Frequency agility broadband chirp signal generating device

Abstract

The invention discloses a frequency agility broadband chirp signal generating device. After laser generated by a distributed feedback semiconductor laser passes through an optical splitter, a first optical path is subjected to fundamental frequency signal carrier suppression single side band modulation through two Mach-Zehnder modulators which are connected in parallel and then is subjected to light amplification and light splitting; the second optical path generates an optical frequency comb through the cascaded electro-absorption modulator, the frequency modulator and the electro-absorption modulator and then carries out wave division; an optical signal split by the first optical path and an optical signal split by the second optical path are respectively coupled and then are sent to an optical switch to realize optical signal agility, through photoelectric conversion and an emission antenna, generation of a large-span frequency agility broadband chirp signal is realized, and a high frequency band can reach a W wave band.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microwave photonics, and particularly to a frequency agile wideband chirp signal generating device. BACKGROUND

[0002] The present application belongs to the field of microwave photonics, and particularly relates to a frequency agile wideband chirp signal generating device, focusing on the urgent demand of modern radar and sensor integration systems for signal sources with large bandwidth, high frequency band and fast frequency agility. Wideband chirp signals can achieve high precision resolution through matching filtering technology, while frequency agility technology can effectively counteract other signal interference and improve spectral efficiency. However, as the demand of radar and sensor integration systems moves to higher frequency bands (such as W-band) and wider bandwidths, the frequency band bottleneck problem of traditional electronics methods is increasingly prominent, limiting the maximum frequency and instantaneous bandwidth of the generated radio frequency signals, making it extremely difficult, costly and complex to generate large instantaneous bandwidth signals in the W-band (75-110 GHz) and higher frequency bands. In the electrical domain, frequency agility usually requires a complex local oscillator switching network or a multi-channel synthesizer, and at higher microwave frequencies, the frequency switching speed, spectral purity and other performance will deteriorate significantly. In addition, traditional frequency agility relies heavily on frequency hopping points, making it difficult to achieve fast frequency hopping of continuous wideband chirp signals of several GHz. To solve this technical bottleneck, by introducing microwave photonics technology, we can take full advantage of the wide bandwidth, high speed response, low power consumption and electromagnetic interference resistance of the optical domain to complete the core functions of frequency conversion and fast switching in the optical domain. However, the generation of agile frequency wideband signals based on microwave photonics technology requires a precisely designed Fourier domain mode-locked optoelectronic oscillation ring or optical injection system, which has the problems of difficult operation and limited frequency conversion range (Nakarmi B, Bai Y, Fang C, et al. Photonically generated frequency hopped linear frequency modulated signal using a DFB laser[J]. Journal of Lightwave Technology, 2022, 40(20): 6729-6736.). Therefore, there is an urgent need to develop a new type of wideband signal generating device that can integrate the wideband advantages of photons and flexible spectral manipulation capabilities, efficiently and quickly complete frequency agility and wideband modulation in the optical domain, and ultimately generate high-performance radio frequency signals that can meet the needs of modern radar and sensor integration systems through photoelectric conversion. SUMMARY

[0003] The present application relates to the field of microwave photonics, and particularly to a frequency agile wideband chirp signal generating device.

[0004] To solve the above technical problems, the application discloses a frequency agile broadband chirp signal generating device, comprising: a distributed feedback semiconductor laser, a first optical splitter, a second optical splitter, a first double-port Mach-Zehnder modulator, a second double-port Mach-Zehnder modulator, a first low-frequency microwave source, an electrical amplifier, a first electrical power divider, a first electrical phase shifter, an optical phase shifter, a first optical coupler, a third optical splitter, an optical amplifier, a second low-frequency microwave source, a second electrical power divider, a second electrical phase shifter, a first electrical absorption modulator, a frequency modulator, a second electrical absorption modulator, a wave divider, a second optical coupler, a third optical coupler, an optical switch, an optical-electricity detector, and a transmitting antenna.

