Control method, storage medium and terminal based on orthogonal polarization mode brillouin laser kerr optical frequency comb

Abstract

The application discloses a control method, a storage medium and a terminal based on a Brillouin laser Kerr optical frequency comb of an orthogonal polarization mode, and is based on a control module; the method comprises the following steps: an initial control step; a secondary pumping control step: a second control command is sent to an adjustable wavelength laser, and based on monitoring data of a fourth optical detector used for monitoring a state of a stimulated Brillouin laser of a cross-polarization TM mode after polarization beam splitting of light, a pumping laser wavelength blue shift speed and an optical power are further adjusted until a Kerr optical frequency comb state appears. The application generates a stimulated Brillouin laser of an orthogonal polarization mode to form a Kerr optical frequency comb through secondary pumping, filters specific comb tooth interval light waves of the optical frequency comb, performs beat frequency on the filtered light wave signals, and obtains a required microwave signal output.

Description

Technical Field

[0001] This invention relates to the field of microwaves, and more particularly to a control method, storage medium, and terminal based on an orthogonal polarization mode Brillouin laser Kerr optical frequency comb. Background Technology

[0002] Modern radar and microwave communication systems both require the transmission and reception of microwave signals. Microwave local oscillator signal sources are used in both the transmitter and receiver. In the transmission channel, the transmitted signal is generally mixed with the local oscillator signal and then amplified before being transmitted. In the reception channel, the received signal is generally mixed with the local oscillator signal to obtain an intermediate frequency signal, which is then detected and processed to extract the required information. Therefore, microwave local oscillator signal sources are indispensable in modern radar and microwave communication systems. Generating local oscillator signals with high spectral purity and low phase noise has always been a goal pursued by modern radar and communication systems.

[0003] Generally, the quality of the microwave signal generated by a microwave oscillator depends on the energy storage performance of the oscillation cavity. To generate a high-quality microwave signal, a high-Q, low-loss energy storage unit is necessary. Most current microwave oscillators are based on electronic (such as dielectric oscillators) and acoustic (such as crystal oscillators) energy storage elements. When these elements operate at frequencies above GHz, their energy storage characteristics deteriorate significantly, resulting in poorer phase noise and spectral purity of the generated high-frequency microwaves.

[0004] To meet the needs of generating, transmitting, and processing high-frequency and ultra-wideband signals in the microwave field, microwave photonics utilizes the advantages of photonics technology, such as its large bandwidth and resistance to electromagnetic interference, to generate and process microwave radio frequency signals. It can generate high-spectral-purity, low-phase-noise signals of several GHz or even hundreds of GHz, demonstrating unique technical advantages in the microwave / millimeter-wave band and exhibiting excellent phase noise performance.

[0005] Optical microcavities, such as traditional Fabry-Perot (FP) cavities and all-solid-state dielectric whispering-gallery mode microcavities, possess stable high-Q resonant modes. By combining a continuous-wave pumped laser with a high-Q microcavity, this novel photonic microwave technology can be used to generate high-quality microwave signals. Currently, companies like OEwaves in the United States have achieved 35GHz Ka-band frequency output OEO opto-oscillators by combining narrow-linewidth DFB lasers with magnesium fluoride crystal whispering-gallery mode resonators. They have also released products that utilize the Kerr nonlinearity effect of magnesium fluoride crystal whispering-gallery mode resonators, using DFB lasers to pump and excite Kerr optical frequency combs, and obtaining ultra-low phase noise 10GHz microwave signal output by beating the optical frequency comb signal.

[0006] The main problems with current photonic microwave solutions that use optical microcavities to generate microwave signals are that the optical microcavities, such as FP cavities, are large in size and difficult to integrate, and the high cost and assembly requirements of the high-reflectivity cavity mirrors. Similarly, whispering-gallery mode resonators made of materials such as magnesium fluoride and silicon also face difficulties in fabrication, requiring extremely high precision in the fabrication equipment. In addition, there are problems such as difficulties in optical assembly and debugging, and complex manufacturing processes. To generate high-quality microwave signal output, this type of photonic microwave technology requires reverse self-injection locking of the DFB laser in order to improve system stability. This requires the reflected light from the resonator to have a special optical mode field and phase matching, which leads to complex debugging and assembly processes. All of these factors seriously increase the difficulty of large-scale application of this type of technology.

[0007] With the development of silicon-based integrated photonics in recent years, the design of micro-ring cavities based on silicon nitride waveguides has attracted increasing attention. Extensive research has been conducted on the Kerr nonlinear effect of silicon nitride-based through-ring waveguide micro-ring cavities. Some schemes have been published that generate 10GHz microwave signals by exciting a Kerr frequency comb using a silicon nitride micro-ring cavity and then beat-frequencying the signal. However, significant technical challenges remain. For example, high-power communication-band laser signals are required for pumping, but high-power DFB lasers have poor noise performance. The output noise performance of the pump laser directly affects the final beat-frequency microwave signal, making it difficult for the system to achieve microwave signal output with good phase noise performance. Furthermore, during the Kerr effect soliton output process based on silicon nitride micro-ring cavities, the pump laser needs detuning. When the pump light is red-detuned in the single soliton state of the Kerr frequency comb, the micro-ring cavity is actually in a thermally unstable state, and the system cannot achieve a stable long-term operating state.

[0008] To address this, some have proposed a laser-assisted heating scheme. This involves adding an auxiliary laser to the pump laser that generates the Kerr frequency comb, injecting it into the micro-ring cavity in the opposite direction to the pump laser's propagation direction. By precisely controlling the red detuning wavelength of the pump laser and the blue detuning wavelength of the auxiliary laser, the thermal balance of the micro-ring cavity in the Kerr frequency comb single soliton state can be controlled and adjusted, avoiding thermal instability in this state and enabling stable long-term operation of the silicon nitride micro-ring cavity. However, adding an auxiliary laser to inject laser light into the micro-ring cavity requires simultaneous real-time control of two lasers, increasing the system's control difficulty and complexity. Therefore, no reports of this scheme being practically applied have been found to date.

[0009] According to the latest research, a Brillouin laser is generated by pumping a pump laser into a fiber microcavity. The Brillouin laser has an ultra-narrow linewidth and very low noise. This Brillouin laser is then used as the pump light to excite the microcavity and generate a Kerr frequency comb. The advantage of this approach is that using a Brillouin laser to pump and excite the Kerr frequency comb avoids the high noise levels associated with initial high-power laser pumping, representing a significant advancement for photonic microwave technology. However, this approach uses fiber FP microcavity technology, which adjusts the internal stress of the fiber material by applying external pressure to the microcavity to regulate its resonant frequency parameters. This method results in a fiber microcavity that is sensitive to external stress, leading to low system stability and complex parameter adjustment processes. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a control method, storage medium, and terminal based on an orthogonal polarization mode Brillouin laser Kerr optical frequency comb.

