369 results about "Rayleigh Light Scattering" patented technology

The invention discloses an optical frequency domain reflection strain sensing method based on the combination of phase demodulation and cross-correlation, and the method comprises the steps: collecting backward Rayleigh scattering signals before and after the strain of a to-be-measured optical fiber, and extracting the phase information of a reference signal and a measurement signal through Fourier transform; a cross-correlation algorithm is combined to match a reference signal and a measurement signal at the same position of the optical fiber, and a dislocation phenomenon on a distance domain is corrected; calculating the relative phase of the matched reference signal and measurement signal at the same position, and performing phase unwrapping; distinguishing a fiber grating area and a non-grating area, and performing continuous correction on phase data by adopting a linear regression fitting algorithm so as to eliminate jump errors; on the basis of the differential relative phase, a window where the sudden change position is located is determined according to the window width obtained in the cross-correlation algorithm, segmented assignment is conducted on the strain of the window, and finally complete strain field distribution data are output. According to the method, the stability, the anti-interference capability and the measurement reliability of the phase demodulation method are improved.

The invention discloses a conveyor carrier roller online monitoring method and device and electronic equipment. The method comprises the following steps of: firstly, acquiring a sound wave vibration signal generated in real time when the carrier roller of the conveyor moves; wherein the sound wave vibration signal is obtained based on reverse Rayleigh scattering light in the optical fiber; performing feature extraction from the sound wave vibration signal to obtain an energy feature value of each frame; performing normalization processing on the energy characteristic value to obtain a target characteristic value; judging whether the target characteristic value exceeds a preset threshold value or not: if the target characteristic value exceeds the preset threshold value, inputting the target characteristic value into a pre-constructed target neural network model, so that the target neural network model outputs a fault type corresponding to the target characteristic value; therefore, online monitoring of the conveyor carrier roller based on optical fiber sensing multi-feature fusion is completed. According to the method, the fault type can be automatically and accurately identified and output, so that the overall performance and safety of the conveyor carrier roller are enhanced.

The invention discloses a photovoltaic panel self-adaptive cleaning system and method based on sand and dust optical thickness monitoring. The photovoltaic panel self-adaptive cleaning system comprises a sand and dust optical thickness monitoring module, a data processing and control module, a cleaning execution module, a power supply module and a remote monitoring module. The sand and dust optical thickness monitoring module is used for monitoring the sand and dust optical thickness AOD of the environment where the photovoltaic panel is located in real time, calculating the AOD by measuring the light intensity attenuation of a specific wavelength, and correcting the atmospheric Rayleigh scattering optical thickness and the gas absorption optical thickness at the same time; the data processing and control module is in communication connection with the sand and dust optical thickness monitoring module and used for receiving the AOD data and comparing the AOD data with a preset dust retention threshold value, and when the AOD value is larger than or equal to the threshold value, a cleaning instruction is generated; and the cleaning execution module is used for receiving the cleaning instruction and executing cleaning operation. Intelligent and self-adaptive control of photovoltaic panel accumulated dust cleaning is achieved, the cleaning opportunity can be adjusted in real time according to the actual sand and dust optical thickness, and the cleaning pertinence and effectiveness are improved.

The invention provides a sensing system fusing optical fiber vibration and acoustic emission, a monitoring method and a device, and relates to the technical field of optical fiber sensing. The device comprises a light source module, a sensing optical fiber, a detection module and a controller, the light source module is used for respectively emitting modulation pulse light for vibration monitoring and continuous wave laser for acoustic emission monitoring; the sensing optical fiber is arranged along a monitored structure or area, and at least one optical fiber acoustic emission sensing head is connected to the optical fiber in series. The detection module collects Rayleigh scattering light and beat frequency signals at all positions in the sensing optical fiber through a circulator and a coherent light receiver, and optical signals are converted into electric signals; wherein the electric signals comprise vibration electric signals and acoustic emission electric signals; the signal processing unit carries out phase demodulation and envelope analysis processing on the collected vibration electric signals and acoustic emission electric signals so as to obtain vibration waveforms and acoustic emission event space-time information along all points of the optical fiber. According to the invention, a monitoring task fusing vibration and acoustic emission can be accurately completed.