[0005] The distributed feedback semiconductor laser is connected with the input end of the first optical splitter.

[0006] The first output end of the first optical splitter is connected with the input end of the second optical splitter.

[0007] The first output end of the second optical splitter is connected with the input end of the first double-port Mach-Zehnder modulator.

[0008] The second output end of the second optical splitter is connected with the input end of the first double-port Mach-Zehnder modulator.

[0009] The output end of the first low-frequency microwave source is connected with the input end of the electrical amplifier.

[0010] The output end of the electrical amplifier is connected with the input end of the first electrical power divider.

[0011] The first output end of the first electrical power divider is connected with the modulation port of the first double-port Mach-Zehnder modulator.

[0012] The second output end of the first electrical power divider is connected with the input end of the first electrical phase shifter.

[0013] The output end of the first electrical phase shifter is connected with the modulation port of the second double-port Mach-Zehnder modulator.

[0014] The output end of the second double-port Mach-Zehnder modulator is connected with the input end of the optical phase shifter.

[0015] The output end of the first double-port Mach-Zehnder modulator is connected with the input end of the optical phase shifter through the first optical coupler and the input end of the third optical splitter.

[0016] The second output end of the first optical splitter is connected with the first electrical absorption modulator, the frequency modulator and the second electrical absorption modulator in sequence through the optical amplifier.

[0017] The output terminal of the second low-frequency microwave source is connected to the modulation port of the first electro-absorption modulator, the second electro-phase shifter, and the modulation port of the second electro-absorption modulator via the second power divider. The second electro-phase shifter is connected to the modulation port of the frequency modulator.

[0018] The output of the second electroabsorption modulator is connected to the input of the wavelength division multiplexing (WDM).

[0019] The first output terminal of the third beam splitter and the first output terminal of the wavelength division multiplexer are connected via the second optical coupler and the first input terminal of the optical switch;

[0020] The second output terminal of the third beam splitter and the second output terminal of the wavelength division multiplexer are connected via the third optical coupler and the second input terminal of the optical switch;

[0021] The output terminal of the optical switch is connected in sequence to the photodetector and the transmitting antenna.

[0022] The operation of the receiving device includes:

[0023] Step 1: The distributed feedback semiconductor laser generates an optical carrier signal, which is split into two paths by the first beam splitter. The first output optical path of the first beam splitter is transmitted to the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator by the second beam splitter.

[0024] Step 2: A first low-frequency microwave source generates a low-frequency signal. This low-frequency signal is first input to a low-noise amplifier (LNA), where it is amplified and then transmitted to a power divider for two-way power splitting. The first power-splitter signal is directly input to a first dual-port Mach-Zehnder modulator (DZD), which modulates it onto the optical carrier. The second power-splitter signal is sequentially phase-adjusted by a first phase shifter and then input to a second DZD, which modulates it onto the optical carrier. The output of the second DZD is connected to the input of the optical phase shifter. Both modulated optical signals are then input to a first optical coupler, where they are coupled to complete carrier-suppressed single-sideband modulation (CSSM).

[0025] Step 3: The second output optical path of the first beam splitter is amplified by optical amplification; the amplified optical signal is connected sequentially to the first electroabsorption modulator, the frequency modulator, and the second electroabsorption modulator along the optical path; the second low-frequency microwave source generates a low-frequency spot frequency signal, which is input to the second power divider for power division; the multi-channel signals after power division are respectively input to the first electroabsorption modulator, the second phase shifter, and the second electroabsorption modulator; the second phase shifter is connected to the modulation port of the frequency modulator to modulate the optical signal in the optical path, thereby completing the generation of the optical frequency comb;

[0026] Step 4: The optical frequency comb output from the second electroabsorption modulator is transmitted to the wavelength division multiplexing (WDM) unit, where it undergoes optical domain filtering. The filtered two optical frequency comb signals are then input to the optical coupler along with the two optical signals output from the third optical splitter. The optical coupler couples the two signals into a composite optical signal. The composite optical signal is then transmitted to the optical switch, where the optical path switching control enables periodic frequency transitions in the optical domain.