[0011] The objective of this invention is achieved through the following technical solution:

[0012] A first aspect of the present invention provides a microwave generator based on an orthogonally polarized mode Brillouin laser Kerr frequency comb, comprising:

[0013] Control module;

[0014] A tunable wavelength laser receives commands from the control module and outputs a pump laser with corresponding wavelength and power.

[0015] An optical amplifier amplifies the pump laser.

[0016] An optical circulator, with its first port used to receive the amplified pump laser;

[0017] The silicon nitride micro-ring cavity receives the pump laser through the second port of the optical circulator at the optical input end. After the Brillouin laser is excited inside the cavity, it is output as a mixed laser along with the reflected pump laser through the optical input end to the second port of the optical circulator.

[0018] The optically polarized beam splitter receives the mixed laser output from the third port of the optical circulator, filters the pump laser in the mixed laser, and outputs the split Brillouin laser.

[0019] The photonic filtering module receives the Brillouin laser from the optically polarized beam splitter, selects the corresponding frequency interval, and then outputs the filtered photonic signal.

[0020] The first photodetector receives the photon signal, beats it, and then outputs a microwave signal.

[0021] The silicon nitride micro-ring cavity generates resonant light under the coupled input pump laser, and excites orthogonally polarized Brillouin lasers within the micro-ring cavity as secondary pump light to form a Kerr frequency comb.

[0022] Furthermore, the Brillouin laser and the pump laser are two orthogonally polarized laser signals; wherein the Brillouin laser is in TM mode and the pump laser is in TE mode, or the Brillouin laser is in TE mode and the pump laser is in TM mode.

[0023] Furthermore, the control module controls the tunable wavelength laser, including:

[0024] The initial input pump laser wavelength is set at the blue detuning point of the resonant peak wavelength corresponding to the TE mode polarized photon in the silicon nitride micro-ring cavity. The wavelength is gradually increased and blue-shifted to bring the pump laser closer to the resonant peak. The input pump laser is coupled into the silicon nitride micro-ring cavity for resonance. The resonant power is gradually increased, and the orthogonally polarized TM mode Brillouin laser is excited by the resonant light in the silicon nitride micro-ring cavity.

[0025] The control module further adjusts the blue shift rate and optical power of the pump laser wavelength until the Kerr optical frequency comb state is achieved. It continues to fine-tune the input pump laser by blue shifting. The stimulated Brillouin laser of the secondary pump laser will red-shift from the red detuning position of the TM mode resonance peak wavelength and gradually leave the resonance peak of the silicon nitride micro-ring cavity. The power of the Kerr optical frequency comb excited in the silicon nitride micro-ring cavity will decrease in a step-like manner until the desired soliton state optical frequency comb output is obtained, and the optical comb tooth spacing is stabilized.

[0026] Furthermore, the microwave generating device further includes one or more of the following photodetectors:

[0027] The second photodetector has its input end connected to the through-output port of the silicon nitride micro-ring cavity, and its output end connected to the control module to monitor the working status of the pump laser.

[0028] The third photodetector has its input end connected to the lower output port of the silicon nitride micro-ring cavity, and its output end connected to the control module to monitor the working status of the resonant light in the silicon nitride micro-ring cavity.

[0029] The fourth photodetector has its input end connected to the optical splitter located between the optical polarization beam splitter and the photon filter module, and its output end connected to the controller, used to monitor the working status of the Kerr optical frequency comb in the micro-ring cavity.

[0030] Furthermore, the second and third photodetectors cooperate to regulate the pump laser process in the initial setup; the fourth photodetector cooperates to further adjust the regulation of the pump laser process.

[0031] Furthermore, the photonic filtering module includes an independent FSR with spectral line spacing. 滤波A photonic filter, wherein the photonic filter filters the orthogonal mode Brillouin laser Kerr frequency comb signal; FSR 滤波 =M×FSR 布里渊 M is an integer, FSR 布里渊 The resonant peak spectral line spacing is for the silicon nitride microring cavity.

[0032] Furthermore, the photonic filtering module includes an optical splitter, a first photonic filter, a second photonic filter, and an optical combiner. The optical splitter receives the laser light from the optically polarized beam splitter and splits it into two beams in a 50:50 ratio, which then enter the first photonic filter and the second photonic filter, respectively. Based on the microwave signal of the required band, the corresponding Kerr optical frequency comb photonic signal is selected. The two photonic signals are then combined and input into the first photodetector.

[0033] Among them, the spectral line spacing FSR of the first photonic filter and the second photonic filter 滤波 It needs to be larger and require a signal response bandwidth greater than that of the first photodetector, and the FSR 滤波 FSR not with Kerr frequency comb 布里渊 They are multiples of each other.

[0034] Furthermore, the resonant peak frequencies of the lasers in TE mode and TM mode in the silicon nitride microring cavity are determined according to the free spectrum interval FSR. 布里渊 GHz interval distribution, n*FSR 布里渊 There are several resonant peak distributions, where n is an integer. The resonant peak frequencies of the orthogonally polarized TE mode laser and TM mode laser have a slight interval, with a difference of ΔυMHz.

[0035] The frequency shift of the Brillouin laser excited by the pump light in the silicon nitride micro-ring cavity is f. ΔSBL Design of FSR for silicon nitride micro-ring cavity 布里渊 The value is (f) ΔSBL +Δυ)=m*FSR 布里渊 m is an integer; based on this FSR 布里渊 The value is calculated according to the formula FSR = Δλ = λ 2 / n g L is used to design the size of the silicon nitride microring cavity, where λ is the wavelength of light, and n is the wavelength of light. g Let L be the group refractive index of the waveguide, and L be the length of the optical microcavity, i.e., the length of the silicon nitride microring cavity.

[0036] Furthermore, in determining the FSR 布里渊 Subsequently, the wavelength of the Brillouin gain region and the FSR of the TM polarized photonic comb were designed. 布里渊 The resonant peaks of the silicon nitride microring cavity overlap, and the peak wavelength of the Brillouin gain region is designed to be located at a slightly reddish detuned position relative to the resonant peak wavelength, according to the Brillouin frequency shift f. ΔSBLThe corresponding TE polarized photon is selected as the center wavelength of the input pump light; through dispersion engineering design, the TM mode polarized photon is optimized to exhibit anomalous dispersion in the BGS wavelength region.

[0037] Furthermore, the tunable wavelength laser is a 1550nm communication band laser, the photon signal obtained by the photon filtering module is in the Ka band, and m is 4, f ΔSBL The value of is 11, and M is 12 or 13.

