Dual-optical-frequency comb generation system and method based on communication algorithm

Abstract

The embodiments of the present application relate to the technical field of optical communications. Provided are a dual-optical-frequency comb generation system and method based on a communication algorithm. In the dual-optical-frequency comb generation system, a communication algorithm module is used for generating a preset time-domain signal by means of a pseudo-random binary sequence, and sending the preset time-domain signal to a dual-optical-frequency comb generation module, wherein in a frequency domain, the preset time-domain signal appears as two sets of comb teeth having a frequency difference; and the dual-optical-frequency comb generation module comprises a laser device, a signal generator, an electro-optic modulator and a microcavity, wherein an input end of the electro-optic modulator is connected to each of the laser device and the signal generator, an output end of the electro-optic modulator is connected to the microcavity, the laser device generates a continuous laser signal of a preset wavelength, the signal generator receives the preset time-domain signal and, on the basis of the preset time-domain signal, generates a dual-frequency-comb time-domain digital electrical signal, and on the basis of the dual-frequency-comb time-domain digital electrical signal, the electro-optic modulator modulates the continuous laser signal into a time-domain pseudo-random sequence optical signal corresponding to a dual-optical-frequency comb, and inputs the time-domain pseudo-random sequence optical signal into the microcavity.

Description

A dual-optical frequency comb generation system and method based on communication algorithm Technical Field

[0001] The present application relates to the field of optical communication technology, and in particular to a dual-optical frequency comb generation system and method based on a communication algorithm. Background Art

[0002] Currently, optical communications and spectroscopy applications rely heavily on the measurement of various types of optical spectra, such as absorption / transmission spectroscopy, fluorescence spectroscopy, and Raman spectroscopy, but resolution and speed are often a bottleneck. Among the various available spectral measurement methods, spectral analysis is the most popular. Dual-frequency comb systems can map broadband comb lines to the radio frequency domain by using two optical frequency combs with slightly detuned repetition rates. This so-called multi-heterodyne or dual-comb process is widely adopted due to its advantages in dynamic range, refresh rate, and spectral resolution. Dual-frequency combs combine many of the advantages of traditional broadband spectroscopy and tunable laser spectroscopy onto a single platform. Like a traditional Fourier transform infrared spectrometer, the receiving and demodulating end only needs to use a single photodetector to detect the spectrum.

[0003] Because they require no moving parts or high-resolution virtual image phased arrays, dual-optical frequency combs offer the potential to surpass traditional Fourier transform spectroscopy. Driven by the increasing demand for data acquisition speed, sensitivity, tuning range, and precision, various dual-optical frequency comb approaches have been explored, spanning the terahertz to ultraviolet range. These approaches are implemented using a variety of optical frequency comb sources, including mode-locked lasers, microresonator combs, quantum cascade lasers, and electro-optical digital frequency combs. For most dual-optical frequency comb generators, the additional phase-locking and control electronics required to maintain mutual coherence are bulky and costly, and the system architecture is complex, significantly hindering the widespread application of dual-comb systems and presenting a critical issue that urgently needs to be addressed. However, due to the mutual phase coherence of electro-optical digital dual-comb interferometers, they do not require long measurements, complex locking systems, or computer algorithms, significantly reducing instrument complexity and finding widespread application in optical coherence tomography and spectroscopy. Furthermore, because the digital signal generated by the code allows for flexible design of the comb teeth spacing, unlike the fixed cavity length of mode-locked lasers and microresonator combs, digital optical frequency combs offer the advantage of flexibility over mode-locked lasers, quantum cascade lasers, and microresonator combs. However, for traditional electro-optical digital optical frequency combs, while the system is simplified, it still requires a two-path implementation, requiring multiple splitters, electro-optic modulators, acousto-optic modulators, balanced detectors, and other components, resulting in a relatively complex system.

[0004] In general, the current dual-optical frequency comb generation systems, whether using mode-locked lasers, microresonator combs, quantum cascade lasers, or traditional electro-optical digital frequency combs, are relatively complex and not conducive to practical application needs.

[0005] Summary of the Invention

[0006] The purpose of the embodiments of the present application is to provide a dual optical frequency comb generation system and method based on a communication algorithm, which can simplify the dual optical frequency comb generation system and improve the practicality of the technical effect.