The invention relates to the technical field of bionic navigation orientation and positioning, in particular to a carrier course angle measuring method based on polarized light imaging in a non-Rayleigh atmosphere. Comprising the steps of real-time sky polarized light imaging, atmospheric polarization mode resolving based on Mueller matrix imaging, non-Rayleigh polarization information interference removal, polarization orientation resolving based on Rayleigh scattering, space projection conversion and sun position information resolving. Alignment information of the sun in a carrier coordinate system is obtained by utilizing a Rayleigh scattering model and actual sky polarization imaging, and then a carrier course angle is obtained according to the orientation of the sun in a local geographic coordinate system, so that an orientation function is realized; meanwhile, the error influence caused by image registration and time-sharing rotation measurement of the multi-view-field polarization detector and the interference of environmental factors on a single point are avoided, the method can adapt to sunny and cloudy weather, is also applicable to cloudy and other non-Rayleigh weather, and is wide in application range.

The invention discloses a distributed OFDR sensing signal demodulation method and system based on local ridge line tracking, relates to the technical field of optical fiber sensing, and is used for solving the problem that a traditional cross-correlation algorithm is difficult to consider robustness and real-time performance at the same time. The method comprises the following steps: respectively processing a reference beat frequency signal of a sensing optical fiber to be measured in a strain-free state and a measurement beat frequency signal of the sensing optical fiber to be measured in a strain state to obtain a reference complex Rayleigh scattering signal and a measurement complex Rayleigh scattering signal containing a plurality of sensing positions along the optical fiber; calculating a cross-correlation function based on the two signals; stacking the cross-correlation functions corresponding to all sensing positions along a distance domain, and constructing a two-dimensional cross-correlation thermodynamic diagram matrix; performing filtering processing and weighting processing on the two-dimensional cross-correlation thermodynamic diagram matrix to obtain an optimal frequency drift distance; and demodulating based on the optimal frequency drift amount to obtain strain distributed along the to-be-measured sensing optical fiber. According to the invention, high-robustness and rapid demodulation of the signal in an application scene with extremely high real-time requirement can be realized.

An optical frequency domain reflectometer with environmental disturbance resistance and large strain measurement capability belongs to the field of distributed optical fiber sensing and comprises an opposite sweep frequency light frequency modulation continuous wave signal generation module, a light splitting device, a modulation device, a circulator, a polarization controller, an optical coupling device, a photoelectric conversion module and a data acquisition and processing module. An optical signal generated by an opposite sweep frequency light frequency modulation continuous wave signal generation module is divided into probe light and local oscillation light through a light splitting device, the probe light is modulated through a modulation device and sent to an optical fiber through a circulator, and a Rayleigh back scattering light signal generated by the optical fiber and the local oscillation light interfere in an optical coupling device to obtain interference light; the photoelectric conversion module mixes beat frequency signals of interference light, and the data acquisition and processing module analyzes and processes the beat frequency signals. According to the invention, the position information of the Rayleigh backscattering point is marked by using the modulated probe light, the Rayleigh scattering signal at the corresponding position is restored, crosstalk between channels is inhibited, and high-precision measurement in a large dynamic range and resistant to environmental disturbance is realized.

The invention discloses a blue-green algae type discrimination method based on a three-dimensional fluorescence spectrum. The method comprises the following steps: S0, obtaining a to-be-detected sample; the method comprises the following steps: S1, acquiring original three-dimensional fluorescence spectrum data; s2, preprocessing the original three-dimensional fluorescence spectrum data; rayleigh scattering and Raman scattering in the original three-dimensional fluorescence spectrum are removed, and smooth denoising is carried out on the original three-dimensional fluorescence spectrum; s3, spectral features are extracted based on a parallel factor-peak ratio method, and spectral feature vectors are obtained; and S4, carrying out missing value supplement and data standardization processing on the obtained spectral feature vectors, inputting the processed feature vectors into a trained LightGBM multi-classifier, outputting probabilities by a classification model, and selecting a category with the maximum probability. According to the method, the distribution mechanism of the blue-green algae fluorescent pigment is combined, and the fluorescent component characteristics and the relative content characteristics of the fluorescent components of the blue-green algae are comprehensively considered, so that the three-dimensional fluorescence spectrum information of the blue-green algae sample can be more comprehensively, completely and meticulously represented, and the variety discrimination of different blue-green algae with smaller difference is realized.

