Flexible channelization device and method based on reconfigurable microwave photonic filter

Abstract

The invention relates to the technical field of microwave photons, and discloses a flexible channelization device and method based on a reconfigurable microwave photonic filter, and the device comprises a coherent optical comb generation module which is used for generating two sets of coherent optical frequency combs with different repetition frequencies; the radio frequency signal modulation module is used for realizing ultra-wideband radio frequency signal broadcasting of the signal optical frequency comb; the optical domain spectrum elastic bandwidth segmentation module is used for realizing segmentation of signals with different bandwidths in the signal branches; the fine frequency shift module is used for realizing fine frequency shift of the local oscillation optical frequency comb; and the demodulation receiving module is used for realizing demodulation and frequency conversion of the signal light and the local oscillation light of the same channel. According to the invention, elastic bandwidth multi-channel division and flexible frequency conversion receiving processing of broadband signals are realized based on the integrated coherent dual-optical comb source chip and the center frequency and bandwidth reconfigurable microwave photonic filter chip. According to the invention, the flexibility and multifunctional comprehensiveness of the microwave photon channelization system structure are improved.

Description

Technical Field

[0001] This invention relates to the field of microwave photonics technology, specifically to a flexible channelization device and method based on a reconfigurable microwave photonic filter, and particularly to achieving highly integrated, multifunctional reconfigurable channelization reception using an integrated coherent dual optical comb source chip and an on-chip tunable optical filter chip. Background Technology

[0002] With the development of information technology, the world has entered the era of information explosion. Whether it's civilian technologies such as broadband multi-service access, communication, navigation, and identification, or technologies required for information warfare such as electronic countermeasures, spectrum monitoring, and intelligence data links, the rapid development of these technologies means that narrowband signal transmission and processing can no longer meet the needs of modern communication and combat. The application of frequency-hopping secure communication and high-frequency agile radar places higher demands on the electromagnetic bandwidth of signal transmission and processing, requiring coverage of GHz or even tens of GHz bandwidth to achieve real-time detection, acquisition, transmission, and processing of information over a wide spectrum. However, microwave technology suffers from inherent electronic bottlenecks: radio frequency (RF) devices exhibit significant losses at high frequencies and cannot support the processing of ultra-wideband, multi-band RF signals. Achieving balanced high performance within one or several octaves is difficult, resulting in a low dynamic range for the system. While using different devices at different frequency bands can increase the operating bandwidth of microwave electronic systems, signal leakage and crosstalk between devices cannot be ignored. The numerous devices across different frequency bands also increase the system's size, weight, and power consumption. High-power clutter and interference signals, under the nonlinear effects of RF device saturation, mixing, intermodulation, and crossmodulation, cause severe signal distortion, leading to reception errors and an inability to cope with highly interfering electromagnetic environments. Therefore, traditional broadband signal reception methods are limited in performance and struggle to meet the demands of today's complex electromagnetic environments and military / civilian electronic systems.

[0003] Microwave photonics technology combines the advantages of photonics, such as broadband, high speed, low power consumption, resistance to electromagnetic interference, flat frequency response, and strong parallel processing capabilities, with the precision and maturity of electronics, providing a new approach to solving the reception and processing of high-frequency broadband signals. Microwave photonics channelized reception of radio frequency broadband signals modulates the radio frequency signal received by the antenna onto an optical carrier, dividing the broadband signal into multiple narrowbands in the optical domain for parallel channelized processing. This bypasses electronic bottlenecks, effectively increasing the receiver's operating bandwidth and alleviating the pressure on subsequent digital signal processing.

[0004] Microwave photonic channelization schemes can generally be divided into three categories: time-division / space-division based channelization schemes, periodic filter bank based channelization schemes, and dual-optical-frequency-comb based channelization schemes. Among these, time-division / space-division based schemes achieve time / space separation of the channel using optical switches / diffraction gratings, but suffer from high loss and cannot achieve instantaneous channelization reception, resulting in low reliability. Periodic filter bank based channelization schemes use optical carriers with equal frequency intervals to modulate broadband radio frequency signals, forming multiple optical carrier radio frequency replicas. Comb filters with specific frequency intervals are then used to filter out different frequency components, enabling simultaneous division and reception of multiple channels. However, the number of filters required increases with the number of channels, increasing system complexity and size. The comb filter bank requires a specific frequency difference from the optical carrier frequency interval, leading to a fixed and unadjustable channel bandwidth. Dual-optical-frequency-comb based channelization schemes employ two coherent optical frequency combs: one as a signal comb for modulating broadband radio frequency signals, and the other as a local oscillator comb array for coherent mixing. The optical radio frequency signal and its corresponding local oscillator input balanced photodetector are mixed using an optical demultiplexer. To avoid overlap of the positive and negative frequency sidebands of the local oscillator light after mixing, this scheme typically requires orthogonal optical mixing and IQ demodulation techniques. Furthermore, the operating frequency band and number of channels in this scheme heavily depend on the comb spacing and number of comb teeth of the coherent dual optical combs; the bandwidth of each channel is determined by the difference in comb spacing between the two optical frequency combs. However, the signal frequencies and bandwidths of different electronic systems are usually different. In the above scheme, once the frequency spacing difference between the signal path and the local oscillator path is determined, the channel bandwidth is fixed, making it impossible to adaptively adjust the bandwidth of each channel according to task requirements. Summary of the Invention

[0005] To address the problems mentioned in the technical background, this invention proposes a flexible channelization device and method based on a reconfigurable microwave photonic filter. This invention achieves flexible bandwidth multi-channel partitioning and flexible frequency conversion reception processing of broadband signals based on an integrated coherent dual-optical comb source chip and a microwave photonic filter chip with reconfigurable center frequency and bandwidth.