[0038] The beneficial effects of this invention are:

[0039] (1) In an exemplary embodiment of the present invention, a Kerr optical frequency comb is formed by secondary pumping of a silicon nitride micro-ring cavity with an orthogonally polarized mode stimulated Brillouin laser. The optical wave with a specific comb tooth spacing of the optical frequency comb is filtered, and the filtered optical wave signal is beat-frequencyed to obtain the desired microwave signal output. The silicon nitride micro-cavity is pumped by an input laser signal to generate a stimulated Brillouin laser. The generated Brillouin laser has a narrow linewidth and low noise. As a secondary pump light to generate a Kerr optical frequency comb, it can effectively isolate and reduce the noise influence caused by the conversion of the input pump laser signal, and can effectively improve the spectral purity of the microwave signal generated by the beat-frequency light, and obtain an ultra-low phase noise microwave signal. At the same time, the Kerr optical frequency comb signal is formed by secondary pumping with an orthogonally polarized mode stimulated Brillouin laser. The input pump laser signal and the orthogonally polarized mode Kerr optical frequency comb signal are separated by a polarization beam splitter. This can effectively reduce the amplitude, noise and other unstable effects caused by the input pump laser signal, and can effectively improve the spectral purity of the microwave signal generated by the beat-frequency light, and obtain an ultra-low phase noise microwave signal.

[0040] (2) In another exemplary embodiment of the present invention, when the pump laser is input, it first enters the blue-shifted position from the blue-detuned position of the resonant peak wavelength corresponding to the TE-mode polarized photon, while the excited secondary pump Brillouin laser is located at the red-detuned position of the TM-mode polarized photon. Initially, the photogenerated heat in the microcavity is mainly contributed by the Brillouin laser of the TM-mode polarized photon. As the input pump light continues to blue-shift, the optical frequency comb is formed and speaks to the soliton state. The Brillouin laser will also gradually red-shift away from the resonant peak of the microcavity, which will lead to a decrease in heat in the microcavity. At this time, the blue-shifted input pump light is close to the resonant peak of the corresponding TE-mode polarized photon, which can compensate for the decrease in cavity heat caused by the red-shift of the Brillouin laser SBL, thereby overcoming the thermal instability phenomenon of the traditional silicon nitride micro-ring cavity Kerr optical frequency comb under red detuning and realizing the stable operation of the Brillouin Kerr optical frequency comb.

[0041] (3) In another exemplary embodiment of the present invention, the present invention uses a photonic filter with spectral line spacing FSR filtering to filter the orthogonal mode Brillouin laser Kerr optical frequency comb signal. The optical comb tooth spacing of the silicon nitride micro-ring cavity spectral line spacing FSR Brillouin is small, and the FSR filtering spacing is large. The design selects FSR filter = M × FSR Brillouin (M is an integer) = Ka band microwave frequency, which can effectively reduce the number of beat frequency photons and effectively reduce the generation of stray signals to obtain high spectral purity microwave signals.

[0042] (4) In yet another exemplary embodiment of the present invention, the frequency shift of the Brillouin radiation is f ΔSBL The frequency difference between the optical resonant peaks of the orthogonally polarized modes (TM and TE) in the silicon nitride microcavity is Δυ, and the resonant spectral line spacing chosen for the silicon nitride microcavity design is FSR. 布里渊 According to (f ΔSBL +Δυ)=m*FSR 布里渊 m = 1, 2, 3, 4...m is an integer. Choosing a larger m results in a smaller spectral line spacing, making it easier for the Brillouin radiation gain region to overlap with the resonant center wavelength of the micro-ring cavity with smaller errors. However, a smaller spectral line spacing makes it difficult to obtain a single photon comb spectral line through photon filtering, and may increase stray signals in the photogenerated microwave signal, leading to a decrease in the spectral purity of the microwave signal. Therefore, the design of the m value here needs to be comprehensively considered. Generally, depending on the required frequency, such as the Ka-band microwave signal frequency, m = 4 or 6 is preferred. It needs to be flexibly adjusted according to the specific application requirements.

[0043] (5) In yet another exemplary embodiment of the present invention, based on the silicon nitride microring cavity, according to (f ΔSBL +Δυ)=m*FSR 布里渊 m = 1, 2, 3, 4...m are integers, determining the FSR of the micro-annular cavity design. 布里渊 Design the Brillouin gain region wavelength (BGS) and the TM polarized photonic comb spacing FSR. 布里渊 The micro-ring cavity resonant peaks overlap, and the BGS peak is designed to be located at a slightly reddish detuned position relative to the resonant peak wavelength, according to the Brillouin frequency shift f. ΔSBL The corresponding TE-polarized photon is selected as the center wavelength of the input pump light. Through dispersion engineering, the anomalous dispersion of the TM-mode polarized photon in the BGS wavelength region is optimized, which facilitates the optimized excitation of the Kerr frequency comb in this wavelength region under TM mode.

[0044] (6) In another exemplary embodiment of the present invention, the control module issues commands to control the wavelength and power of the input pump laser. By monitoring the state of the micro-ring cavity resonant light and the output state of the optical frequency comb, and by big data analysis and table lookup analysis, the optimized input pump light drive control is obtained, thereby realizing the stable operation of the orthogonal polarization mode Brillouin laser Kerr optical frequency comb of the present invention, and obtaining an ultra-low phase noise microwave signal generated by the beat frequency of the optical signal. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the connection structure of a microwave generator based on an orthogonal polarization mode Brillouin laser Kerr frequency comb, provided in an exemplary embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of one of the photonic filtering modules provided in an exemplary embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of another photonic filtering module provided in an exemplary embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram illustrating the principle of an orthogonally polarized mode Brillouin laser Kerr optical frequency comb provided in an exemplary embodiment of the present invention. Detailed Implementation

[0049] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0053] See Figure 1 , Figure 1 An exemplary embodiment of the present invention is shown, providing a microwave generator based on an orthogonally polarized mode Brillouin laser Kerr frequency comb, comprising:

[0054] Control module;

[0055] A tunable wavelength laser receives commands from the control module and outputs a pump laser with corresponding wavelength and power.

[0056] An optical amplifier amplifies the pump laser.

[0057] An optical circulator, with its first port used to receive the amplified pump laser;

[0058] The silicon nitride micro-ring cavity receives the pump laser through the second port of the optical circulator at the optical input end. After the Brillouin laser is excited inside the cavity, it is output as a mixed laser along with the reflected pump laser through the optical input end to the second port of the optical circulator.

[0059] The optically polarized beam splitter receives the mixed laser output from the third port of the optical circulator, filters the pump laser in the mixed laser, and outputs the split Brillouin laser.

[0060] The photonic filtering module receives the Brillouin laser from the optically polarized beam splitter, selects the corresponding frequency interval, and then outputs the filtered photonic signal.

[0061] The first photodetector receives the photon signal, beats it, and then outputs a microwave signal.

[0062] The silicon nitride micro-ring cavity generates resonant light under the coupled input pump laser, and excites orthogonally polarized Brillouin lasers within the micro-ring cavity as secondary pump light to form a Kerr frequency comb.

