Rec-dfb array composite moems microcavity demodulation system and method

Abstract

The present application relates to the technical field of optical fiber sensing demodulation, in particular to a REC-DFB array composite MOEMS microcavity demodulation system and method, the method comprising: driving and controlling a REC-DFB laser array to output a high-speed wavelength scanning optical signal, transmitting the optical signal to a composite MOEMS microcavity sensor through an optical path, and reflecting to form a composite optical signal containing multi-microcavity interference information; synchronously triggering the collection of discrete light intensity data corresponding to the scanning time point; reconstructing the wavelength domain reflection spectrum based on a pre-calibrated time-wavelength mapping relationship; separating the spatial frequency components of different microcavities through fast Fourier transform, filtering and inverse transforming to obtain independent interference spectra of each microcavity; tracking the characteristic peak wavelength change and demodulating multiple physical quantities to be measured. The present application uses a single integrated REC-DFB laser array to realize high-speed scanning, and combines synchronous sampling and frequency domain separation technology, which can realize the synchronous monitoring of multiple parameters such as temperature, vibration and pressure.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensing demodulation technology, specifically to a REC-DFB array composite MOEMS microcavity demodulation system and method. Background Technology

[0002] Fiber optic sensing technology has the advantages of being resistant to electromagnetic interference, small size, high sensitivity, easy long-distance transmission, and suitable for complex environments such as high temperature, high pressure, and strong electromagnetic interference. It has been widely used in aerospace, petrochemical, rail transportation, energy equipment, and structural health monitoring.

[0003] Fiber optic FP microcavity sensors based on the Fabry-Perot (FP) interferometry principle achieve sensing by detecting changes in cavity length, refractive index, or phase caused by external physical quantities. They feature simple structure, fast response speed, and high sensitivity. With the development of optical microelectromechanical systems (MOEMS) fabrication technology, MOEMS microcavity sensors can be miniaturized, mass-produced, and manufactured with high consistency through micro-nano fabrication, wafer bonding, and thin-film structure design.

[0004] Composite MOEMS microcavity sensors typically integrate two or more FP microcavities into the same sensing structure, allowing different microcavities to respond to different physical quantities, thereby achieving simultaneous measurement of multiple parameters. For example, an air cavity can be used for vibration, pressure, displacement, or strain monitoring, while a glass cavity can be used for temperature monitoring.

[0005] Existing composite MOEMS microcavity sensing systems mostly employ broadband light sources in conjunction with spectrometers for spectral acquisition and demodulation. While this approach can obtain complete reflectance spectra, it suffers from drawbacks such as large system size, high power consumption, high cost, limited scanning speed, and unsuitability for long-term deployment in industrial settings. High-speed spectrometers, although capable of improving acquisition speed, are prohibitively expensive, making them unsuitable for large-scale engineering applications.

[0006] Therefore, there is an urgent need for a compact, high-speed, low-cost, and easily integrated composite MOEMS microcavity multi-parameter sensing and demodulation system and method that can replace traditional broadband light sources and spectral analyzers. Summary of the Invention

[0007] To address the aforementioned technical shortcomings, this invention provides a REC-DFB array composite MOEMS microcavity demodulation system and method, thereby solving the technical problems of existing demodulation systems that rely on spectral analyzers, are large in size, costly, slow in scanning speed, and difficult to achieve multi-parameter synchronous high-precision demodulation.

[0008] This invention is achieved through the following technical solution: A method for demodulating REC-DFB arrays combined with MOEMS microcavities is provided, the method comprising the following steps: Step S10: The REC-DFB laser array outputs a synchronous trigger signal and a high-speed wavelength scanning light signal covering a preset wavelength range according to the preset scanning timing and preset injection current waveform; Step S20: The scanning light signal output in step S10 is input into the composite MOEMS microcavity sensor via the optical path transmission module, and reflected to form a composite reflected light signal containing interference information of at least two microcavity with different optical path differences FP, which is then converted into an electrical signal by photoelectric conversion; Step S30: Based on the synchronization trigger signal output in step S10, collect discrete light intensity data that correspond one-to-one with the time points within the scanning period in step S10. Step S40: Based on the pre-calibrated mapping relationship between the scanning time point, the trigger sampling point and the output wavelength, the discrete light intensity data collected in step S30 is reconstructed into a wavelength domain reflectance spectrum. The reflectance spectrum is subjected to a fast Fourier transform to obtain the spatial frequency spectrum. The frequency components corresponding to each target FP microcavity are separated and extracted. The independent interference spectrum of each microcavity is obtained by inverse Fourier transform. Step S50: Perform peak tracking on each independent interference spectrum obtained in step S40 to obtain characteristic peak wavelength change information, and calculate the values ​​of at least two physical quantities to be measured based on the pre-calibrated wavelength-physical quantity correspondence.

[0009] Preferably, a wavelength calibration step is included before step S10: using an FP etalon, a standard wavelength reference device, or a known wavelength reference signal, a mapping relationship between the scan time point, the trigger sampling point, and the output wavelength is established and stored.

