183 results about "Optical time-domain reflectometer" patented technology

The invention discloses an optical cable fault positioning method based on an OTDR (Optical Time Domain Reflectometer), and relates to the technical field of optical cable fault positioning. Periodic waveform data of an optical cable is acquired through OTDR equipment, an echo spectrum is generated, a dynamic threshold algorithm is introduced according to the echo spectrum to carry out fault event identification, and a dynamic threshold value is generated; the processing end judges whether a fault point area exists in the echo based on the dynamic threshold value, if yes, the distance between the fault point and the OTDR equipment is calculated through propagation time delay, the spatial position of the fault point is determined, and after multiple fault points are recognized, fault types are classified according to reflection intensity. According to the positioning method, a dynamic threshold algorithm is introduced, so that the system has adaptive capacity to background environment change, the robustness of the system under long-distance, high-loss optical cable or severe noise conditions is remarkably enhanced, and weak reflection fault or hidden fault events neglected by a traditional method can be effectively identified.

The invention relates to the technical field of optical signal processing and analysis, and particularly provides a seabed crustal activity monitoring method based on a differential phase sensitive optical time domain reflectometer, which comprises the following steps: carrying out differential processing on an echo optical pulse signal to obtain a first differential echo matrix; and setting a dynamic window constraint to obtain a second differential echo matrix. The second differential echo matrix includes a low rank term, a sparse term, and a noise term. And constructing a global optimization problem according to the second differential echo matrix, and solving a sparse item estimation matrix corresponding to the sparse item. And separating irrelevant activities in the sparse item estimation matrix to obtain a target activity matrix, and then obtaining a monitoring result. According to the method, non-low-rank trend features such as slow-varying interference are converted into low-rank features through differential processing, periodic and regular components in received signals are clearer, periodic events and sudden events can be separated through a low-rank sparse decomposition model, human-related activities are further separated, and the accuracy of the received signals is improved. Accurate monitoring of the sudden movement of the seabed crust is realized.

The invention relates to a phase-sensitive optical time domain reflectometer based on multi-frequency reference switching. Continuous laser generated by a continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is incident to a light intensity modulator driven by the signal generation circuit module, and the light intensity modulator is converted into a multi-frequency pulse laser sequence with intensity modulation; the multi-frequency pulse laser sequence enters the sensing optical fiber to be measured through the optical circulator; generated Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving in a polarization coherent receiving module through a circulator; and the signal acquisition circuit adopts a demodulation algorithm to compensate phase drift and sensitivity difference of detection pulse demodulation signals with different frequencies so as to realize dynamic strain sensing. Compared with the prior art, the phase drift and the sensitivity difference between the frequencies are extracted to realize the compensation of the interleaved signals, and the method does not depend on the fixed reference frequency, so that the robustness and the adaptability of the system in a complex environment are remarkably enhanced.

The invention relates to the technical field of data processing, and provides a data processing method for testing avionics equipment, which comprises the following steps of: testing a communication optical cable of an aircraft communication system through an optical time domain reflectometer; analyzing the deviation between the loss value of the reflection intensity of the optical signal at each moment and the reflection loss threshold value to obtain the fault probability of the optical cable in the monitoring time period; analyzing the difference between the moment when the optical signal reaches the bending position of the optical cable and the moment corresponding to the peak point, and obtaining the reflection unpredictability of the optical signal in the monitoring time period; combining the light source power difference to obtain an optical cable performance error in the monitoring time period; obtaining the extra loss degree of the optical cable in the monitoring time period by combining the change condition of the temperature data; determining a test result correction coefficient of the monitoring time period; and correcting the reflected signal oscillogram, and testing the communication optical cable. The invention aims to solve the problem that the actual performance judgment of the optical cable is influenced by the fine change interference of various factors in the optical signal propagation process of the communication optical cable.

