Kerr soliton crystal optoelectronic oscillator

Abstract

The application discloses a Kerr soliton crystal optoelectronic oscillator, and belongs to the technical field of microwave photonics. The optoelectronic oscillator comprises a laser source, a modulator, an optical fiber, a filter, a detector, an electric amplifier, an electric power divider, an electric coupler, a microwave signal source 1 and a microwave signal source 2; when the modulator is a phase modulator and the filter is an optical filter, the switching of three reconfigurable states of a Kerr soliton crystal optoelectronic oscillator outputting a microwave soliton frequency comb signal, a perfect soliton crystal optoelectronic oscillator outputting a pure microwave soliton frequency comb signal and a frequency domain mode-locked perfect soliton crystal optoelectronic oscillator outputting a linear frequency modulation pure microwave soliton frequency comb signal is realized by controlling the switch state, the working mode, the power and the frequency of the microwave signal source 1 and the microwave signal source 2 and the working mode of the laser source. The application is the first to study the controllable perfect soliton crystal optoelectronic oscillator technology, the first to propose a method for suppressing supermode noise in the perfect soliton crystal optoelectronic oscillator by using two microwave signal sources, and generates a pure microwave soliton frequency comb signal with tunable center frequency and comb spacing, which is expected to meet the urgent needs of modern radar and other electronic information systems for high-performance microwave frequency comb signal source technology.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave photonics, and particularly relates to a Kerr soliton crystal optoelectronic oscillator. BACKGROUND

[0002] With the unprecedented development of modern electronic systems such as distributed phase coherent radar, wideband wireless communication, microwave precision measurement, the research on controllable and tunable microwave soliton frequency comb source has become a technology problem with great application demand. The optoelectronic oscillator has important research significance in the field of new generation radar, communication, electronic countermeasure, etc. due to its extremely low phase noise advantage. In a traditional optoelectronic oscillator, it is difficult to realize stable multimode oscillation in the loop due to the random power and phase relationship caused by the competition effect between the oscillation modes, which limits the application of the optoelectronic oscillator in modern electronic information systems. Recently, by introducing the mode-locked technology such as Fourier domain mode locking, time domain mode locking, optoelectronic parametric oscillation in the research of optoelectronic oscillator, the fixed power and phase relationship between the oscillation modes is realized, and high-quality microwave signals such as linear frequency modulation and microwave soliton frequency comb are generated, which improves the performance of modern radar, electronic measurement and other systems.

[0003] In particular, the microwave soliton frequency comb signal source based on the optoelectronic oscillator proposed in the past five years has become a research hotspot due to its breakthrough technology support in the field of Ising calculation and distributed radar. At present, the implementation methods of the microwave soliton frequency comb signal source based on the optoelectronic oscillator can be divided into passive mode-locked optoelectronic oscillator, active mode-locked optoelectronic oscillator and parametric oscillation optoelectronic oscillator. However, from the perspective of application demand, the current microwave soliton frequency comb source based on the optoelectronic oscillator still has the following two problems: first, the supermode noise existing in the frequency domain will cause random pulse loss, and the pure microwave frequency comb signal with complete supermode noise suppression does not exist; second, it is difficult to realize the tunable center frequency and repetition frequency of the microwave soliton in the time domain. Therefore, it is an urgent problem to realize the tunable pure microwave soliton frequency comb signal source. SUMMARY

[0004] The purpose of the present application is to solve the problems in the background art, based on the third-order nonlinear effect of the optoelectronic resonant cavity, a new tunable pure microwave soliton frequency comb signal source, the Kerr soliton crystal optoelectronic oscillator, is proposed, which breaks through the two technical limitations of the traditional microwave soliton frequency comb source based on the optoelectronic oscillator and promotes the development of modern electronic information systems based on the microwave soliton frequency comb source.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A Kerr soliton crystal optoelectronic oscillator comprises a laser source, a modulator, an optical fiber, a filter, a detector, an electrical amplifier, an electrical power divider, an electrical coupler, a microwave signal source 1 and a microwave signal source 2.

[0007] The laser source outputs light into the modulator to generate a modulated optical signal, and the modulated optical signal is transmitted through the optical fiber; the transmitted optical carrier is selected for a center frequency and an oscillation mode through the filter, and then is converted into a microwave signal through photoelectric conversion in the detector; the photoelectrically converted microwave signal is amplified through the electrical amplifier and then enters the electrical power divider; the electrical power divider divides the amplified microwave signal into two paths, one of which outputs a reconfigurable tunable microwave signal, and the other of which is fed back to the modulator through the electrical coupler together with the microwave signal source 1 and the microwave signal source 2 to close the optical-electric oscillation loop.

[0008] The microwave signal source 1 and the microwave signal source 2 constitute a mode control function module.

[0009] When the modulator is a phase modulator and the filter is an optical filter, the laser source, the phase modulator, the optical fiber, the optical filter, the detector and the electrical amplifier constitute a reconfigurable microwave photonic bandpass filter, and the center frequency of the output microwave signal is equal to the center frequency of the microwave photonic bandpass filter; specifically, when the optical filter is an optical notch filter, the laser source outputs optical double sideband modulation signals with equal amplitude and opposite phase in the phase modulator under the modulation of the feedback signal; when the optical notch filter filters out one sideband, the microwave signal falling within the notch is detected, phase-to-intensity conversion is completed, and a reconfigurable microwave photonic bandpass filter is formed, with the center frequency being the difference between the frequency of the optical carrier output by the laser source and the notch frequency of the optical notch filter; when the optical filter is an optical gain filter, the laser source outputs optical double sideband modulation signals with equal amplitude and opposite phase in the phase modulator under the modulation of the feedback signal; when the optical gain filter performs gain on one sideband, phase-to-intensity conversion is completed, and a reconfigurable microwave photonic bandpass filter is formed, with the center frequency being the difference between the frequency of the optical carrier output by the laser source and the gain frequency of the optical gain filter.

