Piezoelectric ceramic-based double-optical-comb-cavity modulated gas measurement system and method

Abstract

The invention provides a piezoelectric ceramic-based double-optical-comb-cavity modulated gas measurement system and method, a double-optical-comb output module is utilized to generate a detection optical comb and a reference optical comb which are coherent, the detection optical comb enters a resonant cavity to interact with gas to be measured, and the reference optical comb directly reaches a data acquisition and analysis module; the piezoelectric ceramic modulation module dynamically adjusts the length of the resonant cavity by applying a periodic voltage signal; and the data acquisition and analysis module demodulates spectral data of the to-be-detected gas through an asynchronous sampling technology based on double optical comb interference signals of the reference optical comb and the detection optical comb. According to the dual-optical-comb-cavity modulated gas measurement system based on the piezoelectric ceramics, the piezoelectric ceramic modulation module is used for dynamically adjusting the length of the resonant cavity according to the detection optical comb and the reference optical comb, dynamic modulation and transient coupling optimization of the cavity length are achieved, and the problems that in the prior art, the dispersion effect of gas can affect optical signal propagation, and the measurement precision is poor are solved. And non-linear modulation occurs in the ring-down process, so that the measurement precision is influenced.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas detection, and in particular relates to a piezoelectric ceramic-based dual-optical comb cavity modulation gas measurement system and method. Background Art

[0002] Gas absorption spectroscopy is a technique that uses the selective absorption properties of matter to qualitatively or quantitatively determine gas composition and concentration by analyzing the absorption of specific wavelengths of light by gas molecules. Cavity ring-down spectroscopy (CRDS) is a highly sensitive spectroscopy technique based on cavity ring-down time measurement. It quantitatively determines gas concentration by detecting the decay time of the light intensity of a light comb caused by gas absorption within an optical resonant cavity.

[0003] However, in actual use of CRDS technology, the gas to be measured generally contains multiple gases. Due to the different absorption characteristics and refractive indices of different gases, a gas dispersion effect occurs, which affects the propagation of the optical signal and causes nonlinear modulation in the ring-down process. This causes the ring-down characteristics of the detection light comb in the optical resonator to shift, thereby affecting the measurement accuracy. Summary of the Invention

[0004] In order to solve the technical problem in the background technology that the dispersion effect of gas will affect the propagation of optical signals, resulting in nonlinear modulation during the ring-down process, and affecting the measurement accuracy, the present invention provides a dual-comb cavity modulation gas measurement system and method based on piezoelectric ceramics.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a dual-comb cavity modulation gas measurement system based on piezoelectric ceramics, the dual-comb cavity modulation gas measurement system based on piezoelectric ceramics comprising: a dual-comb output module, a resonant cavity, a data acquisition and analysis module, and a piezoelectric ceramic modulation module;

[0007] The dual optical comb output module is used to output coherent detection optical comb and reference optical comb;

[0008] The resonant cavity is in communication with the dual optical comb output module, and is used to accommodate the gas to be measured and receive the detection optical comb;

[0009] The piezoelectric ceramic modulation module is partially disposed in the resonant cavity and is electrically connected to the dual-comb output module, and is used to modulate the resonant cavity;

[0010] The data acquisition and analysis module is connected to the resonant cavity and the dual-comb output module, and is used to receive the reference light comb and the detection light comb output from the resonant cavity; the data acquisition and analysis module is used to perform analysis based on the detection light comb and the reference light comb to obtain spectral data of the gas to be measured, and perform composition and concentration analysis of the gas to be measured based on the spectral data.

[0011] Optionally, the resonant cavity includes a cavity body, a first cavity mirror and a second cavity mirror;

[0012] The cavity comprises an input end and an output end which are separated from each other, the input end being connected to the dual optical comb output module for receiving the detection optical comb; the output end being connected to the data acquisition and analysis module for outputting the detection optical comb to the data acquisition and analysis module;

[0013] The first cavity mirror and the second cavity mirror are both arranged in the cavity, wherein the first cavity mirror is arranged close to the input end, and the second cavity mirror is arranged close to the output end;

[0014] The first cavity mirror and the second cavity mirror are both connected to the piezoelectric ceramic modulation module.

