Signal generation device and method

Abstract

The invention provides a signal generation device and method, and the device comprises at least two local oscillator lasers which are used for generating at least two laser signals with different frequencies; the oscillation loop is used for carrying out oscillation based on at least two laser signals with different frequencies and generating a first radio frequency signal corresponding to the laser signal with each frequency; the feedback controllers are in one-to-one correspondence with the local oscillator lasers and are used for generating feedback signals based on the first radio frequency signals corresponding to the laser signals of all frequencies and inputting the feedback signals into the corresponding local oscillator lasers so as to adjust the frequencies of the laser signals output by the local oscillator lasers; wherein after the frequencies of the at least two laser signals generated by the at least two local oscillator lasers are locked to different harmonic peaks corresponding to the optical filter in the oscillation loop, the optical filter is further used for outputting a first optical terahertz signal, and the frequency of the first optical terahertz signal is an integral multiple of the free spectral range of the optical filter.

Description

Technical Field

[0001] The present invention relates to the technical field of signal generation, and in particular to a signal generation device and method. Background Art

[0002] High-quality microwave signals are widely used in the fields of communication, radar, and measurement. The phase noise of microwave signals often affects the performance of the system in the use scenario. In wireless communication systems, excessive phase noise of microwave signals as carriers of the transmitting carrier signal will cause interference between adjacent channels, thereby affecting the communication quality. In radar systems, the phase noise of microwave signals directly affects the resolution and detection distance of radars. With the increasing demand for wireless transmission such as high-bit-rate wireless services, ultra-high-definition video, and data downloads, higher-speed information transmission is also an inevitable trend. In order to meet the future communication bandwidth requirements, it is necessary to explore higher-frequency frequency resources. The terahertz band has a huge bandwidth and can achieve ultra-high wireless communication rates at low spectral efficiency. Therefore, the generation of high-quality terahertz and microwave signals is of great significance in improving system performance. Summary of the invention

[0003] In view of the above problems, the present invention provides a signal generating device and method.

[0004] According to a first aspect of the present invention, a signal generating device is provided, comprising: at least two local oscillator lasers, for generating at least two laser signals with different frequencies; an oscillation loop, for oscillating based on the at least two laser signals with different frequencies, and generating a first radio frequency signal corresponding to the laser signal of each frequency; a feedback controller, corresponding one-to-one to the local oscillator lasers, for generating a feedback signal based on the first radio frequency signal corresponding to the laser signal of each frequency, and inputting the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser; wherein, after the frequencies of the at least two laser signals generated by the at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter in the oscillation loop, the optical filter is further used to output a first light-borne terahertz signal, and the frequency of the first light-borne terahertz signal is an integer multiple of the free spectrum range of the optical filter.

[0005] According to an embodiment of the present invention, the device also includes: a first optical coupler, the input end of the first optical coupler is connected to the output end of at least two local oscillator lasers, and is used to output a second light-borne terahertz signal after the frequencies of at least two laser signals generated by the at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter, and the frequency of the second light-borne terahertz signal is continuously adjustable.

[0006] According to an embodiment of the present invention, the device also includes: an optoelectronic frequency divider, which is arranged at the output end of the optical filter or the output end of the first optical coupler, and is used to perform optoelectronic conversion and frequency division on the first light-borne terahertz signal to obtain a first microwave signal, or to perform frequency division on the second light-borne terahertz signal to obtain a second microwave signal.

[0007] According to an embodiment of the present invention, the oscillation loop includes: an optical phase modulator, which corresponds to the local oscillator laser one by one, and is used to modulate the laser signal output by the corresponding local oscillator laser to obtain multiple modulated optical signals; a second optical coupler, which is used to synthesize multiple modulator optical signals into one path to obtain a combined signal; an optical filter, which is used to perform notch filtering on the combined signal to obtain an optical signal after notch filtering; a first photodetector, which is used to perform beat frequency on the optical signal after notch filtering to obtain a second radio frequency signal; a first radio frequency power divider, which is used to divide the second radio frequency signal into at least two second radio frequency signals with equal power; first radio frequency filters, which correspond to the local oscillator lasers one by one, and each first radio frequency filter is used to perform notch filtering on one second radio frequency signal. The first RF amplifier corresponds to the first RF filter one by one, and is used to amplify the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonant peak angle frequency of the optical filter; the second RF power divider corresponds to the first RF amplifier one by one, and is used to divide the first RF signal into two first RF signals with equal power, and input one of the first RF signals into the corresponding optical phase modulator; wherein the feedback controller is used to generate a feedback signal based on the other first RF signal, and input the feedback signal to the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