[0010] Preferably, in step S10, by adjusting the injection current waveform of each unit DFB laser, the output wavelengths of different channels are seamlessly connected on the time axis at a preset interval, and the output optical power of each channel is balanced to ensure the continuity and flatness of the scanning spectrum.

[0011] Preferably, the composite MOEMS microcavity sensor in step S20 includes a cascaded air cavity and a glass cavity; the air cavity responds to changes in cavity length caused by vibration, displacement, pressure or strain, and the glass cavity responds to changes in refractive index and thermal expansion caused by temperature changes.

[0012] Preferably, the synchronous trigger signal in step S30 includes a periodic trigger signal and a wavelength trigger signal; a new scanning cycle is started at the rising edge of the periodic trigger signal, and the light intensity value at the corresponding moment is latched at the rising edge of each wavelength trigger signal to achieve synchronous scanning and sampling.

[0013] Preferably, the reconstruction of the wavelength domain reflectance spectrum in step S40 specifically involves converting the discrete light intensity data collected within one scanning cycle into a continuous wavelength domain reflectance spectrum with equal wavelength intervals according to a pre-calibrated mapping relationship.

[0014] Preferably, the separation and extraction of frequency components in step S40 specifically involves: calculating the theoretical spatial frequency position of each FP microcavity based on its designed optical path difference, constructing a narrowband filter with this position as the passband center, and extracting the frequency components corresponding to each target FP microcavity.

[0015] Preferably, in step S50, peak tracking employs at least one of single-peak tracking, double-peak tracking, or multi-peak tracking; single-peak tracking is used to obtain the relative optical path difference change, while double / multi-peak tracking is used to obtain the absolute optical path difference or interference order information.

[0016] Furthermore, this invention also proposes a REC-DFB array composite MOEMS microcavity demodulation system, comprising: Drive and temperature control module: Used to output synchronous trigger signals and high-speed wavelength scanning optical signals covering a preset wavelength range through the REC-DFB laser array according to the preset scanning timing and preset injection current waveform; Optical path transmission module: used to input the scanning light signal output by the drive and temperature control module into the composite MOEMS microcavity sensor via the optical path transmission module, reflect it to form a composite reflected light signal containing interference information of at least two microcavity with different optical path differences FP, and then convert it into an electrical signal via photoelectric conversion; Discrete light intensity data acquisition module: used to acquire discrete light intensity data corresponding to the time points within the scanning cycle of the root drive and temperature control module by using the synchronous trigger signal output from the root drive and temperature control module. Demodulation module: Based on the pre-calibrated mapping relationship between the scanning time point, the trigger sampling point and the output wavelength, it reconstructs the discrete light intensity data acquired by the discrete light intensity data acquisition module into a wavelength domain reflection spectrum, performs a fast Fourier transform on the reflection spectrum to obtain the spatial frequency spectrum, separates and extracts the frequency components corresponding to each target FP microcavity, and obtains the independent interference spectrum of each microcavity through inverse Fourier transform. Peak tracking and calculation module: used to track the peaks of each independent interference spectrum obtained by the demodulation module, obtain characteristic peak wavelength change information, and calculate the values ​​of at least two physical quantities to be measured according to the pre-calibrated wavelength-physical quantity correspondence.

[0017] Furthermore, to achieve the above objectives, the present invention also proposes a REC-DFB array composite MOEMS microcavity demodulation device, the device comprising: a memory, a processor, and a REC-DFB array composite MOEMS microcavity demodulation program stored in the memory and executable on the processor, wherein the REC-DFB array composite MOEMS microcavity demodulation program comprises the steps for implementing the REC-DFB array composite MOEMS microcavity demodulation method as described above.

[0018] In addition, to achieve the above objectives, the present invention also provides a computer program product, which includes programs such as REC-DFB array composite MOEMS microcavity demodulation. When the REC-DFB array composite MOEMS microcavity demodulation program is executed by a processor, it implements the REC-DFB array composite MOEMS microcavity demodulation method as described above.

[0019] The advantages and effects of this invention are: The proposed REC-DFB array-based MOEMS microcavity demodulation method reduces system size, cost, and power consumption by replacing the traditional broadband light source and spectrometer combination with a REC-DFB laser array, thus improving system integration. High-speed wavelength scanning is achieved through FPGA control of the multi-channel laser array, and wavelength scanning and intensity sampling are synchronized using periodic and wavelength trigger signals, improving demodulation real-time performance and repeatability. The wavelength domain reflectance spectrum is reconstructed via time-wavelength mapping, eliminating the need for a spectrometer in real-time demodulation, making it suitable for long-term deployment in industrial environments. Fast Fourier Transform (FFT) is used to separate different frequency components in the composite MOEMS microcavity, combined with bandpass filtering, inverse Fourier transform, and peak tracking algorithms, achieving both large dynamic range and high-resolution demodulation capabilities. Multiple cavities in the composite MOEMS microcavity sensor can be independently demodulated, enabling simultaneous monitoring of multiple parameters such as temperature, vibration, pressure, displacement, or strain. The REC-DFB laser array and composite MOEMS microcavity sensor demonstrate good integration and mass production potential, making them suitable for engineering applications. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of the REC-DFB array composite MOEMS microcavity demodulation method of the present invention.

