242 results about "Fiber Bragg grating" patented technology

The invention discloses an electrical equipment operation state monitoring method, system and terminal, full life cycle health management of equipment is realized through multi-dimensional perception and intelligent analysis, a composite sensor network can be constructed from the level of the method, and high-frequency current, ultrahigh frequency, fiber grating temperature vibration, multi-parameter gas and acoustic sensors are integrated. Electromagnetic characteristics, mechanical states, environmental parameters and voiceprint characteristics are covered; the adaptive signal processing technology performs classification and noise reduction on multi-source data, and the three-dimensional digital twin model realizes time-space fusion of a temperature field, a vibration field, an electric field and a sound field; a lightweight space-time convolutional network is deployed to fuse a time domain waveform, a spectrogram and spatial distribution characteristics for diagnosis, and a hidden semi-Markov model and a particle filter algorithm are combined to dynamically predict the residual service life of equipment. The system architecture comprises a self-organizing sensor network with edge computing capability, a time-sensitive industrial communication network and a containerized analysis engine, and supports mixed reality visual interaction.

The invention discloses an aerial optical cable defect detection method based on multi-mode sensing fusion and related equipment, and relates to the field of data processing. The method comprises the following steps: acquiring multi-modal sensing data along an aerial optical cable through sensing equipment of different modals; performing time and space alignment processing on the distributed fiber bragg grating strain data, the acoustic emission signal data and the visual image data to obtain multi-mode time and space alignment data; extracting feature data of each mode based on the multi-mode space-time alignment data; performing fusion processing on the feature data of each modal through an attention mechanism to obtain fused feature data; determining a defect identification result of the aerial optical cable according to the fusion feature data, wherein the defect identification result comprises a defect type and a position of the defect on the optical cable; obtaining the result confidence of the defect recognition result; and generating a final optical cable defect detection result according to the result confidence. According to the invention, the problem that the current aerial optical cable defect detection has relatively large missed detection and false detection risks can be relieved.

The invention discloses a structural health monitoring device for civil engineering. According to the technical scheme, the structural health monitoring device is characterized by comprising a multi-parameter sensing module used for collecting strain, acceleration, displacement, temperature, humidity, vibration frequency and structural surface crack image parameters of a civil engineering structure; the multi-parameter sensing module comprises a strain sensor group, an acceleration sensor group, a displacement sensor group, a temperature and humidity sensor, a vibration sensor and an image acquisition unit; the strain sensor group is composed of a plurality of fiber Bragg grating strain sensors which are installed at key stress parts of the structure in a distributed arrangement mode. According to the structural health monitoring device for civil engineering provided by the invention, by virtue of the unique multi-parameter sensing module, the advanced data processing module and the flexible and reliable data transmission module, various excellent effects are shown in the field of civil engineering structural health monitoring.

The invention discloses a fiber bragg grating femtosecond laser direct writing system and method based on light field regulation and control. The system comprises a femtosecond laser source, a polarization control module, a light beam expanding module, a light field modulation module, a 4f filtering imaging module, an oil immersed objective lens, a precision positioning and optical fiber clamping module, an observation module and a computer control module. The method comprises the following steps: firstly, fixing a standard single-mode optical fiber to be processed on a three-dimensional precision displacement platform; then programmable wavefront modulation is carried out on the femtosecond laser through a light field modulation module, and a multi-focus array is generated; then focusing the multi-focus array into the fiber core through an oil-immersed objective lens to realize one-time parallel inscribing of a plurality of refractive index modulation RIM regions; and finally, the computer control module controls the three-dimensional precision displacement platform to move at a constant speed in the axial direction of the optical fiber, and parallel integrated inscribing of a plurality of FBG structures is completed. According to the invention, the inscribing precision and inscribing efficiency of fiber bragg grating femtosecond laser direct writing are improved.

