Low-speed driven tunable multi-system photonics microwave signal generation method and device
By combining a low-speed DDS and an optical frequency comb module with a cascaded electro-optic external modulator, the high cost problem caused by high sampling rate is solved, realizing low-cost generation and frequency tuning of multi-standard microwave signals, which is suitable for radar and communication integrated systems.
Patent Information
- Application Number
- CN202511751358.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-26
- Publication Date
- 2026-03-03
AI Technical Summary
Existing microwave photonics signal generation technologies require arbitrary waveform generators with high sampling rates and large bandwidths, resulting in high costs and difficulty in generating multi-standard signals, which cannot meet the needs of integrated radar and communication systems.
A low-speed DDS is used to generate a zero-phase linear frequency modulated continuous wave signal. Combined with an optical frequency comb module and a cascaded electro-optic external modulator, multi-mode microwave signals are generated through spectral shaping and photoelectric conversion.
It enables low-speed driven tunable, multi-standard, broadband microwave signal generation, significantly reducing system costs and supporting microwave signal tuning with a frequency coverage greater than 50 GHz.
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Figure CN121603113A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photonic microwave signal generation technology, and more specifically, to a method and apparatus for generating low-speed driven tunable multi-mode photonic microwave signals. Background Technology
[0002] Microwave photonics, with its inherent advantages such as wide spectral coverage, large instantaneous bandwidth, low transmission loss, small size, light weight, and resistance to electromagnetic interference, is widely used in radar, communication, and electromagnetic detection. Among these applications, the generation of broadband microwave signals using microwave photonics technology is of great significance. In particular, the use of microwave photonic frequency doubling systems to generate 8 GHz bandwidth radar linear frequency modulated signals (FZ Zhang, QS Guo, ZQ Wang, P. Zhou, GQ Zhang, J. Sun, and SL Pan. Photonics-based broadband radar for high-resolution and real-time inverse synthetic aperture imaging. Optics Express, 2017, 25(14): 16274-16281.); and the use of photonic-assisted techniques to generate millimeter-wave band broadband phase-coded microwave signals (ZZ Tang, TT Zhang, FZ Zhang, and SL Pan. Photonic generation of a phase-coded microwave signal based on a single dual-drive Mach–Zehndermodulator. Optics Letters, 2013, 38(24): 5365-5368.), etc. However, these methods all require an arbitrary waveform generator with a high sampling rate and large bandwidth to generate the required intermediate frequency drive signal, which is not conducive to the low-cost use of microwave photonic microwave signal generation devices. At the same time, they only generate a signal of a certain format, while for integrated systems with radar and communication functions, it is necessary to generate multiple signal formats such as radar signals and communication signals at the same time.
[0003] Therefore, there is an urgent need for a low-speed signal source-driven photonic microwave signal generation technology to provide broadband, multi-modulation microwave signals, ensuring signal generation for radar, communication, and integrated radar-communication systems. Summary of the Invention
[0004] To address the problem of generating multi-standard broadband signals in new radar, communication, and radar-communication integrated systems, this invention provides a low-speed driven tunable multi-standard photonic microwave signal generation method and apparatus, which can also solve the problem of high cost caused by relying on high sampling rate arbitrary waveform generators in traditional microwave photonic radio frequency signal generation schemes.
[0005] In a first aspect, the present invention provides a method for generating tunable multi-mode photonic microwave signals driven at low speeds, comprising: Step 1: A low-speed DDS generates a zero-phase linear frequency modulated continuous wave signal; Step 2: The optical frequency comb module generates an optical frequency comb signal; Step 3: The electro-optic external modulator converts the zero-phase linear frequency modulated continuous wave signal into an optical frequency comb signal through electro-optic conversion, thereby generating a multi-wavelength carrier-suppressed double-sideband signal. Step 4: The optical amplifier performs optical power compensation on the multi-wavelength carrier-suppressed double-sideband signal; Step 5: The spectral shaper performs dual-channel filtering on the compensated multi-wavelength carrier-suppressed double-sideband signal to obtain a double-sideband linear frequency-modulated optical carrier signal. Step 6: A low-speed arbitrary waveform generator generates a baseband amplitude, phase, and frequency multi-modulation signal; Step 7: Electro-optic external modulator 2 modulates the double-sideband linear frequency modulated optical carrier signal based on the baseband multi-mode modulation signal through the quadrature bias mode, and outputs a multi-mode double-sideband microwave photonic signal. Step 8: The high-frequency photodetector performs photoelectric conversion on the multi-standard double-sideband microwave photonic signals through square law detection, generating tunable, high-frequency multi-standard microwave signals.
