Abstract: A fiber-optic based thrust load measurement system is coupled to a bearing housing. The measurement system includes at least one fiber optic sensor configured to detect one or more parameters related to the bearing housing. An optical coupler is configured to regulate light signals emitted from a light source and light signals reflected from the fiber optic sensor. A detector system is configured to receive light signals from the optical coupler. A processor is configured to receive an output from the detector system and to determine a thrust load on a thrust bearing based on the detected one or more parameters related to the bearing housing.

Abstract: Broad band optical strain sensing systems for a wind turbine. The strain sensing system includes an optical fiber with an input at one end and an output at the opposite end. The optical fiber is provided with Bragg sensors between the input and the output. By injecting light at the input of the fiber, measuring the spectral intensity distribution of at the output of the fiber and determining spectral locations of intensity notches in the spectral intensity distribution, it is possible to determine strain values at the locations of the Bragg sensors from the transmitted light.

Abstract: The invention relates to an optical strain gauge (1) using a glass fibre as a strain sensor. The strain gauge comprises a glass fibre comprising a sheath. The sheath has the following composition: a mixture of polyether ether ketone and an admixture of at least 10 weight percent and a maximum of 40 weight percent of an inorganic filler, with a particle size of between 0.08 [mu]m and 12 [mu]m. The outer diameter of the sheath is between 0.2 mm and 1.2 mm. The ratio D/d between the outer diameter D of the sheath and the diameter d of the glass fibre is between 2 and 6. A pressure of the sheath on the glass fibre is such that essentially no relative movement can occur between the glass fibre and the sheath.

Abstract: The invention relates to an optical strain gauge using a glass fiber (1) comprising a Bragg grating (2). The glass fiber is coated with a sheath (3) of polyether ether ketone with an admixture of at least 10 weight percent and a maximum of 40 weight percent of an inorganic filler, with a particle size of between 0.08 ?m and 12 ?m. The outer diameter of the sheath (3) is between 0.2 mm and 1.2 mm. The ratio D/d between the outer diameter D of the sheath (3) and the diameter d of the glass fiber (1) is between 2 and 6. A pressure of the sheath (3) on the glass fiber (1) is such that essentially no relative movement can occur between the glass fiber (1) and the sheath (3).

Abstract: The general field of the invention is that of fiber-optic sensors comprising at least one measurement optical fiber having an optically pumped doped amplifying medium, the optical characteristics of which are sensitive to a physical quantity, the fiber having at least one Bragg grating. The fiber is designed so as to generate, in the amplifying medium, two optical waves having different optical frequencies that propagate in the same direction after reflection on the Bragg grating and are emitted by the amplifying medium, the two optical frequencies depending on the physical quantity. The two waves may be generated using either a birefringent polarization-maintaining fiber or a DBR (Distributed Bragg Reflector) laser cavity. Notably, this sensor may be used as a hydrophone.

Abstract: A stress measurement device is arranged such that image processing is carried out with respect to each of a plurality of particles dispersed in an RP model to which light is emitted, movement directions and movement amounts of the respective plurality of particles in the RP model are found, and a three-dimensional stress occurring in the RP model is measured by use of a result of the finding. The stress measurement device includes: a retaining section which retains the RP model while soaking the RP model in a refractive index matching solution having a refractive index that matches a refractive index of the RP model; and a load application mechanism and a load application mechanism which apply a load to the RP model retained by the retaining section.

Abstract: A measurement system (10) for detecting repeated large deformation comprising: a fiber optical strain sensor (12) including a flexible polymer optical fiber (POF) (20) in the form of a series of extended loops (40), the loops (40) being flexible to allow rotation in the plane; and notches (41) formed on at least one side of the fiber (20); a light source (11) connected to the POF (20); and a photo-detector (13) to detect a change of the light power transmission loss through the notches (41) caused by the alteration of the shape of the notches (41) when the strain sensor (12) is strained.