[0027] Step 5: The frequency-hopping optical signal output by the optical switch is input to the photodetector, and the photodetector performs photoelectric conversion processing to obtain the corresponding electrical signal; the electrical signal is transmitted to the transmitting antenna, which radiates and transmits it, thereby realizing the generation and transmission of frequency-agile broadband chirped signal.

[0028] In this invention, only a single distributed feedback semiconductor laser is used.

[0029] In this invention, preferably, the modulation bandwidth of the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator can be less than 10 GHz.

[0030] In this invention, preferably, the distributed feedback semiconductor laser realizes carrier-suppressed single-sideband modulation and optical frequency comb generation on two optical paths respectively.

[0031] In this invention, preferably, the device achieves periodic frequency switching of the signal in the optical domain.

[0032] In this invention, preferably, the device is used for generating agile broadband signals suitable for modern radar and integrated sensing systems.

[0033] Beneficial effects:

[0034] This invention achieves wide-span frequency agility through synergistic optical domain processing of carrier-suppressed single-sideband modulation and optical frequency comb. By selecting the comb teeth of the optical frequency comb and mixing them with a low-frequency chirped signal to perform frequency hopping of the optical signal, a rapid, discontinuous, wide-span frequency hopping can be achieved in the high-frequency range from microwave to W-band without the need for a complex RF local oscillator chain. The device maintains coherence by modulating the optical carrier of a single distributed feedback semiconductor laser. All comb teeth in the system originate from the same laser seed source, and their phase coherence is inherited to the RF signal after photoelectric conversion, ensuring extremely low phase noise and frequency stability at any frequency point. This provides a crucial guarantee for high-gain matched filtering of broadband chirped signals. Furthermore, this optical generation method circumvents electronic bottlenecks and possesses inherent electromagnetic interference resistance, providing a high-performance broadband signal source solution for modern radar and integrated sensing systems. Attached Figure Description

[0035] Figure 1 This is a structural diagram of the device of the present invention.

[0036] Figure 2a The spectrum diagram of the low-frequency broadband signal provided in the embodiments of this application.

[0037] Figure 2b The time-frequency diagram of the low-frequency broadband signal provided in the embodiments of this application.

[0038] Figure 3 The spectrum of a low-frequency broadband signal after carrier suppression single-sideband modulation is provided in an embodiment of this application.

[0039] Figure 4 The optical frequency comb spectrum provided in the embodiments of this application.

[0040] Figure 5a The spectrum of the first output terminal of the third beam splitter and the first output terminal of the wavelength division multiplexing (WDM) provided in the embodiments of this application.

[0041] Figure 5b The spectrum of the second output terminal of the third beam splitter and the second output terminal of the wavelength division multiplexing (WDM) provided in the embodiments of this application.

[0042] Figure 6a The spectrum diagram of the frequency-agile broadband chirped signal generated by the device provided in the embodiments of this application.

[0043] Figure 6b The time-frequency diagram of the frequency-agile broadband chirped signal generated by the device provided in the embodiments of this application.

[0044] Figure 1 The markings are as follows: 1. Distributed feedback semiconductor laser; 2. First beam splitter; 3. Second beam splitter; 4. First two-port Mach-Zehnder modulator; 5. Second two-port Mach-Zehnder modulator; 6. First low-frequency microwave source; 7. Electrical amplifier; 8. First electrical power divider; 9. First electrical phase shifter; 10. Optical phase shifter; 11. First optical coupler; 12. Third beam splitter; 13. Optical amplifier; 14. Second low-frequency microwave source; 15. Second electrical power divider; 16. Second electrical phase shifter; 17. First electrical absorption modulator; 18. Frequency modulator; 19. Second electrical absorption modulator; 20. Wavelength division multiplexing; 21. Second optical coupler; 22. Third optical coupler; 23. Optical switch; 24. Photodetector; 25. Transmitting antenna. Detailed Implementation

