231 results about "Time-domain reflectometer" patented technology

The invention relates to the technical field of optical fiber monitoring and maintenance, and discloses an optical fiber monitoring method, device and equipment, a storage medium and a computer program product, and the method comprises the steps: enabling pulse light of a preset period to be coupled into a to-be-detected low-loss optical fiber based on an optical fiber amplifier and a variable optical attenuator, and generating a backward scattering light signal; converting the backward scattering light signal into an electric pulse signal by using a single-photon detector, and counting the electric pulse signal by using a preset period as a period through a synchronous clock to obtain a counting result; adjusting the power of the variable optical attenuator according to a counting result, and drawing a target signal curve of the to-be-measured low-loss optical fiber based on an adjustment result; and analyzing the target signal curve to obtain a monitoring result of the to-be-measured low-loss optical fiber. The power is dynamically adjusted in different measurement sections, and the multi-section measurement results are superposed, so that the dynamic range of the single-photon optical time domain reflectometer is remarkably expanded, and the loss and dead pixels of the low-loss optical fiber can be reflected more comprehensively and accurately.

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 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 the field of optical fiber sensing, in particular to a demodulation device and method for a phase-sensitive optical time domain reflectometer. Comprising an optical fiber sensor, a first data acquisition processor and a second data acquisition processor, sensing signals obtained by the optical fiber sensor enter the first data acquisition processor or the second data acquisition processor in the form of two paths of electric signals; the first data acquisition processor converts the two paths of electric signals into low-speed digital signals by using a band-pass sampling mode, sequentially performs band-pass filtering and Hilbert transformation on the low-speed digital signals, performs fixed point sampling on data after the Hilbert transformation, and correspondingly demodulates the sampled data; and the second data acquisition processor converts the two paths of electric signals into corresponding high-speed digital signals in a low-pass sampling mode, and correspondingly demodulates the high-speed digital signals. According to the invention, demodulation under band-pass sampling can be carried out by using a low-cost ADC and an optimized demodulation algorithm, so that performance requirements and power consumption of a demodulation device are reduced.

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 present invention relates to the technical field of optical fiber sensing, and particularly relates to an optical time-domain reflectometer, and a method for eliminating interference fading. The optical time-domain reflectometer comprises: a laser device, a frequency-division multiplexing modulator, a circulator and a signal processing apparatus, wherein the frequency-division multiplexing modulator comprises a first modulator, a second modulator, a first attenuator and a second attenuator; the laser device is used for generating a coherent light source, and the coherent light source sequentially passes through the first modulator and the first attenuator, so as to obtain a first pulsed light signal; the coherent light source sequentially passes through the first modulator and the second modulator, so as to obtain a second pulsed light signal; and the coherent light source sequentially passes through the second attenuator and the second modulator, so as to obtain a third pulsed light signal. Therefore, by means of different combinations of the first modulator, the second modulator, the first attenuator and the second attenuator, multiple pulsed light signals can be outputted; and compared with the prior art, hardware costs are saved.

Method and apparatus for detecting in impedance change in a transmission line, such as a line in a computer bus. A CMOS-compatible time domain reflectometer circuit comprising a comparator is embedded in one or more chips and connected to the transmission line. The circuit measures the impedance inhomogeneity pattern (IIP) of the transmission line prior to use, and then repeatedly measures the HP during operation of the transmission line to detect a change in IIP, without Interfering with data transfer through the transmission line. The present invention can detect and locate wire-tapping magnetic probing or snooping, and Trojan and cold boot attacks on interconnecting buses between computer chips or integrated circuits in a computer system, such as on external memory buses.

The invention relates to an optical time domain reflectometer, a signal generation method and device, equipment and a medium. The optical time domain reflectometer comprises a laser, a first optical switch, an EDFA amplifier and a second optical switch which are connected in sequence. The optical switch time sequence control unit controls the first optical switch and the second optical switch to be periodically turned on and turned off so as to form a periodic optical pulse signal; wherein the second optical switch is turned on and turned off in a delayed manner relative to the first optical switch in a period, and the pulse width of the required optical pulse can be generated by controlling the delayed turn-on and the delayed turn-off; when a current period optical signal is normally output, the signal light is amplified by erbium ions excited by the pump light of the EDFA amplifier; if input light is cut off, erbium ions in a metastable state are still continuously gathered to a saturation state, signal light input is recovered in the next period, energy jump is generated, light surge is caused, output light power is instantly increased, and a pulse peak value is increased, so that the dynamic range of the optical time domain reflectometer is improved, and detection of the hollow-core optical fiber is realized.

