CN115086130B - Tunable K/W wave band OFDM radar communication integrated system based on photoelectric oscillator - Google Patents
Tunable K/W wave band OFDM radar communication integrated system based on photoelectric oscillator Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2626—Arrangements specific to the transmitter only
- H04L27/2627—Modulators
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- G—PHYSICS
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
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- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
- H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
- H04L27/36—Modulator circuits; Transmitter circuits
- H04L27/362—Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated
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Abstract
The invention discloses a tunable K/W wave band OFDM radar communication integrated system based on a photoelectric oscillator, which is characterized in that an all-optical signal regulation and control module is inserted into an OEO loop to perform asymmetric amplitude filtering and secondary phase regulation and control, and the characteristics of opposite left and right side band phases of a phase modulator are combined, so that high-frequency tunable OEO oscillation can be realized through spectrum regulation and control. And the modulation spectra of the single sideband and the double sideband are maintained in the OEO ring and outside the OEO ring in a self-excitation mode respectively. Outside the OEO ring, different optical sidebands are selected to serve as modulation sidebands and heterodyne reference sidebands respectively, different baseband OFDM signals are modulated for K and W frequency bands, and the signals are converted into an electric domain through photoelectric beat frequency conversion, so that microwave photon frequency multiplication and up-conversion are completed. The invention breaks through the problems of high frequency and difficult tuning in the traditional structure and obtains the OFDM radar communication integrated signal with tunable K/W wave band.
Description
Technical Field
The invention relates to the technical field of radar communication integration, in particular to a tunable K/W wave band OFDM radar communication integration system based on a photoelectric oscillator.
Background
At present, under the support of 5G and 6G networks, the concept of the Internet of things is rapidly and widely developed, wherein intelligent transportation is the most typical application. The vehicle body is provided with various software and hardware devices to complete environment detection sensing and information communication, so that the driving experience of human beings is developed towards safer, more comfortable and more intelligent directions. Along with the gradual convergence of radar and communication hardware architecture and software processing, in order to reduce hardware volume and power consumption and relieve the problem of spectrum congestion, two functions of radar and communication are realized simultaneously on the same platform and in the same frequency band, and the method becomes a research hot spot in the radio field. The working frequency band of the intelligent traffic radar communication integration is expanding from the traditional K wave band to the W wave band at present because of the higher carrier frequency and the higher bandwidth which can bring higher communication capacity and better radar detection resolution capability. Limited by the electronic bottleneck, conventional electronic methods have difficulty in realizing high-quality electronic systems meeting application requirements at high frequencies. The microwave photon technology combines the advantages of high frequency and large bandwidth in light with the flexible and controllable characteristic in electricity, and can provide support for the realization of a high-quality electronic system.
The orthogonal frequency division multiplexing signal (Orthogonal Frequency Division Multiplexing, OFDM) is initially widely used as a traditional communication signal, and has the advantages of multipath interference resistance, high frequency spectrum efficiency and the like. Meanwhile, due to the characteristic of large time bandwidth product, the method accords with the premise of radar pulse compression, when a cyclic prefix is constructed in front of each symbol, sampling offset caused by delay can be embodied as linear phase change between different subcarriers in a frequency domain, and therefore radar range profile is demodulated through pulse compression. The radar velocity image can also be obtained by measuring the slow-changing phase between each time domain symbol caused by Doppler frequency shift, so that OFDM has been used as a mature radar communication integrated common waveform. But densely distributed subcarriers in OFDM are very sensitive to phase noise while delivering high communication efficiency and large time-bandwidth product. The phase noise of the high-frequency local oscillator is introduced into the baseband OFDM in the up-down conversion process, so that the orthogonality of the subcarriers is damaged during demodulation, the inter-subcarrier interference (INTERCARRIER INTERFERENCE, ICI) is generated, the communication constellation diagram generates unrecoverable dispersion, and the signal-to-noise ratio of the radar is also deteriorated. Some researchers have employed algorithms to estimate and recover the effects of phase noise in OFDM to mitigate some of the degradation in communication quality. However, as the OFDM subcarrier spacing decreases and the phase noise deteriorates, ICI is further enhanced, the number of software iterations increases greatly, consuming a lot of computational resources and time costs. An optoelectronic oscillator (Optoelectronic Oscillator, OEO) is a typical application of photon technology in the field of microwave oscillation signal generation, and uses a long optical fiber as a high Q-value resonant cavity to generate a local oscillation signal with low phase noise. By analyzing the generation principle of phase noise in the OEO and the influence mechanism of the phase noise in the OFDM, the phase noise model of the OEO is found to be exactly resistant to the sensitivity of the phase noise of the OFDM, and ICI interference caused by the phase noise is avoided physically and radically. In addition, the OEO has the characteristics of photoelectric dual output, is convenient for subsequent generation and regulation of microwave photon signals, and avoids additional electric-optical-electric conversion loss. The oscillation frequency and the corresponding spectrum are electrically determined by a narrow-band filter in the conventional OEO, but at high frequencies, such a high Q-value electrical filter is a limitation and is difficult to flexibly tune. Furthermore, implementations of OEOs above 40GHz remain challenging, limited by the bandwidth of commercial modulators.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent.
