1110 results about "Optical fibre sensor" patented technology

The invention relates to a method for monitoring the stress of a casing in a well by applying optical-fiber sensors, which mainly solves the problem that the existing research field of the casing erosion of an oil field and oil-water well does not have a direct method for monitoring the stress loading process of the casing in the well and the morphological characters of the casing erosion. The method is characterized in that: optical-fiber grating sensors are circumferentially arranged along the outer surface of the casing; a ground optical-fiber grating demodulation instrument connected with the optical-fiber grating sensors is utilized to monitor the circumferential strain Epsilon Theta of the casing and obtain the circumferential strain data of the casing; meanwhile, Brilliouin optical-fiber sensors are axially arranged along the outer surface of the casing; a ground Brilliouin optical-fiber demodulation instrument connected with the Brilliouin optical-fiber sensors is utilized to monitor the axial strain Epsilon Z of the casing and obtain the axial stain data of the casing; and the obtained circumferential strain Epsilon Theta and the axial strain Epsilon Z of the casing are utilized to obtain the stress of the outer layer of the casing in the well according to a ground stress explanation model. The method is characterized by being capable of permanently monitoring the deformation of the casing and obtaining corresponding stratum pressure under the condition without knowing the casing erosion and the stratum pressure.

The invention discloses an optical fiber disturbance detection method. According to the method, in the measuring process, segmentation frequency scanning is performed, a scattering curve of he same frequency light is used for measuring dynamic disturbance, correlation detection is performed on the distribution curve, obtained through K-set measurement, of the light power of backward Rayleigh scattering light of any point on a sensor fiber along with the frequency and the distribution curve, obtained through first-set measurement, of the light power of backward Rayleigh scattering light of the corresponding point along with the frequency so as to measure quasi-static disturbance, and therefore simultaneous measurement of dynamic disturbance signals and quasi-static disturbance signals is achieved, and the measuring function and application range of a full-distributed type optical fiber sensor are greatly expanded. The invention further discloses an optical fiber disturbance detection device. The device in a measuring system is simple in structure and low in cost, the measuring time is much shorter than the dynamic and quasi-static disturbance measuring time performed by utilizing two sets of systems, and the continuous measurement of dynamic and quasi-static disturbance can be achieved.

The invention discloses a graphene film sensitized D-shaped optical fiber surface plasmon resonance (SPR) sensor. The sensor comprises a D-shaped optical fiber, wherein a silver film layer is arranged on the polished surface of the D-shaped optical fiber; and a graphene film layer is arranged on the surface of the silver film layer. A preparation method comprises the following steps of: (1) preparing the D-shaped optical fiber, and preparing the silver film layer on the polished surface of the D-shaped optical fiber; and (2) preparing the graphene film layer on the surface of the silver film layer. The D-shaped optical fiber is used as a light transmission medium, an SPR structure is formed by plating a silver film on the surface of the D-shaped optical fiber, the sensitivity of the SPR sensing structure is increased by depositing or growing a graphene film material on the surface of the silver film, and the sensor has the prominent advantages of small volume, light weight, high sensitivity, quick response and the like, and has wide application prospects in the aspect of detecting trace gas, liquid, chemical elements, deoxyribonucleic acid (DNA) and the like in the fields of biology, chemistry, medicine and the like.

A distributed optical fiber sensor based on Raman and Brillouin scattering is provided. The distributed optical fiber sensor includes a semiconductor FP cavity pulsed wideband optical fiber laser (11), a semiconductor external-cavity continuous narrowband optical fiber laser (12), a wave separator (13), an electro-optic modulator (14), an isolator (15), an Er-doped optical fiber amplifier (16), a bidirectional coupler (17), an integrated wavelength division multiplexer (19), a first photoelectric receiving and amplifying module (20), a second photoelectric receiving and amplifying module (21), a direct detection system (22), a narrowband optical fiber transmission grating (23), a circulator (24) and a coherence detection module (25). The temperature and the strain can be measured simultaneously, and the signal-to-noise ratio of the system is enhanced.

