WO2024164889A1 - Parametric oscillator and signal processing method thereof - Google Patents

Abstract

The present application relates to a parametric oscillator and a signal processing method thereof. The parametric oscillator comprises a pumping source, a control signal source and a frequency comb generator. The pumping source is used for generating a first signal, the control signal source is used for generating a second signal, and the frequency comb generator is used for generating a frequency comb soliton according to the first signal and the second signal. The frequency comb generator is provided with a resonant cavity, wherein the first signal and the second signal can enter the resonant cavity and generate, by means of a nonlinear effect, the frequency comb soliton in the resonant cavity, the soliton envelope of the frequency comb soliton being formed into a low-frequency electromagnetic wave comprising a plurality of random phases. Regulating the control signal source can change the frequency of the second signal, so as to control the oscillation of input signals in the resonant cavity, and to regulate the number of random phases of the low-frequency electromagnetic wave formed by the generated soliton envelope, thus further expanding the application range of parametric oscillators.

Description

A parametric oscillator and a signal processing method thereof

This application claims the priority of the Chinese patent application filed with the State Intellectual Property Office of China on February 9, 2023, with application number 202310153134.6, and invention name “A parametric oscillator and its signal processing method”, all contents of which are incorporated by reference in this application.

Technical Field

The present application relates to the field of information technology, and in particular to a parametric oscillator and a signal processing method thereof.

Background Art

Combinatorial optimization plays a key role in fields such as drug design, traffic physical planning, wireless network resource optimization, and machine learning. Most combinatorial optimization problems are non-deterministic polynomial hard (NP-hard) problems, which are difficult to solve effectively using current general-purpose computers based on the Turing model. However, combinatorial optimization problems can be mapped to the ground state solution problem of the spin model, and then the spin model simulator built based on physical phenomena is used to simulate and solve the spin model, thereby obtaining the solution to the NP-hard problem.

Spin models include the one-dimensional Ising model and the two-dimensional Potts model (XY/Potts model). Spin model simulators include the Potts model simulator based on polaritons, the Ising model simulator based on the coherent optical Ising machine based on the degenerate optical parametric oscillator, and the Ising model simulator based on the optoelectronic parametric oscillator optoelectronic Ising machine. The spin direction of the Ising model can be upward or downward, while the spin direction of the XY/Potts model can be a continuous value (XY model) or a discrete value (Potts model) within a two-dimensional plane. Therefore, the XY/Potts model has more states than the Ising model, can represent more information, and can solve combinatorial optimization problems with a smaller number of spins. However, polaritons need to work in an ultra-low temperature environment, and the signals output by the current degenerate optical parametric oscillator or optoelectronic parametric oscillator have only two phases, 0 or π, and can only be used to construct the Ising model, not the XY/Potts model.

Application Contents

The present application provides a parametric oscillator and a signal processing method thereof, which are used to solve the problem that the output signal of the above-mentioned existing parametric oscillator has little phase and cannot construct an XY/Potts model.

A first aspect of an embodiment of the present application provides a parametric oscillator, comprising a pump source, a control signal source and a frequency comb generator, wherein the pump source is used to generate a first signal, the control signal source is used to generate a second signal, the frequency comb generator is used to generate frequency comb solitons according to the first signal and the second signal, and the frequency comb generator is provided with a resonant cavity, wherein the first signal and the second signal can enter the resonant cavity and generate the frequency comb solitons in the resonant cavity through a nonlinear effect, and the soliton envelope of the frequency comb soliton is formed as a low-frequency electromagnetic wave including multiple random phases.

In the present application, the pump source generates a first signal, the control signal source generates a second signal, and after the first signal and the second signal are coupled into the resonant cavity, a frequency comb signal is generated in the resonant cavity through a nonlinear effect, and the frequency comb signal can form a frequency comb soliton in the time domain, and the soliton envelope of the frequency comb soliton forms a low-frequency electromagnetic wave, which is the output target signal, so that the parametric oscillator realizes the conversion of the input signal frequency. Since the phase angle of the frequency comb soliton is random, the phase of the low-frequency electromagnetic wave formed by the soliton envelope is random, so the phase of the target signal output by the frequency comb generator can have multiple, that is, the output target signal has more than two phases of 0 or π, so that it can be used to construct an XY/Potts model. In addition, by adjusting the control signal source, the frequency of the second signal can be changed, so that the oscillation of the input signal in the resonant cavity can be controlled, and the number of random phases of the low-frequency electromagnetic wave formed by the generated soliton envelope can be adjusted, so that the scope of application of the parametric oscillator can be further improved, and a variety of XY/Potts model modeling requirements can be met. Furthermore, the parametric oscillator in the embodiment of the present application is a frequency comb-based parametric oscillator, which can operate at room temperature, thereby further reducing the difficulty of constructing an XY/Potts model, saving costs, and improving modeling efficiency.

In a possible design, the second signal is a high frequency signal or a low frequency signal. It can work within the frequency range of high-frequency signals and also within the frequency range of low-frequency signals, thereby increasing the operating range of the parametric oscillator and improving modeling efficiency.