[0008] According to an embodiment of the present invention, an oscillation loop includes: an optical phase modulator, which corresponds to a local oscillator laser one by one, and is used to modulate the laser signal output by the corresponding local oscillator laser to obtain a plurality of modulated optical signals; a polarization regulator, which is arranged at the output end of some optical phase modulators, and performs polarization state adjustment on the modulated optical signal output by the corresponding optical phase modulator, so that the polarization state of the modulated optical signal after polarization state adjustment is orthogonal to the polarization state of the modulated optical signal after polarization state adjustment; a polarization combiner, which is used to combine the modulated optical signal after polarization state adjustment with the modulated optical signal after polarization state adjustment to obtain a combined signal; an optical filter, which is used to perform notch filtering on the combined signal to obtain a notch filtered optical signal; a polarization beam splitter, which is used to split the notch filtered optical signal into at least two notch filtered optical signals; a first optical An electrical detector corresponds one-to-one with a local oscillator laser, and each first photodetector is used to beat a notch filtered optical signal to obtain a second radio frequency signal; a first radio frequency amplifier corresponds one-to-one with a first radio frequency filter, and is used to amplify a third radio frequency signal output by the corresponding first radio frequency filter to obtain a first radio frequency signal; the frequency of the first radio frequency signal is determined by the frequency of the corresponding local oscillator laser and the resonant peak angle frequency of the optical filter; a second radio frequency power divider corresponds one-to-one with the first radio frequency amplifier, and is used to divide the first radio frequency signal into two first radio frequency signals with equal power, and input one of the first radio frequency signals into a corresponding optical phase modulator; wherein the feedback controller is used to generate a feedback signal based on the other first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

[0009] According to an embodiment of the present invention, the oscillation loop includes: an optical phase modulator, which corresponds to the local oscillator laser one by one, and is used to modulate the laser signal output by the corresponding local oscillator laser to obtain a plurality of modulated optical signals; a first optical wavelength division multiplexer, which is used to combine the plurality of modulated optical signals into one path to obtain a combined signal; an optical filter, which is used to perform notch filtering on the combined signal to obtain a notch filtered optical signal; a second optical wavelength division multiplexer, which is used to split the notch filtered optical signal into at least two notch filtered optical signals; first photodetectors, which correspond to the local oscillator lasers one by one, and each first photodetector is used to perform beat frequency on one notch filtered optical signal to obtain a second radio frequency signal; A radio frequency amplifier corresponds one-to-one to the first radio frequency filter, and is used to amplify the third radio frequency signal output by the corresponding first radio frequency filter to obtain a first radio frequency signal; the frequency of the first radio frequency signal is determined by the frequency of the corresponding local oscillator laser and the resonant peak angle frequency of the optical filter; a second radio frequency power divider corresponds one-to-one to the first radio frequency amplifier, and is used to divide the first radio frequency signal into two first radio frequency signals with equal power, and input one of the first radio frequency signals into a corresponding optical phase modulator; wherein the feedback controller is used to generate a feedback signal based on the other first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

[0010] According to an embodiment of the present invention, the oscillation loop includes: a third optical coupler, used to merge at least two laser signals with different frequencies into one laser signal, an optical phase modulator, used to modulate one laser signal to obtain a modulated optical signal; an optical filter, used to perform notch filtering on the modulated optical signal to obtain an optical signal after notch filtering; a first photodetector, used to perform beat frequency on the optical signal after notch filtering to obtain a second radio frequency signal; a first radio frequency power divider, used to divide the second radio frequency signal into at least two second radio frequency signals with equal power; first radio frequency filters, corresponding one to one with local oscillator lasers, each first radio frequency filter is used to filter one second radio frequency signal to obtain a third radio frequency signal, a first radio frequency amplifier, and a first radio frequency filter. The optical filter has a one-to-one correspondence with the first RF filter, and is used to amplify the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonant peak angle frequency of the optical filter; the second RF power splitter has a one-to-one correspondence with the first RF amplifier, and is used to split the first RF signal into two first RF signals with equal power; the RF combiner is used to combine the first RF signals output by each second RF power splitter into a fourth RF signal, and input the second RF signal into the optical phase modulator; wherein the feedback controller is used to generate a feedback signal based on another first RF signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

[0011] According to an embodiment of the present invention, the device also includes: a fourth optical coupler, arranged at the output end of the optical filter, for splitting the first light-borne terahertz signal to obtain two first light-borne terahertz signals; a second photodetector, arranged at the output end of the fourth optical coupler or the output end of the first coupler, for beating the first light-borne terahertz signal to obtain the first terahertz signal, or beating the second light-borne terahertz signal to obtain the second terahertz signal.

[0012] According to an embodiment of the present invention, the feedback controller generates a feedback signal based on the first RF signal corresponding to the laser signal of each frequency, including: mixing the RF reference signal with the first RF signal, extracting the change of the central angular frequency of the local oscillator laser relative to the central angular frequency of the optical filter, obtaining an error signal, and generating a feedback signal based on the error signal.