Therefore, the invention aims to solve the problem that the existing OFDM radar communication integrated system based on the OEO is difficult to expand to high frequency and tunability, and provides a tunable K/W wave band OFDM radar communication integrated system based on an optoelectronic oscillator and an implementation method thereof. And the modulation spectra of the single sideband and the double sideband are maintained in the OEO ring and outside the OEO ring in a self-excitation mode respectively. Outside the OEO ring, different optical sidebands can be selected to serve as modulation sidebands and heterodyne reference sidebands respectively, different baseband OFDM signals are modulated for K and W frequency bands, and are converted into an electric domain through photoelectric beat frequency conversion, microwave photon frequency multiplication and up-conversion are completed, the problems of high frequency and difficult tuning in the traditional structure can be broken through, and the tunable OFDM radar communication integrated signal of the K/W wave band can be obtained.
In order to achieve the above purpose, according to one aspect of the present invention, a tunable K/W band OFDM radar communication integrated system based on a photoelectric oscillator is provided, including:
A laser for emitting light;
A phase modulator connected to the laser, a first optical coupler connected to the phase modulator;
The all-optical signal regulation and control module is connected with the first optical coupler and is used for modulating a first path of light output by the first optical coupler through a closed feedback loop of the photoelectric oscillator, and outputting the modulated light to a radio frequency input port of the phase modulator after photoelectric conversion and amplification;
the optical cross multiplexer is connected with the first optical coupler, and the intensity modulator is connected with the optical cross multiplexer and is used for outputting the light which meets the first preset condition in the second path of light output by the first optical coupler to the intensity modulator for OFDM modulation;
The second optical coupler is connected with the optical interleaver and the intensity modulator and is used for combining the light after OFDM modulation and the light meeting a second preset condition in the second path of light;
and the first photoelectric detector is connected with the second optical coupler and is used for generating a tunable K/W wave band OFDM integrated signal according to the combined light.
In order to achieve the above purpose, another aspect of the present invention provides a method for implementing a tunable K/W band OFDM radar communication integrated system based on a photoelectric oscillator, including:
presetting an oscillation frequency in the OEO;
presetting an amplitude filtering window bandwidth of the all-optical signal regulation module;
Presetting the phase control size of the all-optical signal regulation module;
Outputting light rays meeting a first preset condition in the second path of light rays to the intensity modulator for OFDM modulation so as to generate a K-band OFDM integrated signal; combining the light after OFDM modulation with the light meeting a second preset condition in the second path of light to generate a W-band OFDM integrated signal;
And receiving the K-band and W-band OFDM integrated signals, performing down-conversion to obtain baseband signals, and respectively demodulating communication information and radar distance speed information to obtain the tunable K/W-band OFDM integrated signals.
According to the tunable K/W wave band OFDM radar communication integrated system based on the photoelectric oscillator and the implementation method thereof, the OEO is used as a radio frequency local oscillator to support the OFDM radar communication integrated system, dependence on an external oscillation source is avoided, the problem that OFDM is sensitive to phase noise is radically overcome physically, and radar performance and communication quality are optimized; by carrying out all-optical signal regulation and control in an OEO loop and combining amplitude filtering and phase control, self-oscillation frequency control with a large tuning range is realized, the problems of low Q value and difficult tuning of an electric filter in a traditional structure are overcome, and support is provided for high-frequency and tunable expansion of an OFDM integrated system based on OEO.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic diagram of an OEO-based tunable K/W band OFDM radar communication integrated system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of spectral evolution in the entire system of FIG. 1;
FIG. 3 is a flow chart of a method for implementing an OEO-based tunable K/W band OFDM radar communication integrated system according to an embodiment of the present invention;
FIG. 4 is a diagram of tunable frequency response of an OEO open loop link under different conditions according to an embodiment of the invention;
FIG. 5 is a spectral diagram within a tunable OEO ring according to an embodiment of the invention;
FIG. 6 is a graph of the results of a K/W tunable system radar range profile, a range rate two-dimensional profile, in accordance with an embodiment of the present invention;
fig. 7 is a graph of a K/W tunable system communication BER curve and constellation in accordance with an embodiment of the present invention.