In a possible design, the second signal is a low-frequency signal, the frequency of the second signal is f _c , the free spectrum range of the resonant cavity is Δν, f _c =q*Δν, where q is an integer greater than or equal to 0. When the second signal is a low-frequency signal with a frequency of f _c and satisfies f _c =q*Δν, the frequency interval of the frequency comb signal generated by the first signal and the second signal in the resonant cavity through the nonlinear effect can be Δν, and the threshold condition in the resonant cavity can be satisfied, thereby ensuring the generation of frequency comb solitons, ensuring that the soliton envelope of the frequency comb solitons can form a low-frequency electromagnetic wave output by the frequency comb generator, realizing the change of frequency, and the output of the phase of the low-frequency electromagnetic wave.

In a possible design, the second signal is a high-frequency signal, the frequency of the second signal is v _c , the frequency of the first signal is v _p , the free spectrum range of the resonant cavity is Δν , and the difference between the frequency v _c of the second signal and the frequency v _p of the first signal is an integer q times the free spectrum range Δν , wherein q is an integer greater than or equal to 0. When the second signal is a high-frequency signal with a frequency of v _c , and the frequency difference between the second signal and the first signal is q*Δν (i.e., v _c =v _p ±q*Δν ), the second signal and the first signal interfere with each other to generate a difference frequency phenomenon, which can generate a low-frequency electromagnetic wave with a frequency of f _c , and the interval of the frequency comb signal generated by the first signal and the second signal through the nonlinear effect in the resonant cavity is Δν , which satisfies the threshold condition in the resonant cavity, thereby ensuring the generation of frequency comb solitons, ensuring that the soliton envelope of the frequency comb solitons can form a low-frequency electromagnetic wave output by the frequency comb generator, and realizing the change of frequency, and the output of the target signal phase.

In a possible design, the phase of the low-frequency electromagnetic wave formed by the soliton envelope is ψ, when q=0, ψ∈(-π, π], when q≥1, ψ=2πn/q-π, where n is a natural number less than q. When q=0, during the formation of the frequency comb soliton, the azimuth angle of the frequency comb soliton will randomly stabilize at any position in the interval of (-π, π], and correspondingly, the phase ψ of the low-frequency electromagnetic wave formed by the soliton envelope of the frequency comb soliton is also located at the corresponding position, so that the phase of the target signal output by the frequency comb generator has multiple. When q≥1, the azimuth angle of the frequency comb soliton is There are q azimuth angles, and the azimuth angle of the frequency comb soliton is 2πn/q-π, where n is a natural number less than q. During the formation of the frequency comb soliton, the azimuth angle of the frequency comb soliton will randomly stabilize at one of the q azimuth angles. Correspondingly, the phase ψ of the low-frequency electromagnetic wave formed by the soliton envelope of the frequency comb soliton is also located at the corresponding position, so that the target signal output by the frequency comb generator has q random phases. According to the number of required spins, the value of q is set and the frequency of the second signal is changed, so that the number of random phases of the target signal can be adjusted to meet the modeling requirements of the XY/potts model.

In a possible design, the resonant cavity is provided with a first input end and a second input end, and the first signal can enter the resonant cavity through the first input end, and the second signal can enter the resonant cavity through the second input end. The pump source is coupled to the first input end of the resonant cavity, and the control signal source is coupled to the second input end of the resonant cavity. The first signal and the second signal enter the resonant cavity through the first input end and the second input end respectively to perform nonlinear action, generate frequency comb solitons, and make the frequency comb generator output the target signal. In this structure, the resonant cavity of the frequency comb generator has two input ends, so that the first signal and the second signal can be directly coupled into the resonant cavity, making the structure of the parametric oscillator more compact.

In a possible design, the parametric oscillator further includes a mixer, the resonant cavity is provided with a third input terminal, the mixer is used to mix the first signal and the second signal, and output the first signal and the second signal after mixing, and the first signal and the second signal after mixing can enter the resonant cavity through the third input terminal. The pump source and the control signal source are coupled to the mixer, and the mixer is connected to the third input terminal of the resonant cavity. The first signal generated by the pump source and the second signal generated by the control signal source can enter the mixer for mixing, and the mixed signals can be coupled into the resonant cavity through the third input terminal for nonlinear action, generating frequency comb solitons, so that the frequency comb generator outputs the target signal. In this structure, the resonant cavity of the frequency comb generator has an input terminal, which simplifies the structure of the resonant cavity, and the first signal and the second signal can be mixed in the mixer in advance, thereby improving the efficiency of the signal in the resonant cavity.

In one possible design, a nonlinear medium is provided in the resonant cavity, and the nonlinear medium is silicon nitride or silicon. The first signal and the second signal can generate a nonlinear effect through the nonlinear medium, and the nonlinear medium can compensate for the loss of the signal in the resonant cavity during parametric oscillation, so that the interval of the frequency comb signal generated by the first signal and the second signal in the resonant cavity through the nonlinear effect satisfies the threshold condition in the resonant cavity. Silicon nitride and silicon are both semiconductor materials with a wide transmission spectrum and low transmission loss. Therefore, when the nonlinear medium is silicon nitride or silicon, the loss of the signal in the resonant cavity during parametric oscillation can be further reduced.

