116 results about "Brillouin scattering" patented technology

The invention provides an intelligent optical cable performance prediction method and system for a data center, and relates to the technical field of data center performance analys.The intelligent optical cable performance prediction method comprises the steps that firstly, an optical cable microstructure disturbance quantization model is constructed, and an optical cable is divided into a plurality of virtual quantization units in the longitudinal direction; each unit packages a real-time stress-strain state parameter and a response sensitivity coefficient of the basic structure unit, inputting a Brillouin scattering spectrum frequency shift data flow collected in real time into the model for disturbance source analysis, generating a physical excitation decomposition sequence, driving a virtual quantization unit to perform state evolution iterative operation according to the physical excitation decomposition sequence, and obtaining a Brillouin scattering spectrum frequency shift data flow model; a stress-strain state evolution track set is obtained, a time-space correlation network of optical cable link disturbance propagation is constructed according to the stress-strain state evolution track set, network flow characteristic analysis is conducted on the time-space correlation network, an early warning node set is extracted, the future evolution trend of the early warning node set is calculated, and serialized optical cable performance abnormity early warning information is generated. The optical cable performance abnormity can be predicted in advance, and stable operation of the data center optical cable is guaranteed.

The invention belongs to the technical field of communication, and provides a communication optical cable state real-time online monitoring method and system. Calculating the vibration displacement of the optical cable based on the original back scattering light signal, and calculating the real strain and temperature of the optical cable based on a Brillouin scattering signal and a Raman scattering signal obtained by separating the original back scattering light signal; carrying out filtering, denoising, normalization and time-space alignment processing on the vibration displacement of the optical cable, the real strain of the optical cable and the temperature, and binding the vibration displacement and the real strain with the obtained geographic coordinates; obtaining time domain, frequency domain and time-frequency domain features based on the preprocessed vibration displacement, real strain and temperature data to form a multi-dimensional feature vector, inputting the feature vector into a pre-trained event recognition model, and outputting an abnormal event classification result; and judging and triggering abnormal event early warning based on an output result of the event recognition model and a preset dynamic threshold.

The invention particularly relates to an excitation signal waveform intelligent optimization method for a high-power narrow-linewidth fiber laser, and the method comprises the steps: obtaining an excitation signal, carrying out the processing of a phase modulation waveform of the excitation signal, and extracting an input feature set needed by frequency spectrum prediction; constructing a frequency spectrum prediction model based on the decoupling echo state network, inputting the input features into the frequency spectrum prediction model based on the decoupling echo state network, realizing nonlinear mapping between the phase modulation waveform of the excitation signal and the frequency spectrum response thereof, and obtaining a prediction frequency spectrum; constructing a composite cost function including a mean square error, a spectrum sideband leakage penalty term and a spectrum smoothing term based on the difference between the predicted spectrum and the target spectrum; based on a composite cost function, an Adam optimization algorithm is adopted to iteratively correct a phase waveform in a frequency domain, intelligent waveform optimization of phase modulation is realized, and a threshold value of a stimulated Brillouin scattering effect is reduced. The intelligent optimization of the phase modulation waveform of the excitation signal can be realized.

The invention provides a Brillouin frequency shift extraction method and device, equipment and a storage medium, and relates to the technical field of optical fiber sensing, and the method comprises the steps: carrying out the algebraic conversion of a measured Brillouin scattering gain spectrum into a Brillouin center frequency curve; according to the Brillouin center frequency curve, the approximate value of the center frequency of the maximum value position of the Brillouin scattering gain spectrum is solved, then the center frequency of the Brillouin scattering gain spectrum is determined, that is, a frequency shift extraction result is given in a multi-center-frequency statistical mode, and the method has the advantages of being high in precision and stability. Meanwhile, a fitting tool does not need to be used in the calculation process, and the calculation complexity is extremely low; compared with the prior art, the method provided by the invention has the advantages that the method is not easily influenced by a multi-peak Brillouin form, and particularly, a high-precision result can be given for common bimodal form data, so that the technical problems of large error, high calculation complexity and great influence of an initial value on the fitting success rate and the stability are solved.

