Abstract: A wavelength monitoring circuit obtains a light output proportional to only an input optical signal, independent of wavelength, by adding a light split circuit to the configuration in the related art, or changing the light split circuit to a light trifurcation circuit. In addition, wavelength monitoring with high accuracy is possible while improving the resistance to noise. The extraction of the light output proportional to only the input optical signal is performed by a light split circuit for input light at the top stage of the wavelength monitoring circuit or a light split circuit for interference in a stage in the middle of the circuit. The changed light split circuit causes the MZI included in the wavelength monitoring circuit to operate in a state of losing the balance of the configuration or the optical signal level, and increases the signal level near the bottom portion of the transmission characteristics.

Abstract: Photonic devices are disclosed including a first cladding layer, a first electrical contact comprising a first lead coupled to a first dielectric portion, a second electrical contact comprising a second lead coupled to a second dielectric portion, a waveguide structure comprising a slab layer comprising a first material, and a second cladding layer. The slab layer may be coupled to the first dielectric portion of the first electrical contact and the second dielectric portion of the second electrical contact. The first dielectric portion and the second dielectric portion may have a dielectric constant greater than a dielectric constant of the first material.

Abstract: Example embodiments include an optical interrogation system with a sensing fiber having a single core, the single core having multiple light propagating modes. Interferometric apparatus probes the single core multimode sensing fiber over a range of predetermined wavelengths and detects measurement interferometric data associated with the multiple light propagating modes of the single core for each predetermined wavelength in the range. Data processing circuitry processes the measurement interferometric data associated with the multiple light propagating modes of the single core to determine one or more shape-sensing parameters of the sensing fiber from which the shape of the fiber in three dimensions can be determined.

Abstract: Consistent with some disclosed embodiments, an optical switch includes: a scheduler; and a buffer for buffering an optical packet including, arranged in a circuit, a clock generator for generating a clock signal, an optical unbalanced Mach Zehnder Interferometer (MZI) and a fiber delay line (FDL) having an FDL length, wherein the optical packet has an optical packet signal, wherein the scheduler is configured to insert the optical packet into the buffer and to determine a number of circulations of the optical packet through the circuit, wherein the MZI modulates the clock signal based on the optical packet signal to create a reshaped optical packet after each circulation of the optical packet through the circuit, and wherein the FDL introduces a delay in the optical packet proportional to the FDL length.

Abstract: The technology of this application relates to a data read/write apparatus and an electronic device, which relate to the data storage field, and can improve data read/write performance. The data read/write apparatus includes a first laser, configured to output a first optical pulse based on a control signal, where the control signal is a signal obtained based on to-be-written data, a dispersion compensator, configured to perform dispersion compensation on the first optical pulse to output a second optical pulse, and an optical fiber lens, connected to the dispersion compensator by using an optical fiber, and configured to focus the second optical pulse onto an optical storage medium, to write the to-be-written data to the optical storage medium.

Abstract: A temperature measurement technology includes generating an input optical signal at a wavelength using an optical signal generator, splitting the input optical signal into a first beam and a second beam, optically transmitting the first beam through the first arm of an interferometer, transmitting the second beam through a second arm of the interferometer that introduces a phase shift in the second beam relative to the first beam, combining at least a portion of the transmitted first beam and the transmitted phase-shifted second beam to produce an output optical signal, measuring an optical signal intensity of the output optical signal, and correlating the measured optical signal intensity with a temperature to produce a measured temperature. Alternatively, the input optical signal may be transmitted through two or more interferometers.

Abstract: Disclosed herein is a system, apparatus and method directed to placing a medical device into a body of a patient, each performing or including operations of providing a broadband incident light signal to a plurality of core fibers of a multi-core optical fiber, receiving reflected light signals of different spectral width, processing the reflected light signals associated with the plurality of core fibers to determine (i) a physical state of the multi-core optical fiber relating to the medical device including the multi-core optical fiber, and (ii) an orientation of the multi-core optical fiber relative to a reference frame of the body. Additional operations include generating a display illustrating the physical state of the multi-core optical fiber based at least on the orientation determined during processing of the reflected light. Typically, the display is a two-dimensional representation of the multi-core optical fiber in accordance with the determined orientation.