[0006] In a preferred embodiment, step 1, where the low-speed DDS generates a zero-phase linear frequency modulated continuous wave signal, includes: The low-speed DDS uses a frequency sweep synthesis method to generate a linear frequency modulated signal at the target intermediate frequency. In pulse and continuous wave modes, the initial phase position of the repetitive periodic linear frequency modulated signal is set to zero to obtain a zero-phase linear frequency modulated continuous wave signal.
[0007] In a preferred embodiment, the frequency interval of the optical frequency comb signal is less than 10 GHz, and the number of comb teeth is greater than 5.
[0008] In a preferred embodiment, the optical frequency comb signal is injected into an electro-optic external modulator via a polarization-maintaining fiber.
[0009] In a preferred embodiment, the double-sideband linear frequency modulated optical carrier signal is a linear frequency modulated optical carrier signal with two different optical wavelengths: a -1st order sideband and a +1st order sideband.
[0010] In a preferred embodiment, the baseband multi-mode modulation signal is divided into two modulation modes: digital modulation and analog modulation.
[0011] In a preferred embodiment, the tunable, high-frequency multi-standard microwave signal is represented as follows:
[0012] in, It is a tunable multi-standard microwave signal. Indicates the amplitude of the baseband multi-modulation signal. Indicates the magnitude of optical power conversion. Indicates the responsivity of a high-frequency photodetector; multi-mode microwave signals The center frequency is , Represent the frequencies of the two linear frequency modulated optical carrier signals selected by the spectral shaper, and the intermediate frequency of the zero-phase linear frequency modulated continuous wave signal; the slope is... , This represents the bandwidth of a zero-phase linear frequency modulated continuous wave signal. This represents the pulse width of a zero-phase linear frequency modulated continuous wave signal. This indicates the phase of the baseband multi-modulation signal. Indicates the initial phase.
[0013] In a second aspect, the present invention provides a low-speed driven tunable multi-mode photonic microwave signal generation device, comprising: Low-speed DDS is used to generate zero-phase linear frequency modulated continuous wave signals. Optical frequency comb module, used to generate optical frequency comb signals; Electro-optic external modulator one is used to convert a zero-phase linear frequency modulated continuous wave signal into an optical frequency comb signal through electro-optic conversion, thereby generating a multi-wavelength carrier-suppressed double-sideband signal. An optical amplifier is used for optical power compensation of multi-wavelength carrier-suppressed double-sideband signals. A spectrum shaper is used to perform dual-channel filtering on the compensated multi-wavelength carrier-suppressed double-sideband signal to obtain a double-sideband linear frequency-modulated optical carrier signal. A low-speed arbitrary waveform generator is used to generate baseband multi-mode modulation signals; Electro-optic external modulator 2 is used to modulate a double-sideband linear frequency modulated optical carrier signal based on a baseband multi-mode modulation signal through an orthogonal point bias mode, and output a multi-mode double-sideband microwave photonic signal. High-frequency photodetectors are used to convert multi-standard double-sideband microwave photonic signals into photoelectric signals through square-law detection, generating tunable, high-frequency multi-standard microwave signals.
[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention achieves low-speed driven, tunable, multi-standard, and broadband microwave signal generation through low-speed DDS driving with zero-phase point setting, spectral shaping of multi-wavelength optical frequency combs, and cascaded electro-optic modulation methods. This significantly reduces the cost and practical performance of integrated microwave photonic radar and communication systems.
[0015] 2. This invention achieves broadband, coherent linear frequency modulated radar signal generation by setting the zero phase of a low-speed DDS, thereby reducing the system cost of photonic microwave signal generation.
[0016] 3. This invention achieves microwave signal tuning with a frequency coverage range greater than 50GHz by combining an optical frequency comb and a spectrum shaper.
[0017] 4. This invention achieves the generation of multi-mode microwave signals, including amplitude, frequency, and phase modulation, through the cascading of two electro-optic external modulators, and achieves the generation of broadband microwave signals using a photonic frequency doubling method. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of a method and apparatus for generating low-speed, tunable multi-mode photonic microwave signals, provided in an embodiment of the present invention.
[0019] Figure 2 This is a schematic diagram of a zero-phase linear frequency modulated continuous wave signal in an embodiment of the present invention.