The invention discloses a multidimensional communication sensing system integrating an optical transmission network and BOTDR / DAS distributed sensing, and relates to the technical field of optical fiber communication and optical fiber sensing. The system comprises an OTN transmission subsystem, an optical fiber link and a BOTDR / DAS fusion sensing subsystem. Wherein the OTN transmission subsystem is used for realizing high-capacity data transmission through an optical fiber link; and the BOTDR / DAS fusion sensing subsystem is used for realizing strain, temperature and vibration distributed measurement of an optical fiber link through a Brillouin scattering and Rayleigh backscattering mechanism. According to the system, a double-self-heterodyne demodulation architecture and a reverse wavelength division multiplexing mechanism are adopted, cooperative demodulation and high-isolation transmission of BOTDR and DAS signals are achieved under the common-fiber condition, and high-speed communication and distributed temperature, strain and vibration synchronous monitoring within the 100 km range can be achieved. According to the method, a technical foundation can be laid for realizing physical layer intelligentization of the in-service power OTN.

The application provides an optical system and a monitoring method for monitoring stimulated Brillouin scattering effect. The optical system for monitoring stimulated Brillouin scattering effect firstly delivers a narrow linewidth seed source into a laser amplifier through a first optical device to amplify the narrow linewidth laser, and guides stimulated Brillouin scattering light generated by the laser amplifier to a back light monitoring module to detect the back light power and spectral components of the stimulated Brillouin scattering light in real time through the back light monitoring module, so as to realize the purpose of simultaneously and accurately measuring the stimulated Brillouin scattering light power and observing the laser components, and is more conducive to judging whether the stimulated Brillouin scattering effect occurs. Further, the optical system can adjust the light splitting ratio of the first optical device and the back light monitoring module to protect the narrow linewidth seed source and the spectrometer in the back light monitoring module from the damage of the back light to the greatest extent, and achieve the purpose of accurately judging the stimulated Brillouin scattering effect and protecting the system safety.

The application discloses a kind of photonic crystal fiber of bending resistance and with high Brillouin scattering gain, including surface layer, intermediate layer and core layer;Surface layer includes first oval air hole, and first oval air hole is arranged along the circumferential direction of photonic crystal fiber;Intermediate layer includes first part, second part, third part and fourth part, first part and third part are oppositely arranged, and respectively include a plurality of first circular air hole arranged into trapezoidal;Second part and fourth part are oppositely arranged, and respectively include a plurality of first circular air hole arranged into square;Core layer includes two symmetrically arranged second circular air hole, and the gap between each second circular air hole and first part and third part is filled with symmetrically arranged third circular air hole and third oval air hole.The application not only has good bending resistance, but also has higher Brillouin scattering gain.

The invention discloses an in-operation OPGW icing tension monitoring method based on a micrometeorological temperature demodulation BOTDR. The method comprises the following steps: measuring through a Brillouin optical time domain reflectometer to obtain OPGW Brillouin frequency shift data; calibrating a Brillouin frequency shift temperature sensitivity coefficient and a Brillouin frequency shift tension sensitivity coefficient of the OPGW by using the data of the microclimate icing monitoring terminal; according to the Brillouin scattering principle, all Brillouin frequency shifts are converted into Brillouin equivalent temperatures; the external environment temperature of the OPGW is measured through the micro-meteorological icing monitoring terminal and is defined as temperature data of the micro-meteorological icing monitoring terminal; calculating a difference value between the Brillouin equivalent temperature and the temperature data of the microclimate icing monitoring terminal; and when the temperature difference value is greater than or equal to the temperature measurement precision of the Brillouin optical time domain reflectometer, the icing tension is calculated. According to the invention, the Brillouin frequency shift temperature sensitivity coefficient and the Brillouin frequency shift tension sensitivity coefficient can be directly calibrated on line, and the calibration result and the icing tension monitoring result are more accurate.

This invention discloses a wafer and chip defect detection system and method based on linear array Brillouin microscopy, belonging to the fields of optical precision measurement and wafer inspection. The system connects a Brillouin scattering detection module, a bright-field detection module, and a signal processing and feedback module; the signal processing and feedback module is connected to a displacement module; the signal processing and feedback module is also connected to an imaging and analysis module, transmitting single-shot linear beam measurement data to the imaging and analysis module; the displacement module is connected to the sample; and the Brillouin scattering detection module and bright-field detection module are connected to the sample to acquire sample information. This invention enables line-scan confocal measurement of the mechanical properties of wafers and non-transparent chips using the Brillouin scattering detection module, significantly improving the speed of Brillouin scattering detection; the combination of bright-field linear array detection and Brillouin scattering linear array detection allows for the simultaneous acquisition of geometric and mechanical stress defects in wafer and chip samples, broadening the range of defect detection parameters.