Abstract: A system for measuring thin film stress (anisotropic or isotropic), such as from thin film deposition onto semiconductor substrates found in semiconductor manufacturing. The system uses resettled volume difference (V2?V1) of the surface of a material to calculate stress. The system includes A) A means to collect 3D surface point positions of a body by reflecting an image or light from the material surface into a sensor. B) A method to calculate volume from 3D surface points. C) A method to calculate thin film stress from resettled volume difference (V2?V1). D) A 3D Integrated Magnification Environment (3D-IME) to analyze 3D models of a body with a single axis (the height axis) magnified in an effort to observe the effects of stress on the body, before and after stress is applied, such as from film deposition).

Abstract: Optical fiber sensors adapted to measure strain or pressure are disclosed. The optical fiber sensor has a lead-in optical fiber having an end surface at a forward end, and a first optical element having a body with an outer dimension, Do, a front end surface coupled to the lead-in optical fiber, a pedestal including a retracted surface that is spaced from the front end surface, the retracted surface at least partially defining an optical cavity, a gutter surrounding the pedestal, the gutter having a gutter depth defining an active region of length, L, the first optical element further exhibiting L/Do?0.5. Also provided are systems including the optical fiber sensor, and methods for manufacturing and using the optical fiber sensor. Numerous other aspects are provided.

Abstract: A wind turbine rotor blade having a strain sensor system is described. The strain sensor is insensitive to the effect of twisting motions or edge-wise bending on the measurement of the strain. The sensor comprises one or more strain sensing devices arranged in a circular or regular polygon shaped path enclosing a region of the component. In the sensor system, a plurality of strain sensors are spaced longitudinally along a flap-wise axis of the wind turbine rotor blade.

Abstract: A system measures the strain of an object. The system includes a laser source for generating an output radiation, a strainable optical fiber having first and second facets, and means for calculating a measure of a strain of the optical fiber. The first facet is coupled to the laser source to receive the output radiation and transmit a guided radiation over the optical fiber towards the second facet. The second facet is adapted to receive the guided radiation and to reflect a corresponding reflected radiation towards the first facet. The laser source is a self-mixing type adapted to receive at least part of the reflected radiation and to mix the output radiation with the received radiation. The calculating means calculate the measure of the strain of the optical fiber based on a self-mixing effect in the laser source that is caused by the linear displacement of the second section.

Abstract: A fiber Bragg grating cross-wire sensor may be used to independently determine strain and temperature variation. An example fiber Bragg grating cross-wire sensor comprises a first fiber Bragg grating (FBG) that reflects a first percentage, R1, of light of a first wavelength, ?1, and a second FBG that reflects a second percentage, R2, of light of a second wavelength, ?2. The second FBG is positioned orthogonal to the first FBG, and ?1 is substantially equal to ?2, but R1 is different from R2. As the FBG cross-wire sensor experiences a strain and/or a temperature variation, the wavelengths of light reflected by the first FBG and the second FBG will shift from the first and second wavelength, ?1 and ?2, to first and second shifted wavelengths, ?A and ?T, respectively. Based on R1, R2, ?1, ?A, and ?T, the strain and/or the temperature variation may be independently determined.

Abstract: Particles flowed through a micro-channel are imaged by imaging means. Particle speed measuring means determines the particle speed from the image data. Particle counting means counts the particles flowed for a predetermined time. Particle size measuring means measures the size of the particles. The measurements of the particles flowed at a predetermined timing are managed by data associating means. With this, the speed, number and size of particles flowed through a micro-channel can be determined at a time, and associated data can be obtained.

Abstract: Method for evaluating an asymmetric residual stress for a material by the indentation test comprises applying the residual stresses with an uniaxial and an symmetrical biaxial tensions on the material and then performing an instrumented indentation test indenting an asymmetric indenter on the material; and comparing a slope of indentation load-depth curve when the long diagonal direction of the asymmetric indenter is perpendicular to the direction of the largest residual stress with that in stress-free state, and then a slope of indentation load-depth curve when the long diagonal direction of the asymmetric indenter is parallel to the direction of the largest residual stress with that in stress-free state, so as to evaluate the asymmetric residual stress for the material.