[0015] Optionally, the piezoelectric ceramic modulation module includes a first piezoelectric ceramic, a second piezoelectric ceramic, a first driving source, a second driving source and a signal generator;

[0016] The first piezoelectric ceramic and the second piezoelectric ceramic are both disposed in the cavity, wherein the first piezoelectric ceramic is connected to the first cavity mirror, and the second piezoelectric ceramic is connected to the second cavity mirror;

[0017] The first driving source and the second driving source are both electrically connected to the signal generator, and the first driving source is electrically connected to the first piezoelectric ceramic, and the second driving source is electrically connected to the second piezoelectric ceramic;

[0018] The signal generator is electrically connected to the data acquisition and analysis module.

[0019] Optionally, the data acquisition and analysis module includes a guide component, a beam combiner, a balanced photoelectric detector, an acquisition card and an analysis host;

[0020] The guide assembly is connected to the output end;

[0021] The beam combiner is connected to the dual-comb output module, the guide assembly and the balanced photodetector, and is used to obtain the reference light comb and the detection light comb output from the resonant cavity, combine the detection light comb and the reference light comb to generate a light domain signal, and output the light domain signal to the balanced photodetector;

[0022] The acquisition card is electrically connected to the balanced photoelectric detector and the analysis host.

[0023] Optionally, the system further comprises a first adjustment component and a second adjustment component;

[0024] Wherein, the first adjustment component is arranged between the dual optical comb output module and the input end;

[0025] The second adjustment component is arranged between the dual-comb output module and the beam combining mirror.

[0026] Optionally, the first adjustment component is a first 1 / 2 wave plate;

[0027] The second adjustment component includes a second 1 / 2 wave plate and a 1 / 4 wave plate arranged in sequence.

[0028] Optionally, the dual optical comb output module is any one of an on-chip optical comb, a single-cavity dual comb, and a frequency- and phase-stable dual comb optical comb.

[0029] In a second aspect, the present invention provides a piezoelectric ceramic-based dual-comb cavity modulation gas measurement method, which is used in the piezoelectric ceramic-based dual-comb cavity modulation gas measurement system provided above, comprising:

[0030] S1: Select the gas to be measured, input the gas to be measured into the resonant cavity, and assemble the dual-comb cavity modulation gas measurement system;

[0031] S2: Start the dual-comb output module to output coherent detection and reference optical combs, and obtain the beat frequency difference between the detection and reference optical combs in the dual-grating output module;

[0032] S3: Based on the beat frequency difference between the detection and reference optical combs, the piezoelectric ceramic modulation module is used to adjust the shapes of the first and second cavity mirrors in the resonant cavity in real time, so that the cavity length matches the beat frequency difference in real time;

[0033] S4: Using the data acquisition and analysis module, collect and analyze the ring-down signal in the resonant cavity to obtain spectral data;

[0034] S5: Based on the acquired spectral data, combined with the adaptive filtering algorithm, analysis is performed to obtain the concentration, composition, molecular structure and spectral characteristics of the target gas in the gas to be measured.

[0035] Optionally, step S3 specifically includes:

[0036] S3.1: Calculate the target cavity length change ΔL of the resonant cavity based on the beat frequency difference Δf between the detection and reference optical combs.

[0037] S3.2: Generate a modulation voltage signal corresponding to ΔL using a signal generator. The modulation voltage signal waveform is a radio frequency sine wave, square wave, or sawtooth wave, and the frequency range is 10 Hz to 10 kHz.

[0038] S3.3: Apply a modulated voltage signal to the first piezoelectric ceramic and the second piezoelectric ceramic via the first driving source and the second driving source, and synchronously adjust the positions of the first cavity mirror and the second cavity mirror so that the cavity length matches the beat frequency difference Δf in real time.

[0039] Optionally, step S4 specifically includes:

[0040] S4.1: Use a photoelectric balanced detector to collect the ring-down signal in the resonant cavity, use dual-channel detection to eliminate common-mode noise, and obtain the intermediate signal.