The invention relates to an electric power communication optical fiber fault monitoring and visualization method and system, and belongs to the technical field of optical fiber communication monitoring, and the method comprises the following steps: carrying out the real-time monitoring of an electric power communication optical fiber through a non-intrusive monitoring system, collecting an optical power signal in real time, and constructing an optical fiber resource database; when the non-intrusive monitoring system detects that optical power attenuation exceeds a preset threshold value, an optical time domain reflectometer OTDR is started to perform intrusive detection on an abnormal optical fiber, and an OTDR echo curve is obtained; extracting a composite feature vector of an OTDR echo curve, and identifying a fault type through a multi-stage fusion algorithm in combination with historical fault record data; according to the OTDR detection point coordinates, the optical path distance and the geographic information data, the position of a fault point is calculated, and the optical fiber topology, the position of the fault point and the fault type of the fault point are displayed in a visual interface. According to the invention, accurate fault identification and quick response are realized, and the operation and maintenance efficiency is improved.

The invention relates to a phase-sensitive optical time domain reflectometer based on a parallel frequency division multiplexing sequence. Continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is converted into a pulse laser sequence with intensity modulation through a light intensity modulator driven by a radio frequency signal provided by the signal generation circuit module, and the radio frequency signal is composed of two frequency division multiplexing sequences with difference; the pulse laser sequence enters the sensing link to be measured to generate Rayleigh backscattered light, and the Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving through a circulator; and the signal acquisition circuit is used for sampling and analyzing the interference signal, and performing frequency domain comparison on an interleaving result of the two frequency division multiplexing pulse sequences to eliminate a harmonic frequency and retain a real strain signal frequency. Compared with the prior art, the non-harmonic strain signal measurement is realized, the high-frequency response performance and the high-precision strain measurement capability are excellent, and meanwhile, the long-distance coverage capability is also realized.

The invention relates to an optical time domain reflectometer and a control method of the optical time domain reflectometer, and relates to the technical field of photoelectricity. The optical time domain reflectometer OTDR comprises a single photon detector, and the OTDR is used for being connected with an optical fiber to be measured; the OTDR is further used for sending a plurality of detection signals to the optical fiber to be detected in sequence and receiving a plurality of detection echo signals from the optical fiber to be detected in sequence, and the detection echo signals are used for indicating the transmission state of the same section of transmission area in the optical fiber to be detected; performing amplitude reduction processing on each detection echo signal at a certain time interval to obtain a processed detection echo signal; the positions, corresponding to the same section of transmission area, of the signal sections subjected to amplitude reduction processing in the different processed detection echo signals are not completely the same; each processed detection echo signal is subjected to photoelectric conversion based on the single-photon detector to obtain a first electric signal, a first OTDR oscillogram is output based on the multiple first electric signals, and the first OTDR oscillogram is used for indicating the transmission state of the same section of transmission area. Therefore, the problem of OTDR curve distortion can be solved.

The invention provides a BOTDR (Brillouin optical time domain reflectometry) system fusing Stokes-anti-Stokes light and a demodulation method, and belongs to the technical field of Brillouin distributed optical fiber sensing. The narrow linewidth laser is used for generating continuous optical signals; the input end of the coupler is connected with the laser, and the output end is connected with the pulse light branch and the local oscillator light branch. The pulsed light branch comprises a semiconductor optical amplifier, a random scrambler, a first erbium-doped optical fiber amplifier and a circulator which are connected in sequence; the local oscillator light branch comprises an electro-optical modulator, and the electro-optical modulator regulates and controls sideband frequency through a microwave module; the second erbium-doped optical fiber amplifier is used for extracting the Stokes light and the anti-Stokes light; the single-mode coupler mixes the double-sideband local oscillator light with the anti-Stokes light and the Stokes light; and the electrical beat frequency signals are acquired, filtered and enveloped and demodulated through an acquisition card. The detection capability of the Brillouin scattering signal is enhanced, the system structure is simplified, and the hardware cost and the maintenance difficulty are reduced.