[0007] In a first aspect, an embodiment of the present application provides a dual optical frequency comb generation system based on a communication algorithm, comprising a communication algorithm module and a dual optical frequency comb generation module;

[0008] The communication algorithm module is used to generate a preset time domain signal through a pseudo-random binary sequence, and send the preset time domain signal to the dual optical frequency comb generation module, wherein the preset time domain signal is two sets of comb teeth with a frequency difference in the frequency domain;

[0009] The dual-optical frequency comb generation module includes a laser, a signal generator, an electro-optical modulator, and a microcavity. The input end of the electro-optical modulator is connected to the laser and the signal generator respectively, and the output end of the electro-optical modulator is connected to the microcavity. The laser generates a continuous laser signal of a preset wavelength. The signal generator receives the preset time domain signal and generates a dual-frequency comb time domain digital electrical signal based on the preset time domain signal. The electro-optical modulator modulates the continuous laser signal into a time domain pseudo-random sequence optical signal corresponding to the dual-optical frequency comb based on the dual-frequency comb time domain digital electrical signal, and inputs the time domain pseudo-random sequence optical signal into the microcavity.

[0010] In the above implementation process, the dual-optical frequency comb generation system based on the communication algorithm generates a preset time domain signal through the communication algorithm module, thereby designing the dual-optical frequency comb into two sets of comb teeth with a certain frequency difference in the frequency domain through the communication algorithm. After a fast inverse Fourier transform, a set of integrated dual-comb time domain signals (preset time domain signals) can be obtained; the preset time domain signal is introduced into a signal generator, and the signal generator sends a signal to modulate the continuous laser signal passing through the electro-optical modulator to realize the generation of the dual-optical frequency comb; after the dual-optical frequency comb passes through the microcavity, the receiving end can beat the frequency through the photodetector to realize the process of down-conversion of the dual-optical frequency comb and reduce the detection bandwidth; the dual-optical frequency comb generation system based on the communication algorithm has a simple structure, high flexibility, and strong stability, which can achieve the technical effect of simplifying the dual-optical frequency comb generation system and improving practicality.

[0011] Furthermore, the dual optical frequency comb generation system further includes a photodetector. After the time-domain pseudo-random sequence optical signal resonates through the microcavity, the photodetector receives and detects the resonated time-domain pseudo-random sequence optical signal.

[0012] In the above implementation process, after the time-domain pseudo-random sequence optical signal resonates through the microcavity, a spectral notch caused by specific absorption will exist on the comb teeth in the frequency domain. Therefore, after the beat frequency is detected by the photodetector, this spectral notch can be demodulated in a narrow bandwidth, that is, the spectral information in the original high bandwidth can be highly restored at a low sampling rate.

[0013] Furthermore, the resonance condition of the microcavity is:

[0014] 2πnR=mλ;

[0015] Wherein, n is the effective refractive index of the microring in the microcavity, R is the radius of the microring, m is the resonance order m=1, 2, 3..., λ is the resonance wavelength, and π is the pi.

[0016] In the above implementation process, light that meets the resonance conditions will resonate in the microcavity, and light that does not meet the resonance conditions will be directly output from the original waveguide. In this way, from the swept transmission spectrum, it can be seen that there is a corresponding resonance peak at a specific wavelength. At this time, there will be a spectral notch caused by specific absorption in the comb teeth in the frequency domain.

[0017] Furthermore, the communication algorithm module includes a PRBS code time domain unit, a PRBS code frequency domain unit, a frequency domain integration unit and a dual-comb time domain unit, and the PRBS code time domain unit, the PRBS code frequency domain unit, the frequency domain integration unit and the dual-comb time domain unit are connected in sequence.

[0018] Furthermore, the PRBS code time domain unit generates two groups of PRBS code sequences, and the lengths of the two groups of PRBS code sequences are inconsistent.

[0019] Furthermore, the PRBS code frequency domain unit obtains two groups of PRBS code sequences generated by the PRBS code time domain unit, and generates two groups of frequency combs with the same center frequency and different repetition frequencies based on the two groups of PRBS code sequences through Fourier transform.

