Micro-ring resonator gas concentration detection system and method based on quantum ringing effect

Abstract

The application provides a micro-ring resonance gas concentration detection system and method based on a quantum ringing effect, which can be applied to the technical field of gas concentration detection. The system comprises: an optical frequency comb emitting a first laser beam; a micro-ring resonance cavity enabling the first laser beam to interact with a gas based on an evanescent field effect to obtain a modulated light beam; a double-swing solid angle mirror interferometer delaying a reference light beam and a signal light beam corresponding to the modulated light, and adjusting the frequency of the signal light beam during the delay process, so that the delayed reference light beam and the signal light beam interfere with each other; a detector detecting the interference light beam to obtain a detection signal; a processor performing band-pass filtering on data corresponding to sampling points in the detection signal; performing envelope detection on the detection signal component obtained by filtering to obtain a decay time; and obtaining the concentration of the measured gas according to a plurality of decay times corresponding to a plurality of laser frequencies, thereby improving the gas concentration detection precision and reducing the system volume.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas concentration detection, and more particularly to a micro-ring resonant gas concentration detection system and method based on quantum ringing effect. BACKGROUND

[0002] In the fields of environmental monitoring, industrial production, medical diagnosis, etc., gas sensing technology is a key means to realize accurate detection and safe control, especially the high-sensitivity detection of low-concentration gas, which is directly related to environmental quality assessment, production process optimization and human health protection. As an optical sensing element with high sensitivity and small size, micro-ring resonant cavity has attracted widespread attention in the field of gas detection due to its precise response to changes in gas refractive index, and has become an important research direction to improve the performance of gas sensors.

[0003] In related technologies, the gas sensing scheme based on micro-ring resonant cavity mainly realizes the analysis of gas by detecting the shift of resonant wavelength, but such scheme still faces many challenges in practical application: on the one hand, the absorption of gas in a specific frequency band will produce inter-mode dispersion in the micro-ring resonant cavity, directly affecting the measurement accuracy of the resonant wavelength, causing the detection error to increase, and reducing the stability and reliability of the sensor; on the other hand, the overall size of the system is large. SUMMARY

[0004] Therefore, the present application provides a micro-ring resonant gas concentration detection system and method based on quantum ringing effect.

[0005] According to one aspect of the present application, a micro-ring resonant gas concentration detection system based on quantum ringing effect is provided, comprising: an optical frequency comb for emitting a first laser beam; a micro-ring resonant cavity placed in a gas chamber filled with a gas to be measured, for interacting with the gas based on evanescent field effect when the first laser beam passes through the micro-ring resonant cavity, to obtain a modulated light beam, wherein the normalized scanning frequency of the optical frequency comb is greater than the intrinsic scanning frequency of the micro-ring resonant cavity; a double-swing solid angle mirror interferometer for delaying a reference light beam and a signal light beam corresponding to the modulated light by a predetermined time length, and simultaneously adjusting the frequency of the signal light beam during the delay process, so that the delayed reference light beam and the signal light beam interfere to generate an interference light beam; a detector for detecting the interference light beam to obtain a detection signal; a processor for band-pass filtering the data corresponding to the sampling points in the detection signal; envelope detection of the detection signal components obtained by filtering to obtain the ring-down time corresponding to the ringing effect in the modulated light beam; and obtaining the concentration of the gas to be measured according to the plurality of ring-down times corresponding to the plurality of laser frequencies.

[0006] According to an embodiment of the present application, the processor obtains the concentration of the gas to be measured according to the plurality of decay times corresponding to the plurality of laser frequencies, including: for each laser frequency, obtaining a gas molecule absorption rate corresponding to each laser frequency according to the decay time corresponding to each laser frequency and the decay time when there is no gas in the gas chamber; and analyzing the gas molecule absorption rates corresponding to the plurality of laser frequencies based on the Lambert-Beer law to obtain the concentration of the gas.

[0007] According to an embodiment of the present application, the processor performs envelope detection on the filtered detection signal component to obtain a decay time corresponding to a ringing effect in the modulated light beam, including: performing full-wave rectification and filtering on the detection signal component to obtain envelope discrete data; and performing least square fitting on the envelope discrete data to obtain the decay time.

[0008] According to an embodiment of the present application, the intrinsic photon lifetime in the micro-ring resonator is equal to the external coupling photon lifetime of the straight waveguide device coupled to the micro-ring resonator.

