A reconfigurable microwave photonic filter and filtering method

Abstract

The application discloses a reconfigurable microwave photonic filter, comprising a laser source, an electro-optic modulator, an adjustable feedback type array waveguide grating, a filtering module and a photoelectric detector, the laser source generates an optical signal which is transmitted to the electro-optic modulator, the electro-optic modulator modulates the optical signal after receiving the optical signal, forms a corresponding sideband, the adjustable feedback type array waveguide grating divides the spectrum of the optical signal into different wavelengths, and independently adjusts the amplitude and phase of the optical signals with different wavelengths, then the filtering module filters out the periodically repeated signals, and the photoelectric detector converts the filtered optical signal into an electrical signal, thereby completing the optical-electric conversion. The reconfigurable microwave photonic filter and the filtering method have the advantages of simple structure, highly programmable spectrum shape, fast reconfigurable response and high integration, and will have great attraction in the field of high-frequency signal processing. The application obtains: National Natural Science Foundation of China Youth Science Foundation Project (62204156).

Description

Technical Field

[0001] The present invention relates to the field of microwave optoelectronic signal processing, and in particular to a reconfigurable microwave photon filter and a filtering method. Background Art

[0002] With the deepening integration of microwave photonics with radio frequency engineering and optoelectronics, this interdisciplinary field has become a hot topic of research. Microwave photonics utilizes optical devices to process radio frequency signals, enabling a variety of functions such as filtering, frequency multiplication / conversion, arbitrary waveform generation, phase shifting, and pulse shaping. These functions are crucial for applications such as radar, wireless communications, and sensing. However, traditional electronic microwave filters, limited by electronic bottlenecks, face challenges in meeting the exponentially growing capacity demands of next-generation RF systems. Photonics, with its advantages of wide bandwidth, parallelism, and adaptability, offers a promising alternative. Microwave photonic filters perform filtering operations in the optical domain, offering not only broadband tunability but also high stability, low latency, and strong immunity to electromagnetic interference.

[0003] Although microwave photonic systems are becoming increasingly powerful, their complexity is also increasing, resulting in bulky systems that struggle to meet the requirements of lightweight, miniaturization, low power consumption, and long-term stability. Integrated photonics offers a solution to this problem, integrating multiple high-speed, wide-bandwidth optical devices on a single chip, enabling system compactness and miniaturization. Photonic integration platforms, such as III-V semiconductors, silicon photonics, SiN / SiO2 photonic integration, and hybrid integration of multiple materials, offer diverse options for RF signal processing. Silicon photonic integration, in particular, offers the advantages of high compactness and small chip size due to its high refractive index. In addition, the use of CMOS-compatible processes enables the integration of electronic and optical devices on a single chip, reducing costs and enabling large-scale production.

[0004] Photonic-assisted RF filters play a fundamental role in microwave photonic devices, utilizing optical devices to process RF signals. Microwave photonic filters are primarily categorized into three types: those based on stimulated Brillouin scattering (SBS), those that directly map the optical domain to the frequency domain, and those synthesized using multi-tap delay lines. Each of these filters has its own advantages and applicable scenarios: SBS-based filters require a precise structure to improve performance; direct mapping schemes are limited in filtering performance by optical filters, and the wavelength separation and signal processing structures are complex; while multi-tap filters are flexible, their dispersion structure increases system complexity. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is that existing microwave photonic filters and filtering methods suffer from large system size, high structural precision requirements, complex wavelength separation and signal processing structures, and high system complexity. Therefore, the present invention provides a reconfigurable microwave photonic filter and filtering method. This method utilizes a feedback arrayed waveguide grating structure and combines it with direct optical-to-frequency domain mapping technology to achieve a microwave photonic filter with a simple structure, highly programmable spectral shape, fast and reconfigurable response, and high integration. This innovative combination will demonstrate significant technical advantages and application potential in the field of radio frequency signal processing.