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

[0007] A flexible channelization device based on a reconfigurable microwave photonic filter includes:

[0008] The coherent optical comb generation module is used to generate two sets of optical frequency combs with different repetition frequencies and high coherence with each other, including the optical frequency comb of the local oscillator branch and the optical frequency comb of the signal branch. The optical frequency comb of the signal branch is output to the radio frequency signal modulation module, and the optical frequency comb of the local oscillator branch is output to the fine frequency shifting module.

[0009] The radio frequency signal modulation module is used to broadcast ultra-wideband radio frequency signals from the optical frequency comb of the signal branch and output multiple broadcast copies of the radio frequency signal under test to the optical domain spectrum elastic bandwidth segmentation module.

[0010] The optical spectrum flexible bandwidth segmentation module is used to divide multiple broadcast copies of the radio frequency signal under test in the signal branch into multiple channels, and output the broadcast copies of the radio frequency signal under test after multi-channel division to the demodulation receiving module.

[0011] The fine frequency shift module is used to finely shift the optical frequency comb of the local oscillator branch and output the finely shifted local oscillator optical frequency comb to the demodulation receiving module.

[0012] The demodulation receiving module is used to combine the broadcast copy of the multi-channel divided radio frequency signal under test and the finely frequency-shifted local oscillator optical frequency combing beam to output down-converted signals with different bandwidths in different channels.

[0013] Furthermore, the coherent optical comb generation module includes a laser, a first optical coupler, optical comb generation functional elements for the local oscillator branch, and optical comb generation functional elements for the signal branch;

[0014] The laser generates a continuous wave laser beam, which is output to the first optical coupler. The first optical coupler splits the continuous wave laser beam, with one beam output to the optical comb generating element of the local oscillator branch and the other output to the optical comb generating element of the signal branch. The optical comb generating element of the local oscillator branch generates the optical frequency comb of the local oscillator branch and outputs it to the fine frequency shifting module. The optical comb generating element of the signal branch generates the optical frequency comb of the signal branch and outputs it to the radio frequency signal modulation module.

[0015] Furthermore, the coherent optical comb generation module is based on an integrated electro-optic frequency comb generation method based on the electro-optic effect or a Kerr micro-optic comb generation method based on the nonlinear effect. In the integrated electro-optic frequency comb generation method based on the electro-optic effect, the optical comb generation functional element is a micro electro-optic modulator chip or an electro-optic crystal micro-resonator. In the Kerr micro-optic comb generation method based on the nonlinear effect, the optical comb generation functional element is a nonlinear crystal micro-resonator.

[0016] Furthermore, coherent optical comb generation methods based on the electro-optic effect include the following two:

[0017] (1) The laser beam split by the optical coupler is injected into the micro electro-optic modulator chip, and under the drive of the external radio frequency signal source, the optical frequency comb of the local oscillator branch and the optical frequency comb of the signal branch are generated.

[0018] (2) The laser beam split by the optical coupler is injected into two electro-optic crystal micro-resonant cavities respectively. The two electro-optic crystal micro-resonant cavities generate the optical frequency comb of the local oscillator branch and the optical frequency comb of the signal branch respectively.

[0019] The coherent optical comb generation methods based on nonlinear effects include the following two:

[0020] (1) The laser beam split by the optical coupler is injected into two nonlinear crystal micro-resonator cavities respectively. By thermally tuning or piezoelectric ceramic tuning of the two nonlinear crystal micro-resonator cavities, an optical frequency comb for the local oscillator branch and an optical frequency comb for the signal branch are generated.

[0021] (2) The laser beam split by the optical coupler is injected into a nonlinear crystal microresonator from two coupling points. The continuous wave laser of any branch is frequency shifted and then injected into the nonlinear crystal microresonator, so that the optical frequency combs of the local oscillator branch and the signal branch are generated simultaneously and have different repetition frequencies.

[0022] Furthermore, the radio frequency signal modulation module includes a dual parallel Mach-Zehnder electro-optic modulator and a first DC regulated power supply; wherein, the first DC regulated power supply outputs a DC bias signal to the dual parallel Mach-Zehnder electro-optic modulator, the dual parallel Mach-Zehnder electro-optic modulator broadcasts ultra-wideband radio frequency signals to the optical frequency comb of the signal branch, and outputs multiple broadcast copies of the radio frequency signals to be tested to the optical domain spectrum elastic bandwidth segmentation module.