The invention discloses a high-temperature-resistant flame-retardant carbon fiber cable and an intelligent preparation method thereof, and relates to the technical field of power cables, and the cable is composed of a composite bearing core, a first / second electrical isolation belt, a stranded conductor, an annular composite bearing layer, a high-temperature-resistant main insulator and a low-smoke halogen-free outer sheath. The force bearing core is formed by bundling carbon fiber micro rods, elastic reset layers are arranged between the micro rods, micro-particle friction layers are formed on the outer surfaces of the micro rods, and a stable friction-rebound interface is constructed. A fire-resistant barrier, a phase change microcapsule filling layer and a fiber bragg grating can be arranged, and fire resistance, thermal peak suppression and on-line monitoring are considered. And closed-loop control of pultrusion, surface activation, coating and on-line thickness measurement / friction test is carried out in the manufacturing process. The cable can be operated at 200 DEG C for a long time and at 250 DEG C for a short time, the residual elongation is less than or equal to 0.10%, and light weight, high strength, high temperature resistance, low smoke and flame retardance are realized.

The invention discloses a ground surface settlement and ground fracture monitoring device and method based on distributed fiber sensing (DSS) and fiber bragg grating (FBG). The device comprises a GFRP composite material substrate which stretches across a ground fracture and is fixed on a stable stratum through an anchoring structure, a distributed sensing and temperature measuring optical cable which is pre-embedded in a groove of the substrate, an FBG displacement meter which is connected through a plug-and-play interface, a static force level gauge, an osmometer and other point type sensors, and the data processing unit has the functions of multi-source data acquisition, temperature compensation, data fusion and multistage early warning. According to the method, multi-parameter, distributed and high-precision monitoring of the ground fracture development state is achieved through the steps of field investigation, substrate installation, sensor deployment, system calibration, real-time monitoring and the like. The method has the advantages of high measurement precision, strong anti-interference capability, convenient installation, low cost, capability of predicting the crack propagation trend and the like, and is suitable for long-period safety monitoring of geological disaster frequent areas such as mining areas and landslide areas.

A system and method for collision detection. The method comprises receiving a single optical sensor signal from a plurality of Fiber Bragg Gratings (FBGs), the plurality of FBGs being coupled to a manipulator, the plurality of FBGs distributed spaced apart from one another on the manipulator; determining at least one time-based feature from the single optical sensor signal; determining at least one frequency-based feature from the single optical sensor signal; providing the at least one time-based feature and the at least one frequency-based feature to a machine learning model; determine from an output of the machine learning model, a characteristic of a collision of the manipulator with an external object.

The invention relates to the crossing field of mechanical engineering and intelligent manufacturing, and discloses a real-time monitoring, regulating and controlling method for the manufacturing process of an automobile lightweight component. According to the method, a distributed fiber bragg grating sensing array is embedded in a mold, and a three-dimensional strain field at the flowing front edge of resin is obtained in real time; a multi-scale pore generation kinetic model is combined to perform online inversion on an unwetted area and pore distribution; and the pressure gradient and the mold temperature field of the hot press are adaptively regulated and controlled, and the flow path is dynamically corrected. The system comprises a sensing embedding module, a strain demodulation module, a pore inversion module, a regulation and control instruction generation module and a multi-zone execution module. According to the method, closed-loop precise control over the porosity being lower than 0.5% is achieved, and the consistency and reliability of the mechanical property of the component are remarkably improved.

The invention discloses a closed-loop system for icing state recognition and sound wave ice melting control and a method thereof, and relates to the technical field of icing monitoring and ice melting control. The system has a detection mode and an ice melting mode, can output a frequency response signal in the detection mode, and can output a sound wave vibration signal to be applied to the surface of a structure in the ice melting mode; acquiring a structural strain time sequence and outputting a current strain value through the arranged fiber bragg grating; parameters such as temperature, humidity and air are input; deploying a multi-source feature fusion and domain adaptive recognition model FCD-Net, and performing intelligent classification on icing states; outputting excitation control signals of different power levels according to the identification result; and the ice melting effect is monitored, output is controlled to be terminated, and whole-process closed-loop control is formed. According to the invention, intelligent icing identification and self-adaptive ice melting control of structures such as a power transmission conductor can be realized, and the method has the advantages of high identification precision, low energy consumption, timely response and the like, and is suitable for anti-icing application in multiple fields such as electric power, wind power and communication.

