum of the full aperture can be synthesized from the spectra of all sub-apertures. Based on this principle, a full-resolution SAR image can be formed in the range direction by using the sub-aperture decomposition method.

[0074] One-dimensional azimuth Fourier transform: The number of azimuth lines for a single-point target is in the thousands, and the azimuth Fourier transform can simultaneously complete the processing of point targets at the same range gate. The number of azimuth receiving lines can also be obtained through sub-aperture decomposition + multi-chip co-processing to obtain an equivalent full-resolution SAR image. First, the number of single-chip FT points is used as the segmentation size to complete the time domain segmentation of the azimuth data. Secondly, the different azimuth slices are segmented according to the number of single-chip modulators to achieve azimuth serial and parallel conversion. After interpolation and phase shifting of the low-resolution image of each sub-aperture, all sub-apertures are summed in the time domain to obtain a full-resolution SAR image.

[0075] In summary, the acceleration chip based on photonic planar waveguide in the present invention has a small size and high integration, and the modulator array and the detector array have high processing speed. The current optical computing method based on the on-chip diffraction network has a limited number of channels and is difficult to meet the large-scale and high-throughput imaging requirements of SAR imaging signals. The present invention utilizes photonic planar waveguide technology, and the number of units in the chip increases linearly with the network scale. Combined with wavelength division multiplexing technology, the number of processing channels of the network can be greatly improved.

[0076] On the other hand, the present invention provides a SAR signal acceleration processing device based on a photonic planar waveguide chip, and each unit included in the device can implement each step of the aforementioned method, specifically including:

[0077] A multi-wavelength modulation signal acquisition unit is used to generate a SAR echo signal to be processed by using a signal generator, and modulate it to coherent laser sources of different wavelengths through multiple intensity modulators to obtain a multi-wavelength modulation signal;

[0078] A modulated optical signal acquisition unit, used for combining the multi-wavelength modulated signals into a single optical signal, and adjusting the polarization direction through a polarization controller to obtain a modulated optical signal after polarization optimization;

[0079] The waveguide chip processing unit is used to input the modulated optical signal into the photonic planar waveguide chip, input the modulated optical signal into the first-stage phase shifter array for wavefront phase modulation after serial-to-parallel conversion, perform Fourier transform on the signal output by the first-stage phase shifter array through the first planar waveguide; perform a second wavefront phase modulation on the output signal of the first planar waveguide through the second-stage phase shifter array and then reach the second planar waveguide, and perform inverse Fourier transform on the signal output by the second-stage phase shifter array;

[0080] The photoelectric signal conversion unit is used to couple the optical signal output by the photonic planar waveguide chip to the detector array through the on-chip end face coupler array to complete the conversion of the photoelectric signal.

[0081] In a third aspect, the present invention provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned SAR signal acceleration processing method based on the photonic planar waveguide chip.

[0082] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned SAR signal acceleration processing method based on a photonic planar waveguide chip.

[0083] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A SAR signal acceleration processing method based on a photonic planar waveguide chip, characterized in that: The method comprises: Step 1: The signal generator generates a SAR echo signal to be processed, and modulates it to coherent laser sources of different wavelengths through multiple intensity modulators to obtain a multi-wavelength modulated signal; Step 2: Combining the multi-wavelength modulated signals into a single optical signal, and adjusting the polarization direction to obtain a polarization-optimized modulated optical signal; Step 3, input the modulated optical signal into the photonic planar waveguide chip, and after serial-to-parallel conversion, input the modulated optical signal into the first-stage phase shifter array for wavefront phase modulation, and perform Fourier transform on the signal output by the first-stage phase shifter array through the first planar waveguide; perform a second wavefront phase modulation on the output signal of the first planar waveguide through the second-stage phase shifter array, and then reach the second planar waveguide, and perform inverse Fourier transform on the signal output by the second-stage phase shifter array; Wherein, the step 3 comprises: Step 3.1: The modulated optical signal is processed by the on-chip delay array, and each channel signal is introduced into the unit delay in turn. , complete the serial-to-parallel conversion operation and obtain the parallel input signal, represents the modulation rate of the intensity modulator; Step 3.2: Parallel input signal Enter the first-stage phase shifter array on the chip to control the wavefront phase. The phase shift amount is , where i is the imaginary unit and n represents the signal The discrete time index is k, the wave vector, F is the length of the planar waveguide, is the effective refractive index of the planar waveguide, is the horizontal coordinate of the point in the wave source plane S, and the signal controlled by the phase shifter array is expressed as: ， Where N is the size of the planar waveguide input array, is the impulse function, is the input port interval; The output ports of the first planar waveguide are coupled to each other through a tapered waveguide. , represents the wavelength. After propagating the distance of the planar waveguide length F in the planar waveguide, the signal at the output end is expressed as: ， In the formula, z is the propagation direction, x is the horizontal coordinate of the observation point P, and the signal at the output end is sampled to obtain the parallel input signal Fourier transform of Step 3.3, the output signal of the first planar waveguide is fed into the second-stage phase shifter array on the chip, and frequency domain matching filtering, secondary phase compensation, phase error compensation introduced by the difference in path length between the first and second planar waveguides, and inverse Fourier transform are successively performed; Step 4: The optical signal output by the photonic planar waveguide chip is coupled to the detector array through the on-chip end face coupler array to complete the conversion of the photoelectric signal.