[0063] Specifically, in this exemplary embodiment, the tunable wavelength laser outputs laser light of corresponding wavelength and power according to the command of the control module. This laser signal, after optical amplification, is input to the first port of the optical circulator, and then outputs through the second port of the circulator into a silicon nitride (Si3N4) micro-ring cavity as the input pump laser signal. The orthogonally polarized Brillouin laser (TM mode or TE mode, as described in the exemplary embodiment below), excited by the resonant light in the silicon nitride micro-ring cavity, is reflected in the silicon nitride micro-ring cavity in the opposite direction to the input pump laser transmission direction, and outputs from the port of the silicon nitride micro-ring cavity into the second port of the optical circulator. The output optical signal from the third port of the optical circulator contains orthogonally polarized TE and TM mode photons. After passing through the optical polarization beam splitter, the photon signal related to the input pump laser is filtered out, leaving only the polarized photons related to the Brillouin laser. A photon filter with a corresponding frequency interval is selected and designed to filter out the photon signal with the relevant comb tooth interval in the Kerr optical frequency comb, resulting in two or more photon signals with equal spectral line intervals. The filtered photon signal is then input into the first photodetector, and after beat frequency, the first photodetector outputs a microwave signal, thereby obtaining the required ultra-low phase noise microwave signal.

[0064] Afterwards, the control module performs a second pumping operation after adjusting the wavelength and power of the pump laser, until the silicon nitride micro-ring cavity exhibits a Kerr frequency comb state.

[0065] In this exemplary embodiment, a Kerr frequency comb is formed by secondary pumping of an orthogonally polarized mode stimulated Brillouin laser based on a silicon nitride micro-cavity. The light waves at specific tooth intervals of the frequency comb are filtered, and the filtered light signals are beat-frequencyd to obtain the desired microwave signal output. Specifically, the silicon nitride microcavity is pumped by the input laser signal to generate a stimulated Brillouin laser. The generated Brillouin laser has a narrow linewidth and low noise. As a secondary pump for generating the Kerr frequency comb, it effectively isolates and reduces the noise impact caused by the conversion of the input pump laser signal, effectively improving the spectral purity of the beat-frequency generated microwave signal and obtaining an ultra-low phase noise microwave signal. Simultaneously, the Kerr frequency comb signal is formed by secondary pumping with an orthogonally polarized mode stimulated Brillouin laser. A polarization beam splitter separates the input pump laser signal from the orthogonally polarized mode Kerr frequency comb signal, effectively reducing the amplitude, noise, and other instability effects caused by the input pump laser signal, effectively improving the spectral purity of the beat-frequency generated microwave signal and obtaining an ultra-low phase noise microwave signal.

[0066] Furthermore, this invention is based on a silicon nitride micro-ring cavity. The control module issues commands to control the wavelength and power of the input pump laser. By monitoring the resonant light state of the silicon nitride micro-ring cavity and the output state of the optical frequency comb, and through big data analysis and table lookup analysis, optimized input pump light drive control is obtained, realizing the stable operation of the orthogonal polarization mode Brillouin laser Kerr optical frequency comb of this invention, and obtaining an ultra-low phase noise microwave signal generated by the beat frequency of the optical signal.

[0067] It should be noted that, in one exemplary embodiment, the Brillouin laser and the pump laser are two orthogonally polarized laser signals; wherein the Brillouin laser is in TM mode and the pump laser is in TE mode, or the Brillouin laser is in TE mode and the pump laser is in TM mode. In the following exemplary embodiments, the Brillouin laser is in TM mode and the pump laser is in TE mode.

[0068] More preferably, in an exemplary embodiment, the control module controls the tunable wavelength laser (i.e., primary pump and secondary pump) by including:

[0069] Primary pump: A tunable wavelength laser outputs laser light of corresponding wavelength and power according to the control module's commands. This laser signal is amplified and input to the first port of an optical circulator, then output through the second port of the circulator to the silicon nitride (Si3N4) micro-ring cavity as the input pump laser signal. Initially, the input pump laser wavelength is set at the blue detuning point of the resonance peak wavelength corresponding to the TE-mode polarized photon in the silicon nitride micro-ring cavity. Gradually increasing the wavelength blue shift brings the pump laser closer to the resonance peak, and the input pump laser couples into the silicon nitride micro-ring cavity for resonance. The resonant power gradually increases. (In an exemplary embodiment, the microwave generator further includes one or more of the following photodetectors: such as...) Figure 1 As shown, the second photodetector has its input end connected to the through-output port of the silicon nitride micro-ring cavity and its output end connected to the control module to monitor the working status of the pump laser; the third photodetector has its input end connected to the lower output port of the silicon nitride micro-ring cavity and its output end connected to the control module to monitor the working status of the resonant light in the silicon nitride micro-ring cavity; the second and third photodetectors work together to control the pump laser process in the initial settings, and the orthogonally polarized TM mode Brillouin laser excited by the resonant light in the silicon nitride micro-ring cavity; the reflected light in the silicon nitride micro-ring cavity is in the opposite direction to the transmission direction of the input pump laser, and is output from the port of the silicon nitride micro-ring cavity into the second port of the optical circulator, and then output through the third port of the optical circulator. The output light signal of the third port of the optical circulator contains orthogonally polarized TE and TM mode polarized photons. After passing through the optical polarization beam splitter, the photon signal related to the input pump laser is filtered out, and only the TM mode polarized photons related to the Brillouin laser are output.

[0070] Secondary pumping: The control module further adjusts the blue shift rate and optical power of the pump laser wavelength (in an exemplary embodiment, the microwave generator further includes one or more of the following photodetectors: such as...). Figure 1 As shown, the fourth photodetector, with its input end connected to the optical splitter (90:10 splitter) located between the optical polarization beam splitter and the photon filter module, and its output end connected to the controller, is used to monitor the working state of the Kerr frequency comb within the micro-ring cavity. The fourth photodetector further adjusts the control of the pump laser process. In this step, the stimulated Brillouin laser state of the cross-polarized TM mode is monitored by the fourth photodetector until the Kerr frequency comb state appears (which can be monitored by a preset empirical time, or by the fourth photodetector in the preferred exemplary embodiment). The input pump laser is then further blue-shifted and fine-tuned. The stimulated Brillouin laser from the secondary pump laser will then be released from the TM mode. As the wavelength of the resonance peak red-shifts away from the resonant peak of the silicon nitride microring cavity, the power of the excited Kerr frequency comb in the silicon nitride microring cavity will decrease in a step-like manner until the desired soliton state frequency comb output is obtained, and the spacing of the optical comb teeth is stabilized. At this time, because the input pump light gradually blue-shifts, more photons couple into the microring cavity, thus compensating for the reduction in photothermal activity caused by the red-shift of the stimulated Brillouin (SBL) light. This maintains the photothermal activity in the microring cavity in a relatively stable and continuous state, avoiding the rapid decrease in optical power and heat generation in the cavity during the red-shift state of the pump light in the soliton state of the Kerr frequency comb in traditional silicon nitride microring cavities, which leads to thermal instability. Through the precise control of the control module, the optical resonance and Kerr frequency comb output states in the microring cavity fed back by each photodetector are received and analyzed in real time, enabling the stable operation of the orthogonal polarization mode Brillouin laser Kerr frequency comb photon microwave generator of this invention.