[0009] According to an embodiment of the present application, the free spectral range of the micro-ring resonator is equal to the repetition frequency of the optical frequency comb, and the intrinsic scanning frequency is the maximum scanning frequency such that the laser beam passing through the micro-ring resonator does not have a ringing effect.

[0010] According to an embodiment of the present application, the double pendulum corner cube interferometer includes: a laser for emitting a second laser beam, wherein the wavelength difference between the center wavelength of the second laser beam and the center wavelength of the first laser beam is within a predetermined range; a mirror for transmitting the modulated light beam at a predetermined position and reflecting the second laser beam to obtain a fused light beam; and a beam splitter for splitting the fused light beam to obtain a reference light beam and a signal light beam.

[0011] According to an embodiment of the present application, the double pendulum corner cube interferometer further includes: a first corner mirror adjustment unit for delaying the reference light beam by a predetermined time length; and a second corner mirror adjustment unit for delaying the signal light beam by a predetermined time length and adjusting the frequency of the signal light beam by swinging the swing arm in the second corner mirror adjustment unit during the delay.

[0012] According to an embodiment of the present application, the processor is further configured to: generate a spectrum diagram according to the detection signal; and determine the sampling point according to the zero point position of the spectrum diagram.

[0013] According to an embodiment of the present application, the processor performs full-wave rectification and filtering on the detection signal component to obtain envelope discrete data, including: filtering the full-wave rectified signal using a low-pass filter with a cutoff frequency less than the radio frequency to obtain the envelope discrete data.

[0014] According to another aspect of the present application, a micro-ring resonant gas concentration detection method based on quantum ringing effect is provided, comprising: an optical frequency comb emits a first laser beam; a micro-ring resonant cavity, in a case that the first laser beam passes through the micro-ring resonant cavity, causes the first laser beam to interact with a gas based on evanescent field effect to obtain a modulated light beam, wherein a normalized scanning frequency of the optical frequency comb is greater than an intrinsic scanning frequency of the micro-ring resonant cavity; a double-swing solid corner mirror interferometer delays a reference light beam corresponding to the modulated light and a signal light beam for a predetermined time length, and simultaneously adjusts a frequency of the signal light beam during the delay process, so that the delayed reference light beam and the signal light beam interfere to generate an interference light beam; a detector detects the interference light beam to obtain a detection signal; a processor performs band-pass filtering on data corresponding to sampling points in the detection signal; envelope detection is performed on the detection signal component obtained by filtering to obtain a ring-down time corresponding to the ringing effect in the modulated light beam; and the concentration of the gas to be measured is obtained according to a plurality of ring-down times corresponding to a plurality of laser frequencies.

[0015] According to an embodiment of the present application, the micro-ring resonant gas concentration detection system based on quantum ringing effect adopts a variable-wavelength optical frequency comb as a light source, couples a first laser beam output by the optical frequency comb into a micro-ring resonant cavity placed in a closed gas chamber, and uses the ring-down time of photons in the micro-ring resonant cavity to replace the concentration of the gas to be measured in the conventional frequency intensity measurement, thereby fundamentally eliminating the influence of inter-mode dispersion on the detection result and obtaining the concentration of the gas to be measured with high precision. Meanwhile, the double-swing solid corner mirror interferometer is introduced in the detection process, which reduces the system volume, converts the optical frequency signal into a radio frequency signal, and reduces the detection difficulty. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and other objects, features and advantages of the present application will become more apparent from the following description of embodiments of the present application, taken in conjunction with the accompanying drawings.

[0017] Figure 1 A micro-ring resonant gas concentration detection system based on quantum ringing effect according to an embodiment of the present application is shown.

[0018] Figure 2 A flowchart of a micro-ring resonant gas concentration detection method based on quantum ringing effect according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. It is to be understood, however, that such descriptions are merely exemplary of the application and are intended to provide an overview or framework for understanding the nature and character of the application as it is claimed. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the application. It will be apparent, however, that one or more embodiments can be practiced without

[0020] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "includes" and tautological equivalents thereof, means that the named feature, step, operation, and / or component is included, but not to the exclusion of the presence or addition of one or more other features, steps, operations, or components.