The invention relates to the technical field of data processing, and discloses a gateway service integrated management method and system based on an FTTR demand. The method comprises the following steps: carrying out topology scanning on a test signal of an optical time domain reflectometer to obtain a room-level FTTR topology mapping table, carrying out feature extraction on service traffic of each room according to deep packet inspection to obtain a room function identification tag library, and carrying out attenuation compensation on a corresponding room optical port by an optical power meter to obtain an FTTR link quality evaluation matrix, and bandwidth allocation is carried out through a reinforcement learning algorithm to obtain a room-level QoS strategy configuration set, and building data interaction is carried out based on an MQTT protocol to obtain an FTTR gateway service integrated management scheme. According to the invention, the intelligent level of FTTR network room-level management and the resource allocation efficiency are improved. According to the invention, the real-time performance of optical fiber link quality monitoring and the collaboration of building network management are improved.

The invention discloses a phi-OTDR (Optical Time Domain Reflectometer) vibration signal classification method based on multi-scale residual convolution and a bidirectional long-short-term memory network, relates to the technical field of phase-sensitive optical time domain reflectometer vibration sensing, and solves the problems of insufficient feature extraction, single model fusion mechanism, poor system real-time performance and the like of an existing phi-OTDR vibration signal classification method. The method is realized through the steps of a multi-scale deep convolutional network, a bidirectional long-short term memory network, a cross attention fusion module, a learnable gating mechanism and the like. A cross attention fusion module is adopted, association between spatial features and time sequence features is dynamically established in a double-path network, feature interaction and information coupling are deepened, and the sensing ability of the model to key information is remarkably improved. Meanwhile, the fusion proportion of the multi-path features is adaptively adjusted according to the actual distribution of the input features, background noise interference is effectively suppressed, and the robustness and discrimination performance of the model are enhanced. Accurate identification and classification of external vibration signals are realized.

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 discloses a composite hose structure for fuel gas transmission, and relates to the technical field of fuel gas transmission and distribution equipment, the composite hose structure comprises a dual-mode quick sealing assembly, dual-mode monitoring is formed by an FBG sensor, a phase-sensitive optical time domain reflectometer and a carbon tube composite filament, the FBG sensor can capture fine strain of a reinforced fiber layer in real time, and the phase-sensitive optical time domain reflectometer can capture the fine strain of the reinforced fiber layer in real time; the phase-sensitive optical time domain reflectometer detects and captures stress waves generated by crack propagation in a material through broadband sound waves, early recognition of millimeter-level damage in a pipe is achieved, grids woven by carbon tube composite filaments are utilized, continuity of the grids is monitored in real time through alternating-current impedance measurement, and the detection accuracy of the millimeter-level damage in the pipe is improved. When local grid resistance is increased due to breakage of the reinforced fiber layer, a micro-damage area can be accurately positioned, when leakage occurs, the memory alloy spring receives an electric signal monitored by a dual-mode, then axial thrust is generated to push the outer side of the fluororubber sealing ring, the fluororubber sealing ring expands in the radial direction under the thrust action of the memory alloy spring, and the leakage is prevented. And rapid and effective mechanical hard sealing is realized.

The invention relates to the technical field of optical fiber sensing, in particular to a dual-channel information fusion vibration positioning device and method based on a dual-k method, and aims to improve a traditional single-channel amplitude demodulation phi-OTDR (AD-phi-OTDR) system to obtain a device with a dual-channel phase-sensitive optical time domain reflectometer module. Firstly, vibration signals are collected through a dual-channel amplitude demodulation phi-OTDR system, then the optimal sampling number is designed through the relation between the vibration frequency and the sampling period, the time consumed by system vibration positioning is shortened, the operation efficiency of the system is improved, then vibration positioning is conducted through a dual-k method, and finally vibration is judged through dual-channel information fusion. According to the invention, the authenticity of the signal is improved through dual-channel cross validation. And a dual-channel data fusion mechanism is used for effective discrimination, so that the anti-interference performance of the system is improved, and the reliability of vibration signal discrimination is further improved.