[0023] Furthermore, the optical domain spectrum elastic bandwidth segmentation module includes a reconfigurable microwave photonic filter with reconfigurable center frequency and bandwidth, and a second DC regulated power source; wherein, the second DC regulated power source outputs a DC bias signal to the reconfigurable microwave photonic filter, the reconfigurable microwave photonic filter divides the signal output by the radio frequency signal modulation module into multiple channels, and outputs a broadcast copy of the multi-channel divided radio frequency signal to be tested to the demodulation receiving module.

[0024] Furthermore, the reconfigurable microwave photonic filter can be a parallel microring resonant cavity filter, a series microring resonant cavity filter, a cascaded Mach-Zehnder interferometer structure filter, or a cascaded multi-microring assisted Mach-Zehnder interferometer structure filter.

[0025] Furthermore, the fine frequency shifting module includes an optical frequency shifting device, a third DC regulated power supply, an RF source, and a dense wavelength division multiplexer; wherein, the third DC regulated power supply outputs a DC bias signal to the optical frequency shifting device; the RF source outputs an RF signal to the optical frequency shifting device; the optical frequency shifting device performs fine frequency shifting on the optical frequency comb of the local oscillator branch, and outputs the finely frequency-shifted local oscillator optical frequency comb to the dense wavelength division multiplexer; the dense wavelength division multiplexer performs wavelength division multiplexing and outputs the result to the demodulation receiving module.

[0026] Furthermore, the demodulation receiving module includes N processing branches, each including a second optical coupler and a photodetector; wherein, the second optical coupler combs together a broadcast copy of the multi-channel divided radio frequency signal under test and a finely frequency-shifted local oscillator optical frequency, and the photodetector mixes the combined signal to output down-converted signals of different bandwidths in different channels.

[0027] A flexible channelization method based on a reconfigurable microwave photonic filter, implemented using the aforementioned highly integrated flexible channelization device, specifically includes the following steps:

[0028] (1) In the coherent optical comb generation module, the continuous wave laser emitted from the laser passes through the optical coupler and enters the optical comb generation functional element of the two branches to generate a signal optical frequency comb and a local oscillator optical frequency comb that are coherent with a certain frequency interval. The signal optical frequency comb is input to the radio frequency signal modulation module, and the local oscillator optical frequency comb is input to the fine frequency shifting module.

[0029] (2) In the radio frequency signal modulation module, the DC bias voltage of the dual parallel Mach-Zehnder electro-optic modulator is adjusted to realize the broadcast of the radio frequency signal under test. Multiple broadcast copies of the radio frequency signal under test are input to the optical domain spectrum elastic bandwidth segmentation module. In the optical domain spectrum elastic bandwidth segmentation module, the control voltage of the reconfigurable microwave photonic filter is adjusted to realize the multi-channel division of different bandwidths of the radio frequency signal under test. The broadcast copies of the radio frequency signal under test after multi-channel division are output to the demodulation receiving module. At the same time, in the fine frequency shifting module, the optical frequency shifting device is driven by the radio frequency signal and the DC bias signal to realize the fine frequency shifting of the local oscillator optical frequency comb. After wavelength division multiplexing by the dense wavelength division multiplexer, it is input to the demodulation receiving module.

[0030] (3) In the demodulation receiving module, the optical coupler broadcasts a copy of the radio frequency signal to be tested after multi-channel division and combs the local oscillator optical frequency after fine frequency shifting, and mixes it through a photodetector to output down-converted signals with different bandwidths in different channels.

[0031] The beneficial effects of this invention are as follows:

[0032] 1. This invention utilizes a reconfigurable microwave photonic filter with reconfigurable center wavelength and bandwidth to achieve task-adaptive flexible bandwidth multi-channel signal partitioning, which can meet the needs of integrated broadband signal processing for different electronic system applications.

[0033] 2. This invention utilizes the Kerr effect of a micro-resonant cavity to generate a Kerr optical comb with high repetition rate, large bandwidth, multiple comb teeth, and high integration, or utilizes a lithium niobate thin film structure to realize an electro-optical frequency comb with high repetition rate, multiple comb teeth, and high integration, which can meet the requirements of microwave photonic channelization such as large bandwidth, multiple bands, multiple channels, small size, low power consumption, and low complexity.

[0034] 3. This invention has the advantages of high integration, large bandwidth, multiple channels, and flexible reconfigurability. Compared with traditional periodic optical filters and dual optical comb channelization schemes, this invention achieves flexible control of channel bandwidth based on reconfigurable microwave photonic filters, improving the intelligent broadband signal processing capability of integrated electronic systems and reducing the size and cost of flexible broadband signal processing and downconversion in integrated electronic systems.

[0035] In summary, this invention utilizes a microwave photonic filter with reconfigurable center wavelength and bandwidth to achieve flexible and controllable channel bandwidth. The microwave photonic filter with reconfigurable center wavelength and bandwidth offers advantages such as flexibility, reconfigurability, and high integration, significantly enhancing the flexibility and multifunctionality of the microwave photonic channelization system structure. This provides a reliable technical approach for multifunctional, flexible bandwidth, highly integrated channelized reception, and flexible frequency conversion processing. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the flexible channelization device based on a reconfigurable microwave photonic filter according to the present invention.