In a possible design, the resonant cavity is one of a micro-ring resonant cavity, a rectangular resonant cavity, and a cylindrical resonant cavity. When the resonant cavity is a micro-ring resonant cavity, the micro-ring resonant cavity is small in size and easy to integrate, making the structure of the parametric oscillator more compact. The micro-ring resonant cavity has a simple structure, which can reduce the cost of the parametric oscillator. In addition, the micro-ring resonant cavity also has good filtering performance and low loss. It is also small, further improving the efficiency of the output target signal.

In one possible design, the pump source is a laser. A laser is a device that can emit laser light and can generate periodic optical signals, such as optical pulses. The laser is small in size and easy to integrate, which can improve the compactness of the parametric oscillator. The laser has a low cost, which can further reduce the cost of the parametric oscillator.

In a possible design, the control signal source is a microwave source or a control light source. The control signal source can generate an electromagnetic wave signal or an optical signal as the second signal, which improves the application range of the parametric oscillator. In addition, compared with the degenerate optical parametric oscillator working in the optical frequency range with a higher frequency and the degenerate optoelectronic parametric oscillator working in the electrical frequency range with a lower frequency, the present invention can also realize the degenerate parametric oscillation of microwaves or terahertz waves at an intermediate frequency, further improving the working range of the parametric oscillator and improving the modeling efficiency.

A second aspect of an embodiment of the present application provides a signal processing method for a parametric oscillator, comprising:

The pump source generates a first signal, and the control signal source generates a second signal;

Allowing the first signal and the second signal to enter a frequency comb generator;

The first signal and the second signal generate frequency comb solitons in the resonant cavity of the frequency comb generator through nonlinear effects, and the soliton envelope of the frequency comb soliton is formed into a low-frequency electromagnetic wave including multiple random phases.

In this scheme, the pump source generates a first signal, and the control signal source generates a second signal. After the first signal and the second signal are coupled into the resonant cavity, a frequency comb signal is generated in the resonant cavity through nonlinear effects. The frequency comb signal can form a frequency comb soliton in the time domain, and the soliton envelope of the frequency comb soliton forms a low-frequency electromagnetic wave, which is the output target signal, so that the parametric oscillator realizes the conversion of the input signal frequency. Since the phase angle of the frequency comb soliton is random, the phase of the low-frequency electromagnetic wave formed by the soliton envelope is random, so the phase of the target signal output by the frequency comb generator can have multiple phases, that is, the output target signal has more than two phases of 0 or π, so it can be used to construct an XY/Potts model. In addition, by adjusting the control signal source, the frequency of the second signal can be changed, so that the oscillation of the input signal in the resonant cavity can be controlled, and the number of random phases of the low-frequency electromagnetic wave formed by the generated soliton envelope can be adjusted, so that the application range of the parametric oscillator can be further improved to meet the modeling needs of various XY/Potts models. Furthermore, the parametric oscillator in the embodiment of the present application is a frequency comb-based parametric oscillator, which can operate at room temperature, thereby further reducing the difficulty of constructing an XY/Potts model, saving costs, and improving modeling efficiency.

It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a system architecture diagram of a parametric oscillator provided by the present application;

FIG2 is a diagram showing a conversion process of a signal frequency in a parametric oscillator in FIG1 in an embodiment;

FIG3 is a conversion process of the signal frequency in the parametric oscillator in FIG1 in another embodiment;

Figure 4 is a diagram showing the evolution of frequency comb solitons when q = 0;

Figure 5 is the intensity distribution and phase space evolution diagram of the frequency comb soliton when q = 0;

Figure 6 shows the intensity distribution and phase space evolution of frequency comb solitons when q = 4;

FIG7 is a diagram showing the intensity distribution of frequency comb solitons at different q values;

FIG8 is a structural block diagram of a parametric oscillator provided by the present application in an embodiment;

FIG9 is a structural block diagram of a parametric oscillator provided by the present application in another embodiment;

FIG. 10 is a flow chart of a signal processing method of a parametric oscillator provided in the present application.

Reference numerals:
1-Pump source;
2- Control signal source;
3-Frequency comb generator;
31-resonance cavity;
4- Mixer.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

DETAILED DESCRIPTION

In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

In a specific embodiment, the present application is further described in detail below through specific embodiments and in conjunction with the accompanying drawings.

Combinatorial optimization plays a key role in fields such as drug design, traffic physical planning, wireless network resource optimization, and machine learning. Most combinatorial optimization problems are non-deterministic polynomial hard (NP-hard) problems, which are difficult to solve effectively using current general-purpose computers based on the Turing model. However, combinatorial optimization problems can be mapped to the ground state solution problem of the spin model, and then the spin model simulator built based on physical phenomena is used to simulate and solve the spin model, thereby obtaining the solution to the NP-hard problem.