[0020] Furthermore, two sets of frequency comb teeth with the same center frequency and different repetition frequencies are superimposed and integrated into overlapping frequency comb teeth in the frequency domain integration unit, and the overlapping frequency comb teeth are subjected to inverse fast Fourier transform in the dual-comb time domain unit to be the preset time domain signal.

[0021] In a second aspect, embodiments of the present application further provide a dual-optical frequency comb generation method based on a communication algorithm, which is applied to the dual-optical frequency comb generation system based on a communication algorithm according to any one of the first aspects, the method comprising:

[0022] Generate a preset time domain signal based on the communication algorithm module;

[0023] The preset time domain signal generates a dual-frequency comb time domain digital electrical signal in the signal generator;

[0024] generating a continuous laser signal based on a laser;

[0025] The continuous laser signal is modulated by the dual-frequency comb time-domain digital electrical signal in the electro-optical modulator to obtain a time-domain pseudo-random sequence optical signal corresponding to the dual-frequency comb;

[0026] The time-domain pseudo-random sequence optical signal resonates in the microcavity, and the resonated time-domain pseudo-random sequence optical signal is received and detected by a photodetector.

[0027] Furthermore, the step of generating a preset time domain signal based on the communication algorithm module includes:

[0028] Generate two sets of PRBS code sequences based on the PRBS code time domain unit;

[0029] The two groups of PRBS code sequences are Fourier transformed in the PRBS code frequency domain unit to generate two groups of frequency combs with the same center frequency and different repetition frequencies;

[0030] The two sets of frequency comb teeth are superimposed and integrated into overlapping frequency comb teeth in the frequency domain integration unit, wherein the zero-frequency comb teeth of the two sets of frequency comb teeth overlap;

[0031] The overlapping frequency comb teeth are inversely fast Fourier transformed in the dual-comb time domain unit into the preset time domain signal.

[0032] Furthermore, the time-domain pseudo-random sequence optical signal resonates in the microcavity, and the resonated time-domain pseudo-random sequence optical signal is received and detected by a photodetector, comprising:

[0033] The optical signal in the time-domain pseudo-random sequence optical signal that meets the resonance condition of the microcavity resonates, and the optical signal in the time-domain pseudo-random sequence optical signal that does not meet the resonance condition of the microcavity is output from the original waveguide, and the time-domain pseudo-random sequence optical signal has a corresponding resonance peak at a preset wavelength;

[0034] The resonant time-domain pseudo-random sequence optical signal has a spectrum notch caused by absorption at a preset wavelength in the frequency domain, which is received and detected by a photodetector and the spectrum notch is demodulated.

[0035] Other features and advantages disclosed in the present application will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned technology disclosed in the present application.

[0036] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0038] FIG1 is a schematic diagram of the structure of a dual-optical frequency comb generation system based on a communication algorithm provided in an embodiment of the present application;

[0039] FIG2 is a flow chart of a dual optical frequency comb generation method based on a communication algorithm provided in an embodiment of the present application;

[0040] FIG3 is a flow chart of another dual-optical frequency comb generation method based on a communication algorithm provided in an embodiment of the present application;

[0041] FIG4 is a schematic diagram of a digital frequency comb provided in an embodiment of the present application;

[0042] FIG5 is a schematic diagram of a simulated beat frequency effect provided by an embodiment of the present application;

[0043] FIG6 is a schematic diagram of a frequency comb demodulation principle provided by an embodiment of the present application;

[0044] FIG7 is a schematic diagram of the microcavity resonance measurement results of the dual optical frequency comb provided in an embodiment of the present application.

[0045] Icons: communication algorithm module 100; PRBS code time domain unit 110; PRBS code frequency domain unit 120; frequency domain integration unit 130; dual-comb time domain unit 140; dual optical frequency comb generation module 200; laser 210; signal generator 220; electro-optical modulator 230; microcavity 240; photodetector 250. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0047] In this application, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe this application and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0048] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0049] Furthermore, the terms "installed," "disposed," "provided with," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or point connections; direct connections, indirect connections through an intermediary, or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0050] Furthermore, the terms "first," "second," etc., are primarily used to distinguish between different devices, elements, or components (which may or may not be of the same type and configuration), and are not intended to indicate or imply the relative importance or quantity of the devices, elements, or components indicated. Unless otherwise specified, "plurality" means two or more.