[0022] Figure 2 This is a schematic diagram of the REC-DFB laser array light source in one embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of a composite MOEMS microcavity sensor in one embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the time-wavelength mapping and synchronous triggering sampling principle in one embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of obtaining the spatial frequency spectrum by fast Fourier transform of the composite reflectance spectrum in one embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of the separation of frequency components of different FP microcavities and the extraction of independent interference spectra in one embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram illustrating the peak tracking demodulation principle in one embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram showing the results of an embodiment of the synchronous temperature and vibration monitoring of the present invention.

[0029] Figure 9 A schematic diagram of the structure of a REC-DFB array composite MOEMS microcavity demodulation system in one embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figure 1 As shown, in one embodiment of the present invention, the REC-DFB array combined with MOEMS microcavity demodulation method includes the following steps: Step S10: The REC-DFB laser array outputs a synchronous trigger signal and a high-speed wavelength scanning light signal covering a preset wavelength range according to the preset scanning timing and preset injection current waveform.

[0032] It should be noted that, as Figure 2 As shown, in this embodiment, the REC-DFB laser array adopts a 20-channel 4×5 matrix structure. Four parallel optical waveguide branches are connected in series with five unit DFB lasers of different wavelengths. The output light from each branch is combined into a single optical signal by a three-stage Y-branch combiner, and then amplified by an on-chip semiconductor optical amplifier (SOA) before being output. The FPGA sequentially selects the lasers of different branches, outputting a sawtooth wave scanning voltage, which is converted into an injection current by a voltage-controlled current source to achieve wavelength tuning of the laser. The TEC temperature control circuit stabilizes the operating temperature of the laser array chip at 25℃±0.01℃, suppressing wavelength drift caused by changes in ambient temperature and device self-heating.

[0033] The DFB laser unit employs a reconstructed equivalent chirped grating for wavelength design. By introducing REC technology into the grating design, grating fabrication can be simplified and wavelength control accuracy improved. Preferably, the center wavelengths of each laser channel are distributed at preset intervals to cover the required reflection spectrum range of the composite MOEMS microcavity sensor.

[0034] Understandably, through the drive control in this step, the monolithically integrated laser array can achieve continuous high-speed scanning over a wide wavelength range, replacing traditional bulky broadband light sources and tunable lasers, providing a stable and compact light source foundation for the demodulation system. The matrix arrangement effectively reduces optical crosstalk between adjacent wavelength channels, ensuring the purity of the scanning spectrum. Specifically, the drive control is implemented by a drive and temperature control module, including an FPGA, multiple high-speed digital-to-analog converters, a voltage-controlled current source, and a TEC temperature control circuit. The FPGA, as the control core, controls the on / off state, injection current magnitude, and scanning waveform of different DFB laser units according to a preset scanning sequence. The digital-to-analog converters convert the digital control signals output by the FPGA into analog voltage signals, and the voltage-controlled current source further converts the analog voltage signals into laser injection current.

[0035] To ensure the stability of the output wavelength during scanning, the TEC temperature control circuit is used to maintain the REC-DFB laser array chip at a preset operating temperature. Temperature control reduces the impact of ambient temperature changes and device self-heating on the output wavelength and output power.

[0036] In a preferred embodiment, the drive and temperature control module adjusts the injection current waveform of each DFB laser unit to distribute the output wavelengths of different channels at preset intervals along the time axis and equalizes the output optical power of different channels. This method allows for the formation of a stable light intensity sequence corresponding to wavelength scanning in the time domain, providing a foundation for subsequent wavelength-domain reflectance spectrum reconstruction.

[0037] The FPGA also generates two types of synchronous trigger signals: periodic trigger signals and wavelength trigger signals. The periodic trigger signal is used to mark the start time of each scan cycle; the wavelength trigger signal is used to mark multiple predetermined wavelength sampling points within each scan cycle. The photoelectric detection and data acquisition module starts a new cycle of acquisition when it receives the periodic trigger signal, and acquires the light intensity value at the corresponding time when it receives each wavelength trigger signal.

[0038] Before sensor demodulation, the output wavelength of the REC-DFB laser array can be calibrated using an FP etalon, a standard wavelength reference device, or a known wavelength reference signal to establish a mapping relationship between the scan time point, the trigger sampling point, and the output wavelength. Based on this mapping relationship, the discrete light intensity data collected within one scan cycle can be reconstructed into wavelength domain reflectance spectra with equal or preset intervals.

[0039] It should be understood that traditional tunable lasers suffer from narrow tuning ranges and slow tuning speeds, making it difficult to cover the wide reflection spectrum range of the composite MOEMS microcavity sensor. The multi-channel REC-DFB laser array used in this step can be arranged in matrix, multi-branch, or array configurations as needed. By combining the tuning ranges of multiple lasers, a wide wavelength coverage of over 40nm is achieved, with scanning frequencies exceeding 5kHz, meeting the demodulation requirements of high-frequency dynamic physical quantities.