[0041] S4.2: Use asynchronous sampling to obtain asynchronous sampled data of the intermediate signal;

[0042] S4.3: Based on the frequency domain demodulation algorithm and combined with Fourier transform, the spectral data of the target gas is extracted from the asynchronous sampling data.

[0043] The beneficial effects of the present invention are:

[0044] The present invention provides a piezoelectric ceramic-based dual-comb cavity modulation gas measurement system. A dual-comb output module is used to generate coherent detection and reference optical combs. The detection optical comb enters the resonant cavity and interacts with the gas to be measured, while the reference optical comb directly reaches the data acquisition and analysis module. The piezoelectric ceramic modulation module dynamically adjusts the resonant cavity length by applying a periodic voltage signal. The data acquisition and analysis module uses asynchronous sampling technology to demodulate the spectral data of the gas to be measured based on the dual-comb interference signal of the reference and detection optical combs. The piezoelectric ceramic-based dual-comb cavity modulation gas measurement system of the present invention utilizes the piezoelectric ceramic modulation module to periodically and dynamically adjust the resonant cavity length based on the detection and reference optical combs, achieving dynamic modulation of the cavity length and transient coupling optimization. This significantly improves the system's sensitivity, measurement efficiency, and stability, and addresses the technical problem in the prior art where the dispersion effect of gas affects optical signal propagation, leading to nonlinear modulation during ring-down and affecting measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of the piezoelectric ceramic-based dual-comb cavity modulation gas measurement system of the present invention;

[0046] Figure 2 It is a detailed schematic diagram of the dual-comb cavity modulation gas measurement system based on piezoelectric ceramics in the present invention.

[0047] Among them: 1. Dual-comb output module; 2. Resonant cavity; 21. Cavity; 211. Input end; 212. Output end; 22. First cavity mirror; 23. Second cavity mirror; 3. Data acquisition and analysis module; 31. Guide assembly; 32. Beam combiner; 33. Balanced photodetector; 34. Acquisition card; 35. Analysis host; 4. Piezoelectric ceramic modulation module; 41. First piezoelectric ceramic; 42. Second piezoelectric ceramic; 43. First driving source; 44. Second driving source; 45. Signal generator; 5. First 1 / 2 wave plate; 6. Second 1 / 2 wave plate; 7. 1 / 4 wave plate. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0051] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0052] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0053] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0054] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0055] Traditional CRDS technology is limited by the narrowband nature of a single laser source, resulting in a narrow spectral range. Furthermore, the mechanical cavity length scanning method is susceptible to environmental vibrations, reducing measurement accuracy and stability. Furthermore, intracavity dispersion can affect the light field distribution, causing the signal ring-down characteristics to deviate from ideal conditions, further reducing measurement accuracy. Therefore, maintaining the high sensitivity of CRDS while expanding the measurement spectral range, reducing the impact of dispersion, and improving measurement stability are pressing technical challenges.

[0056] At the same time, existing CRDS technology also has the following technical issues: 1. Limited measurement range of the ring-down cavity: Current cavity ring-down systems can usually only measure the absorption spectrum of a single gas and cannot measure the absorption characteristics of multiple gases simultaneously. Due to the limitations of the light field distribution and cavity mode coupling within the cavity, existing systems are restricted when measuring the absorption spectra of multiple gases or a wide spectral range. 2. Limited measurement efficiency and time resolution: Traditional gas absorption measurements use a stepper mechanical scanning to adjust the cavity length, which has multiple problems, including slow scanning speed, low measurement efficiency, and susceptibility to external vibration and temperature changes, leading to error accumulation, which in turn affects accuracy and stability. Therefore, improving scanning speed and time resolution and reducing error accumulation are key issues that need to be urgently addressed in current technology.