2. The SAR signal acceleration processing method based on the photonic planar waveguide chip according to claim 1 is characterized in that: The step 1 comprises: the SAR echo signal to be processed is first subjected to low-pass filtering to remove high-frequency noise, and then quantized, and then modulated to coherent laser sources of different wavelengths by four intensity modulators, the wavelengths being respectively , , and , the modulation rate is , and obtain a multi-wavelength modulated signal.

3. The SAR signal acceleration processing method based on the photonic planar waveguide chip according to claim 2 is characterized in that: The step 2 comprises: the multi-wavelength modulated signal combines optical carriers of different wavelengths into a single optical signal through a wavelength division multiplexer, and the polarization direction of the single optical signal is adjusted by a polarization controller to obtain a modulated optical signal with optimized polarization.

4. The SAR signal acceleration processing method based on the photonic planar waveguide chip according to claim 3 is characterized in that: In step 3.3, the secondary phase compensation Follow the formula below: ， The signal after being regulated by the second-stage phase shifter array is coupled and input into the second planar waveguide. After the phase-modulated optical signal continues to advance along the propagation direction z in the second planar waveguide region for a distance F, the output end optical field of the second planar waveguide is obtained: ， According to the Fresnel approximation principle, the light field signal at the output end of the second planar waveguide is the result of the inverse Fourier transform.

5. The SAR signal acceleration processing method based on the photonic planar waveguide chip according to claim 4 is characterized in that: The step 4 includes coupling the optical signal output by the second planar waveguide to the detector array through the on-chip end face coupler array to complete the conversion of the photoelectric signal, and the converted electrical signal enters the digital signal processing unit for processing to generate the final SAR image.

6. The SAR signal acceleration processing method based on the photonic planar waveguide chip according to claim 5 is characterized in that: The digital signal processing unit performs processing including amplitude demodulation, phase correction and echo signal reconstruction.

7. A SAR signal acceleration processing device based on a photonic planar waveguide chip, applied to the SAR signal acceleration processing method based on a photonic planar waveguide chip according to any one of claims 1 to 6, characterized in that: include: A multi-wavelength modulation signal acquisition unit is used to generate a SAR echo signal to be processed by using a signal generator, and modulate it to coherent laser sources of different wavelengths through multiple intensity modulators to obtain a multi-wavelength modulation signal; A modulated optical signal acquisition unit, used for combining the multi-wavelength modulated signals into a single optical signal, and adjusting the polarization direction through a polarization controller to obtain a modulated optical signal after polarization optimization; The waveguide chip processing unit is used to input the modulated optical signal into the photonic planar waveguide chip, input the modulated optical signal into the first-stage phase shifter array for wavefront phase modulation after serial-to-parallel conversion, and perform Fourier transform on the signal output by the first-stage phase shifter array through the first planar waveguide; The output signal of the first planar waveguide is subjected to a second wavefront phase modulation by the second-stage phase shifter array, and then reaches the second planar waveguide, and an inverse Fourier transform is performed on the signal output by the second-stage phase shifter array; The photoelectric signal conversion unit is used to couple the optical signal output by the photonic planar waveguide chip to the detector array through the on-chip end face coupler array to complete the conversion of the photoelectric signal.

8. An electronic device, characterized in that: include: one or more processors; A memory for storing one or more programs; When one or more programs are executed by the one or more processors, the one or more processors implement the SAR signal acceleration processing method based on the photonic planar waveguide chip as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: Executable instructions are stored thereon, and when the instructions are executed by the processor, the processor can implement the SAR signal acceleration processing method based on the photonic planar waveguide chip as described in any one of claims 1-6.

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