[0021] All terms used herein including technical and scientific terms have the meanings commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein are defined as having a meaning that is consistent with the context of the specification in which the terms are utilized and that the terms should not be interpreted in an idealized or overly formal sense.

[0022] In situations where similar terminology is used for similar purposes, it is to be understood that there is a correlation between the different uses unless specifically stated to the contrary. In using expressions such as "at least one of A, B, and C," it is generally intended that the inclusion of at least one of A or B or C, or any combinations of them, is within the scope of the present application (e.g., a system that has A; a system that has B; a system that has C; a system that has both A and B; a system that has both A and C; a system that has both B and C; and / or a system that has A, B, and C, etc.).

[0023] In the related art, a micro-ring resonator-based gas sensing scheme mainly realizes the analysis of gas by detecting the shift of the resonant wavelength, but such a scheme has the following problems: 1) the absorption of gas in a specific frequency band will generate inter-mode dispersion in the micro-ring resonator, which will cause the imbalance between the in-cavity resonant point of the micro-ring resonator and the comb teeth of the optical frequency comb, directly affecting the measurement accuracy of the resonant wavelength, causing the detection error to increase, and reducing the stability and reliability of the sensor; 2) the traditional detection method uses a spectrometer to detect the signal, and the overall system volume is large.

[0024] In view of this, the present application provides a micro-ring resonator gas concentration detection system and method based on quantum ringing effect, which can be applied to the technical field of gas concentration detection.

[0025] Figure 1 A micro-ring resonator gas concentration detection system based on quantum ringing effect according to an embodiment of the present application is shown.

[0026] As Figure 1As shown, the micro-ring resonator gas concentration detection system based on the quantum ringing effect can include an optical frequency comb 110, a micro-ring resonator cavity 120, a double swing cube corner mirror interferometer 130, a detector 140, and a processor 150. The micro-ring resonator cavity 120 can be placed in a gas chamber 101 filled with a gas to be measured.

[0027] The source of the gas to be measured in the gas chamber 101 can be determined according to actual conditions. In Figure 1 The embodiments of the present application are only illustratively described by the gas to be measured in the gas cylinder 102, and are not used to limit the source of the gas to be measured. The gas to be measured can be, for example, carbon monoxide, carbon dioxide, oxygen, or hydrogen sulfide gas.

[0028] The optical frequency comb 110 can be used to emit a first laser beam.

[0029] When the first laser beam emitted by the optical frequency comb 110 enters the micro-ring resonator cavity 120, which is placed in the gas chamber 101 filled with the gas to be measured, the first laser beam is coupled into the micro-ring through the straight waveguide device in the micro-ring resonator cavity 120 and interacts with the gas. Among them, the output wavelength of the optical frequency comb 110 changes periodically. The optical frequency comb 110 sequentially inputs different lasers with periodically changing wavelengths into the micro-ring resonator cavity 120. The different lasers with periodically changing wavelengths output by the optical frequency comb 110 form the first laser beam.

[0030] The micro-ring resonator cavity 120 can be used to make the first laser beam interact with the gas based on the evanescent field effect to obtain a modulated light beam when the first laser beam passes through the micro-ring resonator cavity. The micro-ring resonator cavity has a high quality factor.

[0031] Among them, the change rate of the laser output by the optical frequency comb 110 is the normalized scanning frequency of the optical frequency comb The ringing effect condition should be met so that the concentration of the gas to be measured can be obtained according to the decay time corresponding to the ringing effect in the subsequent process.

[0032] For example, the normalized scanning frequency of the optical frequency comb is greater than the intrinsic scanning frequency of the micro-ring resonator cavity. The intrinsic scanning frequency is the maximum scanning frequency that makes the laser beam after passing through the micro-ring resonator cavity 120 not have the ringing effect. The normalized scanning frequency of the optical frequency comb and the intrinsic scanning frequency of the micro-ring resonator cavity satisfy the relationship shown in formula (1).

[0033] (1) ;

[0034] Among them, is the normalized scanning frequency of the optical frequency comb, is the intrinsic scanning frequency of the micro-ring resonator cavity. , is the actual scanning frequency of the optical frequency comb 110, is the intracavity intrinsic photon lifetime of the micro-ring resonator cavity 120.

[0035] The modulated light beam T output by the micro-ring resonator cavity 120 satisfies the relationship shown in equation (2).