[0045] This invention provides a frequency-agile broadband chirped signal generator. A distributed feedback semiconductor laser generates laser light, which is then split. The first optical path uses two parallel Mach-Zehnder modulators to perform carrier-suppressed single-sideband modulation of the fundamental frequency signal before optical amplification and splitting. The second optical path uses a cascaded electroabsorption modulator, frequency modulator, and electroabsorption modulator to generate an optical frequency comb for wave division. The optical signals split by the first and second optical paths are coupled and sent to an optical switch to achieve optical signal agility. After photoelectric conversion and transmission antenna, a wide-span frequency-agile broadband chirped signal is generated, with the high-frequency band reaching the W-band.

[0046] like Figure 1 As shown: A frequency-agile broadband chirped signal generating device includes: a distributed feedback semiconductor laser 1, a first beam splitter 2, a second beam splitter 3, a first two-port Mach-Zehnder modulator 4, a second two-port Mach-Zehnder modulator 5, a first low-frequency microwave source 6, an electrical amplifier 7, a first electrical power divider 8, a first electrical phase shifter 9, an optical phase shifter 10, a first optical coupler 11, a third beam splitter 12, an optical amplifier 13, a second low-frequency microwave source 14, a second electrical power divider 15, a second electrical phase shifter 16, a first electrical absorption modulator 17, a frequency modulator 18, a second electrical absorption modulator 19, a wavelength division multiplexing (WDM) 20, a second optical coupler 21, a third optical coupler 22, an optical switch 23, a photodetector 24, and a transmitting antenna 25.

[0047] The distributed feedback semiconductor laser 1 is connected to the first beam splitter 2;

[0048] The first output terminal of the first beam splitter 2 is connected to the second beam splitter 3;

[0049] The first output terminal of the second beam splitter 3 is connected to the first dual-port Mach-Zehnder modulator 4;

[0050] The second output terminal of the second beam splitter 3 is connected to the first dual-port Mach-Zehnder modulator 5;

[0051] The first low-frequency microwave source 6 and the electrical amplifier 7 are connected;

[0052] The electric amplifier 7 is connected to the first electric power divider 8;

[0053] The first output terminal of the first power divider 8 is connected to the modulation port of the first dual-port Mach-Zehnder modulator 4;

[0054] The second output terminal of the first power divider 8 is connected to the first phase shifter 9;

[0055] The modulation ports of the first electrical phase shifter 9 and the second dual-port Mach-Zehnder modulator 5 are connected.

[0056] The second dual-port Mach-Zehnder modulator 5 is connected to the optical phase shifter 10;

[0057] The first dual-port Mach-Zehnder modulator 4 and the optical phase shifter 10 are connected via the first optical coupler 11 and the third beam splitter 12;

[0058] The second output terminal of the first beam splitter 2 is connected to the first electroabsorption modulator 17, the frequency modulator 18, and the second electroabsorption modulator 19 in sequence via the optical amplifier 13;

[0059] The second low-frequency microwave source 14 is connected to the modulation port of the first electro-absorption modulator 17, the second electro-phase shifter 16, and the modulation port of the second electro-absorption modulator 19 via the second power divider 15. The second electro-phase shifter 16 is connected to the modulation port of the frequency modulator 18.

[0060] The second electroabsorption modulator 19 is connected to the wavelength division multiplexing (WDM) unit 20;

[0061] The first output terminal of the third beam splitter 12 and the first output terminal of the wavelength division multiplexing unit 20 are connected via the second optical coupler 21 and the first input terminal of the optical switch 23.