[0010] Further, the reconfigurable microwave photonic bandpass filter and the mode control function module constitute a reconfigurable module of the Kerr soliton crystal optoelectronic oscillator, and three reconfigurable states are realized, namely, a reconfigured state one Kerr soliton crystal optoelectronic oscillator, a reconfigured state two perfect soliton crystal optoelectronic oscillator and a reconfigured state three frequency domain mode-locked perfect soliton crystal optoelectronic oscillator; the reconfigured state one Kerr soliton crystal optoelectronic oscillator outputs a microwave soliton frequency comb signal, the reconfigured state two perfect soliton crystal optoelectronic oscillator outputs a pure microwave soliton frequency comb signal, and the reconfigured state three frequency domain mode-locked perfect soliton crystal optoelectronic oscillator outputs a linear frequency modulation pure microwave soliton frequency comb signal.

[0011] The reconfigurable process of the Kerr soliton crystal optoelectronic oscillator is:

[0012] After the reconfigurable microwave photonic bandpass filter, the electric power divider and the electric coupler constitute the optoelectronic oscillation loop, the switch state, the working mode, the power and the frequency of the microwave signal source 1 and the microwave signal source 2 are controlled, including a single frequency mode and a sweep frequency mode, and the working mode of the laser source is controlled, including a single frequency laser source and a sweep frequency laser source, and three reconfigurable states of the Kerr soliton crystal optoelectronic oscillator are switched.

[0013] The process of realizing the Kerr soliton crystal optoelectronic oscillator in the first reconfiguration state is as follows: the laser source is turned on and the working mode is a single frequency laser source, at this time, the optoelectronic oscillation loop is a traditional free oscillation optoelectronic oscillator, and the output signal contains a main mode ω M (M is a positive integer, representing the Mth oscillation mode in the free oscillation optoelectronic oscillator) and a plurality of side modes ω M±N (M and N are positive integers, representing the M±Nth oscillation mode in the free oscillation optoelectronic oscillator). Then only the microwave signal source 1 is turned on and the working mode is a single frequency mode in the mode control function module. By controlling the power of the microwave signal source 1 and the frequency mismatch between the frequency and the side mode frequency ω M+i of the M+i th in the free oscillation optoelectronic oscillator (i is a non-zero integer, representing the M+i th oscillation mode in the free oscillation optoelectronic oscillator), the phase and amplitude of the M+i th side mode are controlled. When the main mode ω M and the controlled side mode ω M+i satisfy the amplitude and phase relationship required by the third-order nonlinear parametric amplification, the third-order nonlinear parametric amplification process in the optoelectronic oscillation loop is excited, thereby realizing the Kerr soliton crystal optoelectronic oscillator in the first reconfiguration state, and generating a microwave soliton frequency comb signal, the comb tooth interval of which is the frequency difference i·FSR between the main mode ω M and the controlled side mode ω M+i , wherein FSR is the free spectral range of the optoelectronic oscillation loop.

[0014] The process of realizing the perfect soliton crystal optoelectronic oscillator in the second reconfiguration state is as follows: the laser source is turned on and the working mode is a single frequency laser source, at this time, the optoelectronic oscillation loop is a traditional free oscillation optoelectronic oscillator. The microwave signal source 1 and the microwave signal source 2 are turned on and the working mode is a single frequency mode in the mode control function module, and the power and the frequency of the microwave signal source 1 and the microwave signal source 2 are controlled to respectively control two different side modes ω M+i and ω M+j(i and j are non-zero integers, respectively representing the M+i-th and M+j-th oscillation modes in the free oscillation optical electric oscillator, i is not equal to j), when the frequency difference of microwave signal source 1 and microwave signal source 2 is equal to the integer multiple |i-j| of the free spectral range, and the amplitude and phase relationship between the two controlled side modes meets the requirement of third-order nonlinear parametric amplification, the third-order nonlinear parametric amplification in the optical electric oscillation loop is excited, the two-state perfect soliton crystal optical electric oscillator is reconstructed, and the pure microwave soliton frequency comb signal is generated, the comb tooth interval of which is the frequency difference |i-j|·FSR between the two controlled side modes ω M+i and ω M+j .

[0015] The process of reconstructing the three-state frequency domain mode-locked perfect soliton crystal optical electric oscillator is as follows: on the basis of the two-state reconstruction, the working mode of the laser source is changed to a frequency-sweeping laser source, and the working mode of the microwave signal source 1 and the microwave signal source 2 is changed to a frequency-sweeping mode. The frequency-sweeping laser source will cause the reconfigurable microwave optical bandpass filter to also sweep, and the sweep period of the reconfigurable microwave optical bandpass filter is the same as that of the frequency-sweeping laser source. When the reciprocals of the sweep periods of the reconfigurable microwave optical bandpass filter, the microwave signal source 1 and the microwave signal source 2 are equal to K times (K is a positive integer) of the free spectral range, the third-order nonlinear parametric amplification process in the optical electric oscillation loop is excited and the frequency domain mode-locking technology is completed, the frequency domain mode-locked perfect soliton crystal optical electric oscillator is realized, and the linear frequency modulation pure microwave soliton frequency comb signal is generated. When K is equal to 1, the comb tooth interval of the linear frequency modulation pure microwave soliton frequency comb signal generated is FSR, and the sweep period of a single microwave optical bandpass filter contains |i-j| pulses; when K is equal to |i-j|, the comb tooth interval of the linear frequency modulation pure microwave soliton frequency comb signal generated is |i-j|·FSR, and the sweep period of a single microwave optical bandpass filter contains 1 pulse.