The invention discloses a marine mixed layer water environment parameter measurement method and system based on a stimulated Brillouin scattering acoustic grating, and relates to the field of marine water environment detection.The method comprises the steps that a dependency equation between stimulated Brillouin scattering frequency shift and water environment parameters is established, and a first dependency equation is obtained; the water body environment parameters comprise temperature and salinity; establishing a dependency relationship equation between the acoustic grating reflection spectrum center peak value frequency shift and the water body environment parameters to obtain a second dependency relationship equation; and calculating water body environment parameters based on the first dependency relationship and the second dependency relationship. According to the invention, complete distinguishing of marine mixed layer water body environment parameters can be realized, and the measurement precision is high.

The application discloses an SBS phase conjugation mirror capable of displaying a sound wave field in real time, and belongs to the technical field of nonlinear optics.The application comprises the following steps: pump light passes through a half-wave plate and a polarization beam splitter, passes through an optical isolator, changes a polarization state through a quarter-wave plate, is focused through a focusing lens, and then enters an SBS medium pool, stimulated Brillouin scattering occurs, a periodic density modulation is formed in the medium, and an equivalent acousto-optic grating structure is generated.Through introducing an independent probe light beam, the probe light enters the SBS medium pool at an incident angle satisfying the Bragg diffraction condition, and the probe light will be diffracted on the acousto-optic grating formed by the sound wave field.The intensity of the diffracted light changes with the intensity of the sound wave field, so that the real-time measurement of the sound wave field waveform and the life parameter in the SBS process can be realized by detecting the change of the diffracted light intensity with time.

Suppressing Stimulated Brillouin Scattering (SBS) in an Optical Amplifier system comprising: an optical fan out which splits a coherent optical beam into a set of multiple optical beams, a set of opti

A kind of distributed multi-parameter sensing system based on multi-core optical fiber, including laser, laser light source is sent to the signal generator input trigger pulse drive respectively with the signal input end of phase-sensitive optical time domain reflectometer based on Rayleigh scattering and its demodulation device, Raman optical time domain reflectometer based on Raman scattering and its demodulation device, Brillouin optical time domain reflectometer based on Brillouin scattering and its demodulation device are connected, the signal output end of phase-sensitive optical time domain reflectometer and its demodulation device, Raman optical time domain reflectometer and its demodulation device, Brillouin optical time domain reflectometer and its demodulation device is connected with the signal input end of multi-core optical fiber through multi-core optical fiber fan-in fan-out module;The present application utilizes the principle of space division multiplexing, each fiber core in optical cable as separate sensing channel carries out measurement and signal transmission;Multi-core optical fiber fuses three kinds of distributed optical fiber sensing systems together, realizes in-situ measurement and mutual compensation decoupling of temperature, strain and vibration, improves the measurement precision of sensing system.

The purpose of the present invention is to provide a Brillouin scattering measuring device capable of compensating for fluctuations in a frequency component of broadband probe light and performing highly accurate measurement.　A Brillouin scattering measuring device according to the present invention: acquires broadband probe light that includes Brillouin scattering light and broadband probe light that does not include Brillouin scattering light by using two broadband pulsed light beams having the same optical characteristics; compensates for fluctuations in a frequency component of the broadband probe light that includes Brillouin scattering light on the basis of the broadband probe light that does not include Brillouin scattering light; and performs Lorentzian fitting on a signal obtained by dividing the broadband probe light that includes Brillouin scattering light by the broadband probe light that does not include Brillouin scattering light to determine a peak position in a BGS.

The application discloses a kind of multi-channel wide spectrum scattered light energy simultaneous measurement device and method, wherein multi-channel wide spectrum scattered light energy simultaneous measurement device mainly includes target chamber, spectrometer, gate camera and multiple scattered light imaging light paths.The present multi-channel wide spectrum scattered light energy simultaneous measurement device and method are used, by setting multiple scattered light imaging light paths, realize multi-channel measurement capability, can accurately give the energy of different wavelengths and total energy, realize the simultaneous measurement of stimulated brillouin scattering and stimulated raman scattering scattered light, provide more reliable diagnostic techniques for the scattered light generated by laser target shooting;At the same time, the present measurement method greatly reduces the use of energy probe, not only saves cost, but also improves diagnostic efficiency;And, the present measurement method can be used not only for high-energy scattered light measurement, but also for other light source intensity analysis and comparison.