[0071] Specifically, in this exemplary embodiment, when the pump laser is input, it first enters the blue-shifted region from the blue-detuned position of the resonant peak wavelength corresponding to the TE-mode polarized photon, while the excited secondary pump Brillouin laser is located at the red-detuned position of the TM-mode polarized photon. Initially, the photogenerated heat in the microcavity is mainly contributed by the Brillouin laser of the TM-mode polarized photon. As the input pump light continues to blue-shift, the optical frequency comb is formed and speaks to the soliton state. The Brillouin laser will also gradually red-shift away from the resonant peak of the microcavity, which will lead to a decrease in heat in the microcavity. At this time, the blue-shifted input pump light is close to the resonant peak of the corresponding TE-mode polarized photon, which can compensate for the decrease in cavity heat caused by the SBL red shift. This overcomes the thermal instability phenomenon of the traditional silicon nitride micro-ring cavity Kerr optical frequency comb under red detuning and realizes the stable operation of the Brillouin-Kerr optical frequency comb.

[0072] More preferably, in an exemplary embodiment, the resonant peak frequencies of the laser in TE mode and TM mode in the silicon nitride microring cavity are aligned with the free spectrum spacing FSR. 布里渊 GHz interval distribution, n*FSR 布里渊There are several resonant peak distributions, where n is an integer. The resonant peak frequencies of the orthogonally polarized TE mode laser and TM mode laser have a slight interval, with a difference of ΔυMHz.

[0073] The frequency shift of the Brillouin laser excited by the pump light in the silicon nitride micro-ring cavity is f. ΔSBL Design of FSR for silicon nitride micro-ring cavity 布里渊 The value is (f) ΔSBL +Δυ)=m*FSR 布里渊 m is an integer; based on this FSR 布里渊 The value is calculated according to the formula FSR = Δλ = λ 2 / n g L is used to design the size of the silicon nitride microring cavity, where λ is the wavelength of light, and n is the wavelength of light. g Let L be the group refractive index of the waveguide, and L be the length of the optical microcavity, i.e., the length of the silicon nitride microring cavity.

[0074] More specifically, regarding the silicon nitride microring cavity itself, the pump light enters the silicon nitride microring cavity after being output from end 2 of the optical circulator. This microring cavity is a dual-track upper and lower track ring cavity structure, with one optical input end, one optical pass-through output end, and one optical lower track output end. The input pump light with a certain power couples into the microring cavity, and resonance will excite the generation of two orthogonally polarized photons. The two orthogonally polarized photons are TE mode and TM mode. The resonant peak frequencies of the TE mode and TM mode photons in the microring resonant cavity are determined according to FSR. 布里渊 (Free spectral spacing) GHz spacing distribution, n*FSR 布里渊 There are (n is an integer) resonant peak distributions. The resonant peak frequencies of orthogonally polarized TE mode and TM mode photons have a slight interval, with a difference of ΔυMHz. In the device of this invention, the input pump light and Brillouin laser (SBL) correspond to two orthogonally polarized photon signals, respectively. For simplicity, it is assumed that the polarization direction of the input pump light is aligned with the TE mode polarized photon transmission, and the Brillouin light (SBL) excited by the micro-ring resonator is aligned with the orthogonally polarized TM mode polarized photon transmission. According to the working principle of Brillouin laser, the frequency offset of the pump light-excited Brillouin laser in the silicon nitride-based micro-ring cavity is approximately f. ΔSBL =11GHz, the designed FSR value of the micro-ring cavity is (f ΔSBL +Δυ)=m*FSR, m=1, 2, 3, 4..m is an integer. For simplicity, we take m=4 here. FSR=((Δυ / 4)+2.75)GHz. Based on this FSR value, according to the formula FSR 布里渊 =Δλ=λ 2 / n gThe size of the micro-ring cavity is designed using L, and a special dispersion engineering design is performed on the silicon nitride micro-ring cavity to ensure that the orthogonally polarized TM mode photons at the corresponding SBL wavelength in the 1550nm band have optimized anomalous dispersion. This ensures that the Brillouin radiation gain region (BGS) spectrum range excited by the pump light closely overlaps with the resonant peak frequency of the TM mode photons in the anomalous dispersion region, according to (4*FSR). 布里渊 The -Δυ) interval selects the resonant peak frequency value of the corresponding TE mode photon at that location, and selects it as the input pump light frequency, such as Figure 4 As shown in the figure (SBL represents Brillouin laser), a larger m value results in a smaller spectral line spacing, making it easier and less error-prone to achieve overlap between the Brillouin radiation gain region and the resonant center wavelength of the micro-ring cavity. However, a smaller spectral line spacing makes it difficult to obtain single photon comb lines through photon filtering, and may increase stray signals in the photogenerated microwave signal, leading to a decrease in the spectral purity of the photogenerated microwave signal. Therefore, the design of the m value needs to be comprehensively considered. Generally, depending on the required frequency, such as the Ka-band microwave signal frequency, m = 4 or 6 is preferred, and it needs to be flexibly adjusted according to specific application requirements.

[0075] Following the formation mechanism of the Kerr frequency comb in a silicon nitride micro-cavity, the output power and wavelength of the pump laser are adjusted by a control module. When the pump power exceeds the Brillouin radiation threshold, a Brillouin laser is generated within the cavity. The pump power is further increased, and the initial input pump light wavelength is set at the blue detuning point of the corresponding TE mode resonant peak wavelength. Gradually, a blue shift is applied to change the pump light wavelength closer to the resonant peak. At this point, the Brillouin laser initially set at the red detuning point of the corresponding TM mode photon resonant peak wavelength becomes the pump light for the Kerr frequency comb. The power of this Brillouin laser gradually increases, and when it exceeds the Kerr frequency comb excitation threshold, a Kerr frequency comb of TM mode photons appears, with a comb tooth spacing of k*FSR. 布里渊 (k = 1, 2, 3, 4... integers). When the input pump light is further adjusted to blue-shift closer to the resonance peak, the wavelength of the Brillouin laser SBL light, which is used as the secondary pump, will also shift accordingly. It will gradually red-shift away from the resonance peak of the corresponding TM mode at the red detuning position, and then the power change in the Kerr frequency comb cavity will appear in a step state. Finally, a Kerr frequency comb single soliton state with a comb tooth spacing of 1*FSR will be formed. By keeping the pump light power and wavelength constant, the system will continue to work stably in the Kerr frequency comb single soliton state.