[0037] Figure 2 This is a chip configuration diagram of a flexible channelization device based on a reconfigurable microwave photonic filter according to the present invention.

[0038] Figure 3 This is an experimental diagram of the coherent dual optical comb spectrum based on the micro electro-optic modulator chip of this invention.

[0039] Figure 4 This is a simulation diagram of the coherent dual optical comb spectrum based on the micro electro-optic modulator chip of this invention.

[0040] Figure 5 The diagram shows an example of the structure of the reconfigurable microwave photonic rectangular filter of the present invention, along with the corresponding filtering curve. Detailed Implementation

[0041] The implementation of the present invention will now be described in detail with reference to the accompanying drawings. The following content is based on the technical solution of the present invention, and provides detailed implementation methods and specific operating procedures, but the scope of protection of the present invention is not limited to the following content.

[0042] A flexible channelization device based on a reconfigurable microwave photonic filter is disclosed. This device employs highly integrated flexible channelization technology based on a reconfigurable microwave photonic filter. An optical carrier is generated by a micro-electro-optic modulator chip to produce a signal optical comb and a local oscillator optical comb. A broadband radio frequency signal is broadcast and replicated multiple times on the signal optical comb through electro-optic modulation. Precise tuning of the local oscillator optical comb frequency is achieved by frequency shifting. The signal optical comb carrying the broadband radio frequency copy to be received undergoes flexible bandwidth segmentation and channel selection via a microwave photonic filter with reconfigurable center wavelength and bandwidth. The segmented signal light and its corresponding frequency-shifted local oscillator optical comb teeth are mixed by a photodetector, achieving flexible channelization processing of signals with different frequencies and bandwidths. Finally, a corresponding intermediate frequency electrical signal is output for subsequent processing and analysis of the radio frequency signal.

[0043] like Figure 1 As shown, specifically, the device includes:

[0044] The coherent optical comb generation module is used to generate two sets of optical frequency combs with different repetition frequencies and high coherence with each other, including the optical frequency comb of the local oscillator branch and the optical frequency comb of the signal branch. The optical frequency comb of the signal branch is output to the radio frequency signal modulation module, and the optical frequency comb of the local oscillator branch is output to the fine frequency shifting module.

[0045] Specifically, the coherent optical comb generation module includes a laser, an optical coupler, an optical comb generation functional element for the local oscillator branch, and an optical comb generation functional element for the signal branch. The laser generates a continuous-wave laser and outputs it to the optical coupler. The optical coupler splits the continuous-wave laser beam, outputting one beam to the optical comb generation functional element for the local oscillator branch and the other beam to the optical comb generation functional element for the signal branch. The optical comb generation functional element for the local oscillator branch generates the optical frequency comb for the local oscillator branch and outputs it to the fine frequency shift module. The optical comb generation functional element for the signal branch generates the optical frequency comb for the signal branch and outputs it to the radio frequency signal modulation module.

[0046] Among them, the coherent optical comb generation module is based on the integrated electro-optic frequency comb generation method based on the electro-optic effect or the Kerr micro-optic comb generation method based on the nonlinear effect; in the integrated electro-optic frequency comb generation method based on the electro-optic effect, the optical comb generation functional element is a micro electro-optic modulator chip or an electro-optic crystal micro-resonator, and in the Kerr micro-optic comb generation method based on the nonlinear effect, the optical comb generation functional element is a nonlinear crystal micro-resonator.

[0047] The methods for generating coherent optical combs based on the electro-optic effect include the following two:

[0048] (1) The laser beam split by the optical coupler is injected into the micro electro-optic modulator chip, and under the drive of the external radio frequency signal source, the optical frequency comb of the local oscillator branch and the optical frequency comb of the signal branch are generated.

[0049] (2) The laser beam split by the optical coupler is injected into two electro-optic crystal micro-resonant cavities respectively. The two electro-optic crystal micro-resonant cavities generate the optical frequency comb of the local oscillator branch and the optical frequency comb of the signal branch respectively.

[0050] The coherent optical comb generation methods based on nonlinear effects include the following two:

[0051] (1) The laser beam split by the optical coupler is injected into two nonlinear crystal micro-resonator cavities respectively. By thermally tuning or piezoelectric ceramic tuning of the two nonlinear crystal micro-resonator cavities, an optical frequency comb for the local oscillator branch and an optical frequency comb for the signal branch are generated.

[0052] (2) The laser beam split by the optical coupler is injected into a nonlinear crystal microresonator from two coupling points. The continuous wave laser of any branch is frequency shifted and then injected into the nonlinear crystal microresonator, so that the optical frequency combs of the local oscillator branch and the signal branch are generated simultaneously and have different repetition frequencies.