The invention provides a stimulated Brillouin scattering suppression device and method of an optical fiber amplification system, and the device comprises a seed source, a signal generator, a radio frequency amplifier, a signal modulator and a spectrum filter. And performing power amplification on the LFM radio-frequency signal output by the signal generator by using a radio-frequency amplifier so as to drive the signal modulator to modulate the seed laser and generate a modulation spectrum containing a carrier and a plurality of sidebands, and finally screening out a single target sideband through a spectrum filter to obtain a sweep-frequency light source. Effective suppression of stimulated Brillouin scattering is realized in an optical fiber amplification system. According to the invention, high modulation voltage can be prevented from being applied, and the voltage-withstanding range of an existing commercial signal modulator is adapted; meanwhile, the modulation period range is large and controllable, the short modulation period can meet the short optical fiber scene requirement of the optical fiber amplification system, and the SBS suppression effect of the optical fiber amplification system is effectively improved.

The invention belongs to the field of distributed optical fiber sensing, particularly relates to a highway infrastructure safety early warning device and method based on high-dimensional chaotic optical fiber sensing, and aims to realize multi-parameter synchronous accurate monitoring of highway infrastructures in a complex environment. The device comprises a light source, a light path distribution modulation module, a signal detection and separation module and a data processing module which are connected in sequence, and the light path distribution modulation module is further connected with a to-be-detected optical fiber group. The light source module generates high-dimensional wavelength tunable chaotic laser, the light path distribution modulation module divides the high-dimensional wavelength tunable chaotic laser into a detection path and a pumping path, modulates the high-dimensional wavelength tunable chaotic laser and transmits the modulated high-dimensional wavelength tunable chaotic laser to a selected to-be-detected optical fiber, and meanwhile, receives a backscattering signal and transmits the backscattering signal to the signal detection and separation module. The module separates Raman and Brillouin scattering signals and converts the signals into electric signals, the data processing module processes the electric signals, and intelligent recognition and early warning of highway infrastructure disasters are achieved.

The invention provides a hydraulic steel gate stress detection method, and relates to the technical field of hydraulic engineering safety monitoring, strain and stress detection is realized through a distributed optical fiber sensing unit based on Brillouin scattering, and compared with a traditional point sensor, the hydraulic steel gate stress detection method has the advantages of being small in monitoring blind area and beneficial to realizing global detection. The distributed optical fiber sensing unit is combined with the acoustic phased array excitation unit, so that the false alarm probability is reduced. And when the verification result of the acoustic phased array excitation unit is the microcrack, the found initial damage can be actively intervened in time, and malignant development of the microcrack is avoided.

The invention discloses a strain monitoring system and an optical cable construction technology, and belongs to the technical field of pipelines. According to the system, pump light and detection light are respectively emitted from two ends of a sensing optical cable, the pump light and the detection light generate Brillouin scattering, Brillouin scattering light is emitted from the sensing optical cable and enters an optical detector, the optical detector converts an optical signal into an electric signal and sends the electric signal to electronic equipment, and the electronic equipment sends the electric signal based on the electric signal. And determining the strain conditions of the pipeline body and the nearby soil body. Since one part of the sensing optical cable is laid on the surface of the pipeline and the other part of the sensing optical cable is located in the soil body near the pipeline, the optical signal received by the optical detector can reflect the stress condition of the pipeline body and the soil body near the pipeline body. The electronic equipment not only can determine the strain condition of the pipeline body, but also can determine the strain condition of the soil body near the pipeline based on the electric signal converted from the optical signal, so that the pipeline body and the soil body near the pipeline are jointly monitored, and the monitoring comprehensiveness is improved.

The invention relates to a multi-parameter fusion distributed optical fiber sensing system and method based on a few-mode optical fiber, and relates to the technical field of distributed optical fiber sensing, and the system is characterized in that emergent light of a laser is subjected to beam splitting and is respectively processed; part of the light is modulated to generate LP01 and LP11 mode light for detection, and the other part of the light generates Rayleigh local oscillation light and Brillouin local oscillation light. The detection light is combined and then injected into the sensing optical fiber to generate backscattered light. And the scattered light is separated into LP01 Brillouin scattered light, LP11 Brillouin scattered light and LP11 Rayleigh scattered light through a mode demultiplexer. And performing beat frequency processing on the different types of scattered light and the corresponding local oscillation light by using a balance detector to obtain a first low-frequency signal, a second low-frequency signal and a beat frequency signal. The data processing module analyzes the signals and can obtain a Brillouin frequency shift spectrum and a vibration signal frequency spectrum reflecting a vibration event. The method has the effect of realizing high-precision measurement.