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 provides an optical fiber detection method and system for an optical time domain reflectometer, and relates to the technical field of power grids. According to the invention, the multi-wavelength backscattering signal of the optical fiber link to be detected is acquired, preprocessed and converted into the sample to be detected containing the multi-wavelength one-dimensional waveform data and the multi-wavelength two-dimensional diagram data at the same time, so that the sequence characteristic of the light intensity of each wavelength changing along with time is reserved; and spatial features of correlation and structural information between wavelengths can be reflected through data conversion construction, and multi-dimensional and structured representation of optical fiber events is realized. And combined analysis and recognition are carried out by combining a fault recognition model, and a time sequence rule in a one-dimensional waveform and a spatial distribution mode in a two-dimensional diagram are cooperatively mined, so that deep fusion and intelligent analysis of optical fiber fault spatial-temporal characteristics are realized, and the recognition capability of a complex fault mode is improved. The technical problem of low accuracy of optical fiber fault detection with a single wavelength at present is solved, and the accuracy and reliability of optical cable line fault detection are improved.

The invention discloses a phi-OTDR-based user falling optical fiber sensing monitoring method and system, and the method comprises the steps: carrying out the preprocessing of collected original optical fiber vibration signals which comprise a walking signal, a falling signal, a falling signal during walking, and a human static signal, and obtaining a target optical fiber vibration signal; feature extraction is carried out from three dimensions of a time domain, a frequency domain and a time-frequency domain, and primary features are obtained; screening the primary features through orthogonality analysis and difference analysis to obtain first-level features, and screening the first-level features through a genetic algorithm to obtain second-level features; screening the second-level features through a mutual information evaluation function to obtain target features; respectively inputting the target features into a plurality of behavior recognition models to obtain a result whether the user falls down or not, and when a falling-down result is obtained, obtaining falling-down position information of the user from the target optical fiber vibration signal; and triggering alarm information based on the tumble result and the tumble position information, and sending the alarm information to a terminal of a monitoring person of the user.

The invention discloses a strain tower positioning method and system based on a coherent detection type phi-OTDR and a standard deviation, and relates to the technical field of tower positioning. The method comprises the following steps: carrying out vibration monitoring on the whole OPGW optical cable by using a phi-OTDR system to obtain an optical fiber vibration signal; demodulating the optical fiber vibration signal to obtain a phase disturbance signal along the length direction of the optical fiber; fourier transform is carried out on the phase disturbance signal of each spatial position to obtain corresponding spectrum distribution; synthesizing the spectrum distribution of all spatial positions into a two-dimensional spectrum image, and processing the two-dimensional spectrum image by adopting an image enhancement algorithm; for each spatial position, a sliding window is adopted to calculate the spectrum standard deviation of the enhanced two-dimensional spectrum image; and identifying a spectrum distribution abrupt change area based on the spectrum standard deviation so as to position and connect the strain tower. The method has the advantages of no need of additional sensors, no need of field measurement and high automation degree. The method is suitable for tower intelligent identification and state monitoring in various power transmission line environments.

The invention discloses an optical time domain reflectometer based on ring structure modulation and a working method thereof, and relates to the technical field of optics. The optical time domain reflectometer comprises a laser, an optical fiber coupler, a semiconductor optical amplifier, an acoustic optical modulator, an optical isolator, a delay optical fiber, an erbium-doped optical fiber amplifier, a dense wavelength division multiplexer, a circulator, a Raman laser, piezoelectric ceramics, an arbitrary function generator, an arbitrary waveform generator, a polarization controller, a photoelectric balance detector, a data acquisition card, a computer and the like. Multi-frequency modulation is carried out based on an annular structure, the multi-frequency modulation range is only limited by the bandwidth of a detector and the sampling rate of an acquisition card, a pulse sequence is generated through modulation of the optical annular structure, dependence on the bandwidth performance of a microwave signal source and a modulator is reduced, and the bandwidth is improved; and by injecting the Raman light, the sensing distance is also increased, the equipment cost is effectively controlled, and meanwhile, a new scheme is provided for time sequence pulse sequence modulation.