[0053] The materials of the micro electro-optic modulator chip and the electro-optic crystal micro-resonator include, but are not limited to, lithium niobate and lithium tantalate; the types of the micro electro-optic modulator chip include, but are not limited to, phase modulators, Mach-Zehnder intensity modulators and dual parallel Mach-Zehnder modulators; and the structures of the electro-optic crystal micro-resonator include, but are not limited to, micro-rings, racetracks, micro-disks or micro-spheres.

[0054] The materials used in the nonlinear crystal microresonator include, but are not limited to, silicon nitride, lithium niobate thin film, magnesium fluoride, and silicon dioxide; the structure of the nonlinear crystal microresonator is a microring, microdisk, or microsphere, and the quality factor of the microresonator is in the range of 10. 6 ~10 9 The dispersion design of the microresonator is either normal dispersion or anomalous dispersion. When the dispersion of the microresonator is anomalous dispersion, a bright soliton state Kerr optical frequency comb is generated. When the dispersion of the microresonator is normal dispersion, a dark soliton state Kerr optical frequency comb is generated. When the dispersion of the microresonator is anomalous dispersion and there is dispersion perturbation, a soliton crystal state Kerr optical frequency comb is generated.

[0055] The radio frequency signal modulation module is used to broadcast ultra-wideband radio frequency signals from the optical frequency comb of the signal branch and output multiple broadcast copies of the radio frequency signal under test to the optical domain spectrum elastic bandwidth segmentation module.

[0056] Specifically, the radio frequency signal modulation module includes a dual parallel Mach-Zehnder electro-optic modulator and a DC regulated power supply; the DC regulated power supply outputs a DC bias signal to the dual parallel Mach-Zehnder electro-optic modulator, the dual parallel Mach-Zehnder electro-optic modulator broadcasts ultra-wideband radio frequency signals to the optical frequency comb of the signal branch, and outputs multiple broadcast copies of the radio frequency signals under test to the optical domain spectrum elastic bandwidth segmentation module.

[0057] The optical spectrum flexible bandwidth segmentation module is used to divide multiple broadcast copies of the radio frequency signal under test in the signal branch into multiple channels, and output the broadcast copies of the radio frequency signal under test after multi-channel division to the demodulation receiving module.

[0058] Specifically, the optical domain spectrum elastic bandwidth segmentation module includes a reconfigurable microwave photonic filter with reconfigurable center frequency and bandwidth, and a DC regulated power supply; wherein, the DC regulated power supply outputs a DC bias signal to the reconfigurable microwave photonic filter, the reconfigurable microwave photonic filter divides the signal output by the radio frequency signal modulation module into multiple channels, and outputs a broadcast copy of the multi-channel divided radio frequency signal to be tested to the demodulation receiving module.

[0059] Furthermore, the reconfigurable microwave photonic filter with reconfigurable center frequency and bandwidth includes, but is not limited to, the following four types:

[0060] (1) Parallel micro-ring resonant cavity filter;

[0061] (2) Series micro-ring resonant cavity filter;

[0062] (3) Cascaded Mach-Zehnder interferometer structure filter;

[0063] (4) Cascaded multi-micro-ring assisted Mach-Zehnder interferometer structure filter.

[0064] The fine frequency shift module is used to finely shift the optical frequency comb of the local oscillator branch and output the finely shifted local oscillator optical frequency comb to the demodulation receiving module.

[0065] Specifically, the fine frequency shifting module includes an optical frequency shifting device, a DC regulated power supply, an RF source, and a dense wavelength division multiplexer (DWDM). The DC regulated power supply outputs a DC bias signal to the optical frequency shifting device; the RF source outputs an RF signal to the optical frequency shifting device; the optical frequency shifting device performs fine frequency shifting on the optical frequency comb of the local oscillator branch and outputs the finely shifted local oscillator optical frequency comb to the DWDM; the DWDM performs wavelength division multiplexing and outputs the result to the demodulation receiving module.

[0066] The demodulation receiving module is used to combine the broadcast copy of the multi-channel divided radio frequency signal under test and the finely frequency-shifted local oscillator optical frequency combing beam to output down-converted signals with different bandwidths in different channels.

[0067] Specifically, the demodulation receiving module includes N processing branches, each including an optical coupler and a photodetector; wherein, the optical coupler combs together the broadcast copy of the multi-channel divided radio frequency signal under test and the finely frequency-shifted local oscillator optical frequency, and the photodetector mixes the combined signal to output down-converted signals of different bandwidths in different channels.

[0068] The coherent dual optical comb generation module includes: an indium phosphide laser chip and a thin-film lithium niobate micro electro-optic modulator chip; the radio frequency signal modulation module includes a thin-film lithium niobate electro-optic modulator chip; the fine frequency shifting module includes a thin-film lithium niobate frequency shifting chip, a DC regulated power supply, and a radio frequency source; the flexible bandwidth optical domain segmentation module includes five silicon nitride micro-ring resonator filter chips with tunable center wavelengths and reconfigurable bandwidths; and the demodulation receiving module includes five silicon nitride-based optical combiner chips and five array photodetector chips.