The invention relates to the technical field of sensors, and discloses a decoupling method of a temperature and pressure sensor, and the sensor comprises an F-P resonant cavity and a pressure sensing diaphragm with a fiber bragg grating. The method comprises the following steps: S1, transmitting a wide spectrum signal to a sensor, and collecting a reflection spectrum of the sensor; s2, performing baseline correction and noise reduction processing on the reflection spectrum, and extracting characteristic parameters; s3, if the characteristic parameters exceed the preset range, failure early warning is carried out; establishing and substituting the characteristic parameters into a physical model, performing multi-parameter optimal estimation, and outputting temperature and static pressure; and S4, if the characteristic parameters exceed the preset range, failure early warning is carried out. In order to enable failure early warning to be more accurate, the scheme can be adjusted to monitor the characteristic parameters extracted in the step S2 in real time, and the scheme is not limited to fixed nodes. According to the invention, intrinsic decoupling is realized, the measurement precision, the decoupling efficiency and the intelligent degree are greatly improved, the practicability is high, meanwhile, the self-diagnosis function is realized, and the reliability is ensured.

The invention discloses a grating tilt angle sensor capable of realizing tilt correction in an installation process based on a strain sensitive principle of a fiber bragg grating, and belongs to the technical field of fiber sensing, the grating tilt angle sensor comprises a grating tilt angle sensor body and an installation component used for being connected with a detected body, and the installation component is connected with the sensor body through a universal shaft. A component for fixing the corrected sensor body is also arranged between the grating tilt angle sensor body and the mounting component, or a component for fixing the corrected sensor body is also arranged between the grating tilt angle sensor body and the detected body. According to the invention, the initial inclination angle generated in the installation process can be compensated, and the inclination angle of the inclination angle sensor after installation is ensured to be 0 degree, so that the inclination angle measurement of the device is more accurate, and the installation is more convenient.

The invention discloses a bolt washer sensor based on a fiber Bragg grating, which is characterized by comprising a double-layer composite washer, the double-layer composite washer comprises an inner ring and an outer ring, the inner ring is made of an FR4 epoxy resin material, and the outer ring is made of an aluminum alloy material; the strain body structures are symmetrically arranged on the two sides of the outer ring and comprise a positive strain body and a negative strain body, and the positive strain body and the negative strain body are both made of aluminum alloy materials; two fiber bragg gratings (FBG) with different central wavelengths are inscribed on the optical fiber, the two FBGs are respectively a first FBG (FBG1) and a second FBG (FBG2), the FBG1 is fixed at the central position of the positive strain body, and the FBG2 is fixed at the central position of the negative strain body. The gasket type sensor is compact in overall structure and resistant to corrosion, and has high repeatability, rapid dynamic response and long-term stability.

An optical sensor includes a probe fiber Bragg grating (FBG) coupleable to a light source, the probe fiber Bragg grating defining a probe spectrum and arranged to provide a probe light signal corresponding to the probe spectrum. A sensing fiber Bragg grating (FBG) defines a sensing spectrum. A spectral shift in the sensing spectrum is responsive to a change in at least one external parameter acting on the sensing fiber Bragg grating. The optical coupler couples the probe optical signal with the sensing fiber Bragg grating to output a spectrally overlapped optical signal. An intensity level of the spectrally overlapping light signal corresponds to an overlap between the detection spectrum and the sensing spectrum. And an optical power regulator coupled to the optical coupler, the optical power regulator arranged to adjust a baseline of the intensity level to change a sensitivity of the optical sensor.

The invention relates to the technical field of bionic touch, in particular to a flexible touch sensor based on a filling structure and a preparation method. The flexible touch sensor comprises a flexible layer, and the flexible layer is provided with a containing groove. The liquid filling material is arranged in the accommodating groove; the sensing group is arranged on the side wall of the accommodating groove, the sensing group comprises a first fiber bragg grating and a second fiber bragg grating, and the first fiber bragg grating and the second fiber bragg grating are symmetrically arranged on the two side walls of the accommodating groove; and the packaging film is used for packaging the liquid filler and the sensing group. According to the embodiment of the invention, the miniature accommodating groove and the liquid filler are arranged on the flexible layer, so that the flexibility and the fitting property of the sensor can be improved, the fiber bragg gratings are symmetrically arranged on the accommodating groove, the lateral pressure has two opposite strains, and the temperature influence is eliminated through differential processing; and constant cooling and thermal diffusion stabilization effects on the sensing cavity in a dynamic environment can be realized.