[0016] Further, when the modulator is an intensity modulator and the filter is an electrically tunable filter, the process of reconstructing the one-state, the two-state and the three-state is similar to the above; the electrically tunable filter includes two working modes of bandpass filtering and frequency-sweeping filtering.

[0017] Specifically, the laser is arranged to work in a single-frequency laser source mode, the microwave signal source 1 and the microwave signal source 2 are arranged to work in a single-frequency mode, and the electrically tunable filter is arranged to work in a band-pass filter mode; by adjusting the switch state, power and frequency of the microwave signal source 1 and the microwave signal source 2, the Kerr soliton crystal optoelectronic oscillator proposed in the application can realize a reconfiguration one-state Kerr soliton crystal optoelectronic oscillator and a reconfiguration two-state perfect soliton crystal optoelectronic oscillator, and generate a microwave soliton frequency comb signal and a pure microwave soliton frequency comb signal; on the basis of the reconfiguration two-state, the microwave signal source 1 and the microwave signal source 2 are arranged to work in a sweep frequency mode, and the electrically tunable filter is arranged to work in a sweep frequency filter mode; by adjusting the power and frequency of the microwave signal source 1 and the microwave signal source 2, a reconfiguration three-state frequency domain mode-locked perfect soliton crystal optoelectronic oscillator can be realized, and a linear frequency modulation pure microwave soliton frequency comb signal is generated.

[0018] Further, when the modulator is an intensity modulator and the filter is an electric band-pass filter, the process of realizing the reconfiguration one-state and the reconfiguration two-state is the same as described above, the laser is arranged to work in a single-frequency laser source mode, the microwave signal source 1 and the microwave signal source 2 are arranged to work in a single-frequency mode, and by adjusting the power and frequency of the microwave signal source 1 and the microwave signal source 2, the Kerr soliton crystal optoelectronic oscillator proposed in the application can realize a reconfiguration one-state Kerr soliton crystal optoelectronic oscillator and a reconfiguration two-state perfect soliton crystal optoelectronic oscillator, and generate a microwave soliton frequency comb signal and a pure microwave soliton frequency comb signal.

[0019] Further, when the Kerr soliton crystal optoelectronic oscillator realizes the reconfiguration one-state Kerr soliton crystal optoelectronic oscillator, the frequency of the microwave signal source 1 is tuned to realize the adjustment of different side modes; according to the difference between the frequency of the adjusted side mode and the frequency of the main mode, the comb tooth interval of the generated microwave soliton frequency comb signal can be tuned, and the comb tooth interval is equal to the difference between the frequency of the adjusted side mode and the frequency of the main mode; when the reconfiguration two-state perfect soliton crystal optoelectronic oscillator is realized, the frequency difference between the microwave signal source 1 and the microwave signal source 2 is tuned, and the comb tooth frequency interval of the generated microwave soliton frequency comb signal can be tuned, and the comb tooth interval is equal to the frequency difference between the microwave signal source 1 and the microwave signal source 2; when the reconfiguration three-state perfect soliton crystal optoelectronic oscillator is realized, the sweep frequency period of the microwave photon band-pass filter, the microwave signal source 1 and the microwave signal source 2, and the frequency difference between the microwave signal source 1 and the microwave signal source 2 are tuned, and the comb tooth frequency interval of the generated microwave soliton frequency comb signal can be tuned.

[0020] Further, by tuning the center frequency and bandwidth of the filter and the frequency of the microwave signal source 1 and the microwave signal source 2, the center frequency and the number of comb teeth of the microwave soliton frequency comb signal, the pure microwave soliton frequency comb signal and the linear frequency modulation pure microwave soliton frequency comb signal generated by the Kerr soliton crystal optoelectronic oscillator can be tuned.

[0021] Compared with the prior art, the present application has the beneficial effects that:

[0022] 1、The present application is the first to study controllable perfect soliton crystal optoelectronic oscillator technology, and the first to propose a method for suppressing supermode noise in a perfect soliton crystal optoelectronic oscillator by using two microwave signal sources, to generate a pure microwave soliton frequency comb signal with tunable center frequency and comb spacing, which is expected to meet the urgent needs of modern radar and other electronic information systems for high-performance microwave frequency comb signal source technology.

[0023] 2、The present application is the first to study frequency domain mode-locked perfect soliton crystal optoelectronic oscillator technology, and the first to introduce frequency domain mode-locked technology into a perfect soliton crystal optoelectronic oscillator, to generate a pure microwave soliton frequency comb signal with linear frequency modulation, which is expected to meet the needs of modern radar and other electronic information systems for high-performance linear frequency modulation microwave frequency comb signals. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The present application is a schematic diagram of the structure of a Kerr soliton crystal optoelectronic oscillator;

[0025] Figure 2 The present application is a third-order nonlinear parametric amplification process in the crystal of a Kerr soliton crystal optoelectronic oscillator;

[0026] Figure 3 The present application is a schematic diagram of the structure of a Kerr soliton crystal optoelectronic oscillator of embodiment 1;