The invention discloses a seismic data acquisition device based on a ground 3C-DAS optical cable and an acquisition method thereof, is applied to the field of seismic exploration, and aims to solve the problems of high layout cost, too long construction time and low operation efficiency of an existing ground three-component detector. According to the method, a 3C-DAS armored optical cable is buried under a shallow earth surface in a parallel or orthogonal mode, a ground multichannel low-frequency DAS modulation-demodulation instrument collects phase data of Rayleigh scattering light reflected back from the 3C-DAS armored optical cable and carries out modulation-demodulation processing, and high-density distributed three-component seismic data distributed along the 3C-DAS armored optical cable is obtained; according to the system, high-density distributed three-component ground seismic data along the armored optical cable can be rapidly and efficiently acquired at low cost; the invention also provides a processing method for the collected high-density distributed three-component ground seismic data, an analysis method for a shallow surface velocity structure with high spatial resolution, and an inversion imaging method for longitudinal waves, transverse waves and surface waves.

The invention relates to a damaged point monitoring system and method for a hollow-core optical fiber, computer equipment, a medium and a product, and relates to the technical field of telecommunication operation and maintenance. The system comprises a sensing sending module and a sensing receiving module, wherein the sensing transmitting module is used for transmitting a target optical pulse coding signal corresponding to a current monitoring mode to a to-be-detected hollow-core optical fiber; the monitoring mode comprises an on-line monitoring mode and an off-line monitoring mode, and the wavelength bands of the target optical pulse coded signals corresponding to the on-line monitoring mode and the off-line monitoring mode are different; and the sensing receiving module is used for receiving the backward Rayleigh scattering light reflected by the to-be-detected hollow-core optical fiber and positioning a damaged point of the to-be-detected hollow-core optical fiber according to the backward Rayleigh scattering light and the layout path information of the to-be-detected hollow-core optical fiber. The system can accurately position the damaged point of the hollow-core optical fiber.

The invention discloses polybutadiene latex, a preparation method thereof and transparent ABS (Acrylonitrile Butadiene Styrene) resin. In the preparation process of the polybutadiene latex, the emulsifier is additionally added at a relatively high conversion rate to promote the reaction to generate part of latex particles with small particle sizes. When the latex prepared by the method is used for further preparing the transparent ABS resin, since the latex with the particle size of 30-70nm has a rayleigh scattering effect to a certain extent, a small amount of blue light can be scattered, so that the yellow index of the resin is reduced, and the prepared transparent ABS has better hue.

The invention discloses a dike underwater piping positioning system based on distributed optical fiber vibration sensing, and relates to the technical field of positioning systems, and the dike underwater piping positioning system comprises a distributed optical fiber vibration sensing host which is used for transmitting a laser pulse to a sensing optical cable and demodulating a backward Rayleigh scattering signal; the multi-mode sensing optical cable is arranged along the dike underwater area and comprises a vibration sensing optical fiber and a temperature sensing optical fiber; the data processing module is used for executing time-space synchronous analysis of the vibration signal # imgabs0 # and the temperature signal # imgabs1 #; and the data processing module comprises a multi-modal feature fusion unit, and the multi-modal feature fusion unit is used for generating a combined feature factor # imgabs4 # by fusing the intensity # imgabs2 # and the temperature change rate # imgabs3 # of the vibration signal and carrying out weight distribution. According to the invention, through the technical closed loop of multi-mode sensing, intelligent layout and deep learning, the technical blank of the existing distributed optical fiber monitoring system in the aspects of early recognition, accurate positioning and intelligent early warning of underwater piping is filled.

The invention discloses a carbon dioxide formation leakage monitoring device and method based on distributed optical fiber sensing. The device comprises a simulated formation, an injection system and a DTS system. A thermal insulation device, a thermometer and a production well system are mounted on the simulated stratum; the injection system is used for injecting carbon dioxide and liquid into the simulated stratum; the DTS system comprises a light source assembly, an optical fiber group, a detection assembly and a data acquisition and processing unit which are connected in sequence; a plurality of monitoring points of the optical fiber group are arranged, and the plurality of monitoring points are arranged in the simulated stratum at intervals; the detection assembly is used for detecting Rayleigh scattering frequency shift and Rayleigh backscattering light intensity and phase in the optical fiber group, and the data acquisition and processing unit is used for acquiring signals output by the detection assembly and performing data processing and analysis. According to the invention, fine monitoring and continuous monitoring of carbon dioxide stratum leakage can be realized, the environmental interference resistance is high, and the installation and maintenance cost is low.