[0036] (2) ;

[0037] wherein, . is the ring-down time corresponding to the ringing effect in the modulated light beam, is the laser frequency of the i-th laser output by the optical frequency comb, is the resonant frequency of the micro-ring resonator cavity, . is the total photon lifetime of the micro-ring resonator cavity. t is the detection time. j is the imaginary unit. erf() is the error function. T is proportional to . is the external coupling photon lifetime of the straight waveguide device coupled with the micro-ring resonator cavity. The laser frequency of the i-th laser output by the optical frequency comb can also be referred to as the i-th laser frequency.

[0038] According to the embodiment of the present application, the gas chamber 101 filled with the gas to be measured and the micro-ring resonator cavity 120 placed therein can be used as a sensing module to detect the concentration of the gas to be measured. The modulated light beam output in the sensing module can be split into a signal light beam and a reference light beam by a beam splitter in the double-swing corner cube interferometer 130. The signal light beam and the reference light beam recombine and interfere after different action processes in the double-swing corner cube interferometer 130, and are received by the detector 140.

[0039] The high-stability second laser light beam generated by the laser 131 in the double-swing corner cube interferometer 130 can enter the double-swing corner cube interferometer 130 together with the modulated light beam output by the micro-ring resonator cavity 120.

[0040] The double-swing corner cube interferometer 130 can be used to delay the reference light beam and the signal light beam corresponding to the modulated light for a predetermined time length, and at the same time, the signal light beam is frequency-adjusted during the delay process, so that the delayed reference light beam and the signal light beam interfere to generate an interference light beam.

[0041] For example, the reference light beam returns to the first mirror 1342 via the first corner cube mirror 1341 in the double-swing corner cube interferometer 130. After the signal light beam reaches the moving second corner cube mirror 1351, the control swing arm 1352 is swung to change the optical path difference between the two light beams at a speed uniformly, and a Doppler frequency shift is introduced The reference light beam is delayed for a predetermined time length by the dual-oscillator corner-cube interferometer 130, and then returns to the beam splitter 133 via the second mirror 1353, recombines with the delayed reference light beam at the beam splitter 133, and generates an interference light beam. After being reflected by the beam splitter 133 and the third mirror 136 in the dual-oscillator corner-cube interferometer 130, the interference light beam can be received by the detector 140.

[0042] The interference light beam The expression of the interference light beam is shown in equation (3).

[0043] (3);

[0044] wherein, , is a period variation frequency of a wavelength of the output laser of the optical frequency comb. is a Fourier series of an nth harmonic component corresponding to the ith comb tooth of the optical frequency comb, is a time for Fourier calculation.

[0045] The detector 140 can be used to detect the interference light beam to obtain a detection signal. The detection signal output by the detector 140 is a radio frequency interference signal. The detector 140 is a radio frequency band detector.

[0046] According to the embodiment of the present application, the reference light beam and the signal light beam corresponding to the modulated light are delayed for a predetermined time length by the dual-oscillator corner-cube interferometer 130, and at the same time, the signal light beam is frequency-adjusted during the delay process, so that the delayed reference light beam and the signal light beam interfere with each other to generate an interference light beam, so that the subsequent processor 150 can separate the data corresponding to the plurality of laser frequencies from the detection signal corresponding to the interference light beam, and then calculate the plurality of ring-down times corresponding to the plurality of laser frequencies to obtain the concentration of the gas to be measured.

[0047] According to the embodiment of the present application, the interference light beam received by the detector 140 contains the ring-down times corresponding to different laser frequencies , and thus the subsequent measurement of the concentration of the gas to be measured can be realized.

[0048] The processor 150 can be used to perform band-pass filtering on the data corresponding to the sampling points in the detection signal, perform envelope detection on the detection signal components obtained by filtering to obtain the ring-down time corresponding to the ringing effect in the modulated light beam, and obtain the concentration of the gas to be measured according to the plurality of ring-down times corresponding to the plurality of laser frequencies.

[0049] For example, the processor 150 can be used to obtain an infrared spectrum from the detection signal, and perform equal optical path difference sampling on the interference positions in the spectrum.

[0050] ​For example, the processor 150 can perform band-pass filtering on the data corresponding to the sampling points in the detection signal according to the i th laser frequency corresponding to the i th laser in the first laser beam, to separate out the radio frequency component (i.e., the detection signal component) corresponding to the i th comb tooth, where i is a positive integer. Envelope detection is performed on the filtered detection signal component to obtain the decay time corresponding to the ringing effect in the modulated light beam, and the decay time corresponding to the i th laser frequency is obtained.