[0057] Example 1

[0058] First, see Figures 1 to 2 , shows a schematic diagram of a piezoelectric ceramic-based dual-comb cavity modulation gas measurement system in the present invention, the system comprising: a dual-comb output module 1, a resonant cavity 2, a data acquisition and analysis module 3, and a piezoelectric ceramic modulation module 4; the dual-comb output module 1 is used to output a coherent detection light comb and a reference light comb; the resonant cavity 2 is connected to the dual-comb output module 1, and is used to accommodate the gas to be measured and receive the detection light comb; the piezoelectric ceramic modulation module 4 is partially arranged in the resonant cavity 2 and is electrically connected to the dual-comb output module 1, and is used to modulate the resonant cavity 2; the data acquisition and analysis module 3 is connected to the resonant cavity 2 and the dual-comb output module 1, and is used to receive the reference light comb and the detection light comb output from the resonant cavity 2; the data acquisition and analysis module 3 is used to perform analysis based on the detection light comb and the reference light comb to obtain spectral data of the gas to be measured, and perform composition and concentration analysis on the gas to be measured based on the spectral data.

[0059] In this embodiment, a dual-comb output module 1 generates coherent detection and reference optical combs. The detection optical comb enters resonant cavity 2 and interacts with the gas to be measured, while the reference optical comb directly reaches data acquisition and analysis module 3. A piezoelectric ceramic modulation module 4 dynamically adjusts the length of resonant cavity 2 by applying a periodic voltage signal. Based on the dual-comb interference signal generated by the reference and detection optical combs, data acquisition and analysis module 3 demodulates the spectral data of the gas to be measured using asynchronous sampling techniques. The piezoelectric ceramic-based dual-comb cavity modulation gas measurement system of the present invention utilizes the piezoelectric ceramic modulation module 4 to periodically and dynamically adjust the length of resonant cavity 2 based on the detection and reference optical combs, achieving dynamic modulation of the cavity length and transient coupling optimization. This significantly improves the system's sensitivity, measurement efficiency, and stability, and addresses the prior art technical issue of gas dispersion effects affecting optical signal propagation, leading to nonlinear modulation during ring-down and thus affecting measurement accuracy.

[0060] Optionally, refer to Figure 2The resonant cavity 2 in the present invention includes a cavity 21, a first cavity mirror 22 and a second cavity mirror 23; the cavity 21 includes an input end 211 and an output end 212 that are separated from each other, the input end 211 is connected to the dual-comb output module 1, and is used to receive the detection light comb; the output end 212 is connected to the data acquisition and analysis module 3, and is used to output the detection light comb to the data acquisition and analysis module 3; the first cavity mirror 22 and the second cavity mirror 23 are both arranged in the cavity 21, wherein the first cavity mirror 22 is arranged close to the input end 211, and the second cavity mirror 23 is arranged close to the output end 212; the first cavity mirror 22 and the second cavity mirror 23 are both connected to the piezoelectric ceramic modulation module 4.

[0061] Optionally, refer to Figure 2 The piezoelectric ceramic modulation module 4 in the present invention includes a first piezoelectric ceramic 41, a second piezoelectric ceramic 42, a first driving source 43, a second driving source 44 and a signal generator 45; the first piezoelectric ceramic 41 and the second piezoelectric ceramic 42 are both arranged in the cavity 21, wherein the first piezoelectric ceramic 41 is connected to the first cavity mirror 22, and the second piezoelectric ceramic 42 is connected to the second cavity mirror 23; the first driving source 43 and the second driving source 44 are both electrically connected to the signal generator 45, and the first driving source 43 is electrically connected to the first piezoelectric ceramic 41, and the second driving source 44 is electrically connected to the second piezoelectric ceramic 42; the signal generator 45 is electrically connected to the dual-comb output module 1.

[0062] In this embodiment, the first cavity mirror 22 and the second cavity mirror 23 in the resonant cavity 2 are connected to a piezoelectric ceramic drive source via a first piezoelectric ceramic 41 and a second piezoelectric ceramic 42, respectively. A signal generator 45 is electrically connected to the dual optical comb output module 1. A drive signal is output based on the repetition frequencies of the detection and reference optical combs. The drive signal drives the first and second piezoelectric ceramics 41 and 42, respectively, to modulate the first and second cavity mirrors 22 and 23, thereby dynamically modulating the cavity length of the resonant cavity 2 and optimizing transient coupling. This improves the sensitivity, measurement efficiency, and stability of the system and significantly suppresses ring-down signal distortion caused by gas dispersion effects. For example, a signal generator 45 generates an adjustable square wave signal from 10 Hz to 10 kHz, driving the first and second piezoelectric ceramics 41 and 42 to produce opposite displacements, thereby matching the cavity length to the repetition frequency of the optical comb in real time.