The application belongs to the technical field of distributed optical fiber sensing, and particularly relates to a long-distance distributed optical fiber broadband acoustic vibration sensing system. The application utilizes the same laser to transmit and generate back Rayleigh scattering light and interference light in the same sensing optical fiber, and further constructs a distributed optical fiber acoustic vibration sensing system combined with Φ-OTDR and MZI, which comprehensively utilizes the performance advantages of both, utilizes a very simplified optical system scheme, realizes the function fusion of the two sensing structures on one sensing optical fiber, reduces the resource waste caused by the transmission of sensing signals by different sensing optical cables respectively, maximizes the optical fiber resource utilization rate, and reduces the system cost; utilizes a frequency division multiplexing demodulation scheme in the digital domain, expands the frequency response range on the basis of ensuring the high positioning accuracy of the system, realizes the simultaneous detection of the two systems by a single core, simultaneously realizes the high positioning accuracy and the continuous non-blind area detection in the broadband frequency range, and improves the reliability.

The invention provides a power distribution communication network optical cable fault prediction method and system based on machine learning. The method comprises the following steps: collecting Rayleigh scattering signals of a plurality of monitoring points along an optical cable; performing unsupervised learning on the optical cable adaptive reconstruction model, and calculating a reconstruction error matrix and an abnormal cumulative metric; constructing an optical cable network diagram, calculating a fault propagation probability matrix, predicting a future optical cable health index, and obtaining a future health index matrix; establishing an environment influence matrix, and adopting an optical cable environment adaptive filtering model; and based on the health index and the fault confidence coefficient matrix after filtering optimization, optical cable maintenance priority scores are calculated and sorted, and a self-adaptive inspection and maintenance strategy is formulated. According to the invention, high-precision monitoring, fault propagation prediction and environmental adaptability optimization of the health state of the optical cable are realized, and the intelligent level of operation and maintenance of the optical cable is improved.

The invention belongs to the technical field of distributed optical fiber sensing, and relates to a phase-frequency noise suppression optical frequency domain reflection measurement method and system without an auxiliary interferometer. The measurement method comprises the following steps: acquiring positive and negative double-sideband sweep-frequency light with the same sweep-frequency range and opposite sweep-frequency directions; dividing the positive and negative double-sideband sweep frequency light into double-sideband detection light and double-sideband local oscillation light according to a preset proportion; configuring a pseudo-random noise code, and modulating the pseudo-random noise code to the double-sideband probe light to obtain spread spectrum double-sideband probe light; the spread spectrum double-sideband detection light enters the sensing optical fiber and is reflected back to the backward Rayleigh scattering light, and the backward Rayleigh scattering light and the spread spectrum double-sideband local oscillation light interfere with each other to output up-down sweep frequency beat frequency signals; separating the upper and lower sweep-frequency beat-frequency signals to obtain an upper sweep-frequency beat-frequency signal and a lower sweep-frequency beat-frequency signal; and after the upper sweep frequency beat frequency signal and the lower sweep frequency beat frequency signal are respectively decoded, a beat frequency signal is separated through band-pass filtering, the beat frequency signal is subjected to frequency mixing processing to obtain a frequency mixing signal after phase frequency noise suppression, and the frequency spectrum of the frequency mixing signal is analyzed.

The invention relates to the technical field of optical fiber sensing, in particular to a distributed optical fiber vibration-temperature combined monitoring method and system. Comprising the following steps: carrying out linear frequency modulation on single-frequency light waves output by a light source to enable the single-frequency light waves to serve as probe light for distributed vibration and distributed temperature sensing at the same time; linear sweep frequency light is injected into an optical fiber to be measured, and Rayleigh scattering and Raman scattering light signals in the optical fiber are separated by using a wavelength division multiplexer. And the vibration information of each point along the optical fiber is recovered by combining a Rayleigh scattering light signal with a coherent detection architecture through algorithms such as back-end matched filtering and the like. And the Raman scattering light signal is combined with intensity detection and a dual-wavelength difference algorithm, so that the temperature information of all optical fiber lengths can be recovered. According to the invention, vibration and temperature measurement is realized in the same system, and the problems of temperature and vibration measurement time synchronization, sampling rate alignment and the like in different systems are avoided.