[0013] According to a second aspect of the present invention, a signal generating method is provided. The signal generating method is implemented based on the above-mentioned signal generating device, and the method comprises: generating at least two laser signals with different frequencies by at least two local oscillator lasers; oscillating based on the at least two laser signals with different frequencies by an oscillation loop to generate a first radio frequency signal corresponding to the laser signal of each frequency; generating a feedback signal based on the first radio frequency signal corresponding to the laser signal of each frequency by a feedback controller, and inputting the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser; the feedback controller corresponds to the local oscillator laser one by one; wherein, after the frequencies of the at least two laser signals generated by the at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter in the oscillation loop, a terahertz signal or a microwave signal is output.

[0014] The signal generating device and method provided by the present invention have at least the following technical effects:

[0015] The device and method can lock at least two different local oscillator lasers to different resonance peaks of the same optical filter, and output a terahertz signal with high frequency stability. The frequency of the terahertz signal can be changed by adjusting the frequency of the local oscillator laser, and the frequency of the terahertz signal is only limited by the adjustment range of the local oscillator laser frequency and the bandwidth of the photodetector. The frequency of the generated light-carrying terahertz signal is only limited by the frequency adjustment range of the laser. The frequency stability of the generated terahertz signal is limited by the relative fluctuation between different resonance frequencies of the optical filter.

[0016] The device and method can realize two ways of outputting light-carrying terahertz signals. One way is to directly output from the bandpass filter output port of the optical filter, and the frequency of the first light-carrying terahertz signal generated is an integer multiple of the free spectrum range of the optical filter. The other way is to combine the two locked local oscillator lasers through an optical coupler for output, and the generated second terahertz signal can realize continuous frequency adjustment.

[0017] Since at least two different local oscillator lasers are locked to different resonance peaks of the same optical filter and share part of the optical path, the beat frequency terahertz signal can remove part of the common mode noise, and the generated terahertz signal phase noise is lower than the phase noise of the local oscillator laser locked in a single path.

[0018] The device and method can also be combined with a frequency division method to achieve the generation of microwave signals with lower phase noise. After the optically carried terahertz signal is frequency divided, the phase noise of the generated microwave signal is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above contents and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic diagram showing the structure of a signal generating device according to a first embodiment of the present invention;

[0021] Figure 2 A schematic diagram showing the structure of a signal generating device according to a second embodiment of the present invention;

[0022] Figure 3 Schematically shows a structural diagram of a signal generating device according to a fourth embodiment of the present invention;

[0023] Figure 4 Schematically showing a spectrum diagram and a radio frequency spectrum diagram corresponding to each signal in a signal generation process according to an embodiment of the present invention;

[0024] Figure 5 Schematically shows a structural diagram of a signal generating device according to a fifth embodiment of the present invention;

[0025] Figure 6 A schematic diagram showing the structure of a signal generating device according to a sixth embodiment of the present invention;

[0026] Figure 7 A schematic diagram showing the structure of a signal generating device according to a seventh embodiment of the present invention;

[0027] Figure 8 A flow chart of a signal generating method according to an embodiment of the present invention is schematically shown;

[0028] Fig. 9 A phase noise diagram according to an embodiment of the present invention is schematically shown;

[0029] Fig.10 The diagram schematically shows the phase noise measurement result when the beat signal frequency intervals are 10 GHz and 20 GHz according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0031] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0032] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0033] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0034] In the process of realizing the present invention, the applicant found that the traditional microwave signal generation method is generally to generate directly through an oscillator, but the phase noise of the generated microwave signal is limited by the quality factor of the resonator. The quality factor of the traditional microwave resonator decreases rapidly with the increase of the resonant frequency, and it is difficult to directly generate a high-frequency low-phase noise microwave signal. The crystal oscillator has an extremely high quality factor, but the resonant frequency is often low, and the low-frequency signal needs to be multiplied to the high-frequency range by frequency multiplication, but the frequency multiplication method causes serious deterioration of the phase noise. The optoelectronic oscillator uses a long optical fiber with low transmission loss to form an optoelectronic hybrid resonator with a high quality factor, and the generated RF signal phase noise does not deteriorate with the increase of the microwave signal frequency. However, the resonant cavity using a long optical fiber is more susceptible to the influence of ambient temperature and noise, and the long optical fiber leads to a smaller mode frequency interval, which makes the optoelectronic oscillator prone to higher spurious or even mode hopping, affecting its stability.

[0035] The generation of terahertz signals can be divided into two categories: electronic solutions and photon-assisted solutions. The electronic solution can be generated through mixing or direct generation. The former has the characteristics of high integration and high output power, while the latter has a wider output frequency range but lower output power. The transmission power of the electronic system is high and can support long-distance wireless transmission, but its frequency harmonic interference is large, the phase noise is high, and the frequency stability is poor. Affected by the working bandwidth and modulation efficiency of electronic devices, the capacity of pure electronic systems is limited. The photon-assisted solution can be divided into optical heterodyne generation and direct generation according to the signal generation method. The former has the advantage of flexible and tunable output frequency, while the latter has a larger output power and a larger output frequency range, but requires a low-temperature working environment.