[0051] Embodiments of the present application provide a dual-optical frequency comb generation system and method based on a communication algorithm, which can be applied in the process of generating a dual-optical frequency comb. The dual-optical frequency comb generation system based on the communication algorithm generates a preset time domain signal through a communication algorithm module, thereby designing the dual-optical frequency comb into two sets of comb teeth with a certain frequency difference in the frequency domain through the communication algorithm. After a fast inverse Fourier transform, a set of integrated dual-comb time domain signals (preset time domain signals) can be obtained. The preset time domain signal is introduced into a signal generator, and the signal generator sends a signal to modulate a continuous laser signal passing through an electro-optical modulator to achieve the generation of a dual-optical frequency comb. After the dual-optical frequency comb passes through a microcavity, the receiving end can beat the frequency through a photodetector to achieve the process of down-conversion of the dual-optical frequency comb and reduce the detection bandwidth. The dual-optical frequency comb generation system based on the communication algorithm has a simple structure, high flexibility, and strong stability, and can achieve the technical effect of simplifying the dual-optical frequency comb generation system and improving practicality.

[0052] Please refer to FIG1 , which is a schematic diagram of the structure of a dual-optical frequency comb generation system based on a communication algorithm according to an embodiment of the present application. The dual-optical frequency comb generation system based on a communication algorithm includes a communication algorithm module 100 and a dual-optical frequency comb generation module 200.

[0053] Exemplarily, the communication algorithm module 100 is used to generate a preset time domain signal through a pseudo-random binary sequence and send the preset time domain signal to the dual optical frequency comb generation module. The preset time domain signal is two sets of comb teeth with a frequency difference in the frequency domain.

[0054] Exemplarily, a random bit data stream can be generated by a pseudo-random binary sequence (PRBS), and two sets of PRBS code sequences are generated based on the pseudo-random binary sequence. The lengths of the two sets of PRBS code sequences are inconsistent to achieve slight misalignment in the frequency domain; thus, a preset time domain signal is generated based on the two sets of PRBS codes, and the preset time domain signal is two sets of comb teeth with a frequency difference in the frequency domain.

[0055] Exemplarily, the dual optical frequency comb generation module 200 includes a laser 210, a signal generator 220, an electro-optical modulator 230 and a microcavity 240. The input end of the electro-optical modulator 230 is connected to the laser 210 and the signal generator 220 respectively, and the output end of the electro-optical modulator 230 is connected to the microcavity 240. The laser 210 generates a continuous laser signal of a preset wavelength. The signal generator 220 receives a preset time domain signal and generates a dual frequency comb time domain digital electrical signal based on the preset time domain signal. The electro-optical modulator 230 modulates the continuous laser signal into a time domain pseudo-random sequence optical signal corresponding to the dual optical frequency comb based on the dual frequency comb time domain digital electrical signal, and inputs the time domain pseudo-random sequence optical signal into the microcavity 240.

[0056] Exemplarily, the electro-optical modulator 230 is controlled by a dual-frequency comb time-domain digital electrical signal generated by a signal generator driven by a code (preset time-domain signal), and modulates a single-wavelength, power-stable continuous laser signal into a time-domain pseudo-random sequence optical signal corresponding to the dual optical frequency comb, thereby realizing the conversion from the electrical frequency comb to the optical frequency comb.

[0057] Exemplarily, the dual optical frequency comb generation system further includes a photodetector 250 . After the time-domain pseudo-random sequence optical signal resonates through the microcavity 240 , the photodetector 250 receives and detects the resonated time-domain pseudo-random sequence optical signal.

[0058] For example, after the time-domain pseudo-random sequence optical signal resonates through the microcavity 240, a spectral notch caused by specific absorption will exist on the comb teeth in the frequency domain; thus, after beat frequency detection by the photodetector 250, this spectral notch can be demodulated in a narrow bandwidth, that is, the spectral information in the original high bandwidth can be highly restored at a low sampling rate.

[0059] Exemplarily, the resonance condition of the microcavity 240 is:

[0060] 2πnR=mλ;

[0061] Where n is the effective refractive index of the microring in the microcavity, R is the radius of the microring, m is the resonance order m=1, 2, 3..., λ is the resonance wavelength, and π is the circumference.