Abstract: The present invention relates to an intelligent fiber optical distributed acoustic sensing (FODAS) system and method based on an artificial intelligence (AI) chip, belonging to the field of distributed optical fiber sensing technologies. The system comprises a light source, a modulator, an optical amplifier, a sensing part, a data processor, a photoelectric detector, and an alarm unit, where the data processor is specifically an AI chip; the light source, the modulator, the optical amplifier and port a of a circulator are connected in sequence, port b of the circulator is connected to an optical fiber, port c of the circulator is connected to the photoelectric detector, an output end of a detector is connected to the data processor, an output end of the data processor is connected to the alarm unit; and the data processor receives external acoustic signals and extracts amplitude and frequency features of the external acoustic signals to identify the type.

Abstract: A method for manufacturing an optical modulator is disclosed. The method includes a step of preparing a Mach-Zehnder modulator, a step of acquiring, based on a light transmittance in an arm waveguide, a relationship between a voltage applied to an electrode and a phase change amount of light propagating through the arm waveguide, a step of acquiring, based on the relationship, a voltage in which the phase change amount of the light propagating through the arm waveguide has a predetermined when the light is modulated, and a step of storing the voltage in a storage unit.

Abstract: Apparatuses comprising cascaded or series configurations of Mach-Zehnder electrooptic modulators, where the nonlinearities of the cascaded and series configurations of Mach-Zehnder electrooptic modulators increase signal bandwidth and boost signal fidelity in electronic digital to analog converters. The Mach-Zehnder electrooptic modulators are combined with photodiode detectors that are used to convert signals from the optical domain to the electrical domain.

Abstract: A wearable device includes a device housing configured to be worn on a first surface of a user, a set of one or more SMI sensors, and a processor. The set of one or more SMI sensors is mounted within the device housing and configured to emit a set of one or more beams of electromagnetic radiation, with each beam emitted in a different direction extending away from the first surface. The set of one or more SMI sensors is also configured to generate a set of one or more SMI signals containing information about a relationship between the device housing and a second surface. The processor is configured to extract the relationship between the device housing and the second surface from digitized samples of the set of one or more SMI signals.

Abstract: A device may determine a time-of-flight measurement by performing a sample of a sensor based on light received via at least one first spectral filter, wherein the at least one first spectral filter is associated with a spectral range for a time-of-flight measurement; determine that a condition is satisfied with regard to the time-of-flight measurement, wherein the condition relates to an orientation or a position of the sensor or the sensor device relative to a measurement target; trigger a spectrometry measurement to be performed based on determining that the condition is satisfied with regard to the time-of-flight measurement; and perform, based on light received via at least one second spectral filter and by performing a sample of the sensor, the spectrometry measurement for the measurement target based on the condition being satisfied with regard to the time-of-flight measurement.

Abstract: A particle detection method detects presence and location of particles on a target using measured signals from a plurality of structured illumination patterns. The particle detection method uses measured signals obtained by illuminating the target with structured illumination patterns to detect particles. Specifically, the degree of variation in these measured signals in raw images is calculated to determine whether a particle is present on the target at a particular area of interest.

Abstract: The present invention relates to a device (10) for determining an arterial compliance of a subject (12). The device (10) comprises an inflatable cuff (14), a pressure sensor (18) which is configured to sense a pressure signal (52) that is indicative of a pressure within the cuff (14), a second sensor (20) which is at least partly integrated in the cuff (14) and configured to sense a second signal (56) that is responsive to expansions and contractions of the cuff (14) caused by a pulsating blood flow in an artery (50) of the subject (12), and a processing unit (22). The processing unit is configured to determine based on said part of the pressure signal (52) a pulse pressure of the subject (12), to determine based on said part of the second signal (56) an arterial volume change of the artery (50) of the subject (12) during at least one cardiac cycle, and to determine the arterial compliance of the subject (12) based on pulse pressure and the arterial volume change.

Abstract: A compact spectrometer is disclosed that is suitable for use in mobile devices such as cellular telephones. In preferred embodiments, the spectrometer comprises a filter, at least one Fourier transform focusing element, a micro-lens array, and a detector, but does not use any dispersive elements. Methods for using the spectrometer as an end-user device for performing on-site determinations of food quality, in particular, by comparison with an updatable database accessible by all users of the device, are also disclosed.

Abstract: A device for monitoring and identifying a mountain torrent and debris flow and a method for early warning of disasters relate to the technical field of debris flow protection. The device includes a computation device, sensors, an amplifier and an analog-to-digital converter. The sensors convert an acquired impact force signal into a digital signal by the amplifier and the analog-to-digital converter, and transmits the digital signal to the computation device. The computation device utilizes the digital signal to compute an energy coefficient of a liquid impact signal and a solid-liquid impact energy ratio, and a debris flow mode is monitored and identified in combination with a threshold range of the energy coefficient and a threshold range of the solid-liquid impact energy ratio. The device identifies the nature of the mountain torrent and debris flow through time-frequency analysis of an impact force signal generated by the debris flow to sensors.