[0036] In view of this, an embodiment of the present invention provides a signal generating device, which will be described below in conjunction with specific embodiments.

[0037] Figure 1 The structure of a signal generating device according to the first embodiment of the present invention is schematically shown.

[0038] like Figure 1 As shown, the signal generating device of this embodiment includes: at least two local oscillator lasers, which are used to generate at least two laser signals with different frequencies. An oscillation loop, which is used to oscillate based on at least two laser signals with different frequencies, and generate a first radio frequency signal corresponding to the laser signal of each frequency. A feedback controller, which corresponds one-to-one to the local oscillator lasers, is used to generate a feedback signal based on the first radio frequency signal corresponding to the laser signal of each frequency, and input the feedback signal to the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser. Wherein, after the frequencies of at least two laser signals generated by at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter in the oscillation loop, the optical filter is also used to output a first light-borne terahertz signal, and the frequency of the first light-borne terahertz signal is an integer multiple of the free spectrum range of the optical filter.

[0039] The device locks two local oscillator laser sources with different frequencies to the same optical reference through oscillation feedback, and high-quality terahertz signals can be obtained through heterodyne detection.

[0040] It should be noted that since the quality of the generated terahertz signal is limited by the stability of the optical filter, an optical filter with higher frequency stability needs to be used.

[0041] Figure 2 The structure of a signal generating device according to a second embodiment of the present invention is schematically shown.

[0042] like Figure 2As shown, based on the above signal generating device, in the second embodiment of the present invention, the signal generating device may further include:

[0043] A first optical coupler, whose input end is connected to the output ends of at least two local oscillator lasers, is used to output a second light-borne terahertz signal after the frequencies of at least two laser signals generated by the at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter, and the frequency of the second light-borne terahertz signal is continuously adjustable.

[0044] On the basis of the above signal generating device, in a third embodiment of the present invention, the signal generating device may further include:

[0045] The optoelectronic frequency divider is arranged at the output end of the optical filter or the output end of the first optical coupler, and is used to perform optoelectronic conversion and frequency division on the first light-borne terahertz signal to obtain a first microwave signal, or to perform frequency division on the second light-borne terahertz signal to obtain a second microwave signal.

[0046] Figure 3 The structure of a signal generating device according to a fourth embodiment of the present invention is schematically shown.

[0047] like Figure 3 As shown, based on the signal generating device of the previous embodiment, the oscillation loop in the signal generating device of this embodiment may include:

[0048] The optical phase modulator corresponds to the local oscillator laser one by one and is used to modulate the laser signal output by the corresponding local oscillator laser to obtain multiple modulated optical signals.

[0049] The second optical coupler is used to combine multiple modulator optical signals into one signal to obtain a combined signal.

[0050] The optical filter is used to perform notch filtering on the combined signal to obtain an optical signal after notch filtering.

[0051] The first photoelectric detector is used to perform beat frequency processing on the optical signal after the notch filtering to obtain a second radio frequency signal.

[0052] The first radio frequency power divider is used to divide the second radio frequency signal into at least two second radio frequency signals with equal power.

[0053] The first radio frequency filters correspond to the local oscillator lasers one by one, and each first radio frequency filter is used to filter one second radio frequency signal to obtain a third radio frequency signal.

[0054] The first RF amplifier corresponds to the first RF filter one by one and is used to amplify the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonant peak angle frequency of the optical filter.

[0055] The second RF power splitter corresponds to the first RF amplifier one by one, and is used to split the first RF signal into two first RF signals with equal power, and input one of the first RF signals into the corresponding optical phase modulator.

[0056] The feedback controller is used to generate a feedback signal based on another first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

[0057] It should be noted that Figure 3 Two local oscillator lasers are used as an example for explanation, and the number of local oscillator lasers is not limited in the present invention.

[0058] Figure 4 The optical spectrum diagram and radio frequency spectrum diagram corresponding to each signal in the signal generation process according to an embodiment of the present invention are schematically shown.

[0059] like Figure 3 and Figure 4 As shown, taking two local oscillator lasers as an example, in the optical terahertz signal generation link, two local oscillator lasers with different frequencies are locked to the transmission peaks of different frequencies of the same reference optical filter. The two locked local oscillator lasers are combined and output through an optical coupler to obtain an optical terahertz signal with high frequency stability. The generated optical terahertz signal can be output as a terahertz signal with the same frequency stability through the beat frequency output of the photodetector.