[0051] According to the embodiment of the present application, the micro-ring resonant gas concentration detection system based on the quantum ringing effect adopts a variable wavelength optical frequency comb as a light source, couples the first laser beam output by the optical frequency comb into a micro-ring resonant cavity placed in a closed gas chamber, and uses the decay time of photons in the micro-ring resonant cavity to replace the traditional frequency intensity measurement of the concentration of the measured gas, thereby fundamentally eliminating the influence of intermodal dispersion on the detection result and obtaining a higher precision of the concentration of the measured gas. At the same time, a double swing type solid angle mirror interferometer is introduced in the detection process to separate the decay spectrum line, reduce the system volume, convert the optical frequency signal into a radio frequency signal, and reduce the detection difficulty.

[0052] According to the embodiment of the present application, the micro-ring resonant gas concentration detection system based on the quantum ringing effect realizes high-precision detection of the measured gas by utilizing the ringing effect of the micro-ring resonant cavity.

[0053] According to the embodiment of the present application, the intrinsic photon lifetime in the micro-ring resonant cavity is equal to the external coupling photon lifetime of the straight waveguide device coupled with the micro-ring resonant cavity. In other words, the loss of the first laser beam caused by the micro-ring resonant cavity is equal to the loss of the first laser beam caused by the straight waveguide device coupled with the micro-ring resonant cavity.

[0054] According to the embodiment of the present application, by equalizing the intrinsic photon lifetime in the micro-ring resonant cavity and the external coupling photon lifetime of the straight waveguide device coupled with the micro-ring resonant cavity, the initial state of the micro-ring resonator is ensured to be strictly coupled.

[0055] According to the embodiment of the present application, the free spectral range of the micro-ring resonant cavity is equal to the repetition frequency of the optical frequency comb. The free spectral range of the micro-ring resonant cavity is the frequency interval between adjacent two resonance peaks.

[0056] For example, the free spectral range of the micro-ring resonant cavity and the repetition frequency of the optical frequency comb satisfy the relationship shown in formula (4).

[0057] (4);

[0058] wherein FSR is the free spectral range of the micro-ring resonant cavity, is the repetition frequency of the optical frequency comb.

[0059] According to an embodiment of the present invention, by making the free spectral range of the microring resonator equal to the repetition frequency of the optical frequency comb, the resonance peak of the microring resonator is ensured to strictly correspond to the comb teeth (i.e., laser frequency) of the optical frequency comb, thereby ensuring that the processor can calculate multiple decay times corresponding to multiple laser frequencies and obtain the concentration of the gas to be measured based on the multiple decay times.

[0060] The processor 150 is also used to: generate a spectrum based on the detection signal; and determine the sampling point based on the zero point position of the spectrum.

[0061] The processor 150 performs envelope detection on the filtered detection signal component to obtain the oscillation time corresponding to the ringing effect in the modulated beam. This can include: performing full-wave rectification and filtering on the detection signal component to obtain discrete envelope data; and performing least-squares fitting on the discrete envelope data to obtain the oscillation time.

[0062] According to an embodiment of the present invention, the processor performs curve fitting on the envelope discrete data using the least squares method to obtain the exponential decay term. Extract from this attenuation term .in, Let be the decay time corresponding to the i-th laser frequency.

[0063] The processor 150 can obtain the concentration of the gas to be measured based on multiple decay times corresponding to multiple laser frequencies, including: for each laser frequency, obtaining the gas molecule absorptivity corresponding to each laser frequency based on the decay time corresponding to each laser frequency and the decay time when there is no gas in the gas chamber; and analyzing the gas molecule absorptivity corresponding to multiple laser frequencies based on the Lambert-Beer law to obtain the gas concentration.

[0064] For example, the processor can obtain the gas molecule absorption rate corresponding to each laser frequency based on the decay time corresponding to each laser frequency and the decay time when there is no gas in the gas chamber according to the following formula (5).

[0065] (5);

[0066] in, The gas molecule absorption rate corresponding to the i-th laser frequency, Let c be the ringing time when there is no gas in the gas chamber corresponding to the i-th laser frequency, and c be the speed of light.