[0062] For example, light that meets the resonance conditions will resonate in the microcavity 240, and light that does not meet the resonance conditions will be directly output from the original waveguide. In this way, from the swept transmission spectrum, it can be seen that there is a corresponding resonance peak at a specific wavelength. At this time, there will be a spectrum depression caused by specific absorption in the comb teeth in the frequency domain.

[0063] Exemplarily, the communication algorithm module 100 includes a PRBS code time domain unit 110, a PRBS code frequency domain unit 120, a frequency domain integration unit 130 and a dual-comb time domain unit 140, and the PRBS code time domain unit 110, the PRBS code frequency domain unit 120, the frequency domain integration unit 130 and the dual-comb time domain unit 140 are connected in sequence.

[0064] Exemplarily, the PRBS code time domain unit 110 generates two groups of PRBS code sequences, and the lengths of the two groups of PRBS code sequences are inconsistent.

[0065] Exemplarily, the PRBS code frequency domain unit 120 obtains two sets of PRBS code sequences generated by the PRBS code time domain unit 110, and generates two sets of frequency comb teeth with the same center frequency and different repetition frequencies based on the two sets of PRBS code sequences through Fourier transform.

[0066] Exemplarily, two sets of frequency comb teeth with the same center frequency and different repetition frequencies are superimposed and integrated into overlapping frequency comb teeth in the frequency domain integration unit 130, and the overlapping frequency comb teeth are inversely fast Fourier transformed into a preset time domain signal in the dual-comb time domain unit 140.

[0067] Please refer to FIG. 2 , which is a flow chart illustrating a dual-optical frequency comb generation method based on a communication algorithm according to an embodiment of the present application. The method is applied to the dual-optical frequency comb generation system based on a communication algorithm shown in FIG. 1 . The dual-optical frequency comb generation method based on a communication algorithm includes the following steps:

[0068] S100: Generate a preset time domain signal based on the communication algorithm module;

[0069] S200: generating a dual-frequency comb time-domain digital electrical signal in a signal generator using a preset time-domain signal;

[0070] S300: generating a continuous laser signal based on a laser;

[0071] S400: The continuous laser signal is modulated in the electro-optical modulator by the dual-frequency comb time-domain digital electrical signal to obtain a time-domain pseudo-random sequence optical signal corresponding to the dual-frequency comb;

[0072] S500: The time-domain pseudo-random sequence optical signal resonates in the microcavity, and the resonated time-domain pseudo-random sequence optical signal is received and detected by a photodetector.

[0073] Please refer to FIG3 , which is a flowchart of another dual-optical frequency comb generation method based on a communication algorithm provided in an embodiment of the present application.

[0074] Exemplarily, S100: the step of generating a preset time domain signal based on the communication algorithm module includes:

[0075] S110: Generate two sets of PRBS code sequences based on the PRBS code time domain unit;

[0076] S120: The two sets of PRBS code sequences are Fourier transformed in the PRBS code frequency domain unit to generate two sets of frequency combs with the same center frequency and different repetition frequencies;

[0077] S130: The two sets of frequency comb teeth are superimposed and integrated into overlapping frequency comb teeth in a frequency domain integration unit, wherein the zero-frequency comb teeth of the two sets of frequency comb teeth overlap;

[0078] S140: The overlapping frequency comb teeth are subjected to inverse fast Fourier transform in the dual-comb time domain unit to obtain a preset time domain signal.

[0079] Exemplarily, S500: the step of causing a time-domain pseudo-random sequence optical signal to resonate in a microcavity, and receiving and detecting the resonated time-domain pseudo-random sequence optical signal by a photodetector, includes:

[0080] The optical signal in the time domain pseudo-random sequence optical signal that meets the resonance condition of the microcavity resonates, and the optical signal in the time domain pseudo-random sequence optical signal that does not meet the resonance condition of the microcavity is output from the original waveguide. The time domain pseudo-random sequence optical signal has a corresponding resonance peak at a preset wavelength;

[0081] The resonant time-domain pseudo-random sequence optical signal has a spectrum notch caused by absorption at a preset wavelength in the frequency domain, which is received and detected by a photodetector and demodulated to obtain the spectrum notch.