Detailed Description
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
The tunable K/W band OFDM radar communication integrated system based on the photoelectric oscillator and the implementation method thereof are described below with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of a tunable K/W band OFDM radar communication integrated system based on a photoelectric oscillator according to an embodiment of the present invention.
As shown in fig. 1, the system includes:
a laser 100 for emitting light;
A phase modulator 200 connected to the laser 100, a first optical coupler 300 connected to the phase modulator 200;
the all-optical signal regulation and control module 400 connected with the first optical coupler 300 is configured to modulate the first path of light output by the first optical coupler 300 through the closed feedback loop of the optoelectronic oscillator, and output the modulated light to the radio frequency input port of the phase modulator 200 after photoelectric conversion and amplification;
the optical interleaver 500 is connected to the first optical coupler 300, and the intensity modulator 600 is connected to the optical interleaver 500, where the optical interleaver 500 is configured to output, from the second path of light output by the first optical coupler 300, light that meets a first preset condition to the intensity modulator 600 for OFDM modulation;
A second optical coupler 700 connected to the optical interleaver 500 and the intensity modulator 600, for combining the OFDM-modulated light and the light satisfying the second preset condition in the second light;
The first photodetector 800 connected to the second optical coupler 700 is configured to generate a tunable K/W band OFDM integrated signal according to the combined light.
Specifically, as shown in fig. 1, light emitted by the laser 100 is sent to the phase modulator 200, the output of the phase modulator 200 is split into two paths by the first optical coupler 300, one path passes through the all-optical signal regulation module 400 and includes a long optical fiber, an all-optical signal regulation module, a second photodetector and an amplifier, and then is connected back to the radio frequency input port of the phase modulator 200 to form a closed feedback loop, i.e., OEO, and tuning in a large frequency range is realized by all-optical amplitude phase regulation. All-optical signal conditioning includes asymmetric amplitude filtering with unequal center wavelength and light source, and quadratic phase control.
The other output of the first optical coupler 300 is sent to the intensity modulator 600 through the optical interleaver 500 to select an optical carrier (for K-band) or an optical sideband of-1 (for W-band) to be modulated by a baseband OFDM signal sent by a baseband signal source, and a +1 sideband is selected as an optical heterodyne reference, then the baseband modulation and heterodyne reference sidebands are combined through the second optical coupler 700, and the optical-to-electrical conversion is completed in the first photodetector 800 at beat frequency, so as to generate a K/W tunable OFDM integrated signal. Is transmitted to free space by a transmitting antenna. The receiving antenna receives the integrated signal in free space. At the receiving end, the external local vibration source of the K/W wave band comprises a receiver, the receiving signal is down-converted to a baseband through a mixer, and the receiving signal is acquired and processed through an oscilloscope.
Further, the working bandwidths of the phase modulator 200, the second photoelectric detector and the amplifier should be greater than half of the carrier frequency of the W-band OFDM integrated signal;
Further, the amplitude control of all-optical signal regulation is rectangular filtering window, the filtering center wavelength and the light source keep detuning, the wavelength with minimum detuning amount is adjustable resolution, the filtering bandwidth is tunable, and the filtering bandwidth is respectively W-band OFDM integrated signal carrier frequency or 2 times K-band OFDM integrated signal carrier frequency according to different target signals; the phase processing is to apply an additional quadratic phase, and the magnitude of the phase at different wavelengths should be opposite to the additional phase brought by the wavelength after long fiber dispersion.
Further, the minimum tunable channel spacing of the optical interleaver 500 should be less than the carrier frequency of the K-band OFDM integrated signal.
Further, the bandwidth of the intensity modulator 600, the baseband signal source, should be greater than the bandwidth of the W-band OFDM integrated signal.
Further, the bandwidth of the first photodetector 800 should be greater than the maximum frequency of the W-band OFDM-integrated signal.