[0067] The processor 150 performs full-wave rectification and filtering on the detected signal components to obtain discrete envelope data, which may include: using a low-pass filter with a cutoff frequency lower than the radio frequency to filter the full-wave rectified signal to obtain discrete envelope data.

[0068] For example, the radio frequency can be 300kHz.

[0069] According to an embodiment of the present invention, smooth envelope discrete data is obtained by filtering the full-wave rectified signal using a low-pass filter with a cutoff frequency lower than the radio frequency.

[0070] like Figure 1 As shown, the double-pendulum solid corner mirror interferometer 130 may include a laser 131, a reflector 132, a beam splitter 133, a first corner mirror adjustment unit, and a second corner mirror adjustment unit. The first corner mirror adjustment unit may include a first solid corner mirror 1341 and a first reflector 1342. The second corner mirror adjustment unit may include a second solid corner mirror 1351, a pendulum arm 1352, and a second reflector 1353. The first solid corner mirror 1341 and the second solid corner mirror 1351 have the same structure. The first reflector 1342 and the second reflector 1353 are the same reflector. The first adjustment structure formed by the first solid corner mirror 1341 and the first reflector 1342 is symmetrical with the second adjustment structure formed by the second solid corner mirror 1351 and the second reflector 1353, and is symmetrical based on the plane where the beam splitter 133 is located.

[0071] Laser 131 can be used to emit a second laser beam. The wavelength difference between the center wavelength of the second laser beam and the center wavelength of the first laser beam is within a predetermined range.

[0072] The reflector 132 can be used to transmit the modulated beam at a predetermined position while reflecting the second laser beam to obtain a fused beam.

[0073] Beam splitter 133 can be used to split the fused beam into a reference beam and a signal beam. The modulated beam corresponds to the signal beam, and the reference beam corresponds to the second laser beam.

[0074] According to an embodiment of the present invention, the wavelength difference between the center wavelength of the second laser beam and the center wavelength of the first laser beam is within a predetermined range to ensure that the delayed reference beam and the signal beam can interfere with each other.

[0075] The first corner mirror adjustment unit can be used to delay the reference beam for a predetermined duration.

[0076] The second corner mirror adjustment unit can be used to delay the signal beam for a predetermined duration, and at the same time, the frequency of the signal beam can be adjusted by the swing of the arm in the second corner mirror adjustment unit during the delay.

[0077] According to an embodiment of the present invention, a reference beam and an interference beam are generated sequentially by emitting a second laser beam using a laser, ensuring that the interference beam has a high intensity and the detection signal obtained by the detector has a high intensity, and the processor 150 can identify the sampling point from the spectrum generated based on the detection signal.

[0078] The double-pendulum solid angle mirror interferometer 130 may also include a third reflecting mirror 136 for reflecting the interference beam so that the reflected beam can enter the detector 140.

[0079] The beam splitter 133 can also interfere with the reference beam and the signal beam when they arrive at the beam splitter 133 again after the delay, to obtain an interference beam, and then transmit the interference beam to the third reflector 136.

[0080] According to embodiments of the present invention, the microring resonant gas concentration detection system based on the quantum ringing effect analyzes gases by detecting the shift in resonant wavelength, unlike related technologies. It measures photon ring-down time based on the ringing effect, eliminating the influence of intermodal dispersion on the system and improving detection accuracy, thus achieving higher precision. Furthermore, the system simplifies the structure by combining a single microring with a double-pendulum stereoscope interferometry technique, eliminating the need for multi-ring cascades and facilitating miniaturization, resulting in a smaller volume.

[0081] According to embodiments of the present invention, a microring resonant gas concentration detection system based on the quantum ringing effect utilizes a variable-wavelength optical frequency comb of the output laser to generate a ringing effect with a microring resonant cavity. Gas concentration can be calculated by measuring the optical ring-down time. A Doppler frequency shift is introduced using the pendulum arm in a double-pendulum stereoscope interferometer to accurately measure the gas absorptivity on a specific comb tooth. Compared to other gas sensing methods based on microring resonant cavities, this invention measures photon ring-down time instead of the resonant wavelength, eliminating the influence of intermodal dispersion and improving detection accuracy. The double-pendulum stereoscope interferometer introduces a Doppler frequency shift to separate ring-down spectral lines, further reducing the system size.