[0076] The input pump light is in a blue-detuned position with the wavelength of the corresponding TE mode photonic resonance peak, while the Brillouin laser, which is used as a secondary pump, is in a red-detuned position with the wavelength of the corresponding TM mode photonic resonance peak. When the pump light gradually blue-shifts and excites the Brillouin laser to generate the initial state of the Kerr frequency comb, the photothermal heating in the cavity is mainly driven by the secondary-pumped Brillouin laser. With continuous blue-shifting of the pump light, the Brillouin laser will red-shift away from the resonance peak, which reduces the photothermal heating in the cavity. At this time, the Kerr soliton state is formed. Since the pump light continuously enters the resonant cavity through the blue-detuned position, the total heat generation in the cavity is maintained without a large drop, thus enabling long-term stable operation of the Kerr soliton state.

[0077] Therefore, in this exemplary embodiment, the frequency shift of the Brillouin radiation is f. ΔSBL The frequency difference between the optical resonant peaks of the orthogonally polarized modes (TM and TE) in the silicon nitride microcavity is Δυ, and the resonant spectral line spacing chosen for the silicon nitride microcavity design is FSR. 布里渊 According to (f ΔSBL +Δυ)=m*FSR 布里渊 m = 1, 2, 3, 4...m is an integer. Choosing a larger m results in a smaller spectral line spacing, making it easier for the Brillouin radiation gain region to overlap with the resonant center wavelength of the micro-ring cavity with smaller errors. However, a smaller spectral line spacing makes it difficult to obtain a single photon comb spectral line through photon filtering, and may increase stray signals in the photogenerated microwave signal, leading to a decrease in the spectral purity of the microwave signal. Therefore, the design of the m value here needs to be comprehensively considered. Generally, depending on the required frequency, such as the Ka-band microwave signal frequency, m = 4 or 6 is preferred. It needs to be flexibly adjusted according to the specific application requirements.

[0078] More preferably, in an exemplary embodiment, such as Figure 2 As shown, the photonic filtering module includes an independent FSR with spectral line spacing. 滤波 A photonic filter, wherein the photonic filter filters the orthogonal mode Brillouin laser Kerr frequency comb signal; FSR 滤波 =M×FSR 布里渊 M is an integer, FSR 布里渊 The resonant peak spectral line spacing is for the silicon nitride microring cavity.

[0079] In this exemplary embodiment, the silicon nitride microring cavity spectral line spacing FSR 布里渊 The comb teeth have smaller spacing, FSR 滤波 The interval is relatively large, so the design chooses FSR. 滤波 =M×FSR 布里渊 (M is an integer) = Ka-band microwave frequency, which can effectively reduce the amount of beat frequency light, effectively reduce stray signals, and generate microwave signals with high spectral purity.

[0080] For example, a photonic filter is configured according to the required microwave frequency RF, using the formula RF = p * FSR. 滤波 For example, to obtain a Ka-band microwave signal output, according to the example scheme of this invention, the FSR = ((Δυ / 4) + 2.75) GHz, which is approximately 2.81 GHz, yields the photonic filter FSR. 滤波 =13 * 2.81 = 36.53 GHz or FSR 滤波 =12*2.81=33.72GHz, according to the formula FSR=Δλ=λ 2 / n g L is used to design and optimize photonic microcavity filters, which are based on two consecutive FSRs of the photonic filter. 滤波 Aligning the channel with the 0th, 12th, or 13th comb tooth output from the Brillouinkel optical frequency comb allows filtering of two or more optical signals with the required wavelength interval, where the interval is FSR. 滤波 The optical signal enters the high-speed detector PD1, and after being beat by the high-speed detector, the required microwave signal is obtained, which is then output as FSR. 滤波 =12 * 2.81 = 33.72 GHz or FSR 滤波 =13*2.81=36.53GHz microwave signal; the photonic filter takes into account the alignment and adjustment of the photonic center wavelength, and uses a TEC temperature control module to adjust and control its temperature, so as to fine-tune the frequency alignment between the center wavelength of the photonic filter and the photonic frequency comb.

[0081] More preferably, in an exemplary embodiment, such as Figure 3 As shown, the photonic filtering module includes an optical splitter, a first photonic filter, a second photonic filter, and an optical combiner. The optical splitter receives the laser light from the optically polarized beam splitter and splits it 50:50 into two beams, which enter the first photonic filter and the second photonic filter, respectively. According to the required microwave signal band (e.g., Ka band), the corresponding Kerr optical frequency comb tooth photonic signal is selected (e.g., the center wavelength of photonic filter 1 is aligned with the 0# tooth of the Kerr optical frequency comb, and the center wavelength of photonic filter 2 is aligned with the 12# tooth of the Kerr optical frequency comb). The two photonic signals are then input into the first photodetector after optical combination.

[0082] Among them, the spectral line spacing FSR of the first photonic filter and the second photonic filter 滤波 It needs to be larger and require a signal response bandwidth greater than that of the first photodetector, and the FSR 滤波 FSR not with Kerr frequency comb 布里渊The signals are in integer multiples to avoid redundant optical comb signals. After filtering, two photon signals are obtained after passing through two photon filters. These two photon signals are combined and then input into the first high-speed detector for beat frequency, outputting the required microwave signal and obtaining an ultra-low phase noise microwave signal.

[0083] Based on the output frequency of the Brillouinkel optical frequency comb, the center wavelength of the photonic filter is aligned with a wavelength of the optical frequency comb, such as the 0th comb tooth. According to the formula FSR = Δλ = λ... 2 / n g L is used to design and optimize the photonic microcavity filter. Based on the actual required microwave signal, such as the Ka band, the center wavelength of another photonic filter is aligned with the wavelength of the 12th or 13th comb tooth, similarly according to the formula FSR = Δλ = λ. 2 / n g L is used to design and optimize photonic microcavity filters, and the spectral spacing FSR of the photonic filter is... 滤波 The design should be chosen to have a receiving signal bandwidth greater than that of the detector; for example, for Ka-band reception, an FSR (Free Signal Receiving) could be selected. 滤波 The approximately 50GHz frequency ensures that the photonic filter's comb-shaped filtering spectral lines, except for the center wavelength (e.g., 0#), do not coincide with the wavelengths of the optical comb output from the frequency comb. This means that only the signals from the two optical comb teeth aligned with the center wavelength can pass through after filtering. These two optical signals are then combined and output to the first photodetector. Beat frequency analysis yields the desired Ka-band microwave signal. To ensure proper alignment of the photonic center wavelength, the two photonic filters utilize a TEC temperature control module for temperature adjustment, allowing for fine-tuning to adapt to the frequency alignment between the optical center wavelength and the photonic frequency comb.

[0084] More preferably, in an exemplary embodiment, when determining the FSR 布里渊 Subsequently, the wavelength of the Brillouin gain region and the FSR of the TM polarized photonic comb were designed. 布里渊 The resonant peaks of the silicon nitride microring cavity overlap, and the peak wavelength of the Brillouin gain region is designed to be located at a slightly reddish detuned position relative to the resonant peak wavelength, according to the Brillouin frequency shift f. ΔSBL The corresponding TE polarized photon is selected as the center wavelength of the input pump light; through dispersion engineering design, the TM mode polarized photon is optimized to exhibit anomalous dispersion in the BGS wavelength region.