[0040] For example, in this embodiment, the center wavelength spacing of the 20 channels is 2.1 nm, and the overall wavelength coverage range is 1530 nm to 1570 nm, completely covering the reflection spectrum range of the composite MOEMS microcavity sensor. By adjusting the injection current waveform of each channel, the output wavelengths of adjacent channels are seamlessly connected on the time axis to form a continuous wavelength scanning signal with a scanning period of 0.2 ms.

[0041] Step S20: The scanning light signal output in step S10 is input into the composite MOEMS microcavity sensor via the optical path transmission module. The sensor reflects the light to form a composite reflected light signal containing interference information of at least two microcavity FPs with different optical path differences, which is then converted into an electrical signal by photoelectric conversion.

[0042] It should be noted that in this step, if... Figure 3 As shown, the composite MOEMS microcavity sensor includes at least two cascaded FP microcavities. In this embodiment, the sensor includes a first reflective surface, a second reflective surface, and a third reflective surface. A first FP microcavity FP1 is formed between the first and second reflective surfaces, a second FP microcavity FP2 is formed between the second and third reflective surfaces, and a composite elongated cavity is formed between the first and third reflective surfaces.

[0043] In one specific structure, FP1 is an air cavity, whose optical path difference is mainly affected by changes in cavity length, making it suitable for responding to physical quantities such as vibration, pressure, displacement, or strain; FP2 is a glass cavity, whose optical path difference is affected by temperature-induced changes in refractive index and thermal expansion, making it suitable for temperature monitoring. Since FP1, FP2, and the composite long cavity have different optical path differences, they correspond to different interference spatial frequency components in the reflection spectrum.

[0044] The reflection spectrum of a composite MOEMS microcavity sensor can be considered as a superposition of multiple interference components. When an external physical quantity acts on a microcavity, the optical path difference, phase, or characteristic peak wavelength corresponding to that microcavity changes. By separating and demodulating the frequency components corresponding to different microcavities, information on the changes in different physical quantities can be obtained.

[0045] like Figures 4 to 7As shown, the demodulation module first receives the wavelength domain reflection spectrum within one scan period and performs a Fast Fourier Transform (FFT) on the composite reflection spectrum to obtain the spatial frequency spectrum. Different frequency peaks in the spatial frequency spectrum correspond to different FP microcavities or composite long cavities. The optical path transmission module employs a fiber optic circulator structure to achieve forward transmission of the scanning optical signal and reverse extraction of the composite interference optical signal, ensuring unidirectionality and low loss in the optical path. The composite MOEMS microcavity sensor uses a three-stage reflective surface structure: an air cavity is formed between the first and second reflective surfaces, a glass cavity is formed between the second and third reflective surfaces, and a composite long cavity is formed between the first and third reflective surfaces. The optical path difference between the two cavities is different, and their reflected interference signals correspond to different spatial frequency components in the spectrum.

[0046] Understandably, through sensing and photoelectric conversion in this step, changes in external physical quantities are converted into changes in the wavelength of optical signals, and then into electrical signals that are easy to process digitally. The composite MOEMS microcavity sensor encodes information from multiple physical quantities into different spatial frequency components, providing a foundation for subsequent frequency domain separation and demodulation.

[0047] It should be understood that traditional single-cavity sensors can only measure a single physical quantity and cannot achieve simultaneous monitoring of multiple parameters. The cascaded multi-cavity structure used in this step utilizes the sensitivity of different cavities to different physical quantities to achieve simultaneous sensing of multiple parameters such as temperature and vibration, without the need for multiple independent sensors, thus significantly reducing the size and complexity of the sensing end.

[0048] For example, in this embodiment, the air cavity is approximately 140 μm long and is sensitive to mechanical quantities such as vibration and pressure; the glass cavity is approximately 525 μm long and is sensitive to temperature. When an external vibration of 2500 Hz is applied, the length of the air cavity changes periodically, causing its interference peak wavelength to shift periodically; when the ambient temperature increases, the refractive index and physical length of the glass cavity change, causing its interference peak to shift towards longer wavelengths.

[0049] Step S30: Based on the synchronous trigger signal output by the drive and temperature control module, collect discrete light intensity data corresponding to the scanning time points in step S10.

[0050] It should be noted that in this step, the FPGA generates two types of synchronous trigger signals: a periodic trigger signal and a wavelength trigger signal. The periodic trigger signal is output once every 0.2ms to mark the start of the scan cycle; the wavelength trigger signal is output at each wavelength sampling point. In this embodiment, each scan cycle contains 5000 wavelength sampling points. The photoelectric detection and data acquisition module clears the periodic trigger signal to zero and starts acquisition on the rising edge, and latches the light intensity value at the corresponding moment on the rising edge of each wavelength trigger signal.