[0082] According to an embodiment of the present invention, the steps for detecting gas concentration based on any of the above-mentioned microring resonant gas concentration detection systems based on the quantum ringing effect are as follows: 1) Adjusting the wavelength of the laser output from the microring resonant cavity with a center wavelength of 1550 nm to vary periodically, so that the scanning frequency of the normalized optical frequency comb is greater than the intrinsic scanning frequency of the microring resonant cavity; 2) Adjusting the microring coupling coefficient in the microring resonant cavity to ensure that the microring and the straight waveguide device are in a strictly coupled state; 3) Adjusting the microring so that its FSR is equal to the tooth spacing of the optical frequency comb (i.e., the repetition frequency of the optical frequency comb). ); ); ); CO and H2S gases are introduced into the gas chamber, and the gases interact fully with the microring resonator to change the light intensity at the corresponding frequency; 5) The light beam after interacting with the gas leaves the microring resonator through a straight waveguide and enters the double-pendulum solid angle mirror interferometer; 6) The pendulum arm in the double-pendulum solid angle mirror interferometer is controlled to make the optical path difference between the reference path and the signal path change at a speed of Uniform change, introducing Doppler frequency shift 7) The detector receives the interference signal from the double pendulum stereo mirror interferometer and obtains the detection signal; 8) The gas molecule absorptivity is calculated using the ring-down time in the interference signal, and the gas molecule absorptivity corresponding to multiple laser frequencies is analyzed based on Lambert-Beer's law to obtain the gas concentration.

[0083] Based on the above-mentioned micro-ring resonant gas concentration detection system based on the quantum ringing effect, this embodiment of the invention provides a micro-ring resonant gas concentration detection method based on the quantum ringing effect.

[0084] Figure 2 A flowchart of a microring resonant gas concentration detection method based on the quantum ringing effect according to an embodiment of the present invention is shown.

[0085] like Figure 2 As shown, the microring resonant gas concentration detection method based on the quantum ringing effect in this embodiment may include operations S210 to S250.

[0086] When operating S210, the optical frequency comb emits the first laser beam.

[0087] In operation S220, when the first laser beam passes through the microring resonator, the first laser beam interacts with the gas based on the evanescent field effect to obtain a modulated beam. The scanning frequency of the normalized optical frequency comb is greater than the intrinsic scanning frequency of the microring resonator.

[0088] When operating S230, the double-pendulum solid angle mirror interferometer delays the reference beam and signal beam corresponding to the modulation light for a predetermined time. At the same time, the frequency of the signal beam is adjusted during the delay so that the delayed reference beam and signal beam interfere with each other to generate an interference beam.

[0089] When operating S240, the detector detects the interference beam and obtains the detection signal.

[0090] In operation S250, the processor performs bandpass filtering on the data corresponding to the sampling point in the detection signal; performs envelope detection on the filtered detection signal component to obtain the decay time corresponding to the ringing effect in the modulated beam; and obtains the concentration of the gas to be measured based on the multiple decay times corresponding to multiple laser frequencies.

[0091] According to embodiments of the present invention, the micro-ring resonant gas concentration detection system and method based on the quantum ringing effect has the following two major advantages: First, the time-domain detection mechanism based on the ringing effect eliminates the influence of intermodal dispersion on the detection of the gas concentration, significantly improving accuracy; second, the system size is reduced and the detection difficulty is lowered by using a double-pendulum stereoscope interferometer. Compared with traditional micro-ring sensing schemes, the solution provided by the present invention significantly improves detection accuracy and reduces size, providing a better solution for trace gas analysis in fields such as environmental monitoring and industrial production.

[0092] It should be noted that the micro-ring resonant gas concentration detection method based on quantum ringing effect in the embodiments of the present invention corresponds to the micro-ring resonant gas concentration detection system based on quantum ringing effect in the embodiments of the present invention. For a detailed description of the micro-ring resonant gas concentration detection method based on quantum ringing effect, please refer to the micro-ring resonant gas concentration detection system based on quantum ringing effect, which will not be repeated here.