[0085] Specifically, in this exemplary embodiment, the present invention is based on a silicon nitride microring cavity, according to (f ΔSBL +Δυ)=m*FSR 布里渊 m = 1, 2, 3, 4...m are integers, determining the FSR of the micro-annular cavity design. 布里渊 Design the Brillouin gain region wavelength (BGS) and the TM polarized photonic comb spacing FSR. 布里渊The micro-ring cavity resonant peaks overlap, and the BGS peak is designed to be located at a slightly reddish detuned position relative to the resonant peak wavelength, according to the Brillouin frequency shift f. ΔSBL The corresponding TE-polarized photon is selected as the center wavelength of the input pump light. Through dispersion engineering, the anomalous dispersion of the TM-mode polarized photon in the BGS wavelength region is optimized, which facilitates the optimized excitation of the Kerr frequency comb in this wavelength region under TM mode.

[0086] More preferably, in an exemplary embodiment, the tunable wavelength laser is a 1550nm communication band laser, the photon signal obtained by the photon filtering module is in the Ka band, and m is 4, f ΔSBL The value of is 11, and M is 12 or 13.

[0087] In another exemplary embodiment of the present invention, a control method based on an orthogonal polarization mode Brillouin laser Kerr frequency comb is provided, the method comprising a control module and the following:

[0088] Initial control steps: Send a first control command to the tunable wavelength laser, set the input pump laser wavelength to be at the blue detuning position of the resonant peak wavelength corresponding to the TE mode polarized photon of the silicon nitride micro-ring cavity, and based on the monitoring data of the second photodetector used to monitor the working state of the pump laser at the through-output port of the silicon nitride micro-ring cavity, and the third photodetector used to monitor the working state of the resonant light at the lower output port of the silicon nitride micro-ring cavity, gradually increase the blue shift of the wavelength to make the pump laser closer to the resonant peak;

[0089] Secondary pump control steps: A second control command is sent to the tunable wavelength laser. Based on the monitoring data of the fourth photodetector used to monitor the state of the stimulated Brillouin laser in the cross-polarized TM mode after optical polarization beam splitting, the blue shift rate and optical power of the pump laser wavelength are further adjusted until the Kerr frequency comb state is achieved.

[0090] More preferably, in an exemplary embodiment, the connection relationship between the control module and external components in this control method includes:

[0091] A tunable wavelength laser receives commands from the control module and outputs a pump laser with corresponding wavelength and power.

[0092] An optical amplifier amplifies the pump laser.

[0093] An optical circulator, with its first port used to receive the amplified pump laser;

[0094] The silicon nitride micro-ring cavity receives the pump laser through the second port of the optical circulator at the optical input end. After the Brillouin laser is excited inside the cavity, it is output as a mixed laser along with the pump laser through the optical input end to the second port of the optical circulator.

[0095] The optically polarized beam splitter receives the mixed laser output from the third port of the optical circulator, filters the pump laser in the mixed laser, and outputs the split Brillouin laser.

[0096] The photonic filtering module receives the Brillouin laser from the optically polarized beam splitter, selects the corresponding frequency interval, and then outputs the filtered photonic signal.

[0097] The first photodetector receives the photon signal, beats it, and then outputs a microwave signal.

[0098] The second photodetector has its input end connected to the through-output port of the silicon nitride micro-ring cavity, and its output end connected to the control module to monitor the working status of the pump laser.

[0099] The third photodetector has its input end connected to the lower output port of the silicon nitride micro-ring cavity, and its output end connected to the control module to monitor the working status of the resonant light in the silicon nitride micro-ring cavity.

[0100] The fourth photodetector has its input end connected to the optical splitter located between the optical polarization beam splitter and the photon filter module, and its output end connected to the controller to monitor the operating status of the Kerr frequency comb within the micro-ring cavity.

[0101] The silicon nitride micro-ring cavity forms a Kerr frequency comb by secondary pumping of the tunable wavelength laser through a control module.

[0102] More preferably, in an exemplary embodiment, in this control method, the photon filtering module includes a separate FSR with spectral line spacing. 滤波 A photonic filter, wherein the photonic filter filters the orthogonal mode Brillouin laser Kerr frequency comb signal; FSR 滤波 =M×FSR 布里渊 M is an integer, FSR 布里渊 The resonant peak spectral line spacing is for the silicon nitride microring cavity.

[0103] More preferably, in an exemplary embodiment, in this control method, the photonic filtering module includes an optical splitter, a first photonic filter, a second photonic filter, and an optical combiner. The optical splitter receives the laser light from the optically polarized beam splitter and splits it into two beams at a 50:50 ratio, which then enter the first photonic filter and the second photonic filter, respectively. Based on the microwave signal of the required band, the corresponding Kerr optical frequency comb photonic signal is selected. The two photonic signals are then combined and input into the first photodetector.

[0104] Among them, the spectral line spacing FSR of the first photonic filter and the second photonic filter 滤波 It needs to be larger and require a signal response bandwidth greater than that of the first photodetector, and the FSR 滤波 FSR not with Kerr frequency comb 布里渊They are multiples of each other.

[0105] More preferably, in an exemplary embodiment, in this control method, the resonant peak frequencies of the laser in TE mode and the laser in TM mode in the silicon nitride microring cavity are aligned according to the free spectrum spacing FSR. 布里渊 GHz interval distribution, n*FSR 布里渊 There are several resonant peak distributions, where n is an integer. The resonant peak frequencies of the orthogonally polarized TE mode laser and TM mode laser have a slight interval, with a difference of ΔυMHz.

[0106] The frequency shift of the Brillouin laser excited by the pump light in the silicon nitride micro-ring cavity is f. ΔSBL Design of FSR for silicon nitride micro-ring cavity 布里渊 The value is (f) ΔSBL +Δυ)=m*FSR 布里渊 m is an integer; based on this FSR 布里渊 The value is calculated according to the formula FSR = Δλ = λ 2 / n g L is used to design the size of the silicon nitride microring cavity, where λ is the wavelength of light, and n is the wavelength of light. g Let L be the group refractive index of the waveguide, and L be the length of the optical microcavity, i.e., the size of the silicon nitride microring cavity.

[0107] More preferably, in an exemplary embodiment, in this control method, when determining the FSR 布里渊 Subsequently, the wavelength of the Brillouin gain region and the FSR of the TM polarized photonic comb were designed. 布里渊 The resonant peaks of the silicon nitride microring cavity overlap, and the peak wavelength of the Brillouin gain region is designed to be located at a slightly reddish detuned position relative to the resonant peak wavelength, according to the Brillouin frequency shift f. ΔSBL The corresponding TE polarized photon is selected as the center wavelength of the input pump light; through dispersion engineering design, the TM mode polarized photon is optimized to exhibit anomalous dispersion in the BGS wavelength region.