[0051] Understandably, this synchronous sampling step ensures strict temporal alignment between the light intensity data and the scanning wavelength, avoiding spectral reconstruction errors caused by timing deviations. High-precision synchronous control is a crucial prerequisite for achieving high-resolution wavelength demodulation.

[0052] It should be understood that traditional spectrometers use an internal clock to control sampling, which cannot achieve precise synchronization with an external light source, easily leading to wavelength drift and sampling deviation. The external synchronization triggering mechanism used in this step ensures complete synchronization between light source scanning and data acquisition, significantly improving the accuracy and repeatability of spectral reconstruction.

[0053] For example, in this embodiment, 5000 light intensity data points are collected in each scanning cycle, corresponding to a wavelength range of 1530nm to 1570nm, with a wavelength sampling interval of 0.008nm. The timing accuracy of the synchronous trigger signal is better than 1μs, ensuring a strict correspondence between each sampling point and its corresponding wavelength.

[0054] Step S40: Based on the pre-calibrated time-wavelength mapping relationship, the discrete light intensity data collected in step S30 is reconstructed into a wavelength domain reflectance spectrum; the reflectance spectrum is subjected to a fast Fourier transform to obtain a spatial frequency spectrum, the frequency components corresponding to each target FP microcavity are separated and extracted, and the independent interference spectrum of each microcavity is obtained by inverse Fourier transform.

[0055] It should be noted that in this step, the pre-calibrated time-wavelength mapping relationship is obtained through the FP etalon and stored in the FPGA's non-volatile memory. The acquired discrete light intensity data is converted into wavelength-domain reflectance spectra with equal wavelength intervals according to the mapping relationship. A fast Fourier transform is performed on the reflectance spectrum to obtain a spatial frequency spectrum containing different frequency peaks, with each frequency peak corresponding to an interference component of an FP microcavity. The theoretical frequency position of each microcavity is calculated based on the designed optical path difference, a narrowband filter is constructed to extract the corresponding frequency component, and then an inverse Fourier transform is performed to obtain the independent interference spectrum of each microcavity.

[0056] Understandably, this step of spectral reconstruction and frequency domain separation separates the multiple superimposed microcavity interference signals, enabling independent demodulation of multiple parameters. The frequency domain transformation method effectively suppresses noise and improves the signal-to-noise ratio and accuracy of demodulation.

[0057] It should be understood that traditional demodulation methods directly perform peak fitting in the wavelength domain, which cannot separate multiple overlapping interference peaks and is prone to crosstalk and misjudgment. The frequency domain separation technique used in this step utilizes the difference in optical path difference between different microcavities to achieve complete separation of interference components in the frequency domain, fundamentally solving the crosstalk problem of multi-cavity interference signals.

[0058] For example, in this embodiment, the theoretical frequency position of the air cavity is 6 (normalized frequency), and that of the glass cavity is 26 (normalized frequency). Narrowband filters with a passband width of 6 are constructed respectively. After extracting the two frequency components, an inverse Fourier transform is performed to obtain the independent interference spectra of the air cavity and the glass cavity, with no crosstalk between them.

[0059] Step S50: Perform peak tracking on each independent interference spectrum obtained in step S40 to obtain characteristic peak wavelength change information, and calculate the values ​​of at least two physical quantities to be measured based on the pre-calibrated wavelength-physical quantity correspondence.

[0060] It should be noted that in this step, a Gaussian fitting peak tracking algorithm is used to accurately locate the characteristic peaks in the independent interference spectrum, with a wavelength demodulation accuracy better than 1 pm. Based on the pre-calibrated wavelength-temperature relationship, the temperature value is calculated from the wavelength drift of the glass cavity; the cavity length change is calculated from the wavelength drift of the air cavity, and the vibration frequency and amplitude are obtained from the time series of the cavity length change.

[0061] Understandably, this step of peak tracking and physical quantity calculation converts the wavelength changes of the optical signal into the physical quantity values ​​required by the user, completing the entire demodulation process. The high-precision peak tracking algorithm ensures the accuracy and resolution of the physical quantity measurements.

[0062] It should be understood that traditional peak tracking algorithms are susceptible to noise and have limited demodulation accuracy. The Gaussian fitting algorithm used in this step effectively suppresses the influence of noise by fitting multiple sampling points to calculate the peak position, thus significantly improving the wavelength demodulation accuracy.

[0063] For example, in this embodiment, the temperature sensitivity of the glass cavity is 12 pm / ℃, and the temperature demodulation linearity R... 2 =0.99999; the vibration demodulation frequency accuracy of the air cavity is 0.01Hz, which can accurately measure high-frequency vibrations of 2500Hz.