There are one-dimensional Ising model and two-dimensional Potts model for spin models. There are Potts model simulators based on polaritons, Ising model simulators based on coherent optical Ising machine based on degenerate optical parametric oscillator, and Ising model simulators based on optoelectronic parametric oscillator optoelectronic Ising machine. The spin direction of the Ising model can be upward or downward, while the spin direction of the XY/Potts model can be a continuous value (XY model) or a discrete value (Potts model) within a two-dimensional plane. Therefore, the XY/Potts model has more states than the Ising model, can represent more information, and can solve combinatorial optimization problems with a smaller number of spins. However, polaritons need to work in an ultra-low temperature environment, and the signals output by the current degenerate optical parametric oscillator or optoelectronic parametric oscillator have only two phases, 0 or π, which can only be used to construct the Ising model, not the XY/Potts model.

In order to solve this technical problem, the present application provides a parametric oscillator, which generates a frequency comb in a frequency comb generator through a nonlinear effect using a first signal generated by a pump source and a second signal generated by a control signal source, thereby generating a plurality of parametric oscillations with random phases to construct an XY/Potts model. The parametric oscillator can be used in computing devices to improve the solving ability of computing devices, and can also be used in random number generators. It can also be used as a microwave source (small microwave source, ultra-low phase noise microwave source, high-frequency microwave source) for radar remote sensing, communication and navigation, high-speed electronic devices, high-precision time reference allocation and synchronization, etc., without limitation. Taking the use of parametric oscillators in computing devices as an example, the present application is further described in detail through specific embodiments and in conjunction with the accompanying drawings.

An embodiment of the present application provides a parametric oscillator, as shown in Figure 1, including a pump source 1, a control signal source 2 and a frequency comb generator 3, wherein the pump source 1 is used to generate a first signal, the control signal source 2 is used to generate a second signal, and the frequency comb generator 3 is used to generate frequency comb solitons according to the first signal and the second signal. The frequency comb generator 3 is provided with a resonant cavity 31, wherein the first signal and the second signal can enter the resonant cavity 31, and generate frequency comb solitons in the resonant cavity 31 through nonlinear effects, and the soliton envelope of the frequency comb soliton is formed as a low-frequency electromagnetic wave including multiple random phases.

In this embodiment, as shown in FIG1 , the pump source 1 generates a first signal, and the control signal source 2 generates a second signal. After the first signal and the second signal are coupled into the resonant cavity 31, a frequency comb signal is generated in the resonant cavity 31 through a nonlinear effect. The frequency comb signal can form a frequency comb soliton in the time domain, and the soliton envelope of the frequency comb soliton forms a low-frequency electromagnetic wave, which is the output target signal, so that the parametric oscillator realizes the conversion of the input signal frequency. Since the phase angle of the frequency comb soliton is random, the phase of the low-frequency electromagnetic wave formed by the soliton envelope is random, so the phase of the target signal output by the frequency comb generator 3 can have multiple phases, that is, the output target signal has more than two phases of 0 or π, so that it can be used to construct an XY/Potts model. In addition, by adjusting the control signal source 2, the frequency of the second signal can be changed, so that the oscillation of the input signal in the resonant cavity can be controlled, and the number of random phases of the low-frequency electromagnetic wave formed by the generated soliton envelope can be adjusted, so that the application range of the parametric oscillator can be further improved to meet the modeling needs of various XY/Potts models. Furthermore, the parametric oscillator in the embodiment of the present application is a frequency comb-based parametric oscillator, which can operate at room temperature, thereby further reducing the difficulty of constructing an XY/Potts model, saving costs, and improving modeling efficiency.

The nonlinear effect in this embodiment may be four-wave mixing, that is, the first signal and the second signal are converted into signal frequencies by four-wave mixing in the resonant cavity, thereby obtaining a desired signal frequency.

In addition, the first signal in the embodiment of the present application may be an optical signal, and the second signal may be an electromagnetic wave signal such as an optical signal, a radio frequency signal, or a terahertz wave signal.

In a specific embodiment, as shown in FIG. 2 and FIG. 3 , the second signal is a high-frequency signal or a low-frequency signal.

The degenerate optical parametric oscillator operates in a higher frequency optical frequency range, and the degenerate optoelectronic parametric oscillator operates in a lower frequency electrical frequency range.

In this embodiment, the parametric oscillator can not only work within the frequency range of high-frequency signals, but also work within the frequency range of low-frequency signals. Work within the range, increase the working range of the parametric oscillator, and improve modeling efficiency.

In a specific embodiment, the low-frequency signal range of the parametric oscillator may be 10 ⁹ to 10 ¹² Hz, and the high-frequency signal range may be greater than 10 ¹⁴ Hz. Of course, according to the specific structural setting of the parametric oscillator, the low-frequency signal range and high-frequency signal range of the parametric oscillator may also be other ranges, which are not limited here.

The following is an explanation through two specific embodiments.

In a specific embodiment, as shown in FIG2 , the second signal is a low frequency signal, the frequency of the second signal is f _c , the free spectrum range of the resonant cavity 31 is Δν, f _c =q*Δν, wherein q is an integer greater than or equal to zero.