[0093] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0094] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of the invention is defined by the appended embodiments and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A micro-ring resonant gas concentration detection system based on the quantum ringing effect, characterized in that, include: An optical frequency comb is used to emit the first laser beam. A microring resonator, placed in a gas chamber filled with the gas to be measured, is used to make the first laser beam interact with the gas based on the evanescent field effect to obtain a modulated beam when the first laser beam passes through the microring resonator. The scanning frequency of the normalized optical frequency comb is greater than the intrinsic scanning frequency of the microring resonator. A double-pendulum stereomicroscope interferometer is used to delay a reference beam and a signal beam corresponding to the modulation light for a predetermined time, while adjusting the frequency of the signal beam during the delay, so that the delayed reference beam and the signal beam interfere with each other to generate an interference beam. A detector is used to detect the interference beam and obtain a detection signal; The processor is used to perform bandpass filtering on the data corresponding to the sampling point in the detection signal; to perform envelope detection on the filtered detection signal component to obtain the decay time corresponding to the ringing effect in the modulated beam; and to obtain the concentration of the gas to be measured based on the multiple decay times corresponding to multiple laser frequencies.

2. The system according to claim 1, characterized in that, The processor obtains the concentration of the gas to be measured based on multiple decay times corresponding to multiple laser frequencies, including: For each laser frequency, the gas molecule absorptivity corresponding to each laser frequency is obtained based on the decay time corresponding to each laser frequency and the decay time when there is no gas in the gas chamber. Based on Beer-Lambert's law, the absorption rate of gas molecules corresponding to multiple laser frequencies was analyzed to obtain the gas concentration.

3. The system according to claim 1, characterized in that, The processor performs envelope detection on the filtered detection signal components to obtain the decay time corresponding to the ringing effect in the modulated beam, including: The detected signal components are subjected to full-wave rectification and filtering to obtain envelope discrete data; The least squares method is used to fit the envelope discrete data to obtain the oscillation time.

4. The system according to claim 1, characterized in that, The inherent photon lifetime of the microring resonator is equal to the externally coupled photon lifetime of the straight waveguide device coupled to the microring resonator.

5. The system according to claim 1, characterized in that, The free spectral range of the microring resonator is equal to the repetition frequency of the optical frequency comb, and the intrinsic scanning frequency is the maximum scanning frequency that prevents the laser beam passing through the microring resonator from ringing.

6. The system according to claim 1, characterized in that, The double-pendulum solid angle mirror interferometer includes: A laser for emitting a second laser beam, wherein the wavelength difference between the center wavelength of the second laser beam and the center wavelength of the first laser beam is within a predetermined range; A reflector is used to transmit the modulated beam at a predetermined position while reflecting the second laser beam to obtain a fused beam; A beam splitter is used to split the fused beam into a reference beam and a signal beam.

7. The system according to claim 6, characterized in that, The double-pendulum solid angle mirror interferometer also includes: The first corner mirror adjustment unit is used to delay the reference beam for a predetermined duration; The second corner mirror adjustment unit is used to delay the signal beam for a predetermined time, and at the same time, the frequency of the signal beam is adjusted by the swing of the swing arm in the second corner mirror adjustment unit during the delay.

8. The system according to claim 1, characterized in that, The processor is also used for: A spectrum is generated based on the detected signal; The sampling point is determined based on the zero point position of the spectrum.

9. The system according to claim 3, characterized in that, The processor performs full-wave rectification and filtering on the detected signal components to obtain envelope discrete data, including: The envelope discrete data is obtained by filtering the full-wave rectified signal using a low-pass filter with a cutoff frequency lower than the radio frequency.

10. A method for detecting the concentration of a microring resonant gas based on the quantum ringing effect, characterized in that, include: An optical frequency comb emits the first laser beam; When the first laser beam passes through the microring resonator, the first laser beam interacts with the gas based on the evanescent field effect to obtain a modulated beam, wherein the scanning frequency of the normalized optical frequency comb is greater than the intrinsic scanning frequency of the microring resonator. The double-pendulum solid angle mirror interferometer delays the reference beam and signal beam corresponding to the modulation light for a predetermined time, and simultaneously adjusts the frequency of the signal beam during the delay, so that the delayed reference beam and signal beam interfere with each other to generate an interference beam; The detector detects the interference beam and obtains a detection signal; The processor performs bandpass filtering on the data corresponding to the sampling point in the detection signal; performs envelope detection on the filtered detection signal component to obtain the decay time corresponding to the ringing effect in the modulated beam; and obtains the concentration of the gas to be measured based on the multiple decay times corresponding to multiple laser frequencies.

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