[0064] Specifically, the filter construction of this invention does not rely on general frequency search or empirical frequency band setting, but rather predetermines the theoretical spatial frequency position of each FP microcavity in the composite MOEMS microcavity sensor based on the physical design parameters of each FP microcavity. For a target microcavity with a known design optical path difference OPD = 2nL, the theoretical frequency position of its reflected interference signal in the spatial frequency spectrum is determined by f = 2nL / λ. 2The theoretical frequency position is uniquely determined, where n is the refractive index of the cavity medium, L is the cavity length, and λ is the center wavelength of the wavelength scanning range. This theoretical frequency position is directly used as the center frequency of the filter passband, and the passband width is set according to the frequency spacing between adjacent microcavities and the cavity length manufacturing tolerance. This physical model-driven filter design method utilizes the prior information of the structural parameters of the composite MOEMS microcavity, combined with the precise wavelength control characteristics of the REC-DFB laser array, to achieve deterministic extraction of different microcavity interference components. This avoids the risk of spectral leakage caused by frequency crosstalk and blind search, and is fundamentally different from the general spectral analysis methods in conventional signal processing.

[0065] Based on the frequency position of the target FP microcavity in the spatial frequency spectrum, a bandpass filter is constructed to filter out the frequency components of other microcavities and noise, while retaining the frequency components corresponding to the target microcavity. Subsequently, an inverse Fourier transform is performed on the filtered frequency components to obtain the independent interference spectrum corresponding to the target microcavity.

[0066] Peak tracking of independent interferometric spectra yields changes in the characteristic peak wavelengths of the target microcavity. Peak tracking methods can include single-peak tracking, double-peak tracking, or multi-peak tracking. Single-peak tracking is suitable for obtaining changes in relative optical path difference; double-peak or multi-peak tracking can be used to obtain absolute optical path difference or interference order information.

[0067] For temperature demodulation, it is preferable to select the independent interference spectrum corresponding to FP2 of the glass cavity and track the wavelength position of one or more characteristic peaks. As the temperature changes, the refractive index and physical length of the glass cavity change, causing wavelength shifts in the interference peaks. Based on the pre-calibrated relationship between the peak wavelength and temperature, the real-time temperature value can be calculated.

[0068] For vibration demodulation, the independent interference spectrum corresponding to air cavity FP1 is preferably selected, and the position of its characteristic peak is tracked over time. External vibrations cause changes in the cavity length of the air cavity, resulting in periodic shifts in the interference peaks. By converting the peak wavelength changes into a time series of cavity length changes and further performing a Fourier transform, vibration frequency or vibration amplitude information can be obtained.

[0069] Correspondingly, experimental verification was performed on the above embodiments. In vibration testing, such as... Figure 8 (a) and Figure 8 As shown in (b), when a vibration excitation of 2500 Hz is applied, the system demodulates the corresponding time-domain cavity length variation curve. After Fourier transform, a single sharp power peak is obtained at 2.5 kHz, with a measured frequency of 2500.00 Hz, verifying the system's accurate demodulation capability for high-frequency vibrations. In temperature testing, as... Figure 8 As shown in (c), the sensor was heated in 2°C increments from 46°C to 58°C. The glass cavity interference spectrum shifted towards longer wavelengths as the temperature increased. After peak tracking demodulation, the following result was obtained: Figure 8 The wavelength-temperature relationship curve shown in (d) has a fitting sensitivity of approximately 12 pm / °C and a linearity R² of 0.99999. These results demonstrate that the system of this invention can simultaneously perform high-precision synchronous demodulation of temperature and vibration.

[0070] In other embodiments, the number of channels in the REC-DFB laser array is not limited to 20, the matrix arrangement is not limited to a 4×5 structure, and the wavelength spacing, scanning range, scanning frequency and output power can be adjusted according to the free spectral range of the composite MOEMS microcavity sensor, the range of variation of the physical quantity to be measured and the demodulation speed requirements.

[0071] In other embodiments, the composite MOEMS microcavity sensor may have two, three, or more cavities, each of which may be sensitive to temperature, vibration, pressure, displacement, strain, refractive index, or other physical quantities. The optical path transmission module may employ fiber optic circulators, fiber optic couplers, beam splitters, or other equivalent optical path structures; the photoelectric detection and data acquisition module may be implemented using a combination of structures such as photodetectors, transimpedance amplifier circuits, analog-to-digital converters, and data buffer units. Furthermore, in one embodiment of the present invention, a REC-DFB array composite MOEMS microcavity demodulation system is proposed, wherein the REC-DFB array composite MOEMS microcavity demodulation system includes: Drive and temperature control module: Used to output synchronous trigger signals and high-speed wavelength scanning optical signals covering a preset wavelength range through the REC-DFB laser array according to the preset scanning timing and preset injection current waveform; Optical path transmission module: used to input the scanning light signal output by the drive and temperature control module into the composite MOEMS microcavity sensor via the optical path transmission module, reflect it to form a composite reflected light signal containing interference information of at least two microcavity with different optical path differences FP, and then convert it into an electrical signal via photoelectric conversion; Discrete light intensity data acquisition module: used to acquire discrete light intensity data corresponding to the time points within the scanning cycle of the root drive and temperature control module by using the synchronous trigger signal output from the root drive and temperature control module. Demodulation module: Based on the pre-calibrated mapping relationship between the scanning time point, the trigger sampling point and the output wavelength, it reconstructs the discrete light intensity data acquired by the discrete light intensity data acquisition module into a wavelength domain reflection spectrum, performs a fast Fourier transform on the reflection spectrum to obtain the spatial frequency spectrum, separates and extracts the frequency components corresponding to each target FP microcavity, and obtains the independent interference spectrum of each microcavity through inverse Fourier transform. Peak tracking and calculation module: used to track the peaks of each independent interference spectrum obtained by the demodulation module, obtain characteristic peak wavelength change information, and calculate the values ​​of at least two physical quantities to be measured according to the pre-calibrated wavelength-physical quantity correspondence.