[0082] Illustratively, the embodiment of the present application develops a dual-optical frequency comb system with a simple system structure, high flexibility, and strong stability based on the method of free coding of the communication algorithm: the generation code of the dual-optical comb system is simulated and designed through the computer end (communication algorithm module), and the two optical frequency combs with slightly misaligned repetition frequencies are integrated in the frequency domain at the code end, and a set of dual-comb time domain signals is obtained through fast inverse Fourier transform; the time domain digital signal generated by the code is input into the signal generator, and the signal generator sends a signal to modulate the intensity of the single-frequency light, and converts the electrical signal frequency domain comb teeth generated by the signal generator into optical signal frequency domain comb teeth, thereby realizing the generation of dual-optical frequency combs; the receiving end performs beat frequency through a photodetector to realize the bandwidth compression process of the dual-optical frequency comb detection end.

[0083] For example, with reference to FIG1 to FIG3 , the dual optical frequency comb generation system based on the communication algorithm provided in the embodiment of the present application is mainly divided into two parts:

[0084] The first is the communication algorithm module 100, which mainly generates a time domain signal that is flat in the frequency domain through a pseudo-random binary sequence (PRBS) to achieve the generation of a digital electrical dual-frequency comb time domain signal;

[0085] The second is the dual optical frequency comb generation module 200, which mainly realizes simple, flexible and convenient digital dual optical frequency comb generation and testing functions through a simple system of laser 210, signal generator 220, electro-optical modulator 230 and photodetector 250.

[0086] For example, a PRBS code can generate a random bit data stream. The conventional format of the PRBS code is PRBSn, where n represents the length of the register. The corresponding output length can be expressed as:

[0087] PRBS n=2 n -1;

[0088] For example, PRBS8 means that the register corresponding to the PRBS code is 8 bits, and the data that can be generated in one cycle is 28-1, that is, 255 bits of data. Currently commonly used PRBS codes include PRBS7, PRBS9, PRBS11, PRBS15, PRBS32, etc., which are not limited in this application;

[0089] In some implementation scenarios, according to design requirements, two sets of PRBS code sequences are first generated using PRBS code. The lengths of the two sets of PRBS code sequences are inconsistent to achieve slight detuning in the frequency domain. Then, they are transformed into the frequency domain through Fourier transform and evenly distributed within a fixed range bandwidth. Thus, two sets of frequency comb teeth with a center frequency of f0 and slightly different repetition frequencies are obtained. The comb tooth frequencies of the frequency comb are f and f, respectively. 1,n and f 2,n , the intervals between the two sets of comb teeth are Δf1 and Δf2 respectively, then the frequency difference between them can be written as:

[0090] Δf=Δf2-Δf1;

[0091] The zero-frequency teeth of the two frequency combs overlap, and the frequency domain differences between the teeth on both sides of the frequency comb are Δf, 2×Δf, 3×Δf, …, n×Δf. In terms of code, the horizontal coordinates of the two frequency comb teeth are unified and superimposed on a spectrum. Then, an inverse fast Fourier transform is performed to convert them into the superposition of two sets of PRBS codes in the time domain, thereby reducing the burden and complexity of the experimental system and greatly improving the stability of the system.

[0092] Optionally, as an example, the comb tooth spacing used in the algorithm code simulation is Δf1=65.9MHz, Δf1=63.9MHz, the frequency difference Δf=Δf2-Δf1=2MHz, the total bandwidth is 2GHz, the single sideband is 1GHz, and the dual-comb superposition effect is shown in Figure 4, which is a schematic diagram of the digital frequency comb provided in an embodiment of the present application; the dual comb teeth are beat-frequency demodulated by simulating the photodetector effect, and the comb tooth spacing of the new spectrum is Δf, which successfully compresses the GHz bandwidth to the MHz level, proving that the direct superposition of the dual frequency combs in the time domain can also achieve the effect of dual-comb down-conversion and bandwidth compression. The result is shown in Figure 5, which is a schematic diagram of the simulated beat frequency effect provided in an embodiment of the present application.