[0060] In the link generated by the optical terahertz signal, the two angular frequencies are and The local oscillator lasers are locked to the resonance peaks of different angular frequencies of the optical filter. and After passing through the phase modulator, the local oscillator laser generates a modulated optical signal, which is combined by an optical coupler and input to the optical filter. After input to the optical filter, take one of the channels as an example. In the modulated optical signal generated by the local oscillator laser, the upper sideband (frequency is ) with one of the resonant frequencies of the optical filter The light after the optical filter is notched and filtered has a beat frequency of The frequency of the generated RF signal is determined by the angular frequency of the local oscillator laser. The resonant peak angular frequency of the optical filter Decision, that is The RF signal output by the photodetector is divided into two paths by the RF power divider, one of which has only a frequency of After passing through the RF coupler, part of the signal is input to the optical phase modulator 1, and the other part is used for feedback control of the local oscillator laser 1. Similarly, the local oscillator laser 2 generates a frequency of At this time, local oscillator lasers 1 and 2 are simultaneously locked on different resonance peaks of the optical filter.

[0061] The output optical terahertz signal can be directly output from the bandpass filter port of the optical filter, or it can be output from the output of the local oscillator laser after being combined by an optical coupler. In the modulated optical signal generated by the local oscillator laser, the lower sideband can also be equal to the resonance peak frequency of the optical filter.

[0062] It should be noted that if the phase noise impact on the local oscillator laser source is to be minimized, it is necessary to ensure that the ratio of the delay of the optical filter to the RF delay in the oscillation loop is as large as possible, that is, to increase the delay of the optical filter while reducing the delay of the RF link.

[0063] Figure 5 The structure of a signal generating device according to a fifth embodiment of the present invention is schematically shown.

[0064] like Figure 5 As shown, based on the signal generating device of the previous embodiment, the oscillation loop in the signal generating device of this embodiment may include:

[0065] The optical phase modulator corresponds to the local oscillator laser one by one and is used to modulate the laser signal output by the corresponding local oscillator laser to obtain multiple modulated optical signals.

[0066] The polarization regulator is used to be arranged at the output end of some optical phase modulators to adjust the polarization state of the modulated optical signal output by the corresponding optical phase modulator, so that the polarization state of the modulated optical signal after polarization state adjustment is orthogonal to the polarization state of the modulated optical signal after polarization state adjustment.

[0067] The polarization combiner is used to combine a modulated optical signal after polarization state adjustment with a modulated optical signal after polarization state adjustment to obtain a combined signal.

[0068] The optical filter is used to perform notch filtering on the combined signal to obtain an optical signal after notch filtering.

[0069] The polarization beam splitter is used to split the optical signal after notch filtering into at least two optical signals after notch filtering.

[0070] The first photoelectric detectors correspond to the local oscillator lasers one by one, and each first photoelectric detector is used to perform beat frequency on an optical signal after notch filtering to obtain a second radio frequency signal.

[0071] The first RF amplifier corresponds to the first RF filter one by one and is used to amplify the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonant peak angle frequency of the optical filter.

[0072] The second RF power splitter corresponds to the first RF amplifier one by one, and is used to split the first RF signal into two first RF signals with equal power, and input one of the first RF signals into the corresponding optical phase modulator.

[0073] The feedback controller is used to generate a feedback signal based on another first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

[0074] It should be noted that Figure 5 Two local oscillator lasers are used as an example for explanation, and the number of local oscillator lasers is not limited in the present invention.

[0075] Polarization multiplexing is used to lock two local oscillator laser sources to the optical filter at the same time. After the local oscillator laser source passes through the optical coupler and phase modulator, one path is polarized, so that the polarization state of the modulated optical signal changes by 90°, which is orthogonal to the polarization state of the modulated optical signal of the other path (the polarization state differs by 90°). After passing through the polarization combiner, it is input into the optical filter. After the optical filter notch filtering, the optical signal passes through the polarization beam splitter to separate the two mutually orthogonal polarization state optical signals in the filtered optical signal into two paths. Then they are input into the photodetector respectively.

[0076] It should be noted that for details not fully described in this embodiment, please refer to the aforementioned embodiment section and will not be repeated here.

[0077] Figure 6 The structure of a signal generating device according to a sixth embodiment of the present invention is schematically shown.

[0078] like Figure 6 As shown, based on the signal generating device of the previous embodiment, the oscillation loop in the signal generating device of this embodiment may include:

[0079] The optical phase modulator corresponds to the local oscillator laser one by one and is used to modulate the laser signal output by the corresponding local oscillator laser to obtain multiple modulated optical signals.

[0080] The first optical wavelength division multiplexer is used to combine multiple modulated optical signals into one signal to obtain a combined signal.

[0081] The optical filter is used to perform notch filtering on the combined signal to obtain an optical signal after notch filtering.

[0082] The second optical wavelength division multiplexer is used to split the optical signal after notch filtering into at least two optical signals after notch filtering.

[0083] The first photoelectric detectors correspond to the local oscillator lasers one by one, and each first photoelectric detector is used to perform beat frequency on an optical signal after notch filtering to obtain a second radio frequency signal.