[0072] like Figure 9 The diagram shown is a schematic representation of the REC-DFB array composite MOEMS microcavity demodulation system in one embodiment of the present invention.

[0073] The REC-DFB array composite MOEMS microcavity demodulation system provided in this application, employing the REC-DFB array composite MOEMS microcavity demodulation method described in the above embodiments, can solve the technical problems of existing technologies, such as reliance on spectrometers, large size, high cost, slow scanning speed, and difficulty in achieving simultaneous high-precision demodulation of multiple parameters. Compared with the prior art, the beneficial effects of the REC-DFB array composite MOEMS microcavity demodulation system provided in this application are the same as those of the REC-DFB array composite MOEMS microcavity demodulation method provided in the above embodiments, and other technical features of the REC-DFB array composite MOEMS microcavity demodulation system are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0074] This application provides a REC-DFB array composite MOEMS microcavity demodulation device, the REC-DFB array composite MOEMS microcavity demodulation device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the REC-DFB array composite MOEMS microcavity demodulation method in the above embodiment 1.

[0075] In one embodiment of the present invention, the REC-DFB array composite MOEMS microcavity demodulation device may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), etc., and fixed terminals such as digital TVs, desktop computers, etc. The described REC-DFB array composite MOEMS microcavity demodulation device is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0076] The REC-DFB array composite MOEMS microcavity demodulation device may include a processor (e.g., a central processing unit, graphics processing unit, etc.) that can perform various appropriate actions and processes according to a program stored in read-only memory (ROM) or a program loaded from a storage device into machine-readable storage medium (RAM). The RAM also stores various programs and data required for the operation of the REC-DFB array composite MOEMS microcavity demodulation device. The processor, ROM, and machine-readable storage medium are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus. Typically, the following systems can be connected to the I / O interface: input devices including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices including, for example, magnetic tapes, hard disks, etc.; and a communication unit. The communication unit allows the REC-DFB array composite MOEMS microcavity demodulation device to communicate wirelessly or wiredly with other devices to exchange data. While the above describes REC-DFB array composite MOEMS microcavity demodulation devices with various systems, it should be understood that implementation or having all of the systems shown is not required. More or fewer systems may be implemented alternatively.

[0077] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication unit, or installed from a storage device, or installed from a read-only memory. When the computer program is executed by a processor, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0078] The REC-DFB array composite MOEMS microcavity demodulation device provided in this application employs the REC-DFB array composite MOEMS microcavity demodulation method described in the above embodiments. This method solves the technical problems of existing technologies, such as reliance on spectrometers, large size, high cost, slow scanning speed, and difficulty in achieving simultaneous high-precision demodulation of multiple parameters. Compared with existing technologies, the beneficial effects of the REC-DFB array composite MOEMS microcavity demodulation device provided in this application are the same as those of the REC-DFB array composite MOEMS microcavity demodulation method provided in the above embodiments. Furthermore, other technical features of this REC-DFB array composite MOEMS microcavity demodulation device are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0079] The various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0080] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the REC-DFB array composite MOEMS microcavity demodulation method as described above.

[0081] The computer program product provided in this application can solve the technical problems of existing technologies, such as reliance on spectrometers, large size, high cost, slow scanning speed, and difficulty in achieving multi-parameter synchronous high-precision demodulation. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the REC-DFB array composite MOEMS microcavity demodulation method provided in the above embodiments, and will not be repeated here.

[0082] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A REC-DFB array combined with MOEMS microcavity demodulation method, characterized in that, Includes the following steps: step S10: The REC-DFB laser array outputs a synchronous trigger signal and a high-speed wavelength scanning light signal covering a preset wavelength range according to the preset scanning timing and preset injection current waveform; Step S20: The scanning light signal output in step S10 is input into the composite MOEMS microcavity sensor via the optical path transmission module, and reflected to form a composite reflected light signal containing interference information of at least two microcavity with different optical path differences FP, which is then converted into an electrical signal by photoelectric conversion; Step S30: Based on the synchronous trigger signal output in step S10, collect discrete light intensity data that correspond one-to-one with the time points within the scanning cycle in step S10. Step S40: Based on the pre-calibrated mapping relationship between the scanning time point, the trigger sampling point and the output wavelength, the discrete light intensity data collected in step S30 is reconstructed into a wavelength domain reflectance spectrum. The reflectance spectrum is subjected to a fast Fourier transform to obtain the spatial frequency spectrum. The frequency components corresponding to each target FP microcavity are separated and extracted. The independent interference spectrum of each microcavity is obtained by inverse Fourier transform. Step S50: Perform peak tracking on each independent interference spectrum obtained in step S40 to obtain characteristic peak wavelength change information, and calculate the values ​​of at least two physical quantities to be measured based on the pre-calibrated wavelength-physical quantity correspondence.