This invention discloses an FBG strain sensor based on misaligned fusion spliced ​​coreless optical fiber and its fabrication method. The sensor comprises an input single-mode fiber, multiple segments of coreless optical fiber, and an output single-mode fiber connected sequentially. The input single-mode fiber is fused together with the first segment of the coreless fiber in a misaligned manner, and the next segment of the coreless fiber is fused together with the previous segment in a misaligned manner, with the misalignment direction of the next segment opposite to that of the previous segment, but the misalignment distance being the same. The output single-mode fiber and the last segment of the coreless fiber are fused together axially. The central axes of the input and output single-mode fibers are collinear, and the cores of the input and output single-mode fibers are connected by a photolithographically written straight waveguide. A fiber Bragg grating is then optically etched along the straight waveguide. This invention uses femtosecond lasers to fabricate the FBG on the misaligned fiber structure, increasing the structure's strain response and making the strain sensitivity of the FBG on this structure higher than that of an FBG fabricated on ordinary silica optical fiber.

This invention belongs to the field of optical experimental technology, and particularly relates to a physical experimental device and method integrating multiple fiber optic technologies. In use, the light source component emits light waves, which are reflected by the fiber Bragg grating component and split into two parts. One part of the light wave enters the filtering experimental component and then the signal processing module, which processes the signal and displays the results. The other part of the light wave enters the Mach-Zehnder interferometer experimental component and is split into a first light wave and a second light wave. The first light wave passes through the Young's modulus measurement experimental mechanism, and the second light wave passes through the fiber optic temperature sensor experimental mechanism. After exiting the Young's modulus measurement experimental mechanism and the fiber optic temperature sensor experimental mechanism, the first and second light waves couple into the signal processing module, which processes the signal and displays the results. This invention has good integration and can simultaneously measure minute displacements, mechanical parameters, and temperature.

Method for manufacturing an optical component (1) using laser radiation, comprising the following process steps: - Generation of a structure in the material of the component (1) which gives the component (1) an optical functionality, wherein the optical functionality of the component (1) is that of an optical grating, in particular a fiber Bragg grating, an aperiodic fiber Bragg grating, a long-period grating or a bulk Bragg grating, - Determination of deviations of the generated structure in the material of the component (1) from specified target parameters, wherein the specified target parameters determine a central operating wavelength and / or a dispersion of the component (1), - Modification of the refractive index in the material of the component (1) by means of laser beams in a pre- and / or post-processing step, i.e. before or after the creation of the structure, in order to correct the deviations from the specified target parameters, characterized in that in the pre- and / or post-processing step a beam shaping of the laser radiation directed on the component (1) takes place in order to generate a spatially variable modification of the refractive index in the material of the component (1), wherein the beam shaping is carried out by means of an adaptive optics (4) which dynamically controls the wavefront and intensity profile of the laser radiation in order to flexibly address local deviations in the material of the component (1) individually.

This application discloses an optical parametric oscillator and a laser generating device, relating to the field of laser technology. The optical parametric oscillator includes a first optical fiber, a mirror assembly, a nonlinear crystal, and a second optical fiber. The first optical fiber has a first receiving end and a first output end. The first receiving end is used to receive pump light. The second optical fiber has a second receiving end and a second output end. Light output from the first output end can be transmitted to the second receiving end via the mirror assembly and the nonlinear crystal. The second output end is used to output signal light. The mirror assembly includes multiple mirrors. The nonlinear crystal is located in the optical path between two mirrors. A first grating is disposed on the first optical fiber, and a second grating is disposed on the second optical fiber. Both the first and second gratings are fiber Bragg gratings. Because this application uses a first optical fiber and a second optical fiber to define the light transmission path, compared to a free-space optical path, the optical fiber can be coiled, which is beneficial for reducing the overall size and improving integration.

The invention provides a coal body strain synchronous in-situ monitoring device and method based on true triaxial impact, and relates to the field of coal body dynamic testing and structural damage monitoring. Comprising a sample bearing module, an impact loading module, an internal fiber bragg grating dynamic strain monitoring module, a surface strain gauge monitoring module, a synchronous data acquisition module, a microscopic crack detection module and a macroscopic failure analysis module, the impact loading module is used for applying a transient impact load with a set impact speed to the gas-solid coupling coal sample, and the internal fiber bragg grating dynamic strain monitoring module is embedded with at least one fiber bragg grating sensing grating point along three mutually orthogonal directions of the gas-solid coupling coal sample respectively. The damage evolution mechanism of the gas-solid coupling coal body under the high strain rate condition is disclosed, and a means is provided for risk analysis of the rock burst-coal and gas outburst hybrid power disaster.