The invention provides a phase-sensitive optical time domain reflectometer system and method, and the system comprises a first polarization-maintaining coupler which is used for dividing laser generated by a DC laser, and obtaining first laser and second laser; the optical fiber measurement front-end module is used for processing the random signal through pulse shaping and multi-carrier modulation technologies to generate an electric signal, and sequentially performing modulation, amplification, Rayleigh scattering and amplification on the first laser after the electric signal is generated to obtain amplified Rayleigh backscattered light; the second polarization-maintaining coupler is used for dividing the second laser to obtain third laser and local oscillation light; the delay optical fiber is used for processing the third laser to obtain delay light; the third polarization-maintaining coupler is used for combining the delayed light and the amplified Rayleigh backscattered light to obtain combined light; the receiver is used for processing the combined light and the local oscillation light to obtain multiple paths of target electric signals; and the oscilloscope is used for processing multiple paths of target electric signals through low-pass and high-pass filters and a phase noise compensation algorithm so as to determine power and phase distribution. The system cost can be reduced.

The invention relates to the technical field of optical fiber sensing, in particular to a fusion type optical fiber disturbance detection system and method based on multi-mode scattering. The system comprises a light source module, an optical fiber sensing network, an optical signal demodulation module, a data processing unit and a self-adaptive disturbance identification module. By simultaneously extracting the feature information of Rayleigh scattering and Raman scattering, the detection sensitivity and precision of different types of disturbances can be improved. The system adopts a self-adaptive disturbance recognition algorithm and utilizes information entropy calculation to dynamically adjust the fusion weight of Rayleigh scattering and Raman scattering so as to adapt to disturbance detection requirements under different environmental conditions, the adaptability and reliability of the system are improved, and the false alarm rate is effectively reduced. Besides, the data processing unit is combined with the optical time domain reflection (OTDR) principle, and high-precision disturbance positioning is realized by calculating the time difference of the disturbance signal reaching the demodulation module.

The embodiment of the invention provides a light reflection detection device and a light reflection detection method, which are applied to the technical field of optical communication. The device comprises a light reflectometer, a calibration piece and a signal processor. The calibration member has a preset reflection intensity or a preset Rayleigh scattering intensity. The output end of the light reflectometer is connected with the calibration piece and is used for being connected with the test optical fiber through the calibration piece. The light reflectometer is used for transmitting a test light signal based on the output end of the light reflectometer and receiving an echo light signal of the test light signal. And the signal processor is used for outputting signal insertion loss at different positions of the test optical fiber according to the echo optical signal. The light reflection detection device provided by the embodiment of the invention can realize the purpose of accurately detecting the insertion loss of the near end of the test optical fiber.

The invention discloses an optical fiber optical frequency transmission relay system and method based on a spread spectrum technology. The relay system comprises a receiving module, a regenerative laser module and a sending module. The receiving module is used for demodulating the spread spectrum optical signal according to the second pseudo-random sequence to obtain a demodulated optical signal; the spread spectrum optical signal is a signal which is transmitted through an optical fiber link after a preceding stage performs spectrum spreading on the optical signal; the regeneration laser module is used for locking the frequency of the demodulation optical signal to generate a regeneration optical signal and splitting the regeneration optical signal to obtain a return optical signal and a transmission optical signal; the receiving module is also used for modulating the returned optical signal according to the second pseudo-random sequence and transmitting the modulated returned optical signal back to the preceding stage; and the sending module is used for demodulating the post-stage modulation return optical signal to obtain a demodulated return optical signal, carrying out noise suppression and spectrum spreading on the transmission optical signal according to the demodulated return optical signal and a third pseudo-random sequence, and then transmitting the transmission optical signal to the post-stage. By introducing the spread spectrum technology, the second-order Rayleigh scattering signals are filtered out, and the stability and reliability of the system are remarkably improved.