[0027] Figure 4 The present application is a schematic diagram of the frequency spectrum of the output signal of a Kerr soliton crystal optoelectronic oscillator of embodiment 1 when it is implemented as a Kerr soliton crystal optoelectronic oscillator with one state reconstruction;

[0028] Figure 5 The present application is a schematic diagram of the frequency spectrum of the output signal of a Kerr soliton crystal optoelectronic oscillator of embodiment 1 when it is implemented as a perfect soliton crystal optoelectronic oscillator with two state reconstruction;

[0029] Figure 6 The present application is a schematic diagram of the instantaneous frequency of the output signal of a Kerr soliton crystal optoelectronic oscillator of embodiment 1 when it is implemented as a frequency domain mode-locked perfect soliton crystal optoelectronic oscillator with three state reconstruction;

[0030] Figure 7 The present application is a schematic diagram of the structure of a Kerr soliton crystal optoelectronic oscillator of embodiment 2;

[0031] Figure 8 The present application is a schematic diagram of the structure of a Kerr soliton crystal optoelectronic oscillator of embodiment 3;

[0032] Figure 9This is a schematic diagram of the structure of the Kerr soliton crystal opto-oscillator provided in Embodiment 4 of the present invention. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. The technical solution of the present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] Example 1

[0035] like Figure 3 The diagram shown is a schematic of the structure of a Kerr soliton crystal opto-oscillator provided in this embodiment, including a microwave signal source 1, a microwave signal source 2, a laser source 3, a phase modulator 4, an optical fiber 5, an optical notch filter 6, a photodetector 7, an electrical amplifier 8, an electrical power divider 9, and an electrical coupler 10.

[0036] The output light from laser source 3 enters phase modulator 4 to generate a modulated optical signal, which is then transmitted through optical fiber 5. The transmitted optical carrier is selected by optical notch filter 6 to select the center frequency and oscillation mode, and then photoelectrically converted by photodetector 7 to generate a microwave signal. The photoelectrically converted microwave signal is amplified by electric amplifier 8 and then enters electric power divider 9. Electric power divider 9 splits the amplified microwave signal into two paths. One path outputs a reconfigurable and tunable microwave signal, and the other path, together with microwave signal source 1 and microwave signal source 2, is fed back to phase modulator 4 through electric coupler 10 to close the photoelectric oscillation loop.

[0037] Microwave signal source 1 and microwave signal source 2 constitute a mode control module; laser source 3, phase modulator 4, optical fiber 5, optical notch filter 6, photodetector 7, and electrical amplifier 8 constitute a reconfigurable microwave photonic bandpass filter, the center frequency of the output microwave signal being equal to the center frequency of the microwave photonic bandpass filter. Specifically, laser source 3 is modulated by feedback signal in phase modulator 4 to output a double-sideband optical signal with equal positive and negative sideband amplitudes and opposite phases. When optical notch filter 6 filters out one sideband, the microwave signal falling within the notch is detected, completing the phase-intensity conversion and forming a reconfigurable microwave photonic bandpass filter, the center frequency of which is the difference between the frequency of the output optical carrier of laser source 3 and the notch frequency of optical notch filter 7.

[0038] Further, the reconfigurable microwave photonic bandpass filter and the mode control function module constitute the reconfigurable module of the Kerr soliton crystal optoelectronic oscillator provided in the embodiment, and three reconfigurable states are realized, which are the Kerr soliton crystal optoelectronic oscillator in the reconfiguration one state, the perfect soliton crystal optoelectronic oscillator in the reconfiguration two state, and the frequency domain mode-locked perfect soliton crystal optoelectronic oscillator in the reconfiguration three state; wherein the Kerr soliton crystal optoelectronic oscillator in the reconfiguration one state outputs the microwave soliton frequency comb signal, the perfect soliton crystal optoelectronic oscillator in the reconfiguration two state outputs the pure microwave soliton frequency comb signal, and the frequency domain mode-locked perfect soliton crystal optoelectronic oscillator in the reconfiguration three state outputs the linear frequency modulation pure microwave soliton frequency comb signal.

[0039] The reconfigurable process of the Kerr soliton crystal optoelectronic oscillator provided in the embodiment is as follows:

[0040] After the reconfigurable microwave photonic bandpass filter, the electrical power divider 9 and the electrical coupler 10 constitute the optoelectronic feedback loop of the optoelectronic oscillator, the switch state, the working mode, the power and the frequency of the microwave signal source 1 and the microwave signal source 2 are controlled, including the single frequency mode and the sweep frequency mode, and the working mode of the laser source 3 is controlled, including the single frequency laser source and the sweep frequency laser source, so as to realize the switching of the three reconfigurable states of the Kerr soliton crystal optoelectronic oscillator.

[0041] The process of realizing the Kerr soliton crystal optoelectronic oscillator in the reconfiguration one state is as follows: the laser source 3 is turned on to make the working mode of the laser source 3 as the single frequency laser source, at this time, the optoelectronic oscillation loop is a traditional free oscillation optoelectronic oscillator, and the output signal contains the main mode ω M (M is a positive integer, representing the Mth oscillation mode in the free oscillation optoelectronic oscillator) and many side modes ω M±N (M and N are positive integers, representing the M±Nth oscillation mode in the free oscillation optoelectronic oscillator). Then only the microwave signal source 1 in the mode control module is turned on to make the working mode of the microwave signal source 1 as the single frequency mode. By controlling the power of the microwave signal source 1 and the frequency mismatch between the frequency of the microwave signal source 1 and the side mode frequency ω M+i of the M+i th oscillation mode in the free oscillation optoelectronic oscillator (i is a non-zero integer), the phase and amplitude of the M+i th side mode are controlled. When the main mode ω M in the free oscillation optoelectronic oscillator and the controlled side mode ω M+i satisfy the amplitude and phase relationship required by the third-order nonlinear parametric amplification, the third-order nonlinear parametric amplification process in the optoelectronic oscillation loop is excited, so as to realize the Kerr soliton crystal optoelectronic oscillator in the reconfiguration one state, and the microwave soliton frequency comb signal is generated, and the comb tooth interval is the main mode ω M .M+i frequency difference between the two modulated side modes ω Figure 4 and ω Figure 2 , as shown in FIG. 3.