[0063] Furthermore, the first cavity mirror 22 and the second cavity mirror 23 in this embodiment are both high-reflectivity cavity mirrors with a reflectivity higher than 99.99%, so as to form an optical resonant cavity 2 with long optical path enhancement, thereby improving the sensitivity of the gas absorption signal.

[0064] Specifically, the performance of the high reflectivity resonant cavity 2 is mainly characterized by FSR (free spectral range) and F value (fineness).

[0065]

[0066] Where c is the speed of light, and FSR is directly related to the cavity length L of the resonant cavity 2. A larger cavity length will result in a smaller FSR, thereby improving the spectral resolution. In actual use, it is necessary to ensure that the repetition frequency f of the detection optical comb is rep1 Satisfy f rep1 =N×FSR, where N is an integer, to ensure that the detection optical comb has the same frequency as the longitudinal mode of the resonant cavity 2, thereby improving the measurement accuracy and stability.

[0067]

[0068] Here, R is the reflectivity of the first cavity mirror 22 and the second cavity mirror 23, and its value is approximately 1. The higher the F value, the longer the light field is stored in the resonant cavity 2, and the longer the time optical path (even up to the kilometer level), thereby significantly enhancing the interaction between light and gas and improving the detection sensitivity of gas absorption signals. This high-fineness characteristic is crucial for achieving high-precision gas absorption measurements.

[0069] Optionally, refer to Figure 2 The data acquisition and analysis module 3 in the present invention includes a guide component 31, a beam combining mirror 32, a balanced photodetector 33, an acquisition card 34 and an analysis host 35; the guide component 31 is connected to the output end 212; the beam combining mirror 32 is connected to the dual-comb output module 1, the guide component 31 and the balanced photodetector 33, and is used to obtain the reference light comb and the detection light comb output from the resonant cavity 2, combine the detection light comb and the reference light comb to generate a light domain signal, and output the light domain signal to the balanced photodetector 33; the acquisition card 34 is electrically connected to the balanced photodetector 33 and the analysis host 35.

[0070] In this embodiment, a guiding component 31, such as a reflector, an optical fiber path, etc., is used to guide the detection light comb output from the resonant cavity 2 to the beam combiner 32, and the reference light comb and the detection grating are combined in the beam combiner 32 to generate an optical domain signal; a balanced photodetector 33 is used to effectively suppress common mode noise, especially laser intensity noise and environmental noise, and significantly improve the signal-to-noise ratio of the signal, which not only optimizes the dynamic range of the system, but also ensures that weak absorption signals can be accurately extracted in a high background noise environment, thereby enhancing the stability and accuracy of the measurement; an acquisition card 34 is used to obtain the output signal of the balanced photodetector 33, convert it into a digital signal, and then output it to the analysis host 35, and in the analysis host 35, based on the digital signal, the dual-comb interference signal is demodulated, and the absorption spectrum is extracted in combination with Fourier transform technology to achieve high-precision gas analysis.

[0071] Optionally, the system in the present application further comprises a first adjustment component and a second adjustment component; wherein the first adjustment component is arranged between the dual optical comb output module 1 and the input end 211; and the second adjustment component is arranged between the dual optical comb output module 1 and the beam combiner 32.

[0072] Optionally, referring to Figure 2 , the first adjustment component in the present application is a first 1 / 2 wave plate 5; and the second adjustment component comprises a second 1 / 2 wave plate 6 and a 1 / 4 wave plate 7 arranged in sequence.

[0073] In the present embodiment, the first 1 / 2 wave plate 5 is used to adjust the polarization state of the detection optical comb before entering the resonant cavity 2, so as to ensure the coupling efficiency and cavity mode matching of the optical signal in the resonant cavity 2, and improve the stability in the ring-down process; and the second 1 / 2 wave plate 6 and the 1 / 4 wave plate 7 are used to adjust the polarization direction of the reference optical comb when the beat frequency interference is performed in the beam combiner 32, so as to optimize the coherence and improve the quality and signal-to-noise ratio of the beat frequency signal, thereby ensuring the measurement accuracy and the spectral demodulation performance.