Further, the working frequency range of the mixer should cover the frequency range of the K/W band OFDM integrated signal.
Further, the center frequency of the local oscillator should be equal to the carrier frequency of the K/W band OFDM integrated signal.
Further, the intensity modulator 600 should be a suppressed carrier operating point.
According to the tunable K/W wave band OFDM radar communication integrated system based on the photoelectric oscillator, which is disclosed by the embodiment of the invention, the dependence on an external oscillation source is avoided, the problem that OFDM is sensitive to phase noise is radically overcome physically, and the radar performance and communication quality are optimized; by carrying out all-optical signal regulation and control in an OEO loop and combining amplitude filtering and phase control, self-oscillation frequency control with a large tuning range is realized, the problems of low Q value and difficult tuning of an electric filter in a traditional structure are overcome, and support is provided for high-frequency and tunable expansion of an OFDM integrated system based on OEO.
In order to achieve the above embodiment, as shown in fig. 2, the present embodiment further provides a method for implementing a tunable K/W band OFDM radar communication integrated system based on an optoelectronic oscillator, where the method includes:
s1, presetting an oscillation frequency in an OEO;
S2, presetting an amplitude filter window bandwidth of an all-optical signal regulation module;
s3, presetting the phase control size of the all-optical signal regulation module;
S4, outputting the light rays meeting the first preset condition in the second path of light rays to an intensity modulator for OFDM modulation so as to generate a K-band OFDM integrated signal; combining the light rays subjected to OFDM modulation with the light rays meeting the second preset condition in the second path of light rays to generate a W-band OFDM integrated signal;
S5, receiving the K-band and W-band OFDM integrated signals, performing down-conversion to obtain baseband signals, and respectively demodulating communication information and radar distance speed information to obtain the tunable K/W-band OFDM integrated signals.
Specifically, the implementation method of the tunable K/W band OFDM radar communication integrated system based on the optoelectronic oscillator in this embodiment may include the following steps:
The oscillation frequency in the OEO is half of the K band frequency and the W band frequency;
The bandwidth of an amplitude filtering window of the all-optical signal regulation and control module is set to be twice of the oscillating frequency;
The magnitude of the phase is opposite to the extra phase experienced by the wavelength in long fiber dispersion. The spectrum evolution process is schematically shown in fig. 2, and finally tunable self-oscillation is realized in the OEO ring, the modulation spectrum of the single sideband is maintained, and the modulation spectrum of the double sideband is maintained outside the OEO ring.
For a K-band OFDM integrated system, an OEO starts vibrating in a K-band, an optical cross multiplexer selects and separates an optical carrier and a +1 sideband, the optical carrier is sent to an intensity modulator to be modulated by a K-band baseband OFDM signal sent by a baseband signal source, and then is combined with the +1 sideband serving as a heterodyne reference sideband through an optical coupler and subjected to beat frequency, baseband up-conversion is carried out, and a K-band OFDM integrated signal is generated and transmitted to a free space through an antenna.
For a W-band OFDM integrated system, an OEO starts vibrating at half frequency of a W-band, an optical interleaver selects and separates-1 sidebands and +1 sidebands, the-1 sidebands are sent to an intensity modulator to be modulated by a W-band baseband OFDM signal sent by a baseband signal source, and then the modulated W-band baseband OFDM signal is combined with the +1 sidebands serving as heterodyne reference sidebands through an optical coupler and subjected to frequency doubling up-conversion, so that a W-band OFDM integrated signal is generated, and the W-band OFDM integrated signal is transmitted to a free space through an antenna.
The integrated signals of different wave bands are received by an antenna, mixed by a local oscillator of corresponding frequency, down-converted to a baseband, collected by an oscilloscope, and after digital signal processing, the communication information and the radar distance speed information can be respectively demodulated.