The invention discloses a foreign object intrusion identification and positioning method based on an optical fiber Rayleigh scattering technology. The method comprises the following steps: laying a cable and a double-core optical fiber in parallel; pulse light is injected into the double-core optical fiber, the pulse light generates backward Rayleigh scattering in the double-core optical fiber and is received, and the backward Rayleigh scattering is converted into an electric signal; positioning and verifying a fault position according to the electric signal, calculating attenuation compensation after the fault position verification is passed, calculating a positioning deviation according to the attenuation compensation, and obtaining a positioning result according to the positioning deviation. The distributed sensing characteristic of the optical fiber Rayleigh scattering technology is utilized, and the phase / intensity change of a backscattered light signal is analyzed in real time, so that millisecond-level response and meter-level positioning of disturbance along the underground cable are realized. After the fault position is positioned, the fault position is verified, the positioning accuracy of the fault position is ensured, and after the fault position is verified and positioned, attenuation compensation is performed, and the positioning deviation is eliminated, so that the positioning precision is further improved.

The invention relates to the technical field of optical fiber sensing, and provides an improved moving average method applied to a distributed optical fiber vibration sensing system, and the method comprises the steps: continuously collecting a plurality of backward Rayleigh scattering curves; setting a plurality of different moving average window widths, and performing moving average processing on the plurality of backward Rayleigh scattering curves based on each moving average window width to obtain a plurality of scattering curves after moving average processing corresponding to each moving average window width; for each moving average window width, calculating the variance of the scattering curve after moving average processing at the same time point, and obtaining a variance sequence corresponding to the moving average window width; according to the variance sequence corresponding to each moving average window width, determining the corresponding moving average window width when the variance change tends to be stable, and taking the moving average window width as a target window width; and moving average processing is carried out on a plurality of acquired backward Rayleigh scattering curves by using a target window width, and a disturbance event on the optical fiber is positioned.

The system comprises a phi-OTDR distributed optical fiber sensing optical path, an AD acquisition module, an FPGA circuit and a host, a Rayleigh scattering light signal is generated through the distributed optical fiber sensing optical path, digital orthogonal demodulation is executed by the FPGA circuit after photoelectric conversion and AD acquisition module digitization, and the Rayleigh scattering light signal is transmitted to the host through the phi-OTDR distributed optical fiber sensing optical path. Extracting phase data; processing the phase data by adopting a Hilbert transform algorithm, and establishing a mapping relation between the phase difference and the vibration amplitude and frequency; the host receives the data and generates a time-position two-dimensional waterfall plot, and the running directions of the double trains are judged by analyzing the homonymy or reversibility of vibration point tracks; and calculating the displacement variation and the time difference of the two trains based on a time sequence analysis algorithm, optimizing speed data in combination with moving average filtering and Kalman filtering, and outputting the real-time positions and speeds of the two trains. According to the invention, accurate monitoring of the running state of the double trains is realized, and the accuracy, real-time performance and reliability of railway safety monitoring are improved.

The invention relates to the technical field of optical fiber sensing, in particular to a distributed optical fiber sound wave sensing system based on an on-line interferometer, which is characterized in that a detection light signal sent by a distributed optical fiber sensing host passes through a relay amplifier and then is accessed into a circulator, and enters a downlink transmission optical fiber; a backward Rayleigh scattering signal generated by the detection optical signal in each relay section downlink transmission optical fiber is coherent with a local oscillation optical signal of the optical fiber interferometer to generate a disturbance monitoring signal of the relay section submarine optical cable; a disturbance monitoring signal is accessed to an optical fiber coupler of the relay section and enters an uplink relay amplifier of the uplink transmission optical fiber, and the disturbance monitoring signal is transmitted back to the optical fiber sensing host. And the working modes of the submarine repeaters are the same, so that each relay section can independently detect the optical fiber sound wave sensing signals. Therefore, the problem that the existing distributed optical fiber sound wave sensing technology cannot meet the requirement of relay submarine optical cable full-link detection is solved.

A polarization orientation method based on sky region prior and morphological template matching of transform domain, which reduces an interference of reflected light through the sky region prior and solves sun blur through the morphological template matching of transform domain (MTMTD); a region division standard is given through prior knowledge of a sky region, and the sky region is identified by clustering darkest pixel images in 15-channel polarization images; meanwhile, the MTMTD strategy provided carries out a transform domain treatment on an image of the angle of polarization by an imaging method, and solves the problem of sun blur under a single Rayleigh scattering model without relying on an additional sensor.