[0074] Optionally, the dual optical comb output module 1 in the present application is any one of an on-chip optical comb, a single-cavity dual-comb, and a frequency-stabilized and phase-stabilized dual-comb optical comb.

[0075] Embodiment two

[0076] In a second aspect, the present application further provides a dual optical comb cavity modulation gas measurement method based on a piezoelectric ceramic, which is used for the dual optical comb cavity modulation gas measurement system based on a piezoelectric ceramic in the first aspect, and comprises the following steps:

[0077] S1: selecting a gas to be measured, inputting the gas to be measured into the resonant cavity 2, and assembling the dual optical comb cavity modulation gas measurement system;

[0078] S2: starting the dual optical comb output module 1 to output coherent detection optical combs and reference optical combs, and obtaining the beat frequency difference between the detection optical combs and the reference optical combs in the dual grating output module;

[0079] S3: according to the beat frequency difference between the detection optical combs and the reference optical combs, using the piezoelectric ceramic modulation module 4 to adjust the shape of the first cavity mirror 22 and the second cavity mirror 23 in the resonant cavity 2 in real time, so that the cavity length is matched with the beat frequency difference in real time;

[0080] S4: using the data acquisition and analysis module 3 to collect and analyze the ring-down signal in the resonant cavity, and obtaining spectral data;

[0081] S5: according to the obtained spectral data, combining an adaptive filtering algorithm to analyze, and obtaining the concentration, composition, molecular structure and spectral characteristics of the target gas in the gas to be measured.

[0082] Optionally, the step S3 specifically comprises:

[0083] S3.1: Calculate the target cavity length change ΔL of resonator 2 based on the beat frequency difference Δf between the detection and reference optical combs.

[0084] S3.2: Generate a modulation voltage signal corresponding to ΔL using a signal generator 45 . The modulation voltage signal waveform is a radio frequency sine wave, square wave, or sawtooth wave, and the frequency range is 10 Hz to 10 kHz.

[0085] S3.3: Apply a modulated voltage signal to the first piezoelectric ceramic 41 and the second piezoelectric ceramic 42 through the first driving source 43 and the second driving source 44, and synchronously adjust the positions of the first cavity mirror 22 and the second cavity mirror 23 so that the cavity length matches the beat frequency difference Δf in real time.

[0086] Optionally, step S4 specifically includes:

[0087] S4.1: Use a photoelectric balanced detector to collect the ring-down signal in resonant cavity 2, employ dual-channel detection to eliminate common-mode noise, and obtain an intermediate signal.

[0088] S4.2: Use asynchronous sampling to obtain asynchronous sampled data of the intermediate signal;

[0089] S4.3: Based on the frequency domain demodulation algorithm and combined with Fourier transform, the spectral data of the target gas is extracted from the asynchronous sampling data.

[0090] Furthermore, in this embodiment, after the collected cavity ring-down signal is demodulated using asynchronous sampling technology, the various properties of the cavity gas, including but not limited to spectrum, dispersion and concentration, can be inverted using the Beer-Lambert law.

[0091] I=I 0· e -αL

[0092] Where I is the attenuated light intensity, I0 is the initial intensity of the incident light, a is the gas absorption coefficient, which is typically related to the gas concentration, light wavelength, and physical properties of the gas, and L is the cavity length of resonant cavity 2, that is, the propagation distance of the light comb in the gas. In resonant cavity 2, as the light comb propagates through the gas, absorption processes will cause light intensity to decay. If multiple absorption processes occur within the cavity, the total absorption effect of different gas components must also be considered, which can be comprehensively expressed by the total absorption coefficient.

[0093] Furthermore, the intermediate signal in this embodiment is a differential signal.