[0084] The first RF amplifier corresponds to the first RF filter one by one and is used to amplify the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonant peak angle frequency of the optical filter.

[0085] The second RF power splitter corresponds to the first RF amplifier one by one, and is used to split the first RF signal into two first RF signals with equal power, and input one of the first RF signals into the corresponding optical phase modulator.

[0086] The feedback controller is used to generate a feedback signal based on another first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

[0087] It should be noted that Figure 6 Two local oscillator lasers are used as an example for explanation, and the number of local oscillator lasers is not limited in the present invention.

[0088] It should be noted that for details not fully described in this embodiment, please refer to the aforementioned embodiment section and will not be repeated here.

[0089] Figure 7 The structure of a signal generating device according to a seventh embodiment of the present invention is schematically shown.

[0090] like Figure 7 As shown, based on the signal generating device of the previous embodiment, the oscillation loop in the signal generating device of this embodiment may include:

[0091] The third optical coupler is used to combine at least two laser signals with different frequencies into one laser signal.

[0092] An optical phase modulator is used to modulate a laser signal to obtain a modulated optical signal;

[0093] The optical filter is used to perform notch filtering on the modulated optical signal to obtain an optical signal after notch filtering.

[0094] The first photoelectric detector is used to perform beat frequency processing on the optical signal after the notch filtering to obtain a second radio frequency signal.

[0095] The first radio frequency power divider is used to divide the second radio frequency signal into at least two second radio frequency signals with equal power.

[0096] The first radio frequency filters correspond to the local oscillator lasers one by one, and each first radio frequency filter is used to filter one second radio frequency signal to obtain a third radio frequency signal.

[0097] The first RF amplifier corresponds to the first RF filter one by one and is used to amplify the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonant peak angle frequency of the optical filter.

[0098] The second RF power splitter corresponds to the first RF amplifier on a one-to-one basis and is used to split the first RF signal with equal power into two first RF signals.

[0099] The radio frequency combiner is used to combine the first radio frequency signals respectively output by each second radio frequency power divider into a fourth radio frequency signal, and input the second radio frequency signal into the optical phase modulator.

[0100] The feedback controller is used to generate a feedback signal based on another first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

[0101] In this embodiment, the outputs of the two local oscillator lasers are combined through a third optical coupler, one of which can be used as the output of the locked optically-carried terahertz signal, and the other is used to lock the local oscillator laser source and the optical filter. The optical signal combined through the third optical coupler is input into the optical phase modulator to generate a modulated optical signal. After the modulated optical signal is filtered by the optical filter, the optical signal after the notch filtering is detected by a photodetector, and an oscillating RF signal is output. The oscillating RF signal is divided into two paths by the RF power divider, and after passing through the RF filter, only the frequency equal to the difference between the corresponding local oscillator laser angular frequency and the resonant angular frequency of the optical filter ( , ) RF signal. After passing through the RF amplifier, the RF signal is divided into two paths through the RF power divider. One path is used for feedback control of the local oscillator laser, and the other path is input to the RF port of the phase modulator after passing through the RF combiner.

[0102] It should be noted that Figure 7 Two local oscillator lasers are used as an example for explanation, and the number of local oscillator lasers is not limited in the present invention.

[0103] It should be noted that for details not fully described in this embodiment, please refer to the aforementioned embodiment section and will not be repeated here.

[0104] Stay Engaged Figure 1-Figure 7 , based on the above embodiment, the signal generation further includes:

[0105] The fourth optical coupler is arranged at the output end of the optical filter, and is used for splitting the first light-borne terahertz signal to obtain two paths of the first light-borne terahertz signals.

[0106] The second photodetector is arranged at the output end of the fourth optical coupler or the output end of the first coupler, and is used to beat the first light-borne terahertz signal to obtain the first terahertz signal, or beat the second light-borne terahertz signal to obtain the second terahertz signal.

[0107] Based on the above embodiment, the feedback controller generates a feedback signal based on the first RF signal corresponding to the laser signal of each frequency, including: mixing the RF reference signal with the first RF signal, extracting the change of the central angular frequency of the local oscillator laser relative to the central angular frequency of the optical filter, obtaining an error signal, and generating a feedback signal based on the error signal.

[0108] Based on the signal generating device provided in the above embodiment, an embodiment of the present invention further provides a signal generating method.

[0109] Figure 8 The flowchart of the signal generating method according to the embodiment of the present invention is schematically shown.

[0110] like Figure 8 As shown, the signal generating method includes operations S810 to S830.

[0111] In operation S810, at least two laser signals with different frequencies are generated by at least two local oscillator lasers.

[0112] In operation S820, an oscillation loop is used to oscillate based on at least two laser signals with different frequencies to generate a first radio frequency signal corresponding to the laser signal of each frequency.