[0069] The continuous-wave laser output from the indium phosphide laser chip is first coupled to a thin-film lithium niobate chip, where it is split into two beams. These two beams are connected to miniature electro-optic modulator chips for the signal and local oscillator paths, respectively. An RF signal is applied to the RF input port of the lithium niobate electro-optic modulator chip, and its output port is connected to the input port of a silicon nitride microring resonator filter chip. The five output ports of the silicon nitride microring resonator filter are each connected to one input port of an optical beam combiner. The other branch is similarly connected: the output port of the lithium niobate miniature electro-optic modulator chip is connected to the input port of a lithium niobate frequency shifter. An RF signal controlling the frequency shift is applied to the RF input port of the frequency shifter module, and a DC bias signal is applied to its DC bias input port. The output port of the frequency shifter module is connected to the input of a silicon nitride dense wavelength division multiplexer (DWDM). The five outputs of the DWDM are each connected to another input port of one of the five optical beam combiners. Finally, the output ports of the five optical beam combiners are connected to the five input ports of the photodetector array.

[0070] The flexible channelized reception method implemented using the above-mentioned device is as follows:

[0071] (1) In the coherent optical comb generation module, the continuous wave laser emitted from the laser passes through the optical coupler and enters the optical comb generation functional element of the two branches to generate a signal optical frequency comb and a local oscillator optical frequency comb that are coherent with a certain frequency interval. The signal optical frequency comb is input to the radio frequency signal modulation module, and the local oscillator optical frequency comb is input to the fine frequency shifting module.

[0072] (2) In the radio frequency signal modulation module, the DC bias voltage of the dual parallel Mach-Zehnder electro-optic modulator is adjusted to realize the broadcast of the radio frequency signal under test. Multiple broadcast copies of the radio frequency signal under test are input to the optical domain spectrum elastic bandwidth segmentation module. In the optical domain spectrum elastic bandwidth segmentation module, the control voltage of the reconfigurable microwave photonic filter is adjusted to realize the multi-channel division of different bandwidths of the radio frequency signal under test. The broadcast copies of the radio frequency signal under test after multi-channel division are output to the demodulation receiving module. At the same time, in the fine frequency shifting module, the optical frequency shifting device is driven by the radio frequency signal and the DC bias signal to realize the fine frequency shifting of the local oscillator optical frequency comb. After wavelength division multiplexing by the dense wavelength division multiplexer, it is input to the demodulation receiving module.

[0073] (3) In the demodulation receiving module, the optical coupler broadcasts a copy of the radio frequency signal to be tested after multi-channel division and combs the local oscillator optical frequency after fine frequency shifting, and mixes it through a photodetector to output down-converted signals with different bandwidths in different channels.

[0074] Here is a more specific example:

[0075] A flexible channelization device based on a reconfigurable microwave photonic filter. Figure 2 The schematic diagram is shown below. In this embodiment, the laser is an indium phosphide semiconductor continuous laser (CW), the optical comb generating element is a cascaded Mach-Zehnder electro-optic modulator based on thin-film lithium niobate, the radio frequency signal modulation module is an integrated dual parallel Mach-Zehnder modulator (PM) based on thin-film lithium niobate, and the frequency shifting module is an integrated dual parallel Mach-Zehnder modulator (DPMZM) based on thin-film lithium niobate. The optical comb generating element, radio frequency signal modulation module, and frequency shifting module are integrated on the same thin-film lithium niobate chip. The reconfigurable microwave photonic rectangular filter is a five-tiered micro-ring reconfigurable microwave photonic rectangular filter based on silicon nitride, and the demodulation receiving module is a silicon-based photodiode array, which can simultaneously realize multi-channel photoelectric conversion.

[0076] Specifically, the device includes: an indium phosphide semiconductor continuous laser (CW), two cascaded Mach-Zehnder electro-optic modulators (MZM), two parallel Mach-Zehnder modulators (DPMZM), a 5-cascaded micro-ring filter (Ring), five optical combiners (OC), and five photodetectors (PD) (N is an integer greater than or equal to 2, and its value is the same as the number of channels).

[0077] The operating steps of this device include:

[0078] Step 1: The continuous laser emitted from the indium phosphide semiconductor continuous laser is coupled to the lithium niobate thin film material chip through the chip.

[0079] Step 2: In the upper branch of the lithium niobate thin film material chip, continuous laser light enters the dual-cascaded Mach-Zehnder electro-optic modulator (MZM) in the upper branch, generating a signal optical frequency comb with a repetition frequency of 25 GHz under the drive of an external microwave source.

[0080] Step 3: The signal optical frequency comb enters the dual parallel Mach-Zehnder modulator (DPMZM) in the upper branch to broadcast the broadband RF signal under test input to the RF input port. Its output is then input to the input of the 5-stage micro-ring filter (Ring).

[0081] Step 4: By tuning the phase of each micro-ring resonator in the 5-stage micro-ring filter Ring through the thermo-optical effect, signal segmentation with different center wavelengths and different filtering bandwidths in multiple channels is achieved. The output ports of the 5-stage micro-ring filter Ring are respectively input to one input port of an optical beam combiner.