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
In the embodiment, a K-band tunable OFDM radar communication integrated system device based on OEO is realized by taking a K-band 25-27 GHz and a W-band 89-99 GHz as examples, and experimental verification is carried out. The OEO open loop link frequency response formed by the phase modulator, the long optical fiber, the all-optical phase regulation module and the photoelectric detector is shown in fig. 4, the amplitude response of K-band frequency is shown in (a) (b) of fig. 4, wherein (a) in 4 is only amplitude filtering, and frequency selective passing caused by filtering is suppressed due to periodic fluctuation of frequency caused by chromatic dispersion; 4 (b) adding phase regulation to resist dispersion influence, wherein a window with frequency selectivity passing through is formed at the K wave band; when OEO operates at half the W-band frequency, the amplitude response is as in fig. 4 (c) (d), where (c) in 4 is amplitude-only filtered and (d) in 4 is amplitude-phase joint control. FIG. 5 is a graph of the tunable OEO ring spectra after amplitude phase joint modulation. After the optical interleaver, the spectrum corresponding to the combined modulation sideband and reference sideband is shown in fig. 6 (a) (e), wherein fig. 6 (a) corresponds to the fundamental frequency up-conversion spectrum of the K band, and fig. 6 (c) corresponds to the frequency doubling up-conversion spectrum of the W band. The frequency spectrum after down-conversion of the generated K-band 25-27 GHz and W-band 89-99 GHz signals is shown in (b) (f) of FIG. 6. The demodulated radar range profile is shown in fig. 6 (c) (g), and the demodulated radar range-rate two-dimensional profile is shown in fig. 6 (d) (h). The modulation formats of 16QAM and 64QAM are adopted in the K and W bands respectively, and the result of communication demodulation comprises Bit Error Rate (BER) curves and demodulation constellations as shown in figure 7.
According to the implementation method of the tunable K/W wave band OFDM radar communication integrated system based on the photoelectric oscillator, which is disclosed by the embodiment of the invention, the dependence on an external oscillation source is avoided, the problem that OFDM is sensitive to phase noise is radically overcome physically, and the radar performance and communication quality are optimized; by carrying out all-optical signal regulation and control in an OEO loop and combining amplitude filtering and phase control, self-oscillation frequency control with a large tuning range is realized, the problems of low Q value and difficult tuning of an electric filter in a traditional structure are overcome, and support is provided for high-frequency and tunable expansion of an OFDM integrated system based on OEO.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (10)
1. A tunable K/W wave band OFDM radar communication integrated system based on a photoelectric oscillator is characterized by comprising:
A laser for emitting light;
A phase modulator connected to the laser, a first optical coupler connected to the phase modulator;
The all-optical signal regulation and control module is connected with the first optical coupler and is used for modulating a first path of light output by the first optical coupler through a closed feedback loop of the photoelectric oscillator, and outputting the modulated light to a radio frequency input port of the phase modulator after photoelectric conversion and amplification;
the optical cross multiplexer is connected with the first optical coupler, and the intensity modulator is connected with the optical cross multiplexer and is used for outputting the light which meets the first preset condition in the second path of light output by the first optical coupler to the intensity modulator for OFDM modulation;
The second optical coupler is connected with the optical interleaver and the intensity modulator and is used for combining the light after OFDM modulation and the light meeting a second preset condition in the second path of light;
The first photoelectric detector is connected with the second optical coupler and is used for generating a tunable K/W wave band OFDM integrated signal according to the combined light;
The other output of the first optical coupler is sent to an intensity modulator through an optical interleaving multiplexer to be modulated by a baseband OFDM signal sent by a baseband signal source, a +1 sideband is selected to be used as an optical heterodyne reference, then the baseband modulation and heterodyne reference are combined through a second optical coupler, photoelectric conversion is completed in a first photoelectric detector through beat frequency, a K/W tunable OFDM integrated signal is generated, the K/W tunable OFDM integrated signal is transmitted to a free space through a transmitting antenna, the integrated signal in the free space is received by a receiving antenna, and at a receiving end, the receiver comprises a receiver, an external local vibration source of a K/W wave band down-converts the received signal to the baseband through a mixer, and acquisition and processing are carried out through an oscilloscope;
The amplitude control of all-optical signal regulation is rectangular filtering window, the filtering center wavelength and the light source keep detuning, the wavelength adjustable resolution with the smallest detuning amount is tunable, the filtering bandwidth is tunable, and the filtering bandwidth is respectively W-band OFDM integrated signal carrier frequency or 2 times K-band OFDM integrated signal carrier frequency according to different target signals; the phase processing is to apply additional quadratic phase, and the phase at different wavelengths should be opposite to the additional phase brought by the wavelength after long fiber dispersion;
For a K-band OFDM integrated system, an OEO starts vibrating in a K-band, an optical cross multiplexer selects and separates an optical carrier and a +1 sideband, the optical carrier is sent to an intensity modulator to be modulated by a K-band baseband OFDM signal sent by a baseband signal source, and then is combined with the +1 sideband serving as a heterodyne reference sideband through an optical coupler and subjected to beat frequency, baseband up-conversion is carried out, and a K-band OFDM integrated signal is generated and transmitted to a free space through an antenna;
For a W-band OFDM integrated system, an OEO starts vibrating at half frequency of a W-band, an optical interleaver selects and separates-1 sidebands and +1 sidebands, the-1 sidebands are sent to an intensity modulator to be modulated by a W-band baseband OFDM signal sent by a baseband signal source, and then the modulated W-band baseband OFDM signal is combined with the +1 sidebands serving as heterodyne reference sidebands through an optical coupler and subjected to frequency doubling up-conversion, so that a W-band OFDM integrated signal is generated, and the W-band OFDM integrated signal is transmitted to a free space through an antenna.