Abstract: A sensor apparatus, such as a pressure gauge, comprises a sensor arranged to produce a sensor output signal that varies with a measured parameter such as pressure, and a plurality of output channels each arranged to receive the sensor output signal. The output channels are each optimized for a different range of the measured parameter. The apparatus further comprises an analog to digital converter (ADC) and control module arranged to select one of the output channels and connect it to the ADC so as to produce a digital channel output, and an output module configured to generate an output reading from the digital channel output of the selected channel.

Abstract: A through-bore spool apparatus for use in deploying multiple spoolable media in a bore is disclosed. The through-bore spool apparatus comprises a first spool comprising a first spool axis and a first spoolable medium wound around the first spool axis, and a second spool comprising a second spool axis and a second spoolable medium wound around the second spool axis. The first and second spoolable media are de-spoolable simultaneously from the respective first and second spools during movement of the through-bore spool apparatus along a bore.

Abstract: A digital topographic model of the luminal surface is generated by projecting an optical pattern on the luminal surface from the first location within the lumen. At least a portion of the projected pattern is detected from a second location within the lumen which is based apart from the first location. The dimensions of the luminal wall can be measured by triangulation in order to produce the digital topographic model of the body lumen.

Abstract: Laser Side Mode Suppression Ratio (SMSR) control is provided via a logic controller configured to measure an SMSR of a carrier wave upstream of a modulator and measure an Average Optical Power (AOP) of the carrier wave downstream of the modulator; transmit a bias voltage based on the SMSR and the AOP to a laser driver for a laser generating the carrier wave; and transmit an attenuation level based on the SMSR and the AOP to a Variable Optical Attenuator (VOA) upstream of the modulator. In various embodiments the attenuation level and bias voltage can rise or fall together, or one may rise and one may fall to ensure the output optical signal meets specified SMSR and AOP values.

Abstract: There is described a method of making an acoustic sensor having a frequency response approximating a desired frequency response. The method comprises wrapping optical fiber around a core according to a wrapping pattern. The wrapping pattern is determined from an impulse response of the acoustic sensor. The impulse response is determined from the desired frequency response of the acoustic sensor.

Abstract: The present invention relates to an optical fiber BOCDA sensor. A purpose of the present invention is to provide an optical fiber BOCDA sensor which uses two phase codes to control a correlation peak position, thereby further simplifying control design and device configuration and improving spatial resolution to enhance a sensing performance and detection accuracy in comparison with the prior art.

Abstract: A method for all-optical reduction of inter-channel crosstalk for spectrally overlapped optical signals for maximizing utilization of an available spectrum includes receiving a plurality of spectrally overlapped optical signals modulated with data. The method further includes generating conjugate copies of each of the plurality of optical signals using non-linear optics. The method further includes selecting the conjugate copies and adjusting an amplitude, a phase, and a delay of the conjugate copies. The method further includes performing inter-channel interference (ICI) compensation on the spectrally overlapped optical signals in an optical domain by adding the adjusted conjugate copies to the spectrally overlapped optical signals.

Abstract: An apparatus for monitoring strain in an optical chip in silicon photonics platform. The apparatus includes a silicon photonics substrate shared with the optical chip. Additionally, the apparatus includes an optical input configured in the silicon photonics substrate to supply an input signal of a single wavelength. The apparatus further includes a first waveguide arm and a second waveguide arm embedded in the silicon photonics substrate to form an on-chip interferometer. The second waveguide arm forms a delay line being disposed at a region in or adjacent to the optical chip. The on-chip interferometer is configured to generate an interference pattern serving as an indicator of strain distributed at the region in or adjacent to the optical chip. The interference pattern is caused by a temperature-independent phase shift at the single wavelength of the interferometer between the first waveguide arm and the second waveguide arm.

Abstract: To provide patient status determination device, which receives continuous biological information from a state detection device that continuously detects biological information of a patient and measured biological information from a measuring device that measures biological information of the patient, appropriately determines the state of the patient, based on the received continuous biological information and the measured biological information, whereby it is possible to determine the state of the patient properly, based on the plurality of biological information of the patient.