[0093] In some implementation scenarios, the comb tooth spacing used in the embodiment is Δf1=5MHz, Δf1=5.005MHz, the frequency difference Δf=Δf2-Δf1=5KHz, the total bandwidth is 5GHz, and the single sideband is 2.5GHz. Therefore, the spectral resolution of the system is about 5MHz, which meets the requirements of most microcavities, and the maximum sampling rate is consistent with the frequency difference of 5KHz, which meets the requirements of high-speed sampling. It should be noted that the above parameter indicators can be freely adjusted according to needs, with high flexibility and strong adaptability;

[0094] In the dual optical frequency comb generation module, a single wavelength continuous laser emits a continuous laser signal with a wavelength of λ0 = 1550nm, which enters the electro-optical intensity modulator for modulation. The electro-optical intensity modulator is controlled by the dual frequency comb time domain digital electrical signal generated by the code-driven signal generator, and modulates the single wavelength power stable continuous laser signal into a time domain pseudo-random sequence corresponding to the dual optical frequency comb, realizing the conversion from electrical frequency comb to optical frequency comb; it is then input into the microcavity system. Due to the characteristics of the microcavity, the wavelength that meets the resonance condition in the microring resonant cavity will resonate in the ring, where n is the effective refractive index of the microring, R is the radius of the microring, m is the resonance order m = 1, 2, 3..., and λ is the resonant wavelength. Light that does not meet the resonance condition will be directly output from the original waveguide. From the transmission spectrum of the frequency sweep, it can be seen that there is a corresponding resonance peak at a specific wavelength. The single-sideband 2.5GHz frequency comb is down-converted to 2.5MHz. The result is shown in Figure 6, which is a schematic diagram of the frequency comb demodulation principle provided in the embodiment of the present application.

[0095] Therefore, after passing through the microcavity, the dual optical frequency comb teeth will have a spectral notch in the frequency domain caused by specific absorption. After entering the photodetection system, this notch can be demodulated in the narrow 2.5MHz single-sideband bandwidth after downconversion, effectively restoring the spectral information within the original 2.5GHz bandwidth at a low sampling rate. Simultaneously, by changing the comb teeth's central wavelength λ0, shifting the wavelength toward shorter wavelengths, the corresponding resonant peak in the spectrum shifts to the right, confirming that the notch is indeed caused by microring resonance. Figure 7 shows a schematic diagram of the microcavity resonance measurement results of the dual optical frequency comb provided by an embodiment of the present application. This dual optical frequency comb generation system is capable of high-precision, adjustable, and high-speed detection.

[0096] In all embodiments of the present application, "big" and "small" are relative, "more" and "less" are relative, and "up" and "down" are relative. The expressions of such relative terms will not be elaborated in the embodiments of the present application.

[0097] It should be understood that the phrases “in this embodiment,” “in an embodiment of the present application,” or “as an optional implementation” mentioned throughout the specification mean that specific features, structures, or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, “in this embodiment,” “in an embodiment of the present application,” or “as an optional implementation” appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. Those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required for the present application.

[0098] In the various embodiments of the present application, it should be understood that the size of the serial numbers of the above-mentioned processes does not necessarily mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0099] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A dual optical frequency comb generation system based on a communication algorithm, characterized in that: It includes a communication algorithm module and a dual optical frequency comb generation module; The communication algorithm module is used to generate a preset time domain signal through a pseudo-random binary sequence, and send the preset time domain signal to the dual optical frequency comb generation module, wherein the preset time domain signal is two groups of comb teeth with a frequency difference in the frequency domain; The dual optical frequency comb generation module includes a laser, a signal generator, an electro-optical modulator and a microcavity. The input end of the electro-optical modulator is respectively connected to the laser and the signal generator, and the output end of the electro-optical modulator is connected to the microcavity. The laser generates a continuous laser signal of a preset wavelength. The signal generator receives the preset time domain signal and generates a dual frequency comb time domain digital electrical signal based on the preset time domain signal. The electro-optical modulator modulates the continuous laser signal into a time domain pseudo-random sequence optical signal corresponding to the dual optical frequency comb based on the dual frequency comb time domain digital electrical signal, and inputs the time domain pseudo-random sequence optical signal into the microcavity.