The invention provides a resonant type Fabry-Perot optical fiber sensor which comprises a sensor body and a through hole penetrating through the sensor body. One end of the through hole is provided with a graphene thin film for sensing the to-be-detected air pressure in an attached mode, and the other end of the through hole is provided with transmission optical fibers which penetrate through the through hole and are matched with the through hole. According to the resonant type Fabry-Perot optical fiber sensor, the air pressure of gas is calculated in the mode that graphene thin film resonant frequency changes are caused by damp of the gas to the graphene thin film, so that a closed Fabry-Perot cavity is not needed, and the manufacturing difficulty is reduced; the the original measurement thin film deformation quantity is replaced by resonance to further conduct air pressure measurement, and thin film material creeping caused by repeated film deformation is effectively reduced; digital frequency signals after probe laser detection are output after the sensor conducts detection, and result analysis can be conveniently carried out compared with light wave signals of an interferometric sensor. Stimulation and detection are carried out through the single transmission optical fibers, and long-distance air pressure measurement can be achieved, and the applicability of the sensor is greatly improved.

The invention provides a foundation pit engineering three-dimensional monitoring network realization method based on distributed optical fiber sensors, which relates to a scheme of laying optical fiber sensors on an enclosure and support structure, overall deformation and force bearing analysis on the enclosure and support structure and generation of a strain distribution cloud map. Based on the characteristics that the frequency changes of back Brillouin scattering light formed by scattering of optical wave molecules of the optical fibers and incident light are sensitive to strain and temperature and BOTDA sensing advantages and benefiting from the accurate, stable and real-time monitoring advantages of the optical fiber sensors, the optical fibers on the components are arranged to a three-dimensional monitoring network, comprehensive and three-dimensional deformation and force bearing monitoring can be carried out on enclosure and support components and other components in the foundation pit project, real-time monitored data are guided to surfer to generate a structure strain distribution cloud map, and the method of the invention is a visualized and three-dimensional monitoringmeasurement and control method.

The invention provides red date intelligent selection equipment. The red date intelligent selection equipment comprises a bottom supporting frame, a transmission supporting frame, a control box, a hopper, a feeding transmission device, a horizontal conveying device, a pneumatic mechanism and a division box. The transmission supporting frame is fixed to the upper portion of the bottom supporting frame. The horizontal conveying device is arranged in the transmission supporting frame and provided with a horizontal conveying belt composed of rollers. The hopper is arranged on one side of the bottom support frame. An inclined feeding plate is arranged in the hopper, and the feeding plate is connected with the feeding transmission device. The division box is fixed to the other side of the horizontal conveying belt. The control box is fixed to the middle of the transmission supporting frame. The pneumatic mechanism is arranged at the position, between the control box and the division box, of the transmission supporting frame. Industrial cameras and an industrial personal computer are arranged in the control box. An optical fiber sensor is arranged on one side of a chain wheel of the horizontal conveying device. According to the red date intelligent selection equipment, good dates and bad dates are separated through the image processing technology and the pneumatic mechanism, the detection precision is high, the red data sorting efficiency is improved, and the labor intensity is reduced.

The invention provides a simplified multiplexing white light interference fiber sensing demodulating device, which comprises a single-fiber two-way optical transmitting/receiving module, an optical fiber resonant cavity, a single-mode transmission fiber, and an optical fiber sensing array, wherein the single-fiber two-way optical transmitting/receiving module is composed of a semiconductor light source as the transmitting terminal, a semiconductor photodetector as the receiving terminal and related devices packaged together; and an optical fiber annular cavity is composed of an optical fiber coupler, an optical fiber self-focusing lens and a movable corner reflector. The device can achieve enquiry and measurement of a plurality of optical fiber sensors by embedding the single-fiber two-way optical transmitting/receiving module and the optical fiber resonant cavity in the single-mode optical fiber, and has the advantages of simple structure, easy implementation, no length restriction of the transmission cable, no influence caused by the external environment, and good stability and reliability. The device can be used for the measurement of physical quantities such as distributed deformation, strain and temperature, and can be used for multi-task sensing, multi-element sensing, local strain sensing, large-scale deformation sensing, etc.