[0020] Figure 3 This is a schematic diagram of the optical frequency comb signal in an embodiment of the present invention.
[0021] Figure 4 This is a schematic diagram of a multi-wavelength carrier-suppressed double-sideband signal in an embodiment of the present invention.
[0022] Figure 5 This is a schematic diagram of a double-sideband linear frequency modulated optical carrier signal in an embodiment of the present invention.
[0023] Figure 6 This is a schematic diagram of a tunable, high-frequency multi-standard microwave signal in an embodiment of the present invention. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0026] like Figure 1 As shown, this embodiment of the invention provides a method for generating tunable multi-standard photonic microwave signals with low-speed drive, comprising the following steps: Step 1: Low-speed DDS generates a zero-phase linear frequency modulated continuous wave signal: In this embodiment of the invention, the low-speed DDS mainly uses a frequency sweep synthesis method to generate a zero-phase linear frequency modulated continuous wave signal at the target intermediate frequency (IF) of a 100MHz reference signal. Then, in pulse and continuous wave modes, the initial phase position of the repetitive periodic linear frequency modulated signal is set to zero to obtain the zero-phase linear frequency modulated continuous wave signal. This zero-phase linear frequency modulated continuous wave signal, as a broadband carrier signal with multi-mode modulation, ensures that the synthesized zero-phase linear frequency modulated continuous wave signal is coherent by setting its phase to zero, which is beneficial for the two-dimensional target imaging function of radar signal inverse synthetic aperture imaging; for example... Figure 2 As shown, the zero-phase linear frequency modulated continuous wave signal is represented as:
[0027] in, Represents a zero-phase linear frequency modulated continuous wave signal The range, Represents a zero-phase linear frequency modulated continuous wave signal The intermediate frequency; the slope is , Represents a zero-phase linear frequency modulated continuous wave signal bandwidth, Represents a zero-phase linear frequency modulated continuous wave signal The pulse width; This represents the initial phase, which is set to zero.
[0028] Step 2: The optical frequency comb module generates an optical frequency comb signal. In this embodiment of the invention, the optical frequency comb module generates the optical frequency comb signal by using two cascaded intensity modulators and one phase modulator, such as... Figure 3 As shown; in order to generate frequency-tunable microwave signals, the frequency interval of the generated optical frequency comb signal needs to be less than 10 GHz and the number of comb teeth needs to be greater than 5 so that the frequency coverage of the generated microwave signal is greater than 50 GHz.
[0029] Step 3: The electro-optic external modulator converts the zero-phase linear frequency modulated continuous wave signal into an optical frequency comb signal via electro-optic conversion, generating a multi-wavelength carrier-suppressed double-sideband signal, such as... Figure 4 As shown; In this embodiment of the invention, the optical frequency comb signal is injected into the electro-optic external modulator one through the polarization-maintaining fiber; after the electro-optic external modulator one performs electro-optic conversion on the zero-phase linear frequency modulated continuous wave signal, it adjusts the bias voltage to make it at the minimum bias point, thereby generating a multi-wavelength carrier-suppressed double-sideband signal.
[0030] Step 4: The optical amplifier performs optical power compensation on the multi-wavelength carrier-suppressed double-sideband signal; The optical amplifier can be an erbium-doped fiber amplifier to perform optical power compensation on multi-wavelength carrier suppression signals, so as to facilitate subsequent spectral shaping.
[0031] Step 5: The spectral shaper performs dual-channel filtering on the compensated multi-wavelength carrier-suppressed double-sideband signal to obtain a double-sideband linear frequency modulated optical carrier signal.
[0032] The dual-channel filtering involves selecting two linearly frequency-modulated optical carrier signals with different wavelengths: a -1st-order sideband and a +1st-order sideband. Figure 5 As shown, the center frequency of the generated microwave signal is tuned by filtering the wavelength through the tuning channel.
[0033] Step 6: The low-speed arbitrary waveform generator generates a baseband multi-mode modulation signal, represented as:
[0034] in, It is a baseband multi-mode modulation signal. Indicates baseband multi-mode modulation signal The range, Indicates baseband multi-mode modulation signal The phase. There are two modulation modes: digital modulation and analog modulation. Digital modulation is such as multi-level phase shift keying (N-PSK) signals, and analog modulation is such as orthogonal frequency division multiplexing (OFDM) signals.