Among them, the free spectrum range (FSR) is the optical frequency or wavelength interval between two consecutive maximum or minimum values of the reflected or transmitted light intensity of the interferometer or diffraction optical element. The minimum frequency interval allowed in the resonant cavity 31 is the free spectrum range, that is, Δν.

In this embodiment, the second signal is a low-frequency signal of frequency _fc , and when _fc =q*Δν, the frequency interval of the frequency comb signal generated by the first signal and the second signal in the resonant cavity 31 through the nonlinear effect can be Δν, which satisfies the threshold condition in the resonant cavity 31, thereby ensuring the generation of frequency comb solitons and ensuring that the soliton envelope of the frequency comb soliton can form a low-frequency electromagnetic wave output by the frequency comb generator, thereby realizing the change of frequency and the output of the phase of the low-frequency electromagnetic wave.

In a specific embodiment, as shown in Figures 2 and 3, when the second signal generated by the control signal source 2 is a low-frequency signal with a frequency of _fc , and _fc =q*Δν, the second signal can be first modulated on the first signal generated by the pump source 1, and the frequency of the first signal is _νp . Due to modulation instability (MI), a group of sideband signals with a frequency difference of q*Δν with the first signal will be generated on both sides of the first signal, that is, the frequency of the sideband signal is _νc , _νc = _νp ±q*Δν. At this time, the modulated signal is input into the resonant cavity 31 of the frequency comb generator, and a frequency comb signal with a frequency interval of Δν is generated through four-wave mixing. The frequency of the frequency comb signal is _νs . The frequency comb signal forms frequency comb solitons in the time domain due to dispersion and thermal effects. The soliton envelope of the frequency comb soliton forms a low-frequency electromagnetic wave with a frequency of _fs , _fs = Δν, which is the output target signal, thereby enabling the parametric oscillator to achieve parametric conversion of the input signal frequency from the electromagnetic wave of q*Δν to the output target signal frequency of the low-frequency electromagnetic wave of _fs = Δν. Since the azimuth angle of the frequency comb soliton is random, the phase of the soliton envelope is also random.

In another specific embodiment, as shown in Figure 3, the second signal is a high-frequency signal, the frequency of the second signal is ν _c , the frequency of the first signal is ν _p , the free spectrum range of the resonant cavity 31 is Δν, and the difference between the frequency ν _c of the second signal and the frequency ν _p of the first signal is an integer q times the free spectrum range Δν, where q is an integer greater than or equal to 0.

In this embodiment, when the second signal is a high-frequency signal of frequency ν _c and the frequency difference between the second signal and the first signal is q*Δν (i.e., ν _c =ν _p ±q*Δν), the second signal and the first signal interfere with each other to produce a difference frequency phenomenon, which can generate a low-frequency electromagnetic wave with a frequency of f _c , and the interval between the first signal and the second signal in the resonant cavity 31 to generate a frequency comb signal through a nonlinear effect is Δν, which satisfies the threshold condition in the resonant cavity 31, thereby ensuring the generation of frequency comb solitons, and ensuring that the soliton envelope of the frequency comb soliton can form a low-frequency electromagnetic wave output by the frequency comb generator, thereby realizing the frequency change and the output of the target signal phase.

In a specific embodiment, as shown in Figure 3, when the second signal generated by the control signal source 2 is a high-frequency signal with a frequency of ν _c , and the frequency difference between the second signal and the first signal is q*Δν (that is, ν _c =ν _p ±q*Δν), the second signal and the first signal interfere with each other to produce a difference frequency phenomenon, which can generate a low-frequency electromagnetic wave with a frequency of f _c , f _c =q*Δν. In the resonant cavity 31 of the frequency comb generator, a frequency comb signal with a frequency interval of Δν is continuously generated through four-wave mixing. The frequency comb signal forms a frequency comb soliton in the time domain due to dispersion and thermal effects. The soliton envelope of the frequency comb soliton forms a low-frequency electromagnetic wave with a frequency of f _s , f _s =Δν. The low-frequency electromagnetic wave is the output target signal, thereby enabling the parametric oscillator to achieve parametric conversion of the output target signal low-frequency electromagnetic wave with a frequency of f _s =Δν. Since the azimuth angle of the frequency comb soliton is random, the phase of the soliton envelope is also random.

In addition to ensuring the generation of frequency comb solitons by designing the frequency difference, the generation of frequency comb solitons can also be ensured by designing the resonant cavity 31, adding auxiliary light to reduce thermal effects, etc., which is not limited here.

In addition, by changing the frequency of the second signal, the oscillation of the input signal in the resonant cavity 31 can be controlled, and the number of random phases of the low-frequency electromagnetic wave formed by the generated soliton envelope can be adjusted.

In a specific embodiment, the phase of the low-frequency electromagnetic wave formed by the soliton envelope is ψ, when q=0, ψ∈(-π,π], when q≥1, ψ=2πn/q-π, where n is a natural number less than q.