Abstract: A method or apparatus for narrowing the linewidth of a single mode laser is provided. The linewidth of a single mode laser is narrowed by injecting an optical feedback simultaneously into the first laser cavity mirror and the second laser cavity mirror of the single mode laser.

Abstract: An optical sensing system for detecting fiber events along an optical cable under test (CUT) having forward and feedback fibers and multiple pairs of optical couplers interconnected along the forward and feedback fibers in a ladder topology. An optical transmitter generates an optical probing signal for a forward fiber, wherein the couplers along the forward fiber provide tapped portions of the probing signal to the couplers along a feedback fiber to form a combined optical feedback signal in the feedback fiber. A reference coupler is connected between the transmitter and the forward fiber to tap an optical reference signal from the probing signal, and a feedback coupler is connected to combine the reference signal and the feedback signal. An optical receiver receives and processes the combined reference and feedback signals from the feedback coupler to detect fiber events along the CUT.

Abstract: A measuring arrangement for fiber Bragg grating measurement points and particularly a measuring arrangement for two fiber Bragg gratings (FBG), wherein a first measurement point is subjected to tension and a second measurement point is subjected to pressure, or vice versa. The circuit arrangement includes a broadband light source, a first beam splitter, a second beam splitter, a third beam splitter, a fourth beam splitter, a fifth beam splitter, photodiodes and an optical delay element.

Abstract: The present disclosure relates to a method for determining an impact of optical component degradation on the functionality of an electro-optical sensor system, said method (100) comprising a step of obtaining (110) test data relating to the state of the optical component; a step of providing (130) a set of correlation values based on test data and correlation data, said correlation data correlating test data to an optical component degradation state, wherein the optical component degradation state relates to a functionality impact of the electro-optical sensor system; and a step of obtaining (140) an electro-optical sensor system functionality estimate based on the provided set of correlation values.

Abstract: An improved optical fiber distributed acoustic sensor system uses an optical fiber having reflector portions distributed along its length in at least a first portion. The reflector portions are positioned along the fiber separated by a distance that is equivalent to twice the distance an optical pulse travels along the fiber in a single sampling period of the data acquisition opto-electronics within the sensor system. No oversampling of the reflections of the optical pulses from the reflector portions is undertaken. The sampling points for data acquisition in the sensor system are aligned with the reflections that arrive at the sensor system from along the sensing fiber. Adaptive delay componentry adaptively aligns the reflected optical signals (or their electrical analogues) with the sampling points. Control over the sampling points can re-synchronise the sampling points with the returning reflections. Reflection equalisation componentry may reduce the dynamic range of the returning reflections.

Abstract: Operating an optical frequency comb assembly includes operating an optical frequency comb source to generate laser light constituting an optical frequency comb and introducing the laser light into a common light path and seeding at least one branch light path by the laser light from the common light path, the branch light path comprising at least one optical element. For the branch light path, a phase difference of a first frequency mode ?1 of the optical frequency comb is determined between laser light coupled out at a reference point within the frequency comb assembly upstream of the at least one optical element and laser light coupled out at a measurement point provided in the branch light path downstream of the at least one optical element. Phase correction for the laser light from the branch light path is based on a deviation of the determined phase difference from a target value.

Abstract: An optical waveguide 1, an optical waveguide 2 are formed on a substrate 3 to be crossed with each other, modulator electrodes 11, 12, 13 and 14 are arranged along the optical waveguides 1, 2, and antennas 21, 22, 23, 24 (i.e., square patch antennas having an approximately same shape) are arranged around four corners of the square shape. The modulator electrode 11 is energized from the antenna 21 and the antenna 22, the modulator electrode 12 is energized from the antenna 24 and the antenna 23, the modulator electrode 13 is energized from the antenna 21 and the antenna 24, and the modulator electrode 14 is energized from the antenna 22 and the antenna 23. The light wave propagating through the optical waveguide 1 is modulated by an electric field of Y-direction, and the light wave propagating through the optical waveguide 2 is modulated by an electric field of X-direction.

Abstract: OCT measuring device in the present exemplary embodiment includes: wavelength sweep light source that emits light of which a wavelength is swept; optical interferometer that divides the light into measurement light and reference light, emits measurement light toward measurement surface of measuring target object, and generates an optical interference intensity signal indicating an intensity of interference between measurement light reflected from measurement surface and reference light; electro-optic element which is a phase modulator arranged in a light path of optical interferometer; measurement processor which is a signal generator that derives a position of measurement surface and generates a phase amount indicator signal that indicates a phase amount of phase modulator based on the optical interference intensity signal; and electro-optic element controller which is a phase amount controller that controls the phase amount given to the light that is transmitted through phase modulator.