[0006] To achieve the above objectives, the present invention provides a reconfigurable microwave photonic filter, comprising a laser source, an electro-optical modulator, an arrayed waveguide grating with adjustable feedback, a filtering module, and a photodetector. The laser source generates an optical signal and transmits it to the electro-optical modulator. After receiving the optical signal, the electro-optical modulator modulates the optical signal to form corresponding sidebands. The adjustable feedback arrayed waveguide grating divides the spectrum of the formed sideband signal into different wavelengths and independently adjusts the amplitude and phase of the optical signals of different wavelengths. The filtering module then filters out periodic repetitive signals. The photodetector converts the filtered optical signal into an electrical signal, thereby completing the optical-to-electrical conversion.

[0007] Furthermore, the adjustable feedback array waveguide grating and the filter module are configured as an on-chip integrated structure.

[0008] Furthermore, the laser source, electro-optic modulator, and photodetector are all configured as one or more of on-chip full integration, on-chip semi-integration, and off-chip structures.

[0009] Furthermore, the configuration of the electro-optic modulator and the adjustable feedback arrayed waveguide grating is set based on a method of directly mapping the optical domain to the frequency domain.

[0010] Furthermore, the filtering module is configured to use a broadband high extinction ratio filtering structure.

[0011] Furthermore, the filtering module is configured to use a dual micro-ring assisted Mach-Zehnder filtering structure.

[0012] Furthermore, the filtering module includes two output waveguides, two multimode interference couplers and two microring resonators, wherein the two microring resonators are respectively integrated on the two arms of the Mach-Zehnder interferometer, and the phases of the two microring resonators are adjustable, and the resonance conditions of the microring resonators are used to dynamically adjust the interference effect of the Mach-Zehnder interferometer.

[0013] In a preferred embodiment of the present invention, the present invention provides a filtering method of the above-mentioned reconfigurable microwave photonic filter, comprising the following steps:

[0014] Generate an optical signal of a specific frequency through a laser source, modulate the optical signal using an electro-optical modulator, and encode information by changing the phase or intensity of the optical signal;

[0015] The adjustable feedback arrayed waveguide grating divides the spectrum of the modulated optical signal into multiple different wavelength components;

[0016] Utilize filtering modules to selectively retain or suppress specific wavelength components;

[0017] The photodetector converts the filtered optical signal into an electrical signal, thereby completing the optical-electrical conversion.

[0018] Furthermore, the filtering shape is reconstructed by adjusting the amplitude and phase regulator on the feedback loop of the feedback array waveguide grating.

[0019] Technical Effects

[0020] The present invention provides a reconfigurable microwave photon filter and filtering method, which have the following technical effects:

[0021] 1. Innovative combination of feedback arrayed waveguide grating and frequency domain mapping scheme: This invention combines the direct mapping technology from the optical domain to the frequency domain with the integrated design of the feedback arrayed waveguide grating to create a new type of microwave photonic filter. This combination fully utilizes the advantages of arrayed waveguide grating in wavelength selectivity and realizes efficient and precise filtering of radio frequency signals through the mapping technology from the optical domain to the frequency domain. Each output port of the arrayed waveguide grating corresponds to a specific wavelength, and these wavelengths correspond to the specific frequencies of the radio frequency signal through the frequency mapping scheme. This combination not only improves the selectivity of the filter, but also realizes precise filtering of the radio frequency signal by accurately and independently adjusting the amplitude and phase of signals of different wavelengths, which is difficult to achieve with traditional microwave filters.

[0022] 2. High flexibility and tunability: The reconfigurable microwave photonic filter of the present invention adopts an adjustable feedback array waveguide grating structure, which significantly improves the flexibility and tunability of the filter. It supports structural reconstruction and parameter adjustment, enabling the filter to provide programmable spectral shape and fast response reconstruction, meeting the requirements of modern RF signal processing for rapid adaptability.