In this embodiment, when q=0, during the formation of the frequency comb soliton, the azimuth angle of the frequency comb soliton will randomly stabilize at any position in the interval of (-π, π], and correspondingly, the phase ψ of the low-frequency electromagnetic wave formed by the soliton envelope of the frequency comb soliton is also located at the corresponding Position, so that the phase of the target signal output by the frequency comb generator has multiple. Figure 4 is a diagram of the evolution process of the frequency comb soliton when q=0, and Figure 5 is a diagram of the intensity distribution and phase space evolution of the frequency comb soliton when q=0. As shown in Figures 4 and 5, the signal field in the resonant cavity 31 goes through three stages: continuous, Turing mode and soliton. Finally, the soliton azimuth is randomly stabilized at a position in the interval of (-π,π], and the azimuth of the frequency comb soliton is random.

When q≥1, there are q azimuth angles of the frequency comb soliton, and the azimuth angle of the frequency comb soliton is 2πn/q-π, where n is a natural number less than q. During the formation of the frequency comb soliton, the azimuth angle of the frequency comb soliton will randomly stabilize at one of the q azimuth angles. Correspondingly, the phase ψ of the low-frequency electromagnetic wave formed by the soliton envelope of the frequency comb soliton is also located at the corresponding position, so that the target signal output by the frequency comb generator has q random phases. According to the number of required spins, the value of q is set and the frequency of the second signal is changed, so that the number of random phases of the target signal can be adjusted to meet the modeling requirements of the XY/potts model.

It should be noted that, since the period of the low-frequency electromagnetic wave formed by the soliton envelope, that is, the target signal, is 2π, according to the periodicity, the phase ψ of the target signal coincides at the positions of -π and π. Since the phase ψ of the target signal is in the interval of (-π, π], when n=0, it is recorded as ψ=π.

For example, as shown in Figure 6, when q = 4, there are four azimuth angles of the frequency comb soliton, which are 2πn/q-π, where n = 0, 1, 2, 3. When n = 0, the azimuth angle of the frequency comb soliton is π, when n = 1, the azimuth angle of the frequency comb soliton is -π/2, when n = 2, the azimuth angle of the frequency comb soliton is 0, and when n = 3, the azimuth angle of the frequency comb soliton is π/2, which can indicate that the number of soliton azimuth angles is more than 0 and π. Correspondingly, the low-frequency electromagnetic wave formed by the soliton envelope of the frequency comb soliton, that is, the phase of the target signal is also located at the corresponding 4 positions and has 4 phases. The phase of the target signal output each time is one of the 4 random phases.

In addition, the intensity distribution diagram of frequency comb solitons with different q values is shown in Figure 7. From the figure, it can be seen that the azimuth angle of the frequency comb soliton may also be different when q takes different values. Therefore, it can be shown that by changing the q value, the number of azimuth angles of the frequency comb soliton can be adjusted, thereby adjusting the number of random phases of the low-frequency electromagnetic wave formed by the soliton envelope of the frequency comb soliton.

The specific structure of the parametric oscillator can also be set according to specific circumstances.

In a specific embodiment, as shown in FIG8 , the resonant cavity 31 is provided with a first input end and a second input end, and the first signal can enter the resonant cavity 31 through the first input end, and the second signal can enter the resonant cavity 31 through the second input end.

In this embodiment, as shown in FIG8 , the pump source 1 is coupled to the first input end of the resonant cavity 31, the control signal source 2 is coupled to the second input end of the resonant cavity 31, and the first signal and the second signal enter the resonant cavity 31 through the first input end and the second input end respectively to perform nonlinear action, generate frequency comb solitons, and make the frequency comb generator 3 output the target signal. In this structure, the resonant cavity 31 of the frequency comb generator 3 has two input ends, so that the first signal and the second signal can be directly coupled into the resonant cavity 31, making the structure of the parametric oscillator more compact.

The second signal generated by the control signal source 2 may be a high-frequency signal, and the first signal and the second signal may interfere with each other in the resonant cavity 31 to generate a low-frequency electromagnetic wave signal with a frequency of f _c =q*Δν. Of course, the second signal generated by the control signal source 2 may also be a low-frequency signal, and the second signal may be modulated on the first signal to generate sideband signals ν _c with an interval of Δν on both sides of the first signal.

In another specific embodiment, as shown in FIG9 , the parametric oscillator further includes a mixer 4, the resonant cavity 31 is provided with a third input terminal, the mixer 4 is used to mix the first signal and the second signal, and output the mixed first signal and the second signal, and the mixed first signal and the second signal can enter the resonant cavity 31 through the third input terminal.

In this embodiment, as shown in FIG9 , the pump source 1 and the control signal source 2 are coupled to the mixer 4, and the mixer is connected to the third input terminal of the resonant cavity 31. The first signal generated by the pump source 1 and the second signal generated by the control signal source 2 can enter the mixer for mixing, and the mixed signals can be coupled into the resonant cavity 31 through the third input terminal for nonlinear action, generating frequency comb solitons, so that the frequency comb generator 3 outputs the target signal. In this structure, the resonant cavity 31 of the frequency comb generator 3 has one input terminal, which simplifies the structure of the resonant cavity 31, and the first signal and the second signal can be mixed in the mixer in advance, thereby improving the efficiency of the signal in the resonant cavity 31.