[0113] In operation S830, a feedback controller generates a feedback signal based on the first RF signal corresponding to the laser signal of each frequency, and inputs the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser; the feedback controller corresponds to the local oscillator laser one by one.

[0114] After the frequencies of at least two laser signals generated by at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter in the oscillation loop, a terahertz signal or a microwave signal is output.

[0115] It should be noted that for details not fully described in this embodiment, please refer to the aforementioned embodiment section and will not be repeated here.

[0116] Fig. 9 A phase noise diagram according to an embodiment of the present invention is schematically shown. Fig.10 The diagram schematically shows the phase noise measurement result when the beat signal frequency intervals are 10 GHz and 20 GHz according to an embodiment of the present invention.

[0117] like Fig. 9 As shown in the figure, the phase noise of the beat signal after locking is lower than the phase noise of a single locked local oscillator laser, and much lower than the phase noise of the local oscillator laser before locking, so the generated terahertz signal or microwave signal has a lower phase noise. The phase noise of the microwave signal generated after N-frequency division is reduced by 20*log10(N) dB. Therefore, the microwave signal after frequency division can also obtain a lower phase noise.

[0118] like Fig.10 As shown in Figure 1, the generated signal frequency has almost no effect on the phase noise. The optical signal after bandpass filtering output by the optical filter only contains and The optical signal is the optical terahertz signal, which can generate an angular frequency of of terahertz signals.

[0119] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems and methods according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram may represent a module, a program segment or a part of a code, and the above-mentioned module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box may also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0120] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways, even if such combinations and / or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All of these combinations and / or combinations fall within the scope of the present invention.

[0121] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A signal generating device, characterized in that: include: At least two local oscillator lasers, used to generate at least two laser signals with different frequencies; An oscillation loop, used to oscillate based on at least two laser signals with different frequencies, and generate a first radio frequency signal corresponding to each laser signal of each frequency A feedback controller, corresponding to each of the local oscillator lasers, is used to generate a feedback signal based on the first radio frequency signal corresponding to the laser signal of each frequency, and input the feedback signal to the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser; Wherein, after the frequencies of at least two laser signals generated by the at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter in the oscillation loop, the optical filter is also used to output a first light-borne terahertz signal, and the frequency of the first light-borne terahertz signal is an integer multiple of the free spectrum range of the optical filter.

2. The device according to claim 1, characterized in that The device also includes: A first optical coupler, wherein the input end of the first optical coupler is connected to the output end of the at least two local oscillator lasers, and is used for outputting a second light-borne terahertz signal after the frequencies of at least two laser signals generated by the at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter, wherein the frequency of the second light-borne terahertz signal is continuously adjustable.

3. The device according to claim 2, characterized in that The device also includes: The optoelectronic frequency divider is arranged at the output end of the optical filter or the output end of the first optical coupler, and is used to perform optoelectronic conversion and frequency division on the first light-borne terahertz signal to obtain a first microwave signal, or to perform frequency division on the second light-borne terahertz signal to obtain a second microwave signal.

4. The device according to any one of claims 1 to 3, characterized in that: The oscillation loop comprises: An optical phase modulator, corresponding one-to-one to the local oscillator laser, is used to modulate the laser signal output by the corresponding local oscillator laser to obtain multiple modulated optical signals; A second optical coupler is used to combine multiple modulator optical signals into one path to obtain a combined signal; The optical filter is used to perform notch filtering on the combined signal to obtain an optical signal after notch filtering; A first photodetector, used for performing a beat frequency operation on the optical signal after the notch filtering to obtain a second radio frequency signal; A first radio frequency power splitter, used for splitting the second radio frequency signal into at least two second radio frequency signals with equal power; The first radio frequency filters correspond to the local oscillator lasers one by one, and each first radio frequency filter is used to filter a second radio frequency signal to obtain a third radio frequency signal. a first RF amplifier, corresponding one-to-one to the first RF filter, for amplifying the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonance peak angular frequency of the optical filter; A second RF power splitter, corresponding one-to-one to the first RF amplifier, is used to split the first RF signal into two first RF signals with equal power, and input one of the first RF signals into a corresponding optical phase modulator; The feedback controller is used to generate a feedback signal based on another first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

5. The device according to any one of claims 1 to 3, characterized in that: The oscillation loop comprises: An optical phase modulator, corresponding one-to-one to the local oscillator laser, is used to modulate the laser signal output by the corresponding local oscillator laser to obtain multiple modulated optical signals; A polarization adjuster is used to be arranged at the output end of some optical phase modulators to adjust the polarization state of the modulated optical signal output by the corresponding optical phase modulator, so that the polarization state of the modulated optical signal after the polarization state adjustment is orthogonal to the polarization state of the modulated optical signal after the polarization state adjustment; A polarization combiner is used to combine a modulated optical signal after polarization state adjustment with a modulated optical signal after polarization state adjustment to obtain a combined signal; The optical filter is used to perform notch filtering on the combined signal to obtain an optical signal after notch filtering; A polarization beam splitter, used to split the optical signal after notch filtering into at least two optical signals after notch filtering; A first photodetector, corresponding to each of the local oscillator lasers, each first photodetector is used to perform a beat frequency on a concave filtered optical signal to obtain a second radio frequency signal; a first RF amplifier, corresponding one-to-one to the first RF filter, for amplifying the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonance peak angular frequency of the optical filter; A second RF power splitter, corresponding one-to-one to the first RF amplifier, is used to split the first RF signal into two first RF signals with equal power, and input one of the first RF signals into a corresponding optical phase modulator; The feedback controller is used to generate a feedback signal based on another first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