[0023] 3. High-efficiency performance and compact design: The reconfigurable microwave photonic filter of the present invention achieves chip size reduction, improved integration, reduced power consumption and enhanced stability. The feedback array waveguide grating adopted by the reconfigurable microwave photonic filter of the present invention not only has wavelength division and regulation functions, but can also be used as a multi-wavelength filter and dispersion element. The device has the characteristics of more compact size, lower loss and greater dispersion. While reducing the physical size of the device and the complexity of the system, it maintains high-efficiency performance, which is particularly suitable for space-constrained application scenarios. In addition, this design also allows the performance of the filter to be adjusted by changing the number and configuration of wavelength channels, thereby adapting to different application requirements, and is compatible with CMOS technology, further improving the flexibility and cost-effectiveness of production.

[0024] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a schematic structural diagram of a reconfigurable microwave photon filter according to a preferred embodiment of the present invention;

[0026] Figure 2 1 is a schematic structural diagram of a reconfigurable microwave photon filter according to a preferred embodiment of the present invention;

[0027] Figure 3 It is a structural schematic diagram of a feedback arrayed waveguide grating module of a reconfigurable microwave photonic filter according to a preferred embodiment of the present invention;

[0028] Figure 4 The figure is a schematic structural diagram of a filter module of a reconfigurable microwave photonic filter according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] In the following description, specific details, such as certain internal procedures and techniques, are provided for purposes of illustration and not limitation to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0031] like Figure 1and 2 As shown, an embodiment of the present invention provides a reconfigurable microwave photonic filter, including a laser source 1, an electro-optical modulator 2, an adjustable feedback array waveguide grating 3, a filtering module 4 and a photodetector 5. The laser source generates an optical signal and transmits it to the electro-optical modulator. After receiving the optical signal, the electro-optical modulator modulates the optical signal to form a corresponding sideband. The sideband signal will be further processed by the subsequent adjustable feedback array waveguide grating. The adjustable feedback array waveguide grating divides the spectrum of the optical signal into different wavelengths and independently adjusts the amplitude and phase of the optical signals of different wavelengths. The periodic repeating signal is then filtered out by the filtering module. The photodetector converts the filtered optical signal into an electrical signal, thereby completing the optical-to-electrical conversion. In this embodiment, the laser source 1 is a continuously adjustable single-frequency light source, and the electro-optical modulator 2 is a phase modulator. Specifically, the continuously adjustable single-frequency light source 1 generates an optical signal, which is a single-frequency signal λ c , is input to electro-optic modulator 2. An RF signal is fed into the RF input of electro-optic modulator 2, generating two sidebands. The sideband signals are then further processed by the tunable feedback arrayed waveguide grating. The sidebands consist of an upper sideband and a lower sideband, each with a phase difference of 180 degrees. Without additional filtering, this would cause the upper and lower sideband optical signals to cancel each other out in the beat frequency signal at photodetector 5, resulting in RF suppression.

[0032] The optical signal then passes through the adjustable feedback array waveguide grating 3, which divides the spectrum into N different wavelengths. These N signals repeat periodically in the frequency domain. After passing through the filter module 4 (a wide spectrum filter structure in this embodiment), the periodic repeating signal is filtered out, leaving λ1, λ2 to λ N The amplitude and phase of each wavelength signal can be adjusted individually by the regulator of the adjustable feedback array waveguide grating 3. Assuming that all N groups of wavelengths are located in the upper sideband, at the photodetector 5, the N signals generate beat signals with the carrier respectively, and finally output N frequencies of λ1-λ C ,λ2-λ C to λ N -λ C Each RF signal can be adjusted independently to achieve reconfigurable microwave photonic filtering.