In this structure, the second signal generated by the control signal source 2 can be a high frequency signal or a low frequency signal, and the signal obtained by mixing the first signal and the second signal includes a low frequency electromagnetic wave signal with a frequency of f _c =q*Δν.

In a specific embodiment, the various components of the parametric oscillator can be connected through waveguide coupling, so that the signal can be transmitted through the waveguide coupling, that is, the input signal can be coupled into the resonant cavity 31 through the waveguide, wherein the waveguide can be a waveguide with low transmission loss characteristics, such as a silicon waveguide, etc., to reduce the loss during signal transmission. Of course, the waveguide can also be made of other materials, which is not limited here.

In addition, the various components of the parametric oscillator may also be coupled and connected through other components to achieve signal transmission, which is not limited here.

In another specific embodiment, a nonlinear medium is disposed in the resonant cavity 31, and the nonlinear medium is silicon nitride or silicon.

In this embodiment, the first signal and the second signal can generate a nonlinear effect through the nonlinear medium, and the nonlinear medium can compensate for the loss of the signal in parametric oscillation in the resonant cavity 31, so that the interval of the frequency comb signal generated by the first signal and the second signal in the resonant cavity 31 through the nonlinear effect meets the threshold condition in the resonant cavity 31. Silicon nitride and silicon are both semiconductor materials with a wide transmission spectrum and low transmission loss. Therefore, when the nonlinear medium is silicon nitride or silicon, the loss of the signal in the resonant cavity 31 for parametric oscillation can be further reduced.

Of course, the nonlinear medium may also be other semiconductor materials with a wide transmission spectrum and low transmission loss, such as silicon dioxide, etc., which is not limited here.

In a specific embodiment, the resonant cavity 31 is one of a micro-ring resonant cavity, a rectangular resonant cavity, and a cylindrical resonant cavity. Of course, the resonant cavity 31 can also be other resonant cavities, which is not limited here.

In the embodiment of the present application, the resonant cavity 31 is a micro-ring resonant cavity. The micro-ring resonant cavity is small in size and easy to integrate, which makes the structure of the parametric oscillator more compact. The structure of the micro-ring resonant cavity is simple, which can reduce the cost of the parametric oscillator. In addition, the micro-ring resonant cavity also has good filtering performance and low loss, which further improves the efficiency of the output target signal.

In a specific embodiment, as shown in FIG1 , the pump source 1 is a laser.

In this embodiment, the laser is a device capable of emitting laser light, and can generate periodic optical signals, such as optical pulses. The laser is small in size and easy to integrate, which can improve the compactness of the parametric oscillator, and the laser has a low cost, which can further reduce the cost of the parametric oscillator.

The laser may be a gas laser, a solid laser, a tunable laser, or other types of lasers, which are not limited here.

Of course, depending on the working material and the operating conditions of the laser, other forms of pump source devices may also be used, and are not limited here.

In a specific embodiment, as shown in FIG1 , the control signal source 2 is a microwave source or a control light source.

In this embodiment, the control signal source 2 can generate an electromagnetic wave signal or an optical signal as the second signal, thereby improving the application range of the parametric oscillator. In addition, compared with the degenerate optical parametric oscillator operating in a higher frequency optical frequency range and the degenerate optoelectronic parametric oscillator operating in a lower frequency electrical frequency range, the present invention can also realize degenerate parametric oscillation of microwaves or terahertz waves at an intermediate frequency, further improving the operating range of the parametric oscillator and improving the modeling efficiency.

Among them, when the control signal source 2 is a microwave source, it can generate electromagnetic waves. The microwave source can be a radio wave generating device or a terahertz wave generating device. When the control signal source 2 is a control light source, it can generate optical signals. The control light source can be a laser device. Of course, according to actual conditions, the control signal source 2 can also be other microwave sources or control light sources, which is not limited here.

The embodiment of the present application further provides a signal processing method of a parametric oscillator, as shown in FIG10 , comprising:

S1, pump source 1 generates a first signal, and control signal source 2 generates a second signal.

In this step, the first signal may be an optical signal, and the second signal may be an optical signal, an electromagnetic wave signal, or a terahertz wave signal.

S2, allowing the first signal and the second signal to enter the frequency comb generator 3.

In this step, the frequency comb generator 3 is provided with a resonant cavity 31 , and the first signal and the second signal can generate a nonlinear effect in the resonant cavity 31 after entering the frequency comb generator 3 .

S3, the first signal and the second signal generate frequency comb solitons through nonlinear effect in the resonant cavity 31 of the frequency comb generator 3, and the soliton envelope of the frequency comb soliton is formed into a low-frequency electromagnetic wave including multiple random phases.

In this step, the low-frequency electromagnetic wave is the output target signal, so that the parametric oscillator realizes the conversion of the input signal frequency. Since the phase angle of the frequency comb soliton is random, the phase of the low-frequency electromagnetic wave formed by the soliton envelope is random, so the phase of the target signal output by the frequency comb generator 3 can have multiple phases, that is, the output target signal has more than two phases of 0 or π, so it can be used to construct the XY/Potts model.