The invention discloses a distributed sound wave sensing device based on PDH frequency locking and a demodulation method. The distributed sound wave sensing device comprises a narrow linewidth laser, a first optical fiber coupler, a heterodyne phase sensitive optical time domain reflectometer and a frequency stabilization feedback module. The frequency stabilization feedback module comprises a frequency stabilization modulation and demodulation module, a reference cavity and a server; the frequency stabilization modulation and demodulation module comprises an electro-optical modulator or an acousto-optical modulator, a photoelectric detector, a multiplier and a low-pass filter; the first path of light enters a reference cavity for resonance after being modulated by an electro-optical modulator or an acousto-optical modulator, a resonance signal enters a photoelectric detector through cavity reflection, and a signal output by the photoelectric detector is subjected to signal demodulation by a multiplier and a low-pass filter and then is used as feedback to be input into a server for proportional-integral processing; the laser is fed back and output to a modulation interface of the narrow-linewidth laser, and frequency compensation is performed on the laser, so that the laser is locked on the reference cavity; according to the invention, through frequency stabilization and homologous modulation and demodulation, line width and phase drift of the laser can be suppressed at the same time.

The invention discloses an interference fading point compensation method for a coherent phi-OTDR (Optical Time Domain Reflectometer), which comprises the following steps of: identifying an interference fading point on the basis of complex envelope characteristics obtained by coherent receiving and I / Q (Input / Output) demodulation, and performing interpolation reconstruction on a fading point echo vector by using a neighborhood non-fading point on a complex plane, so as to recalculate a phase and a differential phase; therefore, phase demodulation failure and differential phase artifacts caused by fading can be suppressed. According to the method, on the premise of not increasing hardware transformation, differential phase artifacts and abnormal stripes caused by phase demodulation failure at a fading point are reduced, the stability of a differential phase result and event identifiability are improved, and relatively low calculation complexity is kept to adapt to offline or quasi-real-time processing.

The application provides a phase-sensitive optical time domain reflectometer, a measurement method and a readable storage medium, wherein a signal generation circuit of the phase-sensitive optical time domain reflectometer is configured to generate a radio frequency signal to drive an optical intensity modulator to modulate probe light, so that two groups of frequency division multiplexing sequences with differences can be used to synchronously detect a sensing optical fiber to be measured, a differential unfolding algorithm is combined to accurately solve a phase change amount in adjacent sampling intervals, and then demodulation results corresponding to different frequency parts are respectively unfolded to obtain unfolded phase results, so that the problem of large strain phase folding is solved and a large strain range is recovered, and further, the unfolded phase results are rearranged and combined in time sequence through time sequence interleaving processing of the unfolded phase results, so that a high sampling rate and a distortion-free reconstruction result are reconstructed, and therefore, the application can realize accurate measurement of high frequency response and large strain range dynamic strain.

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.

The present disclosure provides an optical integrated device and an optical time domain reflectometer. The optical integrated device includes: a packaging outer shell, a first collimator, an optical splitting device, a circulator assembly and a second collimator. The optical splitting device is provided close to the first collimator, is used to reflect a part of the detecting light from the first pigtail and couple the part of the detecting light to the third pigtail, and allows the other part of the detecting light to pass through the optical splitting device. The circulator assembly is provided close to the optical splitting device, the circulator assembly is used to couple the detecting light passing through the optical splitting device to the second pigtail, and couple the detecting light returned from the second pigtail to the third pigtail. The optical integrated device integrates the optical splitting device and the circulator assembly to be packaged in one packaging outer shell, the number of components of the optical time domain reflectometer may be reduced, the number of optical fiber fusion joints may be reduced, a space may be saved and performance may be promoted.