2. The system of claim 1, wherein the all-optical signal conditioning module comprises:
A long optical fiber;
an all-optical signal regulation and control module connected with the long optical fiber,
A second photoelectric detector connected with the all-optical signal regulation and control module,
And an amplifier connected with the second photoelectric detector.
3. The system of claim 1, wherein the light rays satisfying the first predetermined condition comprise a K/W band optical carrier or-1 optical sideband, and the light rays satisfying the second predetermined condition comprise a K/W band optical carrier or-1 optical sideband and a K/W band +1 sideband.
4. The system of claim 1, further comprising a receiver,
The receiver is used for receiving the tunable K/W band OFDM integrated signal and carrying out transmission processing on the received signal.
5. The system of claim 4, wherein the receiver comprises:
the receiving antenna is used for receiving the tunable K/W wave band OFDM integrated signal;
The mixer is connected with the receiving antenna, and the local oscillator is connected with the mixer and is used for down-converting the received signal to a baseband through the mixer;
and the oscilloscope is connected with the mixer and used for collecting and processing the baseband signals.
6. The system of claim 2, wherein the operating bandwidth of the phase modulator, second photodetector and amplifier is greater than half of the carrier frequency of the W-band OFDM integrated signal;
The minimum adjustable channel interval of the optical interleaver is smaller than the carrier frequency of the K-band OFDM integrated signal;
The bandwidth of the first photoelectric detector is larger than the maximum frequency of the W-band OFDM integrated signal;
The working frequency range of the mixer covers the frequency range of the K/W wave band OFDM integrated signal.
7. The system of claim 5, wherein the local oscillator has a center frequency equal to a carrier frequency of the K/W band OFDM integrated signal.
8. A method for implementing the tunable K/W band OFDM radar communication integrated system based on an optoelectronic oscillator as claimed in claim 1, comprising:
presetting an oscillation frequency in the OEO;
presetting an amplitude filtering window bandwidth of the all-optical signal regulation module;
Presetting the phase control size of the all-optical signal regulation module;
Outputting light rays meeting a first preset condition in the second path of light rays to the intensity modulator for OFDM modulation so as to generate a K-band OFDM integrated signal; combining the light after OFDM modulation with the light meeting a second preset condition in the second path of light to generate a W-band OFDM integrated signal;
And receiving the K-band and W-band OFDM integrated signals, performing down-conversion to obtain baseband signals, and respectively demodulating communication information and radar distance speed information to obtain the tunable K/W-band OFDM integrated signals.
9. The method of claim 8, wherein outputting the light satisfying the first preset condition from the second light outputted from the first optical coupler to the intensity modulator for OFDM modulation to generate the K-band OFDM integrated signal, comprises:
And the OEO starts oscillation in a K wave band, the optical cross multiplexer is used for selecting and separating an optical carrier and a +1 sideband, the optical carrier is input into the intensity modulator for OFDM modulation, the optical carrier and the +1 sideband are combined through the second optical coupler and then beat frequency is carried out, and baseband up-conversion is carried out to generate a K wave band OFDM integrated signal.
10. The method of claim 8, wherein combining the OFDM modulated light with the light satisfying the second preset condition in the second light to generate a W-band OFDM integrated signal includes:
The OEO starts vibrating at half frequency of the W wave band, the optical interleaver selects and separates-1 side band and +1 side band, the-1 side band is input into the intensity modulator and modulated by the W wave band baseband OFDM signal sent by the baseband signal source, and then the modulated wave band is combined with the +1 side band through the second optical coupler and then beat frequency is carried out, and frequency multiplication up-conversion is carried out to generate the W wave band OFDM integrated signal.
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