[0035] Step 7: Electro-optic external modulator 2 modulates the double-sideband linear frequency modulated optical carrier signal based on the baseband multi-mode modulation signal through the quadrature bias mode, and outputs a multi-mode double-sideband microwave photonic signal.
[0036] Step 8: The high-frequency photodetector performs photoelectric conversion on the multi-standard double-sideband microwave photonic signals through square-law detection, generating tunable, high-frequency multi-standard microwave signals, such as... Figure 6 As shown, it is represented as:
[0037] in, It is a tunable multi-standard microwave signal. Indicates the magnitude of optical power conversion. Indicates the responsivity of a high-frequency photodetector; Multi-standard microwave signals The center frequency is , These represent the frequencies of the two linear frequency modulated optical carrier signals selected by the spectral shaper. Selecting linear frequency modulated optical carrier signals of different wavelengths enables the generation of multi-mode microwave signals. The center frequency is tuned; at the same time, photon frequency doubling increases the bandwidth of the linear frequency modulated carrier signal by two times.
[0038] Based on the same technological concept, such as Figure 1 As shown, this embodiment of the invention also provides a low-speed driven tunable multi-standard photonic microwave signal generation device, which includes: Low-speed DDS is used to generate zero-phase linear frequency modulated continuous wave signals. Optical frequency comb module, used to generate optical frequency comb signals; Electro-optic external modulator one is used to convert a zero-phase linear frequency modulated continuous wave signal into an optical frequency comb signal through electro-optic conversion, thereby generating a multi-wavelength carrier-suppressed double-sideband signal. An optical amplifier is used for optical power compensation of multi-wavelength carrier-suppressed double-sideband signals. A spectrum shaper is used to perform dual-channel filtering on the compensated multi-wavelength carrier-suppressed double-sideband signal to obtain a double-sideband linear frequency-modulated optical carrier signal. A low-speed arbitrary waveform generator is used to generate baseband multi-mode modulation signals; Electro-optic external modulator 2 is used to modulate a double-sideband linear frequency modulated optical carrier signal based on a baseband multi-mode modulation signal through an orthogonal point bias mode, and output a multi-mode double-sideband microwave photonic signal. High-frequency photodetectors are used to convert multi-standard double-sideband microwave photonic signals into photoelectric signals through square-law detection, generating tunable, high-frequency multi-standard microwave signals.
[0039] The working principle of the aforementioned devices in this apparatus can be referred to the description in the foregoing method embodiments, and will not be repeated here.
[0040] An application example: First, an electro-optic frequency comb module is constructed using two intensity modulators and one phase modulator. It is driven by a local oscillator and uses a phase shifter and an electric amplifier to generate multi-wavelength frequency comb signals with a comb tooth count greater than 5 and a comb tooth spacing greater than 10 GHz.
[0041] Then, a linear frequency modulated signal with a frequency range of 1GHz to 2GHz is generated by using a low-cost, low-speed DDS sweep frequency synthesis method. In pulse and continuous wave modes, the initial phase position of the repetitive periodic linear frequency modulated signal is set to zero to obtain a zero-phase linear frequency modulated continuous wave signal to ensure phase coherence.
[0042] Subsequently, a Mach-Zehnder modulator (MZM) with a bandwidth greater than 10 GHz was used as the electro-optic external modulator, an erbium-doped fiber amplifier (EDFA) was used as the optical amplifier, a dual-channel waveshaper was used as the spectral shaper, the bandwidth of the arbitrary waveform generator could be less than 1 GHz, and the bandwidth of the high-frequency photodetector needed to be greater than 50 GHz.
[0043] Finally, a frequency-tunable, high-frequency multi-mode microwave signal is generated through a photonic link, and the initial phase between different periods of the generated microwave signal is zero, so that the two-dimensional target imaging results during radar inverse synthetic aperture imaging can be coherently synthesized.
[0044] As can be seen from the above, the present invention achieves low-speed driven tunable, multi-standard, broadband microwave signal generation through low-speed DDS driving with zero-phase point setting, spectral shaping of multi-wavelength optical frequency combs, and cascaded electro-optic modulation method, which can significantly reduce the cost and practical performance of microwave photonic radar communication integrated system.