[0062] The second output terminal of the third beam splitter 12 and the second output terminal of the wavelength division multiplexing unit 20 are connected via the third optical coupler 22 and the second input terminal of the optical switch 23;

[0063] The output terminal of the optical switch 23 is connected in sequence to the photodetector 24 and the transmitting antenna 25.

[0064] In this example, a distributed feedback semiconductor laser is used to generate a laser with a center frequency of 193.1 THz and a power of 0 dBm. The laser is then split into two beams in a 1:2 ratio by the first beam splitter. The first output terminal of the first beam splitter is connected to the first dual-port Mach-Zehnder modulator.

[0065] The first low-frequency microwave source generates a low-frequency broadband signal, as shown in Figure 2, which is a spectrum diagram of the low-frequency broadband signal provided in the embodiment of this application. Figure 2a ), time-frequency graph ( Figure 2b The low-frequency broadband signal has a center frequency of 3GHz, a bandwidth of 4GHz, and a peak power of -57.6dBm. After passing through a 20dB electrical amplifier, it then passes through the first dual-port Mach-Zehnder modulator, the second dual-port Mach-Zehnder modulator, the first electrical power divider, the first electrical phase shifter, and the optical phase shifter, forming an optical modulation module that achieves carrier-suppressed single-sideband modulation. Figure 3 The image shown is a spectrum of a low-frequency broadband signal after carrier suppression single-sideband modulation provided in an embodiment of this application, with a peak signal power of -41.7 dBm.

[0066] The optical carrier output from the second output terminal of the first beam splitter is amplified by an optical amplifier with a power gain of 15dB, and then sequentially passed through a first electroabsorption modulator, a frequency modulator, and a second electroabsorption modulator. A 30GHz point frequency signal is generated by the second low-frequency microwave source. This signal is then transmitted through a second power divider (1:3) and, together with the optical frequency comb generation module composed of the first electroabsorption modulator, the second phase shifter, the frequency modulator, and the second electroabsorption modulator, generates an optical frequency comb with a frequency interval of 30GHz. Figure 4 The image shown is a spectrum of an optical frequency comb provided in an embodiment of this application. In the range of 193.0THz to 193.2THz, the optical frequency comb has 7 comb teeth, a maximum carrier-to-noise ratio of 38.2dB, and a peak power ratio of less than 4.4dB, which provides a basis for generating high-quality frequency-agile broadband signals.

[0067] The optical frequency comb output from the second electroabsorption modulator is transmitted to the wavelength division multiplexing (WDM) unit. The WDM unit performs optical domain filtering, filtering out optical signals with center frequencies of 193.13 THz and 193.19 THz, respectively, and a bandwidth of 10 GHz. The two filtered optical frequency comb signals are then input to the optical coupler along with the two optical signals output from the third optical splitter. Figure 5 shows the spectra of the first output of the third optical splitter and the first output of the WDM unit after coupling, as provided in this embodiment of the application. Figure 5a The center frequency difference between the point frequency signal and the low-frequency broadband signal is 34 GHz; the spectrum after coupling between the second output terminal of the third optical splitter and the second output terminal of the wavelength division multiplexing (WDM) Figure 5b The center frequency difference between the point frequency signal and the low-frequency broadband signal is 92GHz; then the two optical signals are sent to the optical switch, and the optical path switching control of the optical switch is set to 2ns to achieve periodic frequency jumps in the optical domain.

[0068] The frequency-hopping optical signal output by the optical switch is input to a photodetector, where it undergoes photoelectric conversion to obtain a corresponding electrical signal. This electrical signal is then transmitted to a transmitting antenna, which radiates it, thereby generating and transmitting a frequency-agile broadband chirped signal. Figure 6 shows the spectrum of the frequency-agile broadband chirped signal generated by the device provided in this embodiment. Figure 6a The time-frequency diagram of the frequency-agile broadband chirped signal generated by the device ( Figure 6b It generates a Ka-band signal with a peak power of -56.4dBm, a center frequency of 34GHz, and a bandwidth of 2GHz, and a W-band signal with a peak power of -57.0dBm, a center frequency of 92GHz, and a bandwidth of 2GHz, realizing the generation of wide-span frequency-agile broadband chirped signals, with high frequencies reaching the W-band.