The invention provides a light-emitting device and a preparation method of the light-emitting device. The light-emitting device comprises a substrate, a dodging layer and at least one light-emitting diode chip, the dodging layer comprises a substrate layer and a plurality of nanoparticles, the substrate layer is located on the substrate, the nanoparticles are uniformly distributed in the substrate layer, and the at least one light emitting diode chip is located on the substrate layer. The nanoparticles in the substrate layer can perform Rayleigh scattering and Mie scattering on light emitted by the light emitting diode chip, and the light emitting angle of the light emitting device is changed. When the light-emitting device comprises light-emitting diode chips with different colors, due to the fact that the positions of the light-emitting diode chips with different colors are different, intensity differences of different colors under different visual angles are easily caused, and color deviation is further caused. Scattering intensity of light emitted by light-emitting diodes with different colors to the same area can be balanced, so that color deviation of the light-emitting device is reduced.

The invention relates to a road cavity detection and identification method and system based on multichannel optical fiber sensing. The method comprises the following steps: acquiring and storing Rayleigh scattering light time domain signals which are acquired by a DAS underground sensing system at different positions and different time periods of a detection road section and contain active knocking signals; determining a frequency range of the active knocking signal according to a frequency spectrum obtained after the Rayleigh scattering light time domain signal is subjected to fast Fourier transform processing; carrying out filtering processing on the Rayleigh scattering light time domain signal by adopting a finite impulse response band-pass filter to obtain a filtered signal; the filtered signal is input into a PhaseNetDAS model for seismic phase pickup, and an active source seismic phase is obtained; associating the active source seismic facies with the active source event to obtain a seismic facies report including event latitude and longitude, time and seismic facies arrival time; and inverting the velocity structure of the underground medium by using the seismic phase report by using a tomography method, and determining a road cavity detection and recognition result, thereby improving the accuracy of road cavity detection.

An integrated detection method based on a liquid-filled hollow-core optical fiber enhanced Raman signal comprises the following steps: positioning an optical coupling system, a liquid adapter and a forward Raman signal collection system along the same dovetail groove guide rail, and operating a sliding block fine adjustment mechanism to adjust the relative positions of the optical coupling system, the liquid adapter and the forward Raman signal collection system so as to enable an optical path to be axially aligned; the micro-flow injection system is operated, target liquid is conveyed to the liquid adapter through the micro-flow guide pipe, the liquid adapter keeps the collimation alignment relation between the hollow-core optical fiber and the laser, and then the target liquid is introduced into a fiber core of the hollow-core optical fiber; the laser light source is started to emit laser, and after the laser is collimated and focused through the optical coupling system, a Raman signal is excited and generated; operating a forward Raman signal collection system to capture a Raman signal output by the hollow-core optical fiber, filtering out an exciting light Rayleigh scattering signal in the Raman signal, and transmitting the purified Raman signal to a Raman spectrometer; and analyzing and processing the purified Raman signal, and outputting a detection result of the target liquid.

The utility model belongs to the technical field of optical fiber lasers, and relates to a multi-wavelength random optical fiber laser based on a four-port circulator and Brillouin-Rayleigh scattering, which is a closed-loop random optical fiber laser and comprises the four-port circulator, a seed laser is connected with the first port of the four-port circulator, and a seed laser is connected with the second port of the four-port circulator. The second port is connected with the Brillouin gain optical fiber, the third port is connected with the random Rayleigh scattering optical fiber, and the fourth port is connected with the optical fiber coupler; an erbium-doped fiber and a wavelength division multiplexer are connected between the Brillouin gain fiber and the fiber coupler, and a pump light port of the wavelength division multiplexer is connected with an output port of the 980nm laser. According to the utility model, the Brillouin gain optical fiber is subjected to Brillouin scattering, and the Rayleigh scattering of the random Rayleigh scattering optical fiber and the gain amplification of the erbium-doped optical fiber are combined, so that efficient and stable multi-wavelength output is realized, the number of output wavelengths is adjustable, the stability is high, and the device is suitable for a high-precision optical fiber sensing and dense wavelength division multiplexing system.