The invention discloses a method for realizing optical cable fiber core health prediction by using a B-OTDR technology, which comprises the following steps: a multi-physical quantity fusion detection module synchronously obtains Brillouin scattering and Raman scattering signals by using a double-pulse modulation technology, separates two kinds of scattered light through frequency division multiplexing, and constructs a strain-temperature decoupling model; and the dynamic self-adaptive sampling module automatically switches sampling resolution according to the position of the optical fiber, adopts high-resolution continuous scanning on a historical fault high-incidence area, adopts low-resolution sparse sampling on a normal area, and automatically triggers local encryption sampling when an abnormal event is detected. The double pulses are respectively calculated by adopting a double-pulse modulation technology, so that the prediction accuracy is improved; dynamic self-adaptive sampling is adopted, segmented sampling is carried out on a high fault area and a normal area, meanwhile, local sampling is carried out on an abnormal section, the invalid data volume is reduced, and meanwhile the monitoring precision of a key area is ensured.

An optical fiber characteristic measurement system (1) according to the present disclosure includes an optical fiber (20) including a wet portion and a dry portion, and an optical fiber characteristic measurement apparatus (10) configured to measure a Brillouin frequency shift of Brillouin scattered light from the optical fiber (20). The optical fiber characteristic measurement apparatus (10) measures humidity based on a first Brillouin frequency shift, which is a Brillouin frequency shift at the wet portion, and a second Brillouin frequency shift, which is a Brillouin frequency shift at the dry portion.

This invention provides a method for analyzing the femtosecond laser-induced damage behavior of Zn-doped KDP crystal surfaces, belonging to the field of engineering optics technology based on computer data processing. First, the effects of Zn doping concentration on the bandgap and electroacoustic coupling of the KDP crystal are analyzed using UV-Vis absorption spectroscopy and Brillouin scattering spectroscopy, respectively. Then, a one-dimensional model is constructed, and the time evolution of electron density, lattice temperature, and electron temperature on the Zn-doped KDP crystal surface under femtosecond laser irradiation is simulated using a rate equation for electron density accumulation and a two-temperature model. The influence of Zn doping concentration on the damage behavior of the KDP crystal surface is theoretically analyzed, and a theoretical model for calculating the femtosecond laser-induced damage threshold is established, thus non-destructively determining the optimal Zn doping concentration. This invention avoids contact with real samples, improving sample utilization; the simulation process is more stable and controllable with high data repeatability; it can also shorten the research cycle and accelerate the selection of the optimal doping concentration.

The embodiment of the invention provides a distributed stress measurement method, system and device and a medium, and belongs to the technical field of optical fiber sensing. The method comprises the following steps: collecting Brillouin scattering echo signals distributed along an optical fiber to be measured, and generating corresponding single photon counting data at each spatial sampling position; performing frequency discrete scanning on the Brillouin scattering echo signal, and accumulating corresponding single photon counting data in each frequency scanning state to form counting spectrum data corresponding to each spatial sampling position; performing frequency shift fitting calculation based on the counting spectrum data to obtain Brillouin frequency shift data corresponding to each spatial sampling position; stress distribution data distributed along the to-be-measured optical fiber is obtained through calculation, and a distributed stress measurement result is obtained based on the stress distribution data. According to the scheme, under the condition of weak Brillouin scattering signals, stable reconstruction and spatial positioning of stress information continuously distributed along the optical fiber are achieved.

The invention discloses a high-power high-peak optical fiber laser and a using method, the laser comprises a seed source and a three-stage amplifier, a third gain optical fiber of a tail-end amplifier adopts a special structural design, and a central transmission layer is made of a high-damage-threshold or low-nonlinearity material, so that the nonlinear refractive index of the optical fiber is reduced; the occurrence probability of stimulated Brillouin scattering and stimulated Raman scattering is reduced; meanwhile, the continuous gradually-changing core diameter structure of the central transmission layer can dynamically adjust light field distribution, avoid power density concentration and further suppress the thermally-induced self-focusing effect, so that the laser can still work stably when the average power of the laser breaks through the kilowatt level and the peak power of the laser breaks through the megawatt level, and the power output upper limit is remarkably improved; by optimizing the gain optical fiber structure and the multi-stage amplification link, the nonlinear effect is effectively inhibited, the laser output power and stability are improved, and the device is suitable for the high-end fields of industrial manufacturing, aerospace and the like.