[0069] This invention achieves a single-step 89 GHz frequency jump directly by using carrier-suppressed single-sideband modulation based on the same laser source and coherent optical domain mixing with optical frequency comb tooth selection, skipping the traditional electrical domain frequency doubling step. The switching time is on the nanosecond level. This solves the problem that traditional optical frequency doubling cannot directly achieve discontinuous, large-span frequency agility from microwave low-frequency band to W band (such as 2 GHz to 93 GHz) in the optical domain. It is suitable for scenarios requiring rapid frequency hopping in modern radar and integrated sensing systems.

[0070] This invention provides a frequency-agile broadband chirped signal generator. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A frequency-agile broadband chirped signal generator, characterized in that, include: The system includes a distributed feedback semiconductor laser, a first beam splitter, a carrier-suppressed single-sideband modulation unit, an optical frequency comb generation unit, an optical domain periodic frequency switching unit, and a signal transmission unit. The distributed feedback semiconductor laser is connected to the carrier-suppressed single-sideband modulation unit and the optical frequency comb generation unit via the first beam splitter; After the carrier-suppressed single-sideband modulation unit and the optical frequency comb generation unit are coupled, they are then connected in sequence to the optical domain periodic frequency switching unit and the signal transmission unit.

2. The frequency-agile broadband chirped signal generator according to claim 1, characterized in that, The carrier-suppressed single-sideband modulation unit includes a second beam splitter, a first two-port Mach-Zehnder modulator, a second two-port Mach-Zehnder modulator, a first low-frequency microwave source, an electrical amplifier, a first electrical power divider, a first electrical phase shifter, an optical phase shifter, and a first optical coupler. The optical frequency comb generating unit includes an optical amplifier, a second low-frequency microwave source, a second electrical power divider, a second electrical phase shifter, a first electrical absorption modulator, a frequency modulator, and a second electrical absorption modulator. The optical domain periodic frequency switching unit includes a wavelength division multiplexing (WDM), a third beam splitter, a second optical coupler, a third optical coupler, and an optical switch. The signal transmitting unit includes a photodetector and a transmitting antenna.

3. The frequency-agile broadband chirped signal generator according to claim 2, characterized in that, The distributed feedback semiconductor laser is connected to the input terminal of the first beam splitter; The first output terminal of the first beam splitter is connected to the input terminal of the second beam splitter; The first output terminal of the second beam splitter is connected to the input terminal of the first dual-port Mach-Zehnder modulator; The second output terminal of the second beam splitter is connected to the input terminal of the first dual-port Mach-Zehnder modulator; The output terminal of the first low-frequency microwave source is connected to the input terminal of the electrical amplifier; The output terminal of the electric amplifier is connected to the input terminal of the first electric power divider; The first output terminal of the first power divider is connected to the modulation port of the first dual-port Mach-Zehnder modulator; The second output terminal of the first power divider is connected to the input terminal of the first phase shifter; The output terminal of the first phase shifter is connected to the modulation port of the second dual-port Mach-Zehnder modulator. The output of the second two-port Mach-Zehnder modulator is connected to the input of the optical phase shifter; The output of the first dual-port Mach-Zehnder modulator and the input of the optical phase shifter are connected via a first optical coupler and the input of a third beam splitter. The second output terminal of the first beam splitter is connected in sequence to the first electroabsorption modulator, the frequency modulator, and the second electroabsorption modulator via an optical amplifier; The output terminal of the second low-frequency microwave source is connected to the modulation port of the first electro-absorption modulator, the second electro-phase shifter, and the modulation port of the second electro-absorption modulator via the second power divider. The second electro-phase shifter is connected to the modulation port of the frequency modulator. The output of the second electroabsorption modulator is connected to the input of the wavelength division multiplexing (WDM). The first output terminal of the third beam splitter and the first output terminal of the wavelength division multiplexer are connected via the second optical coupler and the first input terminal of the optical switch; The second output terminal of the third beam splitter and the second output terminal of the wavelength division multiplexer are connected via the third optical coupler and the second input terminal of the optical switch; The output terminal of the optical switch is connected in sequence to the photodetector and the transmitting antenna.