[0094] In this embodiment, a coherent detection light comb and reference light comb are generated by the dual-comb output module 1, and the beat frequency difference (Δf) between the two is used as a real-time control signal to drive the piezoelectric ceramic modulation module 4, so that the cavity length of the resonant cavity 2 dynamically matches the change of the light comb repetition frequency; the data acquisition and analysis module 3 uses asynchronous sampling and frequency domain demodulation algorithms to process the ring-down signal, and combines adaptive filtering technology to analyze the gas spectrum characteristics, deeply integrating the wide spectral coverage capability of the dual-comb, the nanometer-level displacement accuracy of the piezoelectric ceramic, and the anti-interference characteristics of digital signal processing, breaking through the limitations of traditional gas absorption measurement technology: through real-time closed-loop matching of the cavity length and the optical frequency, the gas absorption is dynamically compensated. The cavity mode mismatch caused by the bulk dispersion effect eliminates the nonlinear offset of the ring-down signal, significantly improves the measurement accuracy, and reduces the cross-interference error of the concentrations of various components in complex mixed gases; piezoelectric ceramic modulation replaces the mechanical scanning mechanism, and realizes microsecond cavity length adjustment driven by electrical signals, which not only expands the spectral coverage range, but also eliminates the delay and vibration noise caused by mechanical inertia, ensuring the long-term stability of the system in the high-disturbance environment of industrial sites; the coordinated design of balanced photoelectric detection and asynchronous sampling, combined with Fourier transform and adaptive filtering algorithms, effectively suppresses common-mode noise and extracts weak absorption signals, realizing real-time capture and analysis of transient gas concentration changes.

[0095] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0096] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A dual-comb cavity modulation gas measurement system based on piezoelectric ceramics, characterized in that: The system comprises a dual optical comb output module (1), a resonant cavity (2), a data acquisition and analysis module (3) and a piezoelectric ceramic modulation module (4); The dual optical comb output module (1) is used to output coherent detection optical comb and reference optical comb; The resonant cavity (2) is in communication with the dual optical comb output module (1) and is used for accommodating the gas to be measured and receiving the detection optical comb; The piezoelectric ceramic modulation module (4) is partially arranged in the resonant cavity (2) and is electrically connected to the dual-comb output module (1) for modulating the resonant cavity (2); The data acquisition and analysis module (3) is connected to the resonant cavity (2) and the dual optical comb output module (1), and is used to receive the reference optical comb and the detection optical comb output from the resonant cavity (2); the data acquisition and analysis module (3) is used to perform analysis based on the detection optical comb and the reference optical comb to obtain spectral data of the gas to be measured, and perform composition and concentration analysis on the gas to be measured based on the spectral data.

2. The piezoelectric ceramic-based dual-comb cavity modulation gas measurement system according to claim 1, characterized in that: The resonant cavity (2) comprises a cavity (21), a first cavity mirror (22) and a second cavity mirror (23); The cavity (21) comprises an input end (211) and an output end (212) which are separated from each other, wherein the input end (211) is connected to the dual optical comb output module (1) for receiving the detection optical comb; and the output end (212) is connected to the data acquisition and analysis module (3) for outputting the detection optical comb to the data acquisition and analysis module (3). The first cavity mirror (22) and the second cavity mirror (23) are both arranged in the cavity (21), wherein the first cavity mirror (22) is arranged close to the input end (211), and the second cavity mirror (23) is arranged close to the output end (212); The first cavity mirror (22) and the second cavity mirror (23) are both connected to the piezoelectric ceramic modulation module (4).

3. The piezoelectric ceramic-based dual-comb cavity modulation gas measurement system according to claim 2, characterized in that: The piezoelectric ceramic modulation module (4) comprises a first piezoelectric ceramic (41), a second piezoelectric ceramic (42), a first driving source (43), a second driving source (44) and a signal generator (45); The first piezoelectric ceramic (41) and the second piezoelectric ceramic (42) are both arranged in the cavity (21), wherein the first piezoelectric ceramic (41) is connected to the first cavity mirror (22), and the second piezoelectric ceramic (42) is connected to the second cavity mirror (23); The first driving source (43) and the second driving source (44) are both electrically connected to the signal generator (45), and the first driving source (43) is electrically connected to the first piezoelectric ceramic (41), and the second driving source (44) is electrically connected to the second piezoelectric ceramic (42); The signal generator (45) is electrically connected to the dual optical comb output module (1).