[0042] The process of realizing the perfect soliton crystal optoelectronic oscillator with two states is as follows: turning on the laser source 3 to make it work as a single-frequency laser source, and making the optoelectronic oscillation loop a conventional free-running optoelectronic oscillator. Turning on the microwave signal source 1 and the microwave signal source 2 in the mode control module, and making them work in the single-frequency mode. The power and frequency of the microwave signal source 1 and the microwave signal source 2 are adjusted to control two different side modes ω M+i and ω M+j (i and j are non-zero integers, representing the M+i-th oscillation mode and the M+j-th oscillation mode in the free-running optoelectronic oscillator, respectively, and i is not equal to j), when the frequency difference between the microwave signal source 1 and the microwave signal source 2 is equal to the integer multiple |i-j| of the free spectral range, the amplitude and phase relationship between the two modulated side modes satisfies the requirement of the third-order nonlinear parametric amplification, the third-order nonlinear parametric amplification in the optoelectronic oscillation loop is excited, the perfect soliton crystal optoelectronic oscillator with two states is realized, and the pure microwave soliton frequency comb signal is generated, with the comb tooth interval being the frequency difference |i-j|·FSR between the two modulated side modes ω M+i and ω M+j , as shown in FIG. 4. Figure 5

[0043] The process of realizing the perfect soliton crystal optoelectronic oscillator with three states is as follows: on the basis of the perfect soliton crystal optoelectronic oscillator with two states, the working mode of the laser source 3 is changed to a sweeping-frequency laser source, and the working mode of the microwave signal source 1 and the microwave signal source 2 is changed to a sweeping-frequency mode. The sweeping-frequency laser source 3 causes the reconfigurable microwave photonic bandpass filter to also sweep, and the sweeping period of the reconfigurable microwave photonic bandpass filter is the same as the sweeping period of the sweeping-frequency laser source 3. When the inverse of the sweeping period of the reconfigurable microwave photonic bandpass filter, the microwave signal source 1 and the microwave signal source 2 is equal to K times (K is a positive integer) of the free spectral range, the third-order nonlinear parametric amplification process in the optoelectronic oscillation loop is excited and the frequency domain mode-locking technology is completed, the perfect soliton crystal optoelectronic oscillator with frequency domain mode-locking is realized, and the linear frequency modulation pure microwave soliton frequency comb signal is generated; when K is equal to 1, the comb tooth interval of the linear frequency modulation pure microwave soliton frequency comb signal generated is FSR, and the sweeping period of a single microwave photonic bandpass filter contains |i-j| pulses; when K is equal to |i-j|, the comb tooth interval of the linear frequency modulation pure microwave soliton frequency comb signal generated is |i-j|·FSR, and the sweeping period of a single microwave photonic bandpass filter contains 1 pulse, as shown in FIG. 5.​Figure 6 as shown.

[0044] Further, by tuning the frequency difference of the laser source 3 and the optical wave filter 6, the bandwidth of the optical wave filter 6, and the frequencies of the microwave signal source 1 and the microwave signal source 2, the center frequency and the number of teeth of the microwave soliton frequency comb signal, the pure microwave soliton frequency comb signal, and the linear frequency modulation pure microwave soliton frequency comb signal can be tuned.

[0045] Further, when the Kerr soliton crystal optoelectronic oscillator provided by the embodiment is used to reconstruct a state of the Kerr soliton crystal optoelectronic oscillator, the frequency of the microwave signal source 1 is tuned to control different side modes. According to the difference between the frequency of the controlled side mode and the frequency of the main mode, the tooth interval of the generated microwave soliton frequency comb signal can be tuned, and the tooth interval is equal to the difference between the frequency of the controlled side mode and the frequency of the main mode. When a second state of the perfect soliton crystal optoelectronic oscillator is reconstructed, the frequency difference between the microwave signal source 1 and the microwave signal source 2 is tuned, and the tooth frequency interval of the generated microwave soliton frequency comb signal can be tuned, and the tooth interval is equal to the frequency difference between the microwave signal source 1 and the microwave signal source 2. When a third state of the perfect soliton crystal optoelectronic oscillator is reconstructed, the sweep frequency period of the microwave photon band-pass filter, the microwave signal source 1 and the microwave signal source 2, and the frequency difference between the microwave signal source 1 and the microwave signal source 2 are tuned, and the tooth frequency interval of the generated microwave soliton frequency comb signal can be tuned.