4. The frequency-agile broadband chirped signal generator according to claim 3, characterized in that, The operation process of the device includes: Step 1: The distributed feedback semiconductor laser generates an optical carrier signal, which is then split into two paths by the first beam splitter. Step 2: The first output optical path of the first beam splitter is transmitted to the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator respectively through the second beam splitter, and further carrier suppression single-sideband modulation is performed. Step 3: The second output optical path of the first beam splitter is amplified by an optical amplifier; the amplified optical signal is then connected sequentially along the optical path to the first electroabsorption modulator, the frequency modulator, and the second electroabsorption modulator; and the generation of the optical frequency comb is further completed. Step 4: The optical frequency comb output from the second electroabsorption modulator is transmitted to the wavelength division multiplexing (WDM) unit, where it undergoes optical domain filtering. The two filtered optical frequency comb signals are then input to the optical coupler along with the two optical signals output from the third optical splitter. The optical coupler couples the two signals into a single composite optical signal. This composite optical signal is then transmitted to an optical switch, where the optical path switching control enables periodic frequency transitions in the optical domain. Step 5: The frequency-hopping optical signal output by the optical switch is input to the photodetector, and the photodetector performs photoelectric conversion processing to obtain the corresponding electrical signal; the electrical signal is transmitted to the transmitting antenna, which radiates and transmits it, thereby realizing the generation and transmission of frequency-agile broadband chirped signal.

5. A frequency-agile broadband chirped signal generator according to claim 4, characterized in that, Step 2, specifically, involves the following steps to achieve carrier-suppressed single-sideband modulation: A first low-frequency microwave source generates a low-frequency signal, which is first input to a low-noise amplifier (LNA). After power amplification by the LNA, the signal is transmitted to a power divider for two-way power division. The first power-divided signal is directly input to a first dual-port Mach-Zehnder modulator (DZD), which modulates it onto the optical carrier. The second power-divided signal undergoes phase adjustment via a first phase shifter and is then input to a second DZD, which modulates it onto the optical carrier. The output of the second DZD is connected to the input of the optical phase shifter. Both modulated optical signals are input to a first optical coupler, where they are coupled to complete carrier-suppressed single-sideband modulation.

6. The frequency-agile broadband chirped signal generator according to claim 4, characterized in that, Step 3, which further completes the generation of the optical frequency comb, specifically involves: a second low-frequency microwave source generating a low-frequency spot signal, which is input to a second power divider for power division. The power-divided multiple signals are then input to the first electro-absorption modulator, the second electro-phase shifter, and the second electro-absorption modulator, respectively. The second electro-phase shifter is connected to the modulation port of the frequency modulator to modulate the optical signal in the optical path, thereby completing the generation of the optical frequency comb.

7. A frequency-agile broadband chirped signal generator according to claim 2, characterized in that, The modulation bandwidth of the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator is less than 10 GHz.

8. A frequency-agile broadband chirped signal generator according to claim 2, characterized in that, The distributed feedback semiconductor laser achieves carrier-suppressed single-sideband modulation and optical frequency comb generation on two optical paths, respectively.

9. A frequency-agile broadband chirped signal generator according to claim 1, characterized in that, This device enables periodic frequency switching of signals in the optical domain.

10. A frequency-agile broadband chirped signal generator according to claim 1, characterized in that, The device is suitable for communication systems or radar systems and is used to generate agile broadband signals in such systems.

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