The invention relates to a signal noise suppression system based on an optical time domain reflectometer, and the system comprises a transmitting unit which is used for generating an optical time domain reflection pulse signal with preset parameters according to control information; the testing unit is connected with the transmitting unit and the optical fiber to be tested and is used for injecting the received pulse signal into the optical fiber to be tested and guiding the reflected echo optical signal into the receiving unit; the receiving unit is connected with the testing unit and is used for receiving the echo optical signal and converting the echo optical signal into a digital signal, so that the data processing unit can receive and process the digital signal conveniently; and the data processing unit is respectively connected with the receiving unit and the transmitting unit and is used for carrying out range dynamic filtering processing according to the data signal transmitted by the receiving unit, storing the filtered signal and transmitting control information to the transmitting unit, so that the transmitting unit generates a pulse signal with a preset parameter according to the signal. The technical problems of signal broadening deformation and time delay, slow system operation, increased test blind area and the like in the prior art are solved.

The invention discloses a BOTDR (Brillouin Optical Time Domain Reflectometer)-based OPGW (Optical Fiber Composite Overhead Ground Wire) light icing identification method, which comprises the following steps of: firstly, establishing a thermal conduction model of an OPGW in a non-icing state and an icing state, and constructing a theoretical expression of an OPGW icing thermal hysteresis effect by utilizing a linear relation between Brillouin frequency shift and temperature; then, the Brillouin frequency shift distribution along the line is obtained through a BOTDR system, actually measured data is matched with a model calculation result, and the icing thickness and the distribution interval are obtained through a regularization least square inversion method. According to the invention, clear identification of the light icing section can be realized, and good stability can be maintained under different illumination radiation intensity conditions. The method is clear in mechanism, high in model precision and suitable for early icing identification and anti-icing and deicing early warning application of the long-distance OPGW line.

1. The name of this design product: Multifunctional Optical Time Domain Reflectometer (SW100). 2. Purpose of this product: This product is used to measure optical fiber length, optical fiber transmission attenuation, connector attenuation and fault location. 3. The key point of the design of this product lies in its shape. 4. The picture or photo that best illustrates the design points: three-dimensional picture.

The invention discloses an optical fiber distributed three-component sound wave sensing system, which belongs to the technical field of optical fiber sensing and comprises a vector sensing optical cable, distributed sound wave demodulation equipment and a three-component decoupling algorithm module. Discrete scattering enhanced optical fibers serve as sensing optical fibers to be wound in all sensing channels, and a sensing unit capable of detecting the amplitude and direction of incident sound waves is formed. Acquiring a time domain signal corresponding to each sensing channel output by the optical time domain reflectometer, and performing window taking operation; and inputting the signal in each time window and the inherent directional sensitivity function of each sensing channel into a three-component decoupling algorithm to restore the three-component acoustic signal. Compared with a traditional optical fiber distributed sound wave sensing system, the direction of sound waves can be measured on the basis of measuring the amplitude of the sound waves, and the system has wide application prospects in the fields of geological exploration, seismic monitoring and the like which have more and more requirements for three-component acoustic data.

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.

1. Name of the product in this design: Optical Time Domain Reflectometer (Simplified Version). 2. Purpose of this design: For testing fiber optic signals. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: a 3D model.

Methods and systems for referencing an optical power loss measurement (OPLM) system, and methods and systems for measuring an optical insertion loss of an optical device under test (DUT) using an OPLM system referenced as such. The herein-provided reflectometric one-cord referencing method combines the capabilities of an OPLM system with that of an Optical Time Domain Reflectometer (OTDR). A first test unit comprises an optical source that is used as the light source in the OPLM. A second test unit comprises a power meter which is used as the power meter in the OPLM measurement. Either the first or the second test unit comprises an OTDR acquisition device. The reflectometric one-cord reference measures the connector loss along the reference link using OTDR capabilities of the test unit(s). Once the power reference of the OPLM devices is obtained, the reflectometric one-cord reference method may determine the optical insertion loss of the DUT while eliminating the measured connector loss.