[0046] Embodiment 2

[0047] As shown in the structure schematic diagram of a Kerr soliton crystal optoelectronic oscillator provided by the embodiment, the Kerr soliton crystal optoelectronic oscillator includes a microwave signal source 1, a microwave signal source 2, a laser source 3, a phase modulator 4, an optical fiber 5, an optical gain filter 6, a photodetector 7, an electrical amplifier 8, an electrical power divider 9, and an electrical coupler 10. Figure 7 The laser source 3 outputs light into the phase modulator 4 to generate a modulated light signal, and then the modulated light signal is transmitted through the optical fiber 5. The transmitted optical carrier is selected in center frequency and oscillation mode by the optical gain filter 6, and then is photoelectrically converted by the photodetector 7 to generate a microwave signal. The photoelectrically converted microwave signal is amplified by the electrical amplifier 8 and then enters the electrical power divider 9. The electrical power divider 9 divides the amplified microwave signal into two paths, one of which outputs a reconfigurable and tunable microwave signal, and the other of which is fed back to the phase modulator 4 together with the microwave signal source 1 and the microwave signal source 2 through the electrical coupler 10 to close the optoelectronic oscillation loop.

[0048]

[0049] ​Microwave signal source 1 and microwave signal source 2 constitute a mode control module; laser source 3, phase modulator 4, optical fiber 5, optical gain filter 6, photodetector 7, and electrical amplifier 8 constitute a reconfigurable microwave photonic bandpass filter, the center frequency of the output microwave signal being equal to the center frequency of the microwave photonic bandpass filter. Specifically, laser source 3 is modulated by the feedback signal in phase modulator 4 to output a double-sideband optical signal with equal amplitude and opposite phase of positive and negative sidebands. When the optical gain filter gains one of the sidebands, a phase-intensity conversion is completed, forming a reconfigurable microwave photonic bandpass filter, the center frequency of which is the difference between the frequency of the output optical carrier of laser source 3 and the gain frequency of optical gain filter 7.

[0050] The process of switching between the three reconfigurable states of the Kerr soliton crystal opto-oscillator is the same as that in Example 1.

[0051] Example 3

[0052] like Figure 8 The diagram shown is a schematic of the structure of a Kerr soliton crystal opto-oscillator provided in this embodiment, including a microwave signal source 1, a microwave signal source 2, a single-frequency laser source 3, an intensity modulator 4, an optical fiber 5, a photodetector 6, an electrical amplifier 7, an electrical bandpass filter 8, an electrical power divider 9, and an electrical coupler 10.

[0053] The output light from the single-frequency laser source 3 enters the intensity modulator 4 to generate a modulated optical signal, which is then transmitted through the optical fiber 5. The transmitted modulated optical carrier is photoelectrically converted by the photodetector 6 to generate a microwave signal. The photoelectrically converted microwave signal is amplified by the electric amplifier 7 and then the center frequency of the microwave signal is selected by the electric bandpass filter 8. The filtered microwave signal enters the electric power divider 9 and is split into two paths. One path outputs a reconfigurable and tunable microwave signal, while the other path, together with the microwave signal sources 1 and 2, is fed back to the intensity modulator 4 through the electric coupler 10 to close the photoelectric oscillation loop.

[0054] Among them, microwave signal source 1 and microwave signal source 2 constitute the mode control function module;

[0055] Furthermore, by controlling the power and frequency of microwave signal source 1 and microwave signal source 2, the Kerr soliton crystal opto-oscillator provided in this embodiment can realize a Kerr soliton crystal opto-oscillator in one state and a perfect soliton crystal opto-oscillator in two states.

[0056] The process of reconstructing the Kerr soliton crystal optoelectronic oscillator in a state is: turning on the single-frequency laser source 3 to make it work in a single-frequency mode, so that the optoelectronic oscillation loop is a traditional free-running optoelectronic oscillator, and the output signal contains a main mode with a frequency close to the center frequency of the microwave photonic bandpass filter and a plurality of side modes with frequencies different from the frequency of the main mode by an integer multiple of the free spectral range. Then, only the microwave signal source 1 in the mode control module is turned on to make it work in a single-frequency mode. By adjusting the power of the microwave signal source 1 and the frequency mismatch between the frequency of the microwave signal source 1 and the frequency of the side mode of the free-running optoelectronic oscillator, the phase and amplitude of the side mode are controlled. When the main mode of the free-running optoelectronic oscillator and the controlled side mode satisfy the amplitude and phase relationship required by the third-order nonlinear parametric amplification, the third-order nonlinear parametric amplification process in the optoelectronic oscillation loop is excited, so that the Kerr soliton crystal optoelectronic oscillator in a state is reconstructed, and the microwave soliton frequency comb signal is generated.

[0057] The process of reconstructing the perfect soliton crystal optoelectronic oscillator in a state is: turning on the single-frequency laser source 3 to make it work in a single-frequency mode, so that the optoelectronic oscillation loop is a traditional free-running optoelectronic oscillator. The microwave signal source 1 and the microwave signal source 2 in the mode control module are both turned on and made to work in a single-frequency mode. By adjusting the power and frequency of the microwave signal source 1 and the microwave signal source 2, two different side modes are controlled. When the frequency difference between the microwave signal source 1 and the microwave signal source 2 is equal to an integer multiple of the free spectral range, the two controlled side modes satisfy the amplitude and phase relationship required by the third-order nonlinear parametric amplification, the third-order nonlinear parametric amplification in the optoelectronic oscillation loop is excited, so that the perfect soliton crystal optoelectronic oscillator in a state is reconstructed, and the pure microwave soliton frequency comb signal is generated.

[0058] Embodiment 4

[0059] As shown in Figure 9 Fig. 1 is a structural schematic diagram of a Kerr soliton crystal optoelectronic oscillator provided by the embodiment, which comprises a microwave signal source 1, a microwave signal source 2, a single-frequency laser source 3, an intensity modulator 4, an optical fiber 5, a photodetector 6, an electrical amplifier 7, an electrically tunable filter 8, an electrical power divider 9 and an electrical coupler 10.