The invention relates to an optical-fiber position digital encoder and an application thereof, which is characterized in that the optical-fiber position digital encoder is formed by an optical-fiber position sensing head and a signal demodulation unit, which are mutually separated and are connected through optical fibers, and can realize the distant detection. The optical-fiber position sensing head is passive, is installed in a structure, and is connected with a driving mechanism. An encoder which is formed by a main raster and an indication raster can modulate optical signals which are transmitted from the single demodulation unit into real-time phase change countable optical pulse sequence, and then return to the single demodulation unit on the measured displacement or angle quantity under the effect of the driving mechanism, then the actual displacement or angle values of the optical fiber position sensing head are calculated after being conducted with phase demodulation and pulse counting by the signal demodulation unit, and finally data loading is realized through a standard communication interface. And the displacement sensing with high precision and large range can be realized through the combination of the optical fiber position digital encoder with a driving and exchange mechanism, thereby further forming an optical fiber sensor based on the displacement and angle detecting principle.

The invention relates to the imbedding and test method for a snake optical fiber sensor and the snake optical fiber sensor. The method involves making and imbedding the optical fiber sensor, connecting the optical fiber sensor to a transition optical fiber with a bonding machine to position the the optical fiber sensor, testing the loss initial value, after excavating, test system loss changing curve of the optical fiber test system and observing the deformation and damage condition of the terrain; processing the OTDR test data with program. The bare fiber is covered with a bushing on the outside diameter and equipped with a protecting device on both end. The fiber can form many minor bend point used to monitor the deformation of rock whose strength is lower than quartz glass and the generating, developing, microdeformation and macrodeformation of the cranny of large deformed rocks. The initial deformation of the terrain, even the damage of materials,can be detected with the accuracy within plus or minus 0.01mm. The marodeformation reaches 35-50 mm, far higher than the concrete deformation detection. It is a distributed optical fiber detecting instrument, the fiber is connected with the detecting device, convenient to operating, detection is stable, highly accurate.

The invention discloses an interferometric optical fiber sensor based on a pohotonic crystal optical fiber. The pohotonic crystal optical fiber at the middle section is connected with monomode optical fibers at two ends via core shift connecting structures, wherein the diameters of claddings of the monomode optical fibers at two ends are 125 microns, and the diameters of fiber cores are 8.3 microns; the pohotonic crystal optical fiber at the middle section is a PM-125 type pohotonic crystal optical fiber manufactured by the fiberhome telecommunication, the cladding diameter is 125 microns, the diameter of the fiber core is 7 microns, and the length is 5cm, and the section acts as a sensing region. The interferometric optical fiber sensor is not sensitive to temperature, and is relatively high in refractive index, and can act as a refractive index sensor, and meanwhile, influences on refractive index measurement precision caused by the change of temperature can be alleviated. The interferometric optical fiber sensor based on the pohotonic crystal optical fiber is simple in structure, is easy to manufacture, meanwhile can alleviate influences on the single-parameter measurement precision by temperature, is relatively high in practical value, and is suitable for the fields of industrial production, defense-related science and technology, medical treatment, people's livehood and the like.

The invention relates to a wireless optical fiber sensor network deployment method based on particle swarm optimization. The method comprises the following steps of: establishing a bottom layer network deployment optimization model specific to the aim of minimizing the energy consumption of an optical fiber sensor node and bottom layer network cost, and solving by adopting multi-target particle swarm optimization based on a discrete binary system to obtain a bottom layer network deployment scheme and realize distributed sensing of a monitored area; and establishing an upper layer network deployment optimization model on the basic of the bottom layer network deployment scheme specific to the aim of minimizing upper layer network cost under the constraining action of upper layer network full communication, designing a fitness function for increasing particle difference, and solving by adopting particle swarm optimization based on simulated annealing to obtain an upper layer network deployment scheme and realize multiple hop transmission of sensing data. Due to the adoption of the method, the energy consumption of the optical fiber sensor node can be lowered, the energy consumption of management nodes is balanced, the network life is prolonged, the quantity of deployed routing nodes and management nodes can be reduced on the premise of ensuring full network communication, and network cost is reduced.