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 communication optical cable searching method, electronic equipment and a computer readable storage medium, and belongs to the technical field of communication. According to the technical scheme, under the condition that preset disturbance stress is applied to a point location of an optical cable to be detected, polarization state information of detection light currently transmitted by a target optical cable is dynamically detected through a Brillouin optical time domain reflectometer correspondingly connected with the target optical cable; and according to the dynamically detected polarization state information, determining whether the to-be-identified optical cable at the to-be-detected optical cable point location is a target optical cable. According to the invention, on the basis that the optical cable is not damaged, the accuracy of searching and positioning the optical cable is 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 circuit board high-frequency characteristic detection analysis method and system based on a stub test platform, and the method comprises the steps: obtaining an S parameter of a PCB signal network based on a vector network analyzer (VNA), judging whether the signal transmission loss caused by a stub meets a detection requirement or not, and outputting the length of the stub and carrying out the TDR detection when a VNA detection result is unqualified; the size of a reflected signal of the PCB signal network is obtained based on a time domain reflectometer TDR, whether impedance change caused by a stub in a TDR curve is qualified or not is judged, and when a TDR detection result is not qualified, the specific position of the stub is output, and backdrill capacitance characteristic detection is carried out; capacitance characteristic parameters of the abnormal back drilling via hole are obtained based on back drilling capacitance characteristic detection, and the specific form of the stub is determined. The method and the system are specially used for detecting the stubs in the PCB high-density multilayer board, not only have the remarkable advantages of high precision, high speed and high reliability, but also provide solid technical support for accurate evaluation and strict quality control of product performance.

The invention discloses a high-speed turn-off gating circuit, device and system for a single-photon detector, and belongs to the field of optical time domain reflectometers. A quenching broadening circuit is used for carrying out delay broadening on signal output of a discrimination circuit to generate a quenching pulse signal; a turn-off gate control pulse signal is generated through an FPGA module, the turn-off gate control pulse signal and the turn-off gate control pulse signal are combined to form a first mixed signal, and the first mixed signal is amplified by a driving circuit and then added to a negative electrode high-voltage bias end of an avalanche diode; the de-noising broadening circuit is used for generating a pulse signal which is synchronous with a quenching pulse but is delayed in phase, the FPGA module is used for generating a de-noising gating signal which is synchronous with a turn-off gating pulse but is delayed in phase, and the two signals are combined and superposed on a screening reference signal of the screening circuit; and the FPGA module is used for controlling and discriminating that a denoising pulse superposed by the reference signal is higher than the amplitude of an overshoot signal coupled in the load signal. According to the invention, false signals coupled to the load by gating can be eliminated, the gating mode does not influence photon response signals, and the response speed is high.

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 fault detection. A method of detecting a fault along a cable or transmission line is provided. In the method, the following steps are performed: obtaining an echo response of the cable or transmission line using a time domain reflectometer (TDR), identifying a plurality of reflections in the echo response, generating a representation of the plurality of reflections, normalizing the representation or one of thresholds, and determining a fault condition based on the normalized representation. By doing so, faults in cables of different lengths can be accurately determined.

Disclosed are an optical fiber time domain reflectometer (OTDR), a test system, test method, and a storage medium. The OTDR comprises: an input end for receiving an input service optical signal; a first filter connected with the input end and for filtering an interference signal with a wavelength equal to a test wavelength of the OTDR in the service optical signal; a wavelength division multiplexing WDM device having a reflection end, a transmission end and an output end; and an OTDR basic unit connected with the transmission end and used for emitting an OTDR signal equal to a test wavelength and receiving a return signal of the OTDR signal, wherein the output end of the WDM device is for outputting a filtered service optical signal received from the reflection end, outputting the OTDR signal received from the transmission end, and receiving the return signal returned from the optical fiber.