The invention discloses an FBG (Fiber Bragg Grating) and F-P (Fabry-Perot) cavity multiplexing air pressure sensing system, which comprises a linear tunable laser 1, a Mach-Zehnder interference device 2, a sensing array 3 and a processing unit 4, and is characterized in that an output optical coupler of the linear tunable laser 1 is connected with the Mach-Zehnder interference device 2; the linear tunable laser 1 and the Mach-Zehnder interference device 2 are directly connected with the processing unit 4, and the sensing array 3 is an FBG and F-P cavity sensor multiplexing array and is connected with the Mach-Zehnder interference device 2; according to the invention, multiplexing and distance positioning of the FBG and the F-P cavity sensor are realized, temperature compensation is carried out on pressure measurement while the spatial resolution can reach 20 [mu] m for temperature measurement, and the FBG-F-P cavity sensor can be widely applied to the fields of aviation, precision manufacturing and the like.

Optical networks and methods associated with optical networks for verifying network continuity. A method for verifying network continuity includes providing a fiber Bragg grating (FBG) device at a cable associated with a network, wherein the FBG device is configured to reflect a λ1 wavelength; sending an optical test signal into the cable from a location upstream of the FBG device, the optical test signal having a λ1 wavelength; and detecting a reflected signal associated with the λ1 wavelength to verify network connectivity to the FBG device and measure network insertion loss.

The utility model discloses a protective device for a fiber bragg grating rotating wheel strain sensor of a water-turbine generator set, which comprises a base and a waterproof cover, and a placing groove is arranged between the base and the waterproof cover for accommodating the strain sensor. The two ends of the waterproof cover are provided with optical cable holes and optical cable ends, and the adjacent optical cable holes are connected through optical cable protection tubes. The base comprises a fixed end and an inner boss, a sealing groove on the top surface of the fixed end is matched with a sealing ring, the connecting end is provided with an outer boss, the fixed end and the connecting end are connected through a fixed bolt and waterproof sealant, a sealing cavity filled with sealant is arranged in the waterproof cover, the threaded connection part of the optical cable protection tube is filled with sealant, and the waterproof cover is provided with a spiral drainage groove. The device has the advantages that the sealant is waterproof, the sensor is dry and the precision is improved; the convex surface end disperses impact force, the service life of the device is prolonged, and the protection effect of the device is improved; fixing bolts, sealants and counterbores are designed to enhance waterproofness; the spiral drainage grooves conform to water flow, and impact is reduced; the optical cable protection tube is connected in series to protect the sensor, the hose end is attached to the rotating wheel, and the tube fixing seat ensures that the optical cable is stable and well matched with the rotating wheel.

The invention belongs to the technical field of nondestructive testing, and discloses a TOFD (Time of Flight Diffraction) probe with in-situ force sensing capability and a detection system. The ultrasonic probe main body is mounted on the first carrier, and the first carrier is made of a rigid material; a second carrier is mounted on one side, far away from the ultrasonic probe main body, of the first carrier and is made of an elastic material; the second carrier comprises a contact part used for contacting a measured object, and a deformation part used for generating elastic bending in response to the stress of the contact part is fixed on one side, far away from the measured object, of the contact part; the first carrier is provided with a first fiber bragg grating used for monitoring environment temperature changes. A second fiber bragg grating is arranged on the deformation part; the problems that in the prior art, in-situ, real-time and temperature-drift-resistant contact force accurate sensing and regulation of a TOFD probe in the detection process are difficult to achieve, and the automatic detection precision and reliability are limited are effectively solved.

A Raman fiber laser includes a pump light source, a reflective end mirror, a wavelength division multiplexer, a Raman gain fiber, and an output end mirror. The output end mirror is an ultra-low reflectance fiber Bragg grating. The reflective end mirror is connected to a reflective end of the wavelength division multiplexer. The pump light source is connected to an input end of the wavelength division multiplexer. One end of the Raman gain fiber is connected to a common end of the wavelength division multiplexer, and the other end of the Raman gain fiber is connected to the ultra-low reflectance fiber Bragg grating. The laser of the present invention can reduce loss of laser light at the reflective end mirror, thereby increasing laser light optical conversion efficiency and output power, and simultaneously achieving high time domain stability and extremely low coherence.