2. The REC-DFB array composite MOEMS microcavity demodulation method according to claim 1, characterized in that, In step S10, the REC-DFB laser array is scanned according to a preset timing sequence and a preset injection current waveform. This is achieved by adjusting the injection current waveform of each DFB laser unit to ensure that the output wavelengths of different channels are seamlessly connected at preset intervals on the time axis, and by equalizing the output optical power of each channel to ensure the continuity and flatness of the scanning spectrum.

3. The REC-DFB array composite MOEMS microcavity demodulation method according to claim 1, characterized in that, In step S20, the composite MOEMS microcavity sensor includes a cascaded air cavity and a glass cavity; the air cavity responds to changes in cavity length caused by vibration, displacement, pressure, or strain, while the glass cavity responds to changes in refractive index and thermal expansion caused by temperature changes.

4. The REC-DFB array composite MOEMS microcavity demodulation method according to claim 1, characterized in that, In step S30, the synchronous trigger signal includes a periodic trigger signal and a wavelength trigger signal; a new scanning cycle is started at the rising edge of the periodic trigger signal, and the light intensity value at the corresponding moment is latched at the rising edge of each wavelength trigger signal to achieve synchronous scanning and sampling.

5. The REC-DFB array composite MOEMS microcavity demodulation method according to claim 1, characterized in that, In step S40, the discrete light intensity data collected in step S30 is reconstructed into a wavelength domain reflectance spectrum. Specifically, the discrete light intensity data collected within one scanning cycle is converted into a continuous wavelength domain reflectance spectrum with equal wavelength intervals according to a pre-calibrated mapping relationship.

6. The REC-DFB array composite MOEMS microcavity demodulation method according to claim 1, characterized in that, In step S40, the frequency components corresponding to each target FP microcavity are separated and extracted. Specifically, the theoretical spatial frequency position of each FP microcavity is calculated based on the designed optical path difference. A narrowband filter is constructed with this position as the passband center, and the frequency components corresponding to each target FP microcavity are extracted respectively.

7. The REC-DFB array composite MOEMS microcavity demodulation method according to claim 1, characterized in that, In step S50, peak tracking employs at least one of single-peak tracking, double-peak tracking, or multi-peak tracking; single-peak tracking is used to obtain the relative optical path difference change, while double / multi-peak tracking is used to obtain the absolute optical path difference or interference order information.

8. A REC-DFB array composite MOEMS microcavity demodulation system, characterized in that, The system performs the REC-DFB array composite MOEMS microcavity demodulation method as described in claim 1, including: Drive and temperature control module: Used to output synchronous trigger signals and high-speed wavelength scanning optical signals covering a preset wavelength range through the REC-DFB laser array according to the preset scanning timing and preset injection current waveform; Optical path transmission module: used to input the scanning light signal output by the drive and temperature control module into the composite MOEMS microcavity sensor via the optical path transmission module, reflect it to form a composite reflected light signal containing interference information of at least two microcavity with different optical path differences FP, and then convert it into an electrical signal via photoelectric conversion; Discrete light intensity data acquisition module: used to acquire discrete light intensity data corresponding to the time points within the scanning cycle of the root drive and temperature control module by using the synchronous trigger signal output from the root drive and temperature control module. Demodulation module: Based on the pre-calibrated mapping relationship between the scanning time point, the trigger sampling point and the output wavelength, it reconstructs the discrete light intensity data acquired by the discrete light intensity data acquisition module into a wavelength domain reflection spectrum, performs a fast Fourier transform on the reflection spectrum to obtain the spatial frequency spectrum, separates and extracts the frequency components corresponding to each target FP microcavity, and obtains the independent interference spectrum of each microcavity through inverse Fourier transform. Peak tracking and calculation module: used to track the peaks of each independent interference spectrum obtained by the demodulation module, obtain characteristic peak wavelength change information, and calculate the values ​​of at least two physical quantities to be measured according to the pre-calibrated wavelength-physical quantity correspondence.

9. A REC-DFB array composite MOEMS microcavity demodulation device, characterized in that, include: The device includes a memory, a processor, and a REC-DFB array composite MOEMS microcavity demodulation program stored in the memory and executable on the processor. When the REC-DFB array composite MOEMS microcavity demodulation program is executed by the processor, it implements the REC-DFB array composite MOEMS microcavity demodulation method as described in any one of claims 1 to 7.

10. A computer program product, characterized in that, The computer program product includes a REC-DFB array composite MOEMS microcavity demodulation program, which, when executed by a processor, implements the REC-DFB array composite MOEMS microcavity demodulation method as described in any one of claims 1 to 7.

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