[0060] The output light of the single-frequency laser source 3 enters the intensity modulator 4 to generate a modulated light signal, and then is transmitted through the optical fiber 5; the transmitted modulated light carrier is optoelectronically converted by the photodetector 6 to generate a microwave signal; the optoelectronically converted microwave signal is amplified by the electrical amplifier 7 and then the center frequency of the microwave signal is selected by the electrically tunable filter 8; the filtered microwave signal enters the electrical power divider 9 and is divided into two paths, one of which outputs a reconfigurable and tunable microwave signal, and the other of which is fed back to the intensity modulator 4 together with the microwave signal source 1 and the microwave signal source 2 through the electrical coupler 10 to close the optoelectronic oscillation loop.

[0061] The working mode of the electrically tunable filter 8 includes a band-pass filter mode and a sweep filter mode.

[0062] When the electrically tunable filter 8 works in the band-pass filter mode, the process of reconstructing a state of a Kerr soliton crystal optoelectronic oscillator and a state of a perfect soliton crystal optoelectronic oscillator is the same as that of the process of the embodiment 3.

[0063] The process of reconstructing a three-state frequency-domain mode-locked perfect soliton crystal optoelectronic oscillator is as follows: on the basis of the two-state reconstruction, the working mode of the microwave signal source 1 and the microwave signal source 2 is changed to a sweep mode, and the working mode of the electrically tunable filter 8 is changed to a sweep filter mode. When the reciprocals of the sweep periods of the electrically tunable filter 8, the microwave signal source 1 and the microwave signal source 2 are equal to K times (K is a positive integer) of the free spectral range, the three-order nonlinear parametric amplification process in the optoelectronic oscillation loop is excited and the frequency-domain mode-locking technology is completed, a frequency-domain mode-locked perfect soliton crystal optoelectronic oscillator is realized, and a linear frequency modulation pure microwave soliton frequency comb signal is generated. When K is equal to 1, the comb tooth interval of the generated linear frequency modulation pure microwave soliton frequency comb signal is FSR, and the electrically tunable filter 8 contains |i-j| pulses in a single sweep period. When K is equal to |i-j|, the comb tooth interval of the generated linear frequency modulation pure microwave soliton frequency comb signal is |i-j|·FSR, and the electrically tunable filter 8 contains 1 pulse in a single sweep period.

[0064] The above description of disclosed embodiments enables one skilled in the art to make or use the present application. Numerous modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not to be limited to the implementations illustrated herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A Kerr soliton crystal opto-electronic oscillator, characterized in that, The laser source, the modulator, the optical fiber, the filter, the detector, the electrical amplifier, the electrical power divider, the electrical coupler, the microwave signal source 1 and the microwave signal source 2; The laser source outputs light into the modulator to generate a modulated light signal, and the modulated light signal is transmitted through the optical fiber; the transmitted optical carrier is selected by the filter to have a center frequency and an oscillation mode, and then the optical carrier is converted into a microwave signal in the detector; the microwave signal converted by the optical-electric conversion is amplified by the electrical amplifier and then enters the electrical power divider; the electrical power divider divides the amplified microwave signal into two paths, one of which outputs a reconfigurable and tunable microwave signal, and the other of which is fed back to the modulator together with the microwave signal source 1 and the microwave signal source 2 through the electrical coupler to close the optical-electric oscillation loop; When the modulator is a phase modulator and the filter is an optical filter, the laser source, the phase modulator, the optical fiber, the optical filter, the detector and the electrical amplifier constitute a reconfigurable microwave photonic bandpass filter, and the switching of three reconfiguration states is realized by controlling the switching state, the working mode, the power and the frequency of the microwave signal source 1 and the microwave signal source 2, and the working mode of the laser source; wherein the Kerr soliton crystal optical-electric oscillator in the reconfiguration state one generates a microwave soliton frequency comb signal with tunable comb spacing, center frequency and comb number, the perfect soliton crystal optical-electric oscillator in the reconfiguration state two generates a pure microwave soliton frequency comb signal with tunable comb spacing, center frequency and comb number, and the frequency domain mode-locked perfect soliton crystal optical-electric oscillator in the reconfiguration state three generates a pure microwave soliton frequency comb signal with tunable comb spacing, center frequency and comb number.