The invention discloses a fiber bragg grating production control system and method, and belongs to the technical field of optical fiber sensor manufacturing, and the method comprises the steps: obtaining a pre-stress spectrum curve and an ultraviolet laser parameter set of a target optical fiber before writing, and constructing a feature vector reflecting the disturbance sensitivity of the optical fiber; in the laser writing process, acoustic emission signals and laser parameters are collected in real time, and a joint disturbance function is constructed; identifying a nonlinear stress disturbance event through dynamic matching with the sensitive feature vector, and extracting occurrence time and disturbance intensity of the nonlinear stress disturbance event; constructing a prediction model based on disturbance history, predicting a future disturbance trend and adjusting laser parameters; after writing, a grating reflection spectrum is collected and compared with a target template spectrum, and if the similarity requirement is not met, a disturbance error path is traced back, and parameter compensation writing is executed; according to the invention, real-time perception and response regulation and control of micro-disturbance can be realized, and the writing precision and consistency of the fiber bragg grating are improved.

Measuring system (200) for a motor vehicle (100), the measuring system (200) comprising the following elements: an optical fiber (220) with a first and a second end; wherein a fiber Bragg grating (225) is inscribed in the optical fiber (220) in a predetermined sensor section (225) between the first and the second end; wherein the fiber (220) in the sensor section (225) is configured to be attached to a rim (115) for the motor vehicle (100); a light source (210) configured to couple light into the first end of the fiber (220); a spectrometer (215) configured to determine a wavelength of light exiting the second end; and a processing device (205) configured to determine a deformation of the rim (115) in the region of the fiber Bragg grating (225) based on the determined wavelength.

A fiber amplifier to amplify seed light has a laser diode, an optical fiber segment, and a doped fiber. The laser diode generates pump light at a pump wavelength from an end facet, and optical fiber segment in optical communication with the pump light has a fiber Bragg grating (FBG) configured to lock the pump light from the end facets to the pump wavelength. The pump light from the laser diode interact with an active dopant of the doped fiber and can thereby amplifies the seed light. To provide less coherent light and improve stability of the laser diode over operation conditions, variations in refractive index in the FBG have a chirped period changing linearly along a length of the FBG. The chirped period shifts the reflectivity asymmetrically from a central wavelength region of the FBG, such as blue-shifting the reflectivity for a short wavelength.

Disclosed herein are fiber-based Raman amplifier systems and methods of generating broadband pump light using a fiber Bragg grating (FBG) including a plurality of gratings. In the disclosed system and method, each of the plurality of gratings includes a central wavelength ([lambda] C) corresponding to a wavelength of an output from a laser, respectively, where the central wavelengths ([lambda] C) of at least two gratings of the plurality of gratings are different from each other. Further disclosed are systems and methods of using a pump source, where the pump source includes a plurality of the lasers that are optically connected to a plurality of the FBGs, respectively, where at least two of the FBGs have the same FBG design as a plurality of the gratings.

The invention provides a snakelike arm control system design method combining optical fiber angle compensation and a diffusion strategy, and relates to the technical field of mechanical arm control. According to the method, angle feedback is obtained in real time by embedding the fiber bragg grating in each joint, a digital twin environment is constructed in combination with point cloud, a physically constrained diffusion path generation and simulation verification mechanism is adopted, a motion track with high feasibility is generated, and finally high-precision closed-loop control and attitude correction of the snake-shaped arm in a complex environment are achieved.

An optical fiber having an acoustic sensitive fiber bragg grating includes an optical fiber core having a pair of fiber bragg gratings formed therein such that each fiber bragg grating is spaced apart from each other. A cladding material is disposed on and surrounds at least a portion of the fiber core. The cladding material has at least one material characteristic associated therewith, where the at least one material characteristic may be a Young's modulus less than a Young's modulus of the fiber core, a photoelastic coefficient greater than a photoelastic coefficient of the fiber core, or a combination thereof. The ultrasonic sensor includes at least one optical fiber embedded in a polymer layer and a backing layer and an acoustic matching layer.