4. The piezoelectric ceramic-based dual-comb cavity modulation gas measurement system according to claim 3, characterized in that: The data acquisition and analysis module (3) comprises a guide component (31), a beam combining mirror (32), a balanced photoelectric detector (33), an acquisition card (34) and an analysis host (35); The guide assembly (31) is connected to the output end (212); The beam combining mirror (32) is connected to the dual optical comb output module (1), the guide component (31) and the balanced photodetector (33), and is used to obtain the reference optical comb and the detection optical comb output from the resonant cavity (2), combine the detection optical comb and the reference optical comb to generate an optical domain signal, and output the optical domain signal to the balanced photodetector (33); The acquisition card (34) is electrically connected to the balanced photoelectric detector (33) and the analysis host (35).

5. The piezoelectric ceramic-based dual-comb cavity modulation gas measurement system according to claim 4, characterized in that: The system further includes a first adjustment component and a second adjustment component; Wherein, the first adjustment component is arranged between the dual optical comb output module (1) and the input end (211); The second adjustment component is arranged between the dual-comb output module (1) and the beam combining mirror (32).

6. The piezoelectric ceramic-based dual-comb cavity modulation gas measurement system according to claim 5, characterized in that: The first adjustment component is a first 1 / 2 wave plate (5); The second adjustment component comprises a second 1 / 2 wave plate (6) and a 1 / 4 wave plate (7) which are arranged in sequence.

7. The piezoelectric ceramic-based dual-comb cavity modulation gas measurement system according to claim 6, characterized in that: The dual optical comb output module (1) is any one of an on-chip optical comb, a single-cavity dual comb, and a frequency- and phase-stable dual comb optical comb.

8. A piezoelectric ceramic-based dual-comb cavity modulation gas measurement method, used in the piezoelectric ceramic-based dual-comb cavity modulation gas measurement system according to claim 7, characterized in that: include: S1: Select the gas to be measured, input the gas to be measured into the resonant cavity (2), and assemble the dual-comb cavity modulation gas measurement system; S2: Start the dual-comb output module (1) to output coherent detection light comb and reference light comb, and obtain the beat frequency difference between the detection light comb and the reference light comb in the dual-grating output module; S3: Based on the beat frequency difference between the detection optical comb and the reference optical comb, the piezoelectric ceramic modulation module (4) is used to adjust the shapes of the first cavity mirror (22) and the second cavity mirror (23) in the resonant cavity (2) in real time, so that the cavity length matches the beat frequency difference in real time; S4: using the data acquisition and analysis module (3), collecting and analyzing the ring-down signal in the resonant cavity (2) to obtain spectrum data; S5: Based on the acquired spectral data, combined with the adaptive filtering algorithm, analysis is performed to obtain the concentration, composition, molecular structure and spectral characteristics of the target gas in the gas to be measured.

9. The gas measurement method based on dual-comb cavity modulation of piezoelectric ceramics according to claim 8, characterized in that: The step S3 specifically includes: S3.1: Calculate the target cavity length change ΔL of the resonant cavity (2) based on the beat frequency difference Δf between the detection optical comb and the reference optical comb; S3.2: Generate a modulation voltage signal corresponding to ΔL using a signal generator (45), wherein the modulation voltage signal waveform is a radio frequency sine wave, square wave, or sawtooth wave, and the frequency range is 10 Hz to 10 kHz; S3.3: A modulation voltage signal is applied to the first piezoelectric ceramic (41) and the second piezoelectric ceramic (42) via the first driving source (43) and the second driving source (44), and the positions of the first cavity mirror (22) and the second cavity mirror (23) are synchronously adjusted so that the cavity length matches the beat frequency difference Δf in real time.

10. The gas measurement method based on dual-comb cavity modulation of piezoelectric ceramics according to claim 8, characterized in that: The step S4 specifically includes: S4.1: Use a photoelectric balanced detector to collect the ring-down signal in the resonant cavity (2), use dual-channel detection to eliminate common-mode noise, and obtain an intermediate signal; S4.2: Use asynchronous sampling to obtain asynchronous sampled data of the intermediate signal; S4.3: Based on the frequency domain demodulation algorithm and combined with Fourier transform, the spectral data of the target gas is extracted from the asynchronous sampling data.

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