[0033] Furthermore, the adjustable feedback array waveguide grating and the filter module are configured as an on-chip integrated structure. The laser source, electro-optic modulator, and photodetector are all configured as one or more of on-chip full integration, on-chip semi-integration, and off-chip structures. This embodiment adopts CMOS integration technology, including on-chip full integration, on-chip semi-integration, and optimized combination with off-chip structures of key optoelectronic devices in microwave photonic filters. This integration method not only improves the integration and performance of the system, but also significantly reduces cost and power consumption. Using CMOS technology, combined with photonic integration technology, it is possible to realize complex optoelectronic systems on a single chip, including laser sources, electro-optical modulators, and photodetectors. The models and parameters of these modules are specially designed to meet the requirements of high-performance microwave photonic filters. Compared with traditional technologies, this innovative integration method enables the filter to achieve a smaller chip size while maintaining high bandwidth, low loss, and high integration, thereby demonstrating excellent versatility, adaptability, and flexibility in a variety of application scenarios.

[0034] The configuration of electro-optic modulator and tunable feedback arrayed waveguide grating is based on the method of directly mapping the optical domain into the frequency domain.

[0035] like Figure 3 As shown, the adjustable feedback arrayed waveguide grating module includes an input module 31, an arrayed waveguide module 32, an output module 33, and a feedback loop 34. Input module 1 includes N+1 strip waveguides connected to an input slab waveguide, where the N+1 strip waveguides include one input waveguide and N feedback waveguides. Arrayed waveguide module 2 is connected to the slab waveguides of the input and output sections at both ends to form an arrayed waveguide grating. Output module 33 includes N+1 strip waveguides connected to an output slab waveguide, where the N+1 strip waveguides include one output waveguide and N feedback waveguides. Feedback loop 34 includes N feedback waveguides, each equipped with an independent amplitude and phase regulator to adjust the amplitude and phase of signals of different wavelengths. Each output port of the arrayed waveguide grating corresponds to a specific wavelength. These wavelengths correspond to specific frequencies of the RF signal through a frequency mapping scheme. This not only improves the selectivity of the filter, but also achieves precise filtering of the RF signal by precisely controlling the wavelength. The reconfigurable microwave photonic filter provided in an embodiment of the present invention adopts an adjustable feedback arrayed waveguide grating structure, which gives the filter higher flexibility and tunability, supports structural reconstruction and parameter adjustment, and enables the filter to provide programmable spectral shape and fast response reconstruction, meeting the requirements of modern RF signal processing for rapid adaptability.

[0036] The filter module is configured to use a broadband, high-extinction-ratio filtering structure to filter out periodically repetitive interference signals. Any filter module that achieves broadband, high-extinction-ratio filtering can be used for this purpose. The filter module in this embodiment of the present invention functions to filter out periodically repetitive signals output by an arrayed waveguide grating (AWG), and the filter module meets the requirements for high-extinction-ratio broadband filtering.

[0037] like Figure 4 As shown, in this embodiment, the filtering module is configured to use a dual-microring assisted Mach-Zehnder filtering structure. The filtering module includes two output waveguides 41, two multimode interference couplers 42 and two microring resonators 43, wherein the two microring resonators are respectively integrated on the two arms of the Mach-Zehnder interferometer, and the phases of the two microring resonators are adjustable, and the resonance conditions of the microring resonators are used to dynamically adjust the interference effect of the Mach-Zehnder interferometer. When the dual-microring assisted Mach-Zehnder filtering structure is working, the two microring resonators and the coupled waveguides are in an over-coupling state. This solution causes the phase of the coupled waveguide to change dramatically near the resonant wavelength of the microring, so that the Mach-Zehnder interferometer does not need to rely on increasing the arm length to introduce a π phase shift, thereby achieving a smaller size and a higher filtering extinction ratio. The operating wavelength can be selected at the midpoint of the two microring resonance peaks and can be dynamically adjusted. The dual-microring assisted Mach-Zehnder filtering structure is represented by the following transfer matrix:

[0038]

[0039] Among them E bar and E cross represent the electric field E at the through port and cross port of the Mach-Zehnder interferometer respectively. in is the electric field at the input port. κ and τ are the coupling coefficient and transmission coefficient of the input and output multimode interference (MMI) couplers. For an ideal 3dB coupler, κ 2 =τ 2 =0.5, at this time (i = 1, 2) is the electric field transmitted through the two arms of the Mach-Zehnder interferometer coupled to the microring. Increasing the bandwidth can be achieved by adjusting the resonance conditions of the microring. In the dual-microring-assisted Mach-Zehnder filter structure, the resonance conditions of the microrings directly affect the amplitude and phase responses of the two arms of the Mach-Zehnder interferometer, thereby affecting the frequency response of the entire system. Amplitude and phase response T i and It is given by the following formula:

[0040]

[0041] Where t is the field transmission coefficient, θ i(i = 1, 2) is the round-trip phase in the microring, and a is the ring loss factor. By adjusting these parameters, the amplitude and phase response of the two arms of the Mach-Zehnder interferometer can be changed, thereby affecting the frequency response of the entire system and achieving bandwidth adjustment.

[0042] The extinction ratio is defined as the ratio of the maximum transmittance to the minimum transmittance. The input normalized output power at the transverse port and the cross port is thus expressed as:

[0043]

[0044] By adjusting the resonance conditions of the microring, the interference effect of the Mach-Zehnder interferometer can be controlled to achieve modulation and routing of optical signals. By adjusting the resonance conditions of the microring, the transmittance P of the cross port can be adjusted to a certain frequency. x reaches its maximum, while the transmittance P at the transverse port b Close to 0, thus achieving a high extinction ratio. The dual-microring-assisted Mach-Zehnder filter structure optimizes the amplitude and phase response of the two arms of the Mach-Zehnder interferometer by adjusting the resonance conditions of the microring, thereby achieving a larger extinction ratio and a larger bandwidth. This design provides an effective method to control the transmission characteristics of optical signals, which is of great significance for optical communications and other photonics applications. By adjusting the resonance conditions of the microring, the dual-microring-assisted Mach-Zehnder filter structure makes the phase change of the coupled waveguide near the resonant wavelength of the microring more dramatic, thereby achieving a larger bandwidth and a higher extinction ratio without increasing the arm length.

[0045] Another preferred embodiment of the present invention provides a cascaded Mach-Zehnder filter structure. This structure cascades two Mach-Zehnder interferometers, each with adjustable phases. In this cascaded Mach-Zehnder interferometer structure, the key to improving the extinction ratio and bandwidth lies in utilizing the cascade effect of multiple Mach-Zehnder interferometers.

[0046] The increase in bandwidth can be achieved by adjusting the phase difference of each Mach-Zehnder interferometer. In a cascaded Mach-Zehnder interferometer, the phase difference of each Mach-Zehnder interferometer unit can be adjusted independently, allowing designers to control the frequency response of the entire system by finely adjusting the phase difference. Specifically, the transfer function of the cascaded Mach-Zehnder interferometer involves the product of multiple cosine functions, which results in a more complex frequency response, thereby providing effective filtering over a wider frequency range.

[0047] For the cascaded Mach-Zehnder interferometer, the total transfer function is expressed as:

[0048]

[0049] Where N is the number of cascaded Mach-Zehnder interferometers, φ i is the phase difference of the i-th Mach-Zehnder interferometer, Δφ(f) is the frequency-dependent phase difference, and this structure is a two-stage cascaded Mach-Zehnder interferometer, with N being 2. This expression shows that the overall transfer function is a complex function of frequency, providing the desired filtering characteristics over a wider frequency range, thereby increasing the bandwidth.

[0050] The input normalized output power is described by the following formula:

[0051]

[0052] Among them, T i and (i=1,2) are the amplitude and phase responses of the i-th Mach-Zehnder interferometer, respectively. By cascading Mach-Zehnder interferometers, the phase modulation effects of each Mach-Zehnder interferometer are accumulated, thereby achieving deeper attenuation at certain frequencies, that is, a higher extinction ratio.