2. The Kerr soliton crystal optoelectronic oscillator of claim 1, wherein, The microwave signal source 1 and the microwave signal source 2 constitute a mode regulation function module; The process of reconstructing a Kerr soliton crystal photoelectric oscillator to a single state is as follows: The laser source is turned on and its operating mode is set to single-frequency laser source. At this time, the photoelectric oscillation loop is a free-oscillating photoelectric oscillator. Only microwave signal source 1 is turned on in the mode control module and its operating mode is set to single-frequency mode. The power and frequency of microwave signal source 1 are adjusted in relation to the side-mode ω of the free-oscillating photoelectric oscillator. M±N Frequency detuning between frequencies, achieving the side mode ω M±N The phase and amplitude are modulated when the main mode ω of the free-oscillating photoelectric oscillator... M With the regulated side mode ω M±N When the amplitude and phase relationship between the two phases satisfies the requirements of third-order nonlinear parametric amplification, the third-order nonlinear parametric amplification process in the photoelectric oscillation loop is excited, thereby realizing the Kerr soliton crystal photoelectric oscillator and generating a microwave soliton frequency comb signal, with the comb tooth spacing being the dominant mode ω. M With the regulated side mode ω M±N The frequency difference between them is N·FSR, where FSR is the free spectrum range of the photoelectric oscillation loop; and the side mode ω M±N The corresponding M±Nth oscillation mode in the free-oscillating photoelectric oscillator, the dominant mode ω M This corresponds to the Mth oscillation mode in the free-oscillating photoelectric oscillator, where M and N are positive integers. The process of realizing the reconstruction of the perfect soliton crystal optoelectronic oscillator of two states is as follows: the laser source is started to work in the mode of single-frequency laser source, at this time the optoelectronic oscillation loop is a free oscillation optoelectronic oscillator, the microwave signal source 1 and the microwave signal source 2 in the mode control function module are set to be turned on, and the working mode of the microwave signal source 1 and the microwave signal source 2 is single-frequency mode, the power and the frequency of the microwave signal source 1 and the microwave signal source 2 are controlled to respectively control two different side modes ω M+i and ω M+j When the frequency difference of the microwave signal source 1 and the microwave signal source 2 is equal to the integer multiple |i-j| of the free spectral range, the amplitude and phase relationship between the two controlled side modes ω M+i and ω M+j satisfy the third-order nonlinear parametric amplification requirement, the third-order nonlinear parametric amplification in the optoelectronic oscillation loop is excited, the perfect soliton crystal optoelectronic oscillator is realized, and the pure microwave soliton frequency comb signal is generated, the comb tooth interval of which is the frequency difference |i-j|·FSR between the two controlled side modes ω M+i and ω M+j . The process of realizing the frequency domain mode-locked perfect soliton crystal optical-electric oscillator is as follows: the laser source is turned on to have a sweep frequency laser source, the microwave signal source 1 and the microwave signal source 2 in the mode regulation function module are both turned on and have a sweep frequency mode, and when the reciprocal of the sweep frequency period of the reconfigurable microwave photonic bandpass filter, the microwave signal source 1 and the microwave signal source 2 is equal to K times of the free spectral range, the third-order nonlinear parametric amplification process in the optical-electric oscillation loop is excited and frequency domain mode-locking is completed, realizing the frequency domain mode-locked perfect soliton crystal optical-electric oscillator and generating a pure microwave soliton frequency comb signal with linear frequency modulation; when K is equal to 1, the comb spacing of the generated pure microwave soliton frequency comb signal with linear frequency modulation is FSR, and the sweep frequency period of a single microwave photonic bandpass filter contains|i-j| pulses; when K is equal to|i-j|, the comb spacing of the generated pure microwave soliton frequency comb signal with linear frequency modulation is|i-j|·FSR, and the sweep frequency period of a single microwave photonic bandpass filter contains 1 pulse.

3. The Kerr soliton crystal opto-electronic oscillator of claim 1, wherein, When the modulator is replaced by an intensity modulator and the filter is replaced by an electrically tunable filter, by adjusting the switch state, working mode, power and frequency of microwave signal source 1 and microwave signal source 2, and the working mode of the electrically tunable filter, a Kerr soliton crystal optoelectronic oscillator in a state of reconstruction, a perfect soliton crystal optoelectronic oscillator in a state of reconstruction and a frequency domain mode-locked perfect soliton crystal optoelectronic oscillator in a state of reconstruction are realized, and microwave soliton frequency comb signals, pure microwave soliton frequency comb signals and linear frequency modulation pure microwave soliton frequency comb signals are generated.

4. The Kerr soliton crystal opto-electronic oscillator of claim 1, wherein, When the modulator is replaced by an intensity modulator and the filter is replaced by an electric band-pass filter, by adjusting the power and frequency of microwave signal source 1 and microwave signal source 2, switching between two reconfigurable states of a Kerr soliton crystal optoelectronic oscillator outputting microwave soliton frequency comb signals and a perfect soliton crystal optoelectronic oscillator outputting pure microwave soliton frequency comb signals is realized.

5. The Kerr soliton crystal optoelectronic oscillator of claim 1, wherein, When the Kerr soliton crystal optoelectronic oscillator is realized, by tuning the frequency of microwave signal source 1, the different side modes are adjusted, and according to the difference between the frequency of the adjusted side mode and the frequency of the main mode, the comb tooth interval of the generated microwave soliton frequency comb signal is tunable, and the comb tooth interval is equal to the difference between the frequency of the adjusted side mode and the frequency of the main mode. When the perfect soliton crystal optoelectronic oscillator is realized, by tuning the frequency difference of microwave signal source 1 and microwave signal source 2, the comb tooth frequency interval of the generated microwave soliton frequency comb signal is tunable, and the comb tooth interval is equal to the frequency difference of microwave signal source 1 and microwave signal source 2; when the frequency domain mode-locked perfect soliton crystal optoelectronic oscillator is realized, the sweep frequency period of the microwave photon band-pass filter, microwave signal source 1 and microwave signal source 2, and the frequency difference of microwave signal source 1 and microwave signal source 2 are tuned, to realize the tuning of the comb tooth frequency interval of the generated microwave soliton frequency comb signal.

6. The Kerr soliton crystal optoelectronic oscillator of claim 1, wherein, When the Kerr soliton crystal optoelectronic oscillator is realized, by tuning the center frequency and bandwidth of the filter, and the frequency of microwave signal source 1 and microwave signal source 2, the center frequency and the number of comb teeth of the generated microwave soliton frequency comb signal, pure microwave soliton frequency comb signal and linear frequency modulation pure microwave soliton frequency comb signal are tunable.

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