The invention discloses a fault repairing method of a server single board and electronic equipment, and relates to the field of server hardware reliability, and the method comprises the steps: scanning a plurality of target signal links of the server single board through a time domain reflectometer, correspondingly comparing the new impedance value and the new reflection waveform characteristic in the scanning result with the initial impedance value and the initial reflection waveform characteristic, determining at least one fault link of the server single board when the comparison result is inconsistent, and performing multi-modal analysis by combining the operation state data of the server single board. And determining the fault level of at least one fault link in the server single board and correspondingly generating a fault repair strategy to switch the fault link to the standby link, thereby solving the problems of single detection dimension, complex fault monitoring blind area, high-frequency signal monitoring failure and the like in the related technology, and improving the detection accuracy. Through time domain reflectometer monitoring, multi-modal data fusion analysis and redundancy switching, fault prediction, accurate positioning and lossless self-repairing of a server single board target signal link are realized.

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.

In order to assist in determining the physical nature of an optical event as monitored by an OTDR in an optical fiber network, there are herein provided OTDR methods and system which leverage historical values measured on reflective events for characterizing events along an optical fiber link. A plurality of OTDR acquisitions is performed toward the optical fiber link over a period of time. Parameters characterizing a target event are derived using the recorded OTDR acquisitions. One of said parameters represents a stability, over the period of time, of a reflectance peak level associated with the event. The event is classified at least based on said stability.

The invention discloses an experimental device and an experimental method for monitoring oil-gas-water components in a shaft, and particularly relates to the technical field of monitoring equipment.The experimental device comprises the shaft, a single-mode laser, a polarization maintaining optical fiber, a Brillouin optical time domain reflectometer, a condensate gas tank, a pressurization driving device, a stratum water tank, a condensate oil tank, a natural gas tank, a conveying device, an oil-gas-water separator and a waste oil tank; the polarization-maintaining optical fiber is spirally wound outside the shaft, and two ends of the polarization-maintaining optical fiber are respectively connected with the single-mode laser and the Brillouin optical time domain reflectometer; the pressurization driving device is used for pressurizing the condensate gas to the dew point pressure higher than that of the condensate gas and driving the condensate gas to leave the condensate gas tank; the conveying device is used for conveying formation water of the formation water tank, condensate oil of the condensate oil tank and natural gas of the natural gas tank to the shaft, and an outlet of the shaft is connected with the waste oil tank through the oil-gas-water separator. The oil-gas-water three-phase fluid in the shaft can be captured and dynamically tracked in real time, the measurement precision is high, and the experimental device is simple in structure and convenient to install.

The invention relates to the technical field of elevator equipment detection, and discloses an elevator traveling cable dynamic fault detection method, system and device and a medium, and the method comprises the following steps: obtaining multi-mode state data of each line of a traveling cable and elevator operation state data; inputting the operation state data into a preset electromechanical coupling model to obtain a corresponding multi-dimensional health reference signal vector; performing time alignment on the multi-modal state data and the reference vector, and performing subtraction to obtain a multi-dimensional signal residual sequence; inputting the residual error sequence into a pre-training deep learning classification model to obtain a preliminary fault judgment result; a final result is confirmed through causal analysis; and if the fault exists, target fault information is obtained through the time domain reflectometer, and visual information is generated and sent to the human-computer interaction interface. According to the embodiment of the invention, the electrical characteristics of the cable and the mechanical motion state of the elevator are dynamically coupled, and high-precision and high-efficiency fault early warning and diagnosis are realized.

The invention discloses a method for determining the optimal frequency of a ground penetrating radar for detecting frozen soil, which relates to the technical field of frozen soil exploration and comprises the following steps: determining the type of frozen soil based on geological data, and acquiring a shallow soil dielectric constant by using a time-domain reflectometer; the low-frequency ground penetrating radar detects the contour and position of frozen soil; establishing a frozen soil simulation model by combining dielectric constants, and performing multi-frequency scanning to obtain a radar image; processing the image through Hilbert-Huang transform, drawing an instantaneous frequency-time curve, and calculating three groups of errors; according to the method provided by the invention, the signal-to-noise ratio of the ground penetrating radar during frozen soil detection is enhanced, the influence of clutters on frozen soil reflection waves is reduced, and the underground frozen soil range is clearly displayed in a radar image.