2. The dual optical frequency comb generation system based on communication algorithm according to claim 1, characterized in that: The dual optical frequency comb generation system further includes a photodetector. After the time domain pseudo random sequence optical signal resonates through the microcavity, the photodetector receives and detects the resonated time domain pseudo random sequence optical signal.

3. The dual optical frequency comb generation system based on communication algorithm according to claim 1, characterized in that: The resonance condition of the microcavity is: 2πnR=mλ; Wherein, n is the effective refractive index of the microring in the microcavity, R is the radius of the microring, m is the resonance order m=1, 2, 3..., λ is the resonance wavelength, and π is the pi.

4. The dual optical frequency comb generation system based on communication algorithm according to claim 1, characterized in that: The communication algorithm module includes a PRBS code time domain unit, a PRBS code frequency domain unit, a frequency domain integration unit and a dual-comb time domain unit, and the PRBS code time domain unit, the PRBS code frequency domain unit, the frequency domain integration unit and the dual-comb time domain unit are connected in sequence.

5. The dual optical frequency comb generation system based on communication algorithm according to claim 4, characterized in that: The PRBS code time domain unit generates two groups of PRBS code sequences, and the lengths of the two groups of PRBS code sequences are inconsistent.

6. The dual optical frequency comb generation system based on communication algorithm according to claim 5, characterized in that: The PRBS code frequency domain unit obtains two groups of PRBS code sequences generated by the PRBS code time domain unit, and generates two groups of frequency comb teeth with the same center frequency and different repetition frequencies based on the two groups of PRBS code sequences through Fourier transform.

7. The dual optical frequency comb generation system based on communication algorithm according to claim 6, characterized in that: Two groups of frequency comb teeth with the same center frequency and different repetition frequencies are superimposed and integrated into overlapping frequency comb teeth in the frequency domain integration unit, and the overlapping frequency comb teeth are subjected to inverse fast Fourier transform in the dual-comb time domain unit to be the preset time domain signal.

8. A dual optical frequency comb generation method based on a communication algorithm, characterized in that: The dual optical frequency comb generation system based on the communication algorithm according to any one of claims 1 to 6, the method comprising: Generate a preset time domain signal based on a communication algorithm module; The preset time domain signal generates a dual-frequency comb time domain digital electrical signal in the signal generator; generating a continuous laser signal based on a laser; The continuous laser signal is modulated in the electro-optic modulator by the dual-frequency comb time-domain digital electrical signal to obtain a time-domain pseudo-random sequence optical signal corresponding to the dual-optical frequency comb; The time-domain pseudo-random sequence optical signal resonates in the microcavity, and the resonated time-domain pseudo-random sequence optical signal is received and detected by a photoelectric detector.

9. The dual optical frequency comb generation method based on communication algorithm according to claim 8, characterized in that: The step of generating a preset time domain signal based on the communication algorithm module includes: Generate two groups of PRBS code sequences based on the PRBS code time domain unit; The two groups of PRBS code sequences are transformed by Fourier in the PRBS code frequency domain unit to generate two groups of frequency comb teeth with the same center frequency and different repetition frequencies; the two groups of frequency comb teeth are superimposed and integrated into overlapping frequency comb teeth in the frequency domain integration unit, wherein the zero-frequency comb teeth of the two groups of frequency comb teeth overlap; The overlapping frequency comb teeth are inversely fast Fourier transformed in a dual-comb time domain unit into the preset time domain signal.

10. The dual optical frequency comb generation method based on communication algorithm according to claim 8, characterized in that: The time-domain pseudo-random sequence optical signal resonates in the microcavity, and the resonated time-domain pseudo-random sequence optical signal is received and detected by a photodetector, comprising: The optical signal in the time domain pseudo-random sequence optical signal that meets the resonance condition of the microcavity resonates, and the optical signal in the time domain pseudo-random sequence optical signal that does not meet the resonance condition of the microcavity is resonated from the original waveguide Output, the time domain pseudo-random sequence optical signal has a corresponding resonance peak at a preset wavelength; The resonant time-domain pseudo-random sequence optical signal has a spectrum notch caused by absorption at a preset wavelength in the frequency domain, which is received and detected by a photoelectric detector and the spectrum notch is demodulated.

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