The application discloses a temperature-insensitive submarine cable health detection method based on forward stimulated Brillouin scattering under ocean current scouring, which measures the transverse pressure generated by seawater scouring on the surface of the optical fiber body wrapped outside the submarine cable to determine the strength of the submarine cable subjected to the ocean current scouring, and comprises the following steps: step one, laying the optical fiber on the submarine cable; step two, measuring the pressure of the ocean current scouring and collecting the forward Brillouin frequency shift change caused by the transverse pressure; and step three, processing the relationship between the forward Brillouin frequency shift change and the pressure to obtain the transverse pressure on the surface of the optical fiber, i.e. the pressure brought by the ocean current scouring on the submarine cable. The application can provide the ocean current velocity measurement result without temperature influence by using the frequency shift information of two FBS scattering peaks. The transverse pressure detection device has the advantage of distributed pressure measurement and can continuously measure the transverse pressure in a long distance range.

The invention relates to the technical field of slip form concrete, and discloses a concrete slip form construction anti-cracking method and device, and the method comprises the following steps: S1, carrying out the pre-embedding positioning of a distributed optical fiber sensor in the height direction; s2, in the layered pouring process, the distributed optical fiber sensors are embedded into a newly-poured concrete layer; s3, signals are continued through the distributed optical fiber sensor; s4, the collected Brillouin scattering signals are processed, and strain distribution data are solved; s5, calculating real-time strength in combination with a preset concrete strength-strain relation model; and S6, generating a sliding mode lifting instruction. A closed-loop control logic for generating a lifting instruction is carried out through strain data and real-time strength conversion, a strength-strain correction model established based on site concrete and a mix proportion test block is combined with environment temperature and humidity to dynamically adjust a correction coefficient, full-height concrete real-time strength is accurately calculated, and dynamic balance of construction efficiency and structural safety is achieved. And the slip-form construction quality stability is improved.

The invention discloses a method, a system and a laser for adaptively suppressing stimulated Brillouin scattering. The method comprises the following steps: performing phase modulation on target laser based on a first phase modulation signal in a signal set to obtain optimized laser; a return light signal of the optimized laser in the current system state is obtained, the value of a first objective function of the first phase modulation signal is calculated, the value of the first objective function is related to a first preset optimization dimension, and the first preset optimization dimension is an optimized SBS suppression effect, or the value of the first objective function is related to a second preset optimization dimension. The first preset optimization dimension comprises optimization of the SBS inhibition effect and optimization of the broadened estimated spectral width; based on a preset optimization algorithm, taking a first preset optimization dimension as a target, and according to a value of a first target function corresponding to each phase modulation signal in the signal set, iteratively adjusting a waveform parameter of the phase modulation signal so as to update the signal set; and after iterative optimization is finished, outputting a waveform parameter which enables the first preset optimization dimension to be optimal as an optimal solution. Therefore, dynamic optimization is realized, and the SBS suppression efficiency is improved.

The invention discloses an all-fiber high-power narrow-linewidth laser long-distance transmission system and method. The system comprises a narrow-linewidth laser, a pumping source, a pumping beam combiner, a gain fiber, a cladding light stripper, a coupling device, a double-core fiber and an output device. The laser outputs initial laser, the initial laser and pumping source light are injected into the gain optical fiber through the beam combiner to form high-power laser, the stripper removes residual pumping light, the coupling device guides the laser into the double-core optical fiber, the laser is periodically coupled between fiber cores to disperse power density and suppress stimulated Brillouin scattering, and finally the laser is shaped and output through the output device. System devices are connected through an optical fiber fusion splicer, a passive double-core optical fiber is replaced by an active double-core optical fiber and can be applied to an optical fiber amplifier, and long-distance stable transmission is achieved.

This invention relates to the field of fiber optic detection technology, and discloses a distributed fiber optic detection method and system based on Brillouin and Rayleigh scattering analysis algorithms. The method includes splitting a probe beam and a local oscillator beam from the same narrow-linewidth laser beam, and multiplexing and transmitting them according to measurement frames. This allows the same sensing fiber to obtain Rayleigh scattering coherent echo signals and Brillouin scattering signals. The Rayleigh signal is demodulated to obtain vibration information and event location. The Brillouin signal is frequency-shifted and inverted to obtain a temperature field or static strain field. A mapping model between temperature, static strain, and Rayleigh phase drift is established. Drift compensation and baseline calibration are performed on the vibration signal. Distance calibration, time synchronization, anti-aliasing filtering, interpolation resampling, and fusion identification are performed on the two-channel data. The event type, location, and corresponding temperature or strain change are output, along with graded alarms and visualization. This invention achieves dual-scattering collaborative detection, improving identification accuracy and early warning capabilities.