An optical module, an optical communication device, and an optical communication system, where the optical module may include a control unit, a laser service driving circuit, an optical transmitting unit, and a first optical receiving unit. The control unit determines a target mode of the optical module from a plurality of working modes, and controls the optical module to output a target signal corresponding to the target mode to the laser service driving circuit. The plurality of working modes includes at least one of an OTDR mode and a service mode. The laser service driving circuit outputs a laser signal to the optical transmitting unit based on the target signal. When the target mode is the OTDR mode, the first optical receiving unit receives and transmits, to the control unit, a second OTDR signal returned in an optical fiber.

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 utility model relates to the technical field of optical fiber monitoring devices, in particular to a portable optical time domain reflectometer. The utility model aims to solve the problem of poor heat dissipation performance. The portable optical time domain reflectometer comprises a shell, a main control board, an optical device, a power supply device, a heat absorption part and a heat dissipation device, the interior of the shell is hollow to form a mounting cavity, an opening communicated with the mounting cavity is formed in the surface of the shell, the main control board is supported in the mounting cavity and abuts against the opening, the optical device is arranged on the surface, back to the opening, of the main control board, the power supply device is arranged in the mounting cavity and abuts against the surface, back to the opening, of the main control board, and the heat absorption component covers the opening and abuts against the main control board. The heat dissipation device is arranged on the surface, back to the main control board, of the heat absorption component. The power supply device is electrically connected with the main control board, the optical device and the heat dissipation device, the heat absorption component is used for absorbing heat generated by the main control board, and the heat dissipation device is used for dissipating heat of the heat absorption component.

The invention relates to the technical field of circuit board impedance measurement, and provides a multilayer soft board FA impedance board measurement method, which comprises the following steps: S1, cutting and drilling a base material; s3, target drilling and laser windowing: 1) drilling positioning target holes in four corners of a laminated plate by using an X-ray target drilling machine, and windowing; and S4, impedance testing: carrying out impedance measurement on the exposed FA impedance line by using a time domain reflectometer. According to the technical scheme, the problems that in the existing FPC industry, due to the fact that a dielectric layer of a multi-layer soft board is complex, glue layers and PI layers are stacked repeatedly, and an impedance analog value is often greatly different from an actual value, in general, an impedance FA batch needs to be tried to be made before a formal batch of products is made, and whether the impedance is qualified or not needs to be verified are solved; the problem that the delivery cycle of a formal product is seriously influenced due to the fact that impedance measurement can only be carried out after an outer layer etching circuit is manufactured due to the fact that an impedance product is contained in the inner layer of the multi-layer soft board is solved.

A method of performing optical time domain reflectometry (OTDR) on a fiber under test (FUT) that comprises a portion of hollow core fiber (HCF) and a portion of solid core fiber (SCF) is described. The method comprises determining a position of a transition between the SCF and the HCF in the FUT; setting a time delay in switch control circuitry using the determined position of the transition; and generating an OTDR trace graph using light detected by a photodetector, wherein the time delay is used to control an optical switch to block light backscattered within the SCF from reaching the photodetector (e.g. by absorbing, attenuating or diverting the backscattered light).

An Optical Time-Domain Reflectometer (OTDR) trace correction method, an electronic device, and a storage medium are disclosed. The method may include: establishing a parameter decoupling equation according to a fiber loss coefficient and a Stimulated Raman Scattering (SRS) transfer coefficient in response to ignoring an SRS transfer amount amplified or absorbed by an OTDR wavelength in an Optical Transport Network (OTN) service; disabling a service wavelength of an OTN of an optical fiber transmission system, and acquiring, according to the parameter decoupling equation, a first OTDR trace of an OTDR simulation wavelength in the optical fiber transmission system when the service wavelength of the OTN is in a disabled state; determining a fiber loss coefficient according to the first OTDR trace.