[0082] Step 5: In the lower branch of the lithium niobate thin film material chip, continuous laser light enters the dual-cascaded Mach-Zehnder electro-optic modulator (MZM) in the lower branch, which generates a local oscillator optical frequency comb with a repetition frequency of 22 GHz under the drive of an external microwave source.

[0083] Step 6: The local oscillator optical frequency comb enters the dual parallel Mach-Zehnder modulator (DPMZM) in the lower branch. The radio frequency signal generated by the radio frequency source is input to its radio frequency input port to achieve fine frequency shifting of the local oscillator optical frequency comb. Its output is then input to the input of the silicon nitride material dense wavelength division multiplexer. The five output ports of the wavelength division multiplexer are respectively connected to the other input port of the five optical beam combiners.

[0084] Step 7: The signal optical combs with different frequencies and bandwidths input into the optical combiner and the finely frequency-shifted local oscillator optical comb are combined.

[0085] Step 8: The output signals of the 5 optical beam combiners are input into the 5 photodetectors respectively, and coherent mixing occurs to achieve multi-channel frequency conversion signal output.

[0086] Figure 3 and Figure 4 This is a spectral example of a coherent optical comb based on a dual-cascaded Mach-Zehnder electro-optic modulator (MZM). Among them, Figure 3 This is an experimental diagram. Figure 4 This is a numerical simulation diagram.

[0087] Figure 5 This is a graph showing the filtering curves for each stage of a 5-stage Ring micro-loop filter.

[0088] In summary, this invention achieves highly integrated flexible channelization processing of signals with flexible bandwidths from different electronic systems based on reconfigurable microwave photonic filters. It utilizes a dual-coherent optical frequency comb based on a cascaded Mach-Zehnder electro-optic modulator to achieve multi-channel uniformization processing of broadband signals. The cascaded Mach-Zehnder electro-optic modulator chip solution greatly simplifies the structure of the optical frequency comb generation module in the microwave photonic channelization system, effectively reducing system complexity. The reconfigurable microwave photonic rectangular filter effectively overcomes the deficiency of fixed intermediate frequency bandwidth in existing microwave photonic channelization schemes, enabling flexible channelization processing of signals with flexible bandwidths.

[0089] The above-described embodiments are merely examples of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that those skilled in the art can make several equivalent modifications and substitutions based on the content disclosed in this invention. The material, type, and structure of the reconfigurable microwave photonic filter; the material and structure of the micro-ring resonator; the form of the coherent optical frequency comb; the generation method of the coherent dual optical frequency comb; the repetition frequency, number of comb teeth, number of channels, carrier frequency band, intermediate frequency, type and structure of the reconfigurable microwave photonic filter; and the optical carrier frequency and power can all be changed. These equivalent modifications, substitutions, and adjustments to the parameters of each device should also be considered within the scope of protection of this invention.

Claims

1. A flexible channelization device based on reconfigurable microwave photonic filter, characterized in that, The application relates to a coherent light comb generation module, a radio frequency signal modulation module, an optical domain spectrum elastic bandwidth division module, a fine frequency shift module and a demodulation receiving module. The coherent light comb generation module comprises a laser, a first optical coupler, a local branch light comb generation functional element and a signal branch light comb generation functional element. The laser generates continuous wave laser which is output to the first optical coupler; the first optical coupler divides the continuous wave laser into two parts, one part is output to the local branch light comb generation functional element, and the other part is output to the signal branch light comb generation functional element; the local branch light comb generation functional element generates the local branch optical frequency comb which is output to the fine frequency shift module; and the signal branch light comb generation functional element generates the signal branch optical frequency comb which is output to the radio frequency signal modulation module. The coherent light comb generation module is based on an integrated electro-optical frequency comb generation method based on an electro-optical effect or a Kerr micro-light comb generation method based on a nonlinear effect; when the integrated electro-optical frequency comb generation method based on the electro-optical effect is used, the light comb generation functional element is a micro electro-optical modulator chip or an electro-optical crystal micro resonant cavity; and when the Kerr micro-light comb generation method based on the nonlinear effect is used, the light comb generation functional element is a nonlinear crystal micro resonant cavity. The coherent light comb generation method based on the electro-optical effect comprises the following two methods: (1) the laser divided by the optical coupler is injected into a micro electro-optical modulator chip, and under the driving of an external radio frequency signal source, the local branch optical frequency comb and the signal branch optical frequency comb are generated; 2. The flexible channelization device based on reconfigurable microwave photonic filter according to claim 1, wherein, (2) the laser divided by the optical coupler is injected into two electro-optical crystal micro resonant cavities, and the two electro-optical crystal micro resonant cavities generate the local branch optical frequency comb and the signal branch optical frequency comb respectively; The coherent light comb generation method based on the nonlinear effect comprises the following two methods:

3. The high-integration flexible channelization device based on reconfigurable microwave photonic filter according to claim 2, characterized in that, (1) the laser divided by the optical coupler is injected into two nonlinear crystal micro resonant cavities, and through thermal tuning or piezoelectric ceramic tuning of the two nonlinear crystal micro resonant cavities, the local branch optical frequency comb and the signal branch optical frequency comb are generated; 4. The flexible channelizer based on reconfigurable microwave photonic filter according to claim 3, characterized in that, (2) the laser divided by the optical coupler is injected into two nonlinear crystal micro resonant cavities, and through thermal tuning or piezoelectric ceramic tuning of the two nonlinear crystal micro resonant cavities, the local branch optical frequency comb and the signal branch optical frequency comb are generated. ​ ​ ​ ​ (2) the light coupler injects the split laser into a nonlinear crystal micro-cavity from two coupling points, and the continuous wave laser of any branch is injected into the nonlinear crystal micro-cavity after frequency shift, so that the optical frequency combs of the local oscillator branch and the signal branch are generated simultaneously and have different repetition frequencies.