[0108] More preferably, in an exemplary embodiment, in this control method, the tunable wavelength laser is a 1550nm communication band laser, the photon signal obtained by the photon filtering module is a Ka band, and m is 4, f ΔSBL The value of is 11, and M is 12 or 13.

[0109] In another exemplary embodiment of the present invention, a storage medium is provided having computer instructions stored thereon, wherein the computer instructions, when executed, perform the steps of a control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode as described in any of the above exemplary embodiments.

[0110] Another exemplary embodiment of the present invention provides a terminal including a memory and a processor, wherein the memory stores computer instructions executable on the processor, and the processor executes the steps of a control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode as described in any of the above exemplary embodiments when executing the computer instructions.

[0111] Based on this understanding, the technical solution of this embodiment, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0112] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode, based on a control module, characterized in that: The method includes: Initial control steps: Send a first control command to the tunable wavelength laser, set the input pump laser wavelength to be at the blue detuning position of the resonant peak wavelength corresponding to the TE mode polarized photon of the silicon nitride micro-ring cavity, and based on the monitoring data of the second photodetector used to monitor the working state of the pump laser at the through-output port of the silicon nitride micro-ring cavity, and the third photodetector used to monitor the working state of the resonant light at the lower output port of the silicon nitride micro-ring cavity, gradually increase the blue shift of the wavelength to make the pump laser closer to the resonant peak; Secondary pump control steps: Send a second control command to the tunable wavelength laser, and based on the monitoring data of the fourth photodetector used to monitor the state of the stimulated Brillouin laser in the cross-polarized TM mode after optical polarization beam splitting, further adjust the blue shift speed and optical power of the pump laser wavelength until the Kerr frequency comb state appears. In this control method, the connection relationship between the control module and external components includes: A tunable wavelength laser receives commands from the control module and outputs a pump laser with corresponding wavelength and power. An optical amplifier amplifies the pump laser. An optical circulator, with its first port used to receive the amplified pump laser; The silicon nitride micro-ring cavity receives the pump laser through the second port of the optical circulator at the optical input end. After the Brillouin laser is excited inside the cavity, it is output as a mixed laser along with the pump laser through the optical input end to the second port of the optical circulator. The optically polarized beam splitter receives the mixed laser output from the third port of the optical circulator, filters the pump laser in the mixed laser, and outputs the split Brillouin laser. The photonic filtering module receives the Brillouin laser from the optically polarized beam splitter, selects the corresponding frequency interval, and then outputs the filtered photonic signal. The first photodetector receives the photon signal, beats it, and then outputs a microwave signal. The second photodetector has its input end connected to the through-output port of the silicon nitride micro-ring cavity, and its output end connected to the control module to monitor the working status of the pump laser. The third photodetector has its input end connected to the lower output port of the silicon nitride micro-ring cavity, and its output end connected to the control module to monitor the working status of the resonant light in the silicon nitride micro-ring cavity. The fourth photodetector has its input end connected to the optical splitter located between the optical polarization beam splitter and the photon filter module, and its output end connected to the controller, used to monitor the working status of the Kerr optical frequency comb in the micro-ring cavity; The silicon nitride micro-ring cavity forms a Kerr frequency comb by secondary pumping of the tunable wavelength laser through a control module.

2. The control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode according to claim 1, characterized in that: The photon filtering module includes an independent FSR with spectral line spacing. 滤波 A photonic filter, wherein the photonic filter filters the orthogonal mode Brillouin laser Kerr frequency comb signal; FSR 滤波 =M×FSR 布里渊 M is an integer, FSR 布里渊 The resonant peak spectral line spacing is for the silicon nitride microring cavity.

3. The control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode according to claim 1, characterized in that: The photonic filtering module includes an optical splitter, a first photonic filter, a second photonic filter, and an optical combiner. The optical splitter receives the laser light from the optically polarized beam splitter and splits it into two beams in a 50:50 ratio, which then enter the first photonic filter and the second photonic filter, respectively. Based on the microwave signal of the required band, the corresponding Kerr optical frequency comb photonic signal is selected. The two photonic signals are then combined and input into the first photodetector. Among them, the spectral line spacing FSR of the first photonic filter and the second photonic filter 滤波 It needs to be larger and require a signal response bandwidth greater than that of the first photodetector, and the FSR 滤波 FSR not with Kerr frequency comb 布里渊 They are multiples of each other.

4. A control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode according to claim 2 or 3, characterized in that: The resonant peak frequencies of lasers in TE mode and TM mode in the silicon nitride microring cavity are determined according to the free spectrum spacing FSR. 布里渊 GHz interval distribution, n*FSR 布里渊 There are several resonant peak distributions, where n is an integer. The resonant peak frequencies of the orthogonally polarized TE mode laser and TM mode laser have a slight interval, with a difference of ΔυMHz. The frequency shift of the Brillouin laser excited by the pump light in the silicon nitride micro-ring cavity is f. ΔSBL Design of FSR for silicon nitride micro-ring cavity 布里渊 The value is (f) ΔSBL +Δυ)=m*FSR 布里渊 m is an integer; based on this FSR 布里渊 The value is calculated according to the formula FSR = Δλ = λ 2 / n g L is used to design the size of the silicon nitride microring cavity, where λ is the wavelength of light, and n is the wavelength of light. g Let L be the group refractive index of the waveguide, and L be the length of the optical microcavity, i.e., the length of the silicon nitride microring cavity.

5. The control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode according to claim 4, characterized in that: In determining FSR 布里渊 Subsequently, the wavelength of the Brillouin gain region and the FSR of the TM polarized photonic comb were designed. 布里渊 The resonant peaks of the silicon nitride microring cavity overlap, and the peak wavelength of the Brillouin gain region is designed to be located at a slightly reddish detuned position relative to the resonant peak wavelength, according to the Brillouin frequency shift f. ΔSBL The corresponding TE-polarized photon is selected as the center wavelength of the input pump light; through dispersion engineering design, the TM-mode polarized photon is optimized to exhibit anomalous dispersion in the BGS wavelength region of the Brillouin gain spectrum.

6. The control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode according to claim 5, characterized in that: The tunable wavelength laser is a 1550nm communication band laser, and the photonic signal obtained by the photonic filtering module is in the Ka band, where m is 4 and f is... ΔSBL The value of is 11, and M is 12 or 13.

7. A storage medium storing computer instructions thereon, characterized in that: When the computer instructions are executed, they perform the steps of the control method for a Brillouin laser Kerr optical frequency comb based on orthogonal polarization mode as described in any one of claims 1 to 6.

8. A terminal comprising a memory and a processor, wherein the memory stores computer instructions executable on the processor, characterized in that: When the processor executes the computer instructions, it performs the steps of the control method for a Brillouin laser Kerr frequency comb based on orthogonal polarization mode as described in any one of claims 1 to 6.

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