The invention relates to an avalanche photodetector signal compensation device and a method, which belong to the field of distribution type optical fiber sensing. By the aid of a hardware detection controller based on negative feedback, the avalanche photodetector signal compensation device comprises a digital temperature sensor, a voltage comprehensive control module, an external E2PROM (electrically erasable programmable read-only memory) and an avalanche photodetector (APD), and adopts a non-linear curve fitting data calculating method to accurately compensate response nonlinearity of the avalanche photodetector (APD), so that gain of the avalanche photodetector (APD) keeps constant within a wide temperature range (from minus 5 DEG C to 50 DEG C), and measurement precision and stability of a distribution type optical fiber sensor within the wide temperature range are improved greatly.

The invention discloses a device and a method for continuously manufacturing optical fiber sensors. The device comprises an optical fiber drawing mechanism, a bare optical fiber storage and linear velocity regulation mechanism, an optical fiber sensor manufacture mechanism, an optical protection layer coating and curing mechanism and a take-up mechanism. The bare optical fiber storage and linear velocity regulation mechanism stores a bare optical fiber drawn by the optical fiber drawing mechanism temporally, so that the optical fiber sensor manufacture mechanism can process the optical fiber sensors on the static bare optical fiber. Therefore, the optical fiber sensors can be manufactured continuously under the premise that drawing velocity, diameter accuracy, optical performance and mechanical performance of optical fibers are not affected. By means of the device and the method for continuously manufacturing the optical fiber sensors, drawing of the optical fibers, manufacture of the optical fiber sensors, protection coating and curing process of the optical fibers can be completed for one time, and production efficiency is increased greatly. Furthermore, stripping and recoating of protective layers required by manufacture of the optical fiber sensors do not need to be performed in an off-line mode, and effect on characteristics of the optical fiber sensors caused by unevenness of the protective layers can be reduced to the largest extent.

A device and a method for detecting SF6 decomposed gas by a spectrum absorption optical fiber sensor belong to the technical field of SF6 gas insulated electrical equipment partial discharge on-line monitoring. The device of the invention mainly comprises an induction voltage regulator, a non-corona experimental transformer, a non-partial discharge protective resistor, a standard capacitive voltage divider, a GIS simulation element, a non-inductance resistor, an oscilloscope, a spectrum absorption optical fiber sensor, and the like; The method of the invention performs experiment of standard gases with different concentrations of SF6 decomposed gas and absorption properties of absorbance under partial discharge in the GIS simulation element at a constant wavelength by using the device of the invention. The device of the invention has the characteristics of small size, simple structure, less coupling loss, convenient operation, rapid response time, high detection accuracy, high precision, etc. The invention is widely applicable to SF6 gas insulated electrical equipment, and especially to the detection of SF6 partial discharge decomposed gas in GIS equipment.

The invention relates to an optical fiber collimator with an elliptical light spot. The collimator is characterized in that: (1) an exit light spot of the optical fiber collimator is the elliptical light spot, that is, the radii of the light spots in two vertical directions are unequal; (2) a collimating lens of the optical fiber collimator comprises a cylindrical surface, and a circular light spot is changed into the elliptical light spot; (3) the surface of the collimating lens is plated with an anti-reflection film to increase return loss; and (4) input optical fiber can be either single optical fiber or double optical fiber, and the single optical fiber and the double optical fiber form a single optical fiber elliptical light spot locking collimator and a double optical fiber elliptical light spot collimator respectively. An MEMS optical attenuator, an optical switch and an elliptical light spot 2*2 switch formed by the collimator greatly reduce the moving stroke of micro-mirrors and meet the requirements of MEMS optical devices; meanwhile, the collimator can also be applied to MEMS optical fiber sensors.