5. The flexible channelizer based on reconfigurable microwave photonic filter according to claim 1, wherein, The radio frequency signal modulation module comprises a double parallel Mach-Zehnder electro-optical modulator and a first direct current voltage stabilizer; wherein the first direct current voltage stabilizer outputs a direct current bias signal to the double parallel Mach-Zehnder electro-optical modulator, the double parallel Mach-Zehnder electro-optical modulator broadcasts the optical frequency comb of the signal branch with an ultra-wideband radio frequency signal, and outputs multiple to-be-measured radio frequency signal broadcast copies to the optical domain spectrum flexible bandwidth division module.

6. The flexible channelizer based on reconfigurable microwave photonic filter according to claim 1, wherein, The optical domain spectrum flexible bandwidth division module comprises a reconfigurable microwave photon filter with reconfigurable center frequency and bandwidth and a second direct current voltage stabilizer; wherein the second direct current voltage stabilizer outputs a direct current bias signal to the reconfigurable microwave photon filter, the reconfigurable microwave photon filter divides the signal output by the radio frequency signal modulation module into multiple channels, and outputs the multiple-channel divided to-be-measured radio frequency signal broadcast copies to the demodulation receiving module.

7. The flexible channelization apparatus based on reconfigurable microwave photonic filter according to claim 6, wherein, The reconfigurable microwave photon filter is a parallel micro-ring resonant cavity filter, a series micro-ring resonant cavity filter, a cascaded Mach-Zehnder interferometer structure filter or a cascaded multi-micro-ring assisted Mach-Zehnder interferometer structure filter.

8. The flexible channelizer based on reconfigurable microwave photonic filter according to claim 1, wherein, The fine frequency shift module comprises an optical frequency shift device, a third direct current voltage stabilizer, a radio frequency source and a dense wavelength division multiplexer; wherein the third direct current voltage stabilizer outputs a direct current bias signal to the optical frequency shift device; the radio frequency source outputs a radio frequency signal to the optical frequency shift device; the optical frequency shift device performs fine frequency shift on the optical frequency comb of the local oscillator branch, and outputs the fine frequency shifted local oscillator optical frequency comb to the dense wavelength division multiplexer; and the dense wavelength division multiplexer performs wavelength division multiplexing and outputs to the demodulation receiving module.

9. The flexible channelizer based on reconfigurable microwave photonic filter according to claim 1, wherein, The demodulation receiving module comprises N processing branches, each comprising a second optical coupler and a photodetector; wherein the second optical coupler combines the multiple-channel divided to-be-measured radio frequency signal broadcast copies and the fine frequency shifted local oscillator optical frequency comb, the photodetector mixes the combined signals, and outputs the down-converted signals of different bandwidth signals in different channels.

10. A flexible channelization method based on reconfigurable microwave photonic filter, characterized in that, The high-integration flexible channelization device based on any one of claims 1-9 comprises the following steps: (1) the coherent light comb generation module generates a signal optical frequency comb and a local oscillator optical frequency comb with a certain frequency interval from the continuous wave laser emitted by the laser through the light coupler, the signal optical frequency comb is input to the radio frequency signal modulation module, and the local oscillator optical frequency comb is input to the fine frequency shift module; (2) In the radio frequency signal modulation module, the direct current bias voltage of the double parallel Mach-Zehnder electro-optic modulator is adjusted to realize the broadcasting of the to-be-tested radio frequency signal, and multiple to-be-tested radio frequency signal broadcast copies are input to the optical domain spectrum flexible bandwidth division module; in the optical domain spectrum flexible bandwidth division module, the control voltage of the reconfigurable microwave photon filter is adjusted to realize the multi-channel division of different bandwidths of the to-be-tested radio frequency signal, and the multi-channel divided to-be-tested radio frequency signal broadcast copy is output to the demodulation receiving module; at the same time, in the fine frequency shift module, the optical frequency shift device is driven by the radio frequency signal and the direct current bias signal to realize the fine frequency shift of the local oscillator optical frequency comb, and after wavelength division multiplexing by the dense wavelength division multiplexer, the fine frequency shift module is input to the demodulation receiving module; (3) In the demodulation receiving module, the optical coupler combines the multi-channel divided to-be-tested radio frequency signal broadcast copy and the fine frequency shifted local oscillator optical frequency comb, and the photoelectric detector mixes the combined beam to output the down-converted signals of different bandwidth signals in different channels.

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