[0053] The cascaded Mach-Zehnder interferometer structure improves the extinction ratio by cascading multiple Mach-Zehnder interferometers and utilizing the phase modulation effect of each unit. Simultaneously, by independently adjusting the phase difference of each Mach-Zehnder interferometer, the frequency response of the entire system is controlled, thereby increasing bandwidth. This design is of great significance in optical communications and other photonics applications because it allows for more precise control of the transmission characteristics of optical signals. By designing cascaded Mach-Zehnder interferometers, optical filters with higher extinction ratios and wider bandwidths can be achieved without increasing physical size.

[0054] The filtering structure selects an integrated broadband high extinction ratio structure, which, together with the feedback array waveguide grating, can achieve fine control of microwave filtering while meeting the requirements of integration, making the microwave filtering system more compact.

[0055] In a preferred embodiment of the present invention, the present invention provides a filtering method of the above-mentioned reconfigurable microwave photonic filter, comprising the following steps:

[0056] Generate an optical signal of a specific frequency through a laser source, modulate the optical signal using an electro-optical modulator, and encode information by changing the phase or intensity of the optical signal;

[0057] The adjustable feedback arrayed waveguide grating divides the spectrum of the modulated optical signal into multiple different wavelength components;

[0058] Utilize filtering modules to selectively retain or suppress specific wavelength components;

[0059] The photodetector converts the filtered optical signal into an electrical signal, thereby completing the optical-electrical conversion.

[0060] Furthermore, the filtering shape is reconstructed by adjusting the amplitude and phase regulator on the feedback loop of the feedback array waveguide grating.

[0061] Specifically, optical signals of specific frequencies are generated by a laser source, and these signals are modulated by an electro-optical modulator to form upper and lower sidebands.

[0062] The adjustable feedback array waveguide grating divides the spectrum of the modulated optical signal into multiple wavelength components and finely controls the intensity of these optical signals.

[0063] Specific wavelength components are selectively retained or suppressed through the filtering module.

[0064] The photodetector converts the filtered optical signal into an electrical signal, realizing the optical-electrical conversion process.

[0065] Because microwave filtering employs an optical-to-frequency domain mapping scheme, the optical signal's spectrum can be mapped into the frequency domain. Therefore, the microwave spectrum's characteristics are primarily influenced by the feedback arrayed waveguide grating (AWG) and the filtering module. To describe this filtering process in detail, corresponding formulas are constructed to mathematically deduce the feedback arrayed waveguide grating and filtering module.

[0066] For a feedback array waveguide grating, the transmission spectrum of each channel can be represented by a Gaussian function. Now there are N such channels, the peak of each channel is controlled by the amplitude and phase modulator, and the transmission spectrum of all channels is the superposition of these Gaussian functions. The mth channel at wavelength λ m The transmission spectrum at can be expressed as:

[0067]

[0068] Among them, λ m is the central wavelength of the mth channel, T 0m is the wavelength λ of the mth channel m The normalized peak transmittance at Δλ is controlled by the amplitude and phase modulators of each channel and can be adjusted independently. m is the wavelength λ of the mth channel m The full width at half maximum (FWHM) at λ is affected by the characteristics of the arrayed waveguide grating. Each channel has a fixed period FSR interval and a recurring wavelength signal. For the mth channel in the arrayed waveguide grating, its transmission spectrum is at wavelength λ m The peak value T 0m , and the transmission spectrum λ of each channel m The same peak value T is also reached at +k·FSR (where k is an integer) 0mSpecifically, FSR represents the interval between the periodic repetition wavelengths of the same output port, which is affected by the inherent characteristics of the arrayed waveguide grating, such as the diffraction order, the length difference of the arrayed waveguide, the effective refractive index of the waveguide, etc. k is an integer representing the distance from the center wavelength λ m The number of FSR shifts. A positive number indicates an FSR shift above the center wavelength, and a negative number indicates an FSR shift below the center wavelength. Affected by the periodic repetitive wavelength signal, the transmission spectra of all periodic repetitive wavelengths in the mth channel are superimposed as follows:

[0069]

[0070] The feedback arrayed waveguide grating can realize the superposition of the transmission spectra of all N channels. Therefore, after the feedback arrayed waveguide grating, the transmission spectra of N channels are superimposed as follows:

[0071]

[0072] Above T total (λ) is the transmission spectrum of the feedback array waveguide grating. After the signal passes through the filtering module, the periodic repetitive signal is filtered out, leaving only λ1, λ2 to λ n Because the filter module has the characteristics of broadband and high extinction ratio, after filtering out the periodic repetitive signal, it can be approximately regarded as adding an amplitude coefficient T to the transmission spectrum system. f , the transmission spectrum is:

[0073]

[0074] After the optical domain to frequency domain conversion, the transmission spectrum is mapped to the frequency domain to complete the microwave filtering.

[0075] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A reconfigurable microwave photonic filter, characterized in that: The system comprises a laser source, an electro-optical modulator, an adjustable feedback arrayed waveguide grating, a filtering module, and a photodetector. The laser source generates an optical signal and transmits it to the electro-optical modulator. After receiving the optical signal, the electro-optical modulator modulates the optical signal to form corresponding sidebands and transmits them to the adjustable feedback arrayed waveguide grating. The adjustable feedback arrayed waveguide grating divides the spectrum of the formed sideband signal into different wavelengths and independently adjusts the amplitude and phase of the optical signals of different wavelengths. The filtering module then filters out periodic repetitive signals. The photodetector converts the filtered optical signal into an electrical signal, thereby completing optical-to-electrical conversion. Each output port of the arrayed waveguide grating corresponds to a specific wavelength, and these wavelengths correspond to the specific frequency of the radio frequency signal through frequency mapping; The adjustable feedback arrayed waveguide grating includes an input module, an arrayed waveguide module, an output module and a feedback loop. Specifically, the input module includes N +1 first strip waveguide is connected to the input slab waveguide, where: N +1 first strip waveguide including 1 input waveguide and N a first feedback waveguide; The two ends of the arrayed waveguide module are connected to the slab waveguide of the input and output parts to form an arrayed waveguide grating; The output module includes N +1 second strip waveguide is connected to the output slab waveguide, where N +1 second strip waveguide including 1 output waveguide and N a second feedback waveguide; The feedback loop includes N A third waveguide, each integrating a set of independently adjustable amplitude and phase regulators; The configuration of the electro-optical modulator and the adjustable feedback arrayed waveguide grating is based on a method of directly mapping the optical domain to the frequency domain; The filtering module is configured to use a dual micro-ring assisted Mach-Zehnder filtering structure.

2. The reconfigurable microwave photonic filter according to claim 1, wherein: The adjustable feedback array waveguide grating and the filtering module are configured as an on-chip integrated structure.

3. The reconfigurable microwave photonic filter according to claim 1, wherein: The laser source, the electro-optic modulator, and the photodetector are all configured as one or more of on-chip full integration, on-chip semi-integration, and off-chip structures.

4. The reconfigurable microwave photonic filter according to claim 1, wherein: The filtering module includes two output waveguides, two multimode interference couplers and two microring resonators; wherein, the two microring resonators are respectively integrated on the two arms of the Mach-Zehnder interferometer, and the phases of the two microring resonators are adjustable, and the resonance conditions of the microring resonators are used to dynamically adjust the interference effect of the Mach-Zehnder interferometer.

5. A filtering method based on the reconfigurable microwave photonic filter according to any one of claims 1 to 4, characterized in that: The following steps are involved: Generate an optical signal of a specific frequency through a laser source, modulate the optical signal using an electro-optical modulator, and encode information by changing the phase or intensity of the optical signal; The adjustable feedback arrayed waveguide grating divides the spectrum of the modulated optical signal into multiple different wavelength components; Utilize filtering modules to selectively retain or suppress specific wavelength components; The photodetector converts the filtered optical signal into an electrical signal, thereby completing the optical-electrical conversion.

6. The filtering method according to claim 5, wherein: The filtering shape is reconstructed by adjusting the amplitude and phase regulator on the adjustable feedback array waveguide grating feedback loop.

Images