Abstract: A wearable device includes a device housing configured to be worn on a first surface of a user, a set of one or more SMI sensors, and a processor. The set of one or more SMI sensors is mounted within the device housing and configured to emit a set of one or more beams of electromagnetic radiation, with each beam emitted in a different direction extending away from the first surface. The set of one or more SMI sensors is also configured to generate a set of one or more SMI signals containing information about a relationship between the device housing and a second surface. The processor is configured to extract the relationship between the device housing and the second surface from digitized samples of the set of one or more SMI signals.

Abstract: An optical resonant modulator based on coupling modulation, comprising a resonant structure with an embedded Mach-Zehnder interferometer that is differentially driven to induced amplitude modulation at the output port. The principle of coupling modulation enables high data/baud rates to be achieved in a photonic integrated circuit, e.g. silicon, footprint that is considerably smaller than that of a conventional traveling-wave Mach-Zehnder modulator, in particular by utilizing space saving features, such as ring resonator phase shifters and bend waveguide arms.

Abstract: The invention relates to a method for optically sensing a parameter of the group of temperature, humidity or mechanical stress using at least one optical sensor which includes a chirped Bragg grating and an optical reference reflector.

Abstract: A 90-degree optical hybrid includes two optical splitters that respectively split inputted light into two beams, two optical combiners that respectively combine two beams of inputted light and thereby output two beams of interfering light respectively, and four arm waveguides that input light splitted by any of the two optical splitters into any of the two optical combiners. Each of the four arm waveguides has a bend waveguide arranged at its center and a plurality of optical waveguides including a tapered waveguide having a width that decreases toward the bend waveguide. Both ends of each of the plurality of optical waveguides are respectively in contact with a end surface of any one of the two optical splitter, the two optical combiners, the bend waveguide and the other of the plurality of optical waveguides, and each of the plurality of waveguides is the tapered waveguide or a linear waveguide.

Abstract: The deep penetration of optical transmission from the very edges of the network with optical access networks to the very core with routing data within data centers before transmission has resulted in competing demands for increased functionality, reduced cost, enhanced manufacturability, and reduced footprint. At the same time monitoring and fault detection with prior art optical time domain reflectometry systems have not kept up to the demands of these networks and systems as they are expensive test equipment based solutions. It would be beneficial to provide embedded OTDR functionality within each transmitter, receiver or transceiver deployed within the network allowing every link to be monitored continuously. It would be further beneficial for such embedded OTDRs to meet the demands for lower cost, high volumes, and smaller footprints with enhanced manufacturability.

Abstract: An apparatus includes a base having walls that define a track. The track has input and output ends and defines a coiled path that spirals inward from the input end, reaches an inflection point where a direction of curvature is reversed, and spirals outward towards the output end. The track is configured to receive and maintain a majority of an optical fiber in an at least substantially planar coiled arrangement. The apparatus also includes a first transition arm positioned at the input end and a second transition arm positioned at the output end. Each transition arm is configured to be mechanically coupled to the base and includes a groove configured to receive and maintain a portion of the optical fiber in an at least substantially straight orientation. The walls and transition arms are configured to maintain thermal contact with the optical fiber along its entire length.

Abstract: The disclosed systems and methods are directed to monitor optical performance comprising receiving optical channel signals, wherein the optical channel signals are superimposed with pilot tone (PT) signals, operating a local oscillator (LO) including a tunable laser in a coarse scanning mode and a fine scanning mode and generate different LO signals in accordance with the mode in which the LO is being operated, combining the optical channel signals with at least one LO signal generated by the LO and generating a combined optical signal, detecting and converting the combined optical signal into an electrical signal, amplifying the electrical signal, converting the amplified electrical signal into a digital signal, processing the digital signal and extracting channel specific information included in the PT signals, computing channel power based on the channel specific information, and maintaining a management table.

Abstract: An optical modulator includes a plurality of Mach-Zehnder optical modulation units. Each of the plurality of Mach-Zehnder optical modulation units include a pair of first signal wirings, a pair of first ground wirings, a pair of first signal electrode pads, and a pair of first ground electrode pads. The pair of first ground electrode pads is displaced by less than the first interval from the pair of first signal electrode pads so as to separate from a center line of each of the plurality of Mach-Zehnder optical modulation units.