In this embodiment, as shown in FIG. 1 and FIG. 10 , the pump source 1 generates a first signal, and the control signal source 2 generates a second signal. After the first signal and the second signal are coupled into the resonant cavity 31, a frequency comb signal is generated in the resonant cavity 31 through a nonlinear effect. The frequency comb signal can form a frequency comb soliton in the time domain. The soliton envelope of the frequency comb soliton forms a low-frequency electromagnetic wave, which is the output target signal, so that the parametric oscillator realizes the conversion of the input signal frequency. Since the phase angle of the frequency comb soliton is random, the soliton The phase of the low-frequency electromagnetic wave formed by the envelope is random, so the phase of the target signal output by the frequency comb generator 3 can have multiple phases, that is, the output target signal has more than two phases of 0 or π, so that it can be used to construct the XY/Potts model. In addition, by adjusting the control signal source 2, the frequency of the second signal can be changed, so that the oscillation of the input signal in the resonant cavity can be controlled, and the number of random phases of the low-frequency electromagnetic wave formed by the generated soliton envelope can be adjusted, so as to further improve the scope of application of the parametric oscillator and meet various XY/Potts model modeling requirements. And the parametric oscillator in the embodiment of the present application is a parametric oscillator based on a frequency comb, which can work at room temperature, so as to further reduce the difficulty of constructing the XY/Potts model, save costs, and improve modeling efficiency.

The nonlinear effect in this embodiment may be four-wave mixing, that is, the first signal and the second signal are converted into signal frequencies by four-wave mixing in the resonant cavity, thereby obtaining a desired signal frequency.

In addition, the first signal in the embodiment of the present application may be an optical signal, and the second signal may be an electromagnetic wave signal such as an optical signal, a radio frequency signal, or a terahertz wave signal.

The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the embodiment of the present application should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application should be based on the protection scope of the claims.

Claims (12)

A parametric oscillator, comprising: A pump source, the pump source is used to generate a first signal; A control signal source, wherein the control signal source is used to generate a second signal; A frequency comb generator, the frequency comb generator is used to generate frequency comb solitons according to the first signal and the second signal, and the frequency comb generator is provided with a resonant cavity; The first signal and the second signal can enter the resonant cavity and generate the frequency comb soliton through nonlinear effect in the resonant cavity, and the soliton envelope of the frequency comb soliton is formed into a low-frequency electromagnetic wave including multiple random phases. The parametric oscillator according to claim 1, characterized in that the second signal is a high-frequency signal or a low-frequency signal. The parametric oscillator according to claim 2, characterized in that the second signal is a low-frequency signal, the frequency of the second signal is f _c , the free spectrum range of the resonant cavity is Δν, and f _c =q*Δν; Here, q is an integer greater than or equal to 0. The parametric oscillator according to claim 2, characterized in that the second signal is a high-frequency signal, the frequency of the second signal is ν _c , the frequency of the first signal is ν _p , the free spectrum range of the resonant cavity is Δν , and the difference between the frequency ν _c of the second signal and the frequency ν _p of the first signal is an integer q times the free spectrum range Δν ; Here, q is an integer greater than or equal to 0. The parametric oscillator according to claim 3 or 4, characterized in that the phase of the low-frequency electromagnetic wave formed by the soliton envelope is ψ; When q=0, ψ∈(-π,π]; When q≥1, ψ＝2πn/q-π, wherein n is a natural number less than q. The parametric oscillator according to any one of claims 1 to 4, characterized in that the resonant cavity is provided with a first input terminal and a second input terminal; The first signal can enter the resonant cavity through the first input end; The second signal can enter the resonant cavity through the second input terminal. The parametric oscillator according to any one of claims 1 to 4, characterized in that the parametric oscillator further comprises a mixer, and the resonant cavity is provided with a third input terminal; The mixer is used to mix the first signal and the second signal, and output the mixed first signal and the second signal; The mixed first signal and the second signal can enter the resonant cavity through the third input terminal. The parametric oscillator according to any one of claims 1 to 4, characterized in that a nonlinear medium is provided in the resonant cavity; The nonlinear medium is silicon nitride or silicon. The parametric oscillator according to any one of claims 1 to 4 is characterized in that the resonant cavity is one of a microring resonant cavity, a rectangular resonant cavity, and a cylindrical resonant cavity. The parametric oscillator according to any one of claims 1 to 4, characterized in that the pump source is a laser. The parametric oscillator according to any one of claims 1 to 4, characterized in that the control signal source is a microwave source or a control light source. A signal processing method for a parametric oscillator, characterized by comprising: The pump source generates a first signal, and the control signal source generates a second signal; Allowing the first signal and the second signal to enter a frequency comb generator; The first signal and the second signal generate frequency comb solitons in the resonant cavity of the frequency comb generator through nonlinear effects, and the soliton envelope of the frequency comb soliton is formed into a low-frequency electromagnetic wave including multiple random phases.