[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for generating tunable multi-mode photonic microwave signals driven at low speed, characterized in that, include: Step 1: A low-speed DDS generates a zero-phase linear frequency modulated continuous wave signal; Step 2: The optical frequency comb module generates an optical frequency comb signal; Step 3: The electro-optic external modulator converts the zero-phase linear frequency modulated continuous wave signal into an optical frequency comb signal through electro-optic conversion, thereby generating a multi-wavelength carrier-suppressed double-sideband signal. Step 4: The optical amplifier performs optical power compensation on the multi-wavelength carrier-suppressed double-sideband signal; Step 5: The spectral shaper performs dual-channel filtering on the compensated multi-wavelength carrier-suppressed double-sideband signal to obtain a double-sideband linear frequency-modulated optical carrier signal. Step 6: A low-speed arbitrary waveform generator generates a baseband amplitude, phase, and frequency multi-modulation signal; Step 7: Electro-optic external modulator 2 modulates the double-sideband linear frequency modulated optical carrier signal based on the baseband multi-mode modulation signal through the quadrature bias mode, and outputs a multi-mode double-sideband microwave photonic signal. Step 8: The high-frequency photodetector performs photoelectric conversion on the multi-standard double-sideband microwave photonic signals through square law detection, generating tunable, high-frequency multi-standard microwave signals.
2. The method for generating low-speed driven tunable multi-mode photonic microwave signals according to claim 1, characterized in that, In step 1, the low-speed DDS generates a zero-phase linear frequency modulated continuous wave signal, including: The low-speed DDS uses a frequency sweep synthesis method to generate a linear frequency modulated signal at the target intermediate frequency. In pulse and continuous wave modes, the initial phase position of the repetitive periodic linear frequency modulated signal is set to zero to obtain a zero-phase linear frequency modulated continuous wave signal.
3. The method for generating low-speed driven tunable multi-mode photonic microwave signals according to claim 1, characterized in that, The frequency interval of the optical frequency comb signal is less than 10 GHz, and the number of comb teeth is greater than 5.
4. The method for generating low-speed driven tunable multi-mode photonic microwave signals according to claim 1, characterized in that, The optical frequency comb signal is injected into the electro-optic external modulator through a polarization-maintaining fiber.
5. The method for generating low-speed driven tunable multi-mode photonic microwave signals according to claim 1, characterized in that, The double-sideband linear frequency modulated optical carrier signal is a linear frequency modulated optical carrier signal with two different optical wavelengths: a -1st order sideband and a +1st order sideband.
6. The method for generating low-speed driven tunable multi-mode photonic microwave signals according to claim 5, characterized in that, The baseband multi-standard modulation signal is divided into two modulation modes: digital modulation and analog modulation.
7. The method for generating low-speed driven tunable multi-mode photonic microwave signals according to claim 5, characterized in that, The tunable, high-frequency multi-mode microwave signal is represented as follows: in, It is a tunable multi-standard microwave signal. Indicates the amplitude of the baseband multi-modulation signal. Indicates the magnitude of optical power conversion. Indicates the responsivity of a high-frequency photodetector; multi-mode microwave signals The center frequency is , Represent the frequencies of the two linear frequency modulated optical carrier signals selected by the spectral shaper, and the intermediate frequency of the zero-phase linear frequency modulated continuous wave signal; the slope is... , This represents the bandwidth of a zero-phase linear frequency modulated continuous wave signal. This represents the pulse width of a zero-phase linear frequency modulated continuous wave signal. This indicates the phase of the baseband multi-modulation signal. Indicates the initial phase.
8. A low-speed driven tunable multi-standard photonic microwave signal generation device, characterized in that, include: Low-speed DDS is used to generate zero-phase linear frequency modulated continuous wave signals. Optical frequency comb module, used to generate optical frequency comb signals; Electro-optic external modulator one is used to convert a zero-phase linear frequency modulated continuous wave signal into an optical frequency comb signal through electro-optic conversion, thereby generating a multi-wavelength carrier-suppressed double-sideband signal. An optical amplifier is used for optical power compensation of multi-wavelength carrier-suppressed double-sideband signals. A spectrum shaper is used to perform dual-channel filtering on the compensated multi-wavelength carrier-suppressed double-sideband signal to obtain a double-sideband linear frequency-modulated optical carrier signal. A low-speed arbitrary waveform generator is used to generate baseband multi-mode modulation signals; Electro-optic external modulator 2 is used to modulate a double-sideband linear frequency modulated optical carrier signal based on a baseband multi-mode modulation signal through an orthogonal point bias mode, and output a multi-mode double-sideband microwave photonic signal. High-frequency photodetectors are used to convert multi-standard double-sideband microwave photonic signals into photoelectric signals through square-law detection, generating tunable, high-frequency multi-standard microwave signals.