Abstract: A device may use a camera to capture an image of an end face of an optical fiber in a field of view of the camera. The device may monitor a focus metric associated with the image while the image is manually focused using an opto-mechanical assembly. The device may automatically initiate a test to inspect the image of the end face of the optical fiber for compliance with a set of criteria related to cleanliness and damage based on the focus metric satisfying a condition. The device may output a result from the test indicating whether the end face of the optical fiber satisfies the set of criteria related to cleanliness and damage.

Abstract: A compressive/transform imager comprising a lens array positioned above input ports for collecting light into the input ports, waveguides routing the light from the input port to waveguide mixing regions (e.g. multi-mode interference couplers), and detectors for receiving outputs of the waveguide mixing regions.

Abstract: The at least one value is respectively determined from at least one measured value of the sensors (20-29) in a method for determining at least one physical value in a space (10) in which several sensors (20-29) are arranged which are set up to measurer the at least one value, for several positions (30) in the space (10) where there is no sensor (20-29). A system which is set up in order to determine the at least one physical value in the space (10) has several sensors (20-29) which are arranged in the space (10). Furthermore, it has a database, in which information about the space (10) is stored, and a computer which is set up in order to determine the at least one value by means of the method.

Abstract: Example embodiments add an optical amplifier to an multi-channel, continuously swept OFDR measurement system, adjust amplified swept laser output power between rising and falling laser sweeps, and/or utilize portions of a laser sweep in which OFDR measurements are not typically performed to enhance the integrity of the OFDR measurement system, improve the performance and quality of OFDR measurements, and perform additional measurements and tests.

Abstract: Disclosed are methods for the free solution measurement of molecular interactions by refractive index sensing other than backscattering interferometry. The disclosed methods can have very low detection limits and/or very low sample volume requirements. Also disclosed are various biosensor applications of the disclosed techniques. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.

Abstract: An optical inspection system includes an optical fiber sensor, an optical filter, a signal processor, and a corrector. The optical fiber sensor outputs a first optical signal having a temporal change in a wavelength corresponding to a temporal change in an amplitude of a vibration propagating in an inspection target object or a temporal change in a displacement of the inspection target object. The optical filter converts the first optical signal into a second optical signal having a temporal change in an intensity. The signal processor acquires inspection information on the inspection target object on the basis of the second optical signal. The corrector corrects a correspondence relationship between the temporal change in the wavelength and the temporal change in the intensity by changing a wavelength characteristic of the optical filter. The correspondence relationship is directed to converting the first optical signal into the second optical signal.

Abstract: A method for detecting coherent light that includes configuring a spatial interferometer, receiving the coherent light through the spatial interferometer, and disposing a photo detector adjacent to the spatial interferometer. The spatial interferometer is configured such that a coherent light passing through the spatial interferometer interferes with itself. The interference of the coherent light with itself creates a light fringe. The light fringe projects onto the photo detector. The photo detector has an array of pixels operable to detect an intensity of coherent light. The array of pixels provides a plurality of outputs corresponding to coherent light received by discrete pixels of the array of pixels. The method includes determining an interference pattern of the light fringe based on the plurality of outputs of the array of pixels, and determining one or more wavelengths of the coherent light from the interference pattern.

Abstract: This invention relates to elastomeric coatings for electronics. Disclosed is a electronic device comprising a substrate layer, a conductive layer and an encapsulant layer. The encapsulant layer comprises at least a butyl rubber material. The butyl rubber encapsulant prevents a change in resistivity of the conductive layer following exposure to nitric acid vapour for 12 hours or hydrochloric acid vapour for 10 hours.

Abstract: A distributed fibre sensing system and a vibration detection and positioning method therefor are disclosed. The system comprises: a signal generating module, a light source module, an optical frequency comb generating module, a frequency sweeping and pulse generating module, an optical circulator, a sensing fibre, an interference module, a photoelectric conversion module and a detection and position module. The method comprises: obtaining a plurality of Rayleigh backscattering signals of the sensing fibre; performing a fading elimination processing on the Rayleigh backscattering signals, thereby obtaining a plurality of averaged Rayleigh backscattering signals of non-interference fading and polarization fading; performing a phase processing on the averaged Rayleigh backscattering signals, thereby obtaining phase variance curves; and determining a vibration point according to variances in the phase variance curves, and finally obtaining a position and a vibration waveform of the vibration point.