The invention discloses an on-line automatic detection device for a silicon wafer, which is used for detecting whether a plurality of silicon wafers synchronously and successively conveyed along with a transmission line are fragments, and the fragments are sorted from the transmission line. The on-line automatic detection device for the silicon wafer comprises a detection unit, a control unit and a sorting unit, wherein the detection unit is arranged above the transmission line; the control unit is in signal connection with the detection unit; the sorting unit is in signal connection with the control unit; an optical fiber sensor is adopted in the detection unit; and the control unit is used for controlling the sorting unit to sort the fragments according to the detection signal of the detection unit. The fragments in the silicon wafer can be detected by the optical fiber sensor, and the fragments are sorted by controlling the sorting unit. With the method, most fragments in the silicon wafers conveyed on line can be sorted. The on-line automatic detection device for a silicon wafer has the advantages of simple structure, low cost and obvious effect and lays a foundation for subsequent scanning so as to efficiently and quickly sort fragments.

The invention discloses a novel distributed temperature and stress measuring optical fiber sensor, and relates to a distributed optical fiber temperature and stress sensor implemented by the aid of a Rayleigh scattering spectrum in an optical fiber and the optical time domain reflection principle. The Rayleigh scattering strength of each point of the optical fiber can be obtained by measuring backward Rayleigh scattering of pulsed light according to the optical time domain reflection principle, an event occurrence position can be positioned, and the Rayleigh scattering spectrum of each point of the optical fiber can be obtained by continuously changing the output wavelength of a laser. When the temperature or the stress of a certain position of the optical fiber is changed, the backward Rayleigh scattering spectrum of the optical fiber at the position can integrally, linearly and horizontally move, the variable quantity of the temperature and the stress can be obtained by comparing the backward Rayleigh scattering spectrum with the scattering spectrum before the temperature or the stress is changed, and the distributed temperature and stress can be measured. As the Rayleigh scattering strength is much higher than the Raman scattering strength and the Brillouin scattering strength, and the measuring method of the sensor is higher in signal-to-noise ratio and measuring accuracy as compared with that of spontaneous Raman and Brillouin scattering distributed sensors.

The invention discloses an optical fiber sensor strain sensitivity calibration method based on a bare optical fiber, belongs to the technical field of detection, and relates to the optical fiber strain sensor sensitivity calibration method based on the bare optical fiber. According to the method, an universal testing machine is used as an intermediary, when same force is loaded on a same specimen,same stress-strain is obtained, and the un-packaged bare optical fiber is used as a reference for calibrating a fiber bragg grating stress-strain sensor. In a calibration process, by operating a computer, the force loaded by a loading device every time is controlled, an optical fiber demodulation instrument is controlled to acquire measurement data, calibration data is used for being compared with the bare optical fiber, and the sensitivity of the fiber bragg grating strain sensor is obtained, so that a strain character of the fiber bragg grating sensor is accurately calibrated. The method issuitable for calibrating sensitivity coefficients of any optical fiber strain study sensors, errors caused by the problem of taking conversion from the loaded force to stretching stress, a specimen elasticity modulus range and the like into account are avoided, the calibration precision is greatly improved, moreover, operation is convenient, and the method is fast and easy to popularize.

The invention discloses a distributed optical fiber sensor vibration signal classification method and an identification classification system. The method comprises the following steps: firstly, usingan optical fiber sensing system for obtaining vibration signals acting on an optical cable; preprocessing the optical fiber vibration signal; calculating the short-time energy and the short-time zero-crossing rate of the optical fiber vibration signal; setting double thresholds of short-time energy and a short-time zero-crossing rate, if the double thresholds exceed the thresholds, extracting an effective data segment, and judging the effective data segment as a disturbance event; drawing a spectrogram on the time-frequency domain of the optical fiber vibration signal; extracting a Mel frequency cepstrum coefficient of the optical fiber vibration signal; establishing a deep learning recognition model based on the Mel frequency cepstrum coefficient and the time-frequency domain spectrogramof the disturbance event signal; and matching with a deep learning recognition model based on two characteristics of a spectrogram and a Mel frequency cepstrum coefficient in a vibration signal time-frequency domain, and judging the type of the optical fiber vibration signal. According to the invention, feature extraction and accurate identification and classification of the optical fiber sensingsignals are realized, and the technical problem of low identification and classification accuracy of the optical fiber sensing intrusion signals is solved.