6. The device according to any one of claims 1 to 3, characterized in that: The oscillation loop comprises: An optical phase modulator, corresponding one-to-one to the local oscillator laser, is used to modulate the laser signal output by the corresponding local oscillator laser to obtain multiple modulated optical signals; A first optical wavelength division multiplexer, used for combining multiple modulated optical signals into one channel to obtain a combined signal; The optical filter is used to perform notch filtering on the combined signal to obtain an optical signal after notch filtering; A second optical wavelength division multiplexer, used for splitting the optical signal after notch filtering into at least two optical signals after notch filtering; A first photodetector, corresponding to each of the local oscillator lasers, each first photodetector is used to perform a beat frequency on a concave filtered optical signal to obtain a second radio frequency signal; a first RF amplifier, corresponding one-to-one to the first RF filter, for amplifying the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonance peak angular frequency of the optical filter; A second RF power splitter, corresponding one-to-one to the first RF amplifier, is used to split the first RF signal into two first RF signals with equal power, and input one of the first RF signals into a corresponding optical phase modulator; The feedback controller is used to generate a feedback signal based on another first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

7. The device according to any one of claims 1 to 3, characterized in that: The oscillation loop comprises: The third optical coupler is used to combine at least two laser signals with different frequencies into one laser signal. An optical phase modulator is used to modulate a laser signal to obtain a modulated optical signal; The optical filter is used to perform notch filtering on the modulated optical signal to obtain an optical signal after notch filtering; A first photodetector, used for performing a beat frequency operation on the optical signal after the notch filtering to obtain a second radio frequency signal; A first radio frequency power splitter, used for splitting the second radio frequency signal into at least two second radio frequency signals with equal power; The first radio frequency filters correspond to the local oscillator lasers one by one, and each first radio frequency filter is used to filter a second radio frequency signal to obtain a third radio frequency signal. a first RF amplifier, corresponding one-to-one to the first RF filter, for amplifying the third RF signal output by the corresponding first RF filter to obtain the first RF signal; the frequency of the first RF signal is determined by the frequency of the corresponding local oscillator laser and the resonance peak angular frequency of the optical filter; A second RF power splitter, corresponding one-to-one to the first RF amplifier, for splitting the first RF signal into two first RF signals with equal power; A radio frequency combiner, used for combining the first radio frequency signals respectively outputted by the second radio frequency power dividers into a fourth radio frequency signal, and inputting the second radio frequency signal into the optical phase modulator; The feedback controller is used to generate a feedback signal based on another first radio frequency signal, and input the feedback signal into the corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser.

8. The device according to claim 2, characterized in that The device also includes: a fourth optical coupler, disposed at an output end of the optical filter, and configured to split the first light-borne terahertz signal to obtain two first light-borne terahertz signals; The second photodetector is arranged at the output end of the fourth optical coupler or the output end of the first coupler, and is used to beat the first light-borne terahertz signal to obtain a first terahertz signal, or beat the second light-borne terahertz signal to obtain a second terahertz signal.

9. The device according to claim 1, characterized in that The feedback controller generates a feedback signal based on the first radio frequency signal corresponding to the laser signal of each frequency, including: A radio frequency reference signal is mixed with the first radio frequency signal to extract a change in the central angular frequency of the local oscillator laser relative to the central angular frequency of the optical filter to obtain an error signal, and a feedback signal is generated based on the error signal.

10. A signal generating method, characterized in that: The signal generating method is implemented based on the signal generating device according to any one of claims 1 to 9, and the method comprises: Generate at least two laser signals with different frequencies by at least two local oscillator lasers; The oscillation loop is used to oscillate based on at least two laser signals with different frequencies to generate a first radio frequency signal corresponding to each laser signal of each frequency. A feedback controller generates a feedback signal based on a first radio frequency signal corresponding to a laser signal of each frequency, and inputs the feedback signal into a corresponding local oscillator laser to adjust the frequency of the laser signal output by the local oscillator laser; the feedback controller corresponds to the local oscillator laser one by one; After the frequencies of at least two laser signals generated by at least two local oscillator lasers are locked to different resonance peaks corresponding to the optical filter in the oscillation loop, a terahertz signal or a microwave signal is output.

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