Abstract: Methods and apparatus for measuring a parameter (e.g., temperature, pressure, strain, or vibration) of at least a portion of a wind turbine generator using distributed sensing with optical fiber technology are provided. Fiber optic technology with distributed sensing offers a fast, low cost solution for measuring the parameter at myriad locations along substantial lengths of optical fiber. In this manner, the health or status of one or more components of the wind turbine generator may be monitored during or after the different stages of fabrication, transportation, site assembly, operation, and repair over time. Furthermore, data from multiple wind turbine generators may be sent to a local control station for processing and monitoring an entire wind farm in real time. Data from multiple wind farms may be transmitted from multiple local control stations to a remote station such that multiple wind farms may be monitored from a single location.

Abstract: A measuring device including at least one optical fiber which contains a series of Bragg gratings distributed between first and second ends of the fiber. A light source is arranged to emit a luminous flux at multiple wavelengths incident on the first end of the fiber, and an instrument connected to the second end of the fiber measures the power of the light transmitted at each emitted wavelength, enabling implementation of the method. In the method the power of the light transmitted by the optical fiber in a spectrum including wavelengths is measured.

Abstract: A living body monitoring activity system detects major activities, or feeble living body activities. In a method for monitoring existence of human movements or living body activities in living environments (e.g., sleeping activities involving a bed, a Futon-mat, a pad, or a Tatami-mat), an optical fiber type flat shaped body sensor including an optical fiber affixed or fitted to a flat shaped body is used, and light is emitted into the optical fiber from a light source, and changes of polarized wave conditions of light propagating in the optical fiber are brought about by changes in form of the optical fiber type flat shaped body sensor caused by human movements or living body activities and are detected by a measuring apparatus for polarized wave fluctuations so human activities or movements are discriminated based on the detected value of the polarized wave fluctuations.

Abstract: An optical fiber sensing device for detecting physical parameters such as pressures, strains and temperatures comprises a probe housing therein an optical fiber. The distal end of the probe houses a distal portion of the optical fiber having a section provided with a fiber Bragg grating. The proximal end of the probe is mounted into a holder. The optical fiber is sealably mounted into the probe housing with a first seal overlaid the proximal portion of the optical fiber The seal may extend to about the proximal end of the optical fiber section with the Bragg grating. A second seal is overlaid the distal portion of the optical fiber and extends from the distal end of the probe to about the distal end of the optical fiber section with the Bragg grating. The proximal end of the probe is communicable with a fiber Bragg grating interrogation system.

Abstract: A reinforcement element, comprises at least one sensor fiber adapted for strain measurements based on stimulated Brillouin scattering within said sensor fiber.

Abstract: A method and a device for dynamic measurement of the radial deformation of a bearing ring (12) of a rolling bearing (10) for a rotating element (16), a glass fiber segment (22) of a fiber optic sensor (24) that is fixed in or to the periphery of the bearing ring, a light signal which has been generated by the light source (30) being injected into the glass fiber segment, and the light signal passing through the glass fiber segment being detected by a detector (34), the longitudinal deformation of the glass fiber segment being determined from the change of at least one parameter of the light signal, when the light signal passes through the glass fiber segment, in order to determine the corresponding radial deformation of the bearing ring.

Abstract: A system and method are provided for determining wall thickness of a structure such as a metallic pressurized pipe. The system includes an optical fiber having a plurality of Fiber Bragg Gratings (FBGs), and a mounting for securing the FBGs over discrete portions of the exterior surface of the pipe such that strain in the pressurized pipe wall is transmitted to the FBGs. The system further includes a light source and a light sensor coupled to an end of the optical fiber. The light sensor converts light reflected back from the FBGs into electrical signals that a digital processor converts into strain measurements. The FBGs are mounted around portions of the pipe expected to have significant metal loss as well as portions of the pipe expected to have negligible metal loss.

Abstract: A fiber optic strain and temperature sensor is disclosed. The fiber can directly measure strain and temperature or the fiber can be coated with a magnetostrictive coating to measure magnetic flux, or coated with a hydroscopic coating to measure humidity or moisture content. The optical fiber sensors can be embedded in different locations in a generator to provide real time measurement of operating conditions.

Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device can include a fiber Bragg grating and a narrowband optical source. The narrowband optical source can be configured to generate light. A first portion of light can be transmitted along a first optical path extending along and through the length of the fiber Bragg grating at a group velocity. The light can have a wavelength at or in the vicinity of a wavelength at which one or more of the following quantities is at a maximum value: (a) the product of the group index spectrum and a square root of the power transmission spectrum, (b) the slope of a product of the group index spectrum and one minus the power transmission spectrum, and (c) the slope of a product of the group index spectrum and the power transmission spectrum.

Abstract: A structural displacement sensor that includes an arched member having two ends, where each end is attached to a fastening member. In an embodiment of the invention, the fastening members are configured to be attached to a structure. Further, a strain gauge is attached to the arched member, and the strain gauge is operatively connected to a signal processing device. In an embodiment, the arched member and strain gauge are configured to measure a displacement of the structure based on the amount of strain detected on the strain gauge.

Abstract: The invention relates to a broad band optical strain sensing system for a wind turbine. The strain sensing system includes an optical fiber with an input at one end and an output at the opposite end. The optical fiber is provided with Bragg sensors between the input and the output. By injecting light at the input of the fiber, measuring the spectral intensity distribution of at the output of the fiber and determining spectral locations of intensity notches in the spectral intensity distribution, it is possible to determine strain values at the locations of the Bragg sensors from the transmitted light.

Abstract: A method and device for facilitating measurement of thermo-optically induced material phase change response in a thin planar or a grating film stack is disclosed. The method may include using small-spot visible and ultraviolet spectra (ellipsometric or reflectance) for measuring a material phase change response. The device may include a measurement system platform, at least one electrical resistor, at least one external electric probe, and ohmic contact circuitry.

Abstract: An optical measurement instrument includes a measurement head and mechanical support elements arranged to support a sample well plate. The measurement head is moved towards the sample well plate and, after the measurement head has touched the sample well plate, the measurement head is moved backwards away from the sample well plate so as to provide a desired distance between the measurement head and the sample well plate. A sensor device is attached to the mechanical support elements and arranged detect a mechanical effect occurring in the mechanical support elements due to force directed by the measurement head to the sample well plate. Hence, the situation in which the measurement head touches the sample well plate can be detected without a need to provide the measurement head with a force sensor. This is advantageous because the measurement head can be a changeable module of the optical measurement instrument.

Abstract: A current transformer (5) having a plurality of primary and secondary windings, comprising a top Strain measuring system of wind turbine blades (11) during the performance of static tests that comprises an equipment for measuring the strain at multiple locations in mono-mode optical fibres (5, 7, 9) using Rayleigh scattered light, that includes an OBR interrogator (23), an interface device (25) and an Acquisition System (27), said mono-mode optical fibres (5, 7, 9) being attached to the blade (11) subjected to said tests for obtaining high spatial resolution measurements of the blade strain during said tests. Said optical fibres (5, 7, 9) may be placed whether in a longitudinal direction or in a non-longitudinal direction or in a non-linear shape in given blade sections and may be bonded whether to the outer skin (31) of the blade (11), or into grooves (51, 53) in the outer skin (31) of the blade (11) or embedded between two structural laminates (33, 35) of the blade (11).

Abstract: A sensor system and method for a power electronics module is discussed. The system comprises a optical fibre 318 mounted inside the module housing 302 and connected to an external sensor system 320 (not shown). The optical fibre 318 is arranged so that it lies proximate to one or more semiconductor dies 308 within the housing, and can sense their temperature. The fibre can be connected to the die 308 by glue, mechanical connection, or can in other examples by provided in the underlying support structure such as a DCB (direct copper bonded ceramic structure) or base plate 304. The fibre can contain an optical grating, such as an FBG or LPG, or can operate based on interferometry, to detect temperature or strain.

Abstract: A sensing device includes a first layer, a second layer, and an optical sensor. The first layer includes a first surface for supporting an associated load. The first layer transmits a strain to a second surface due to the associated load located on the first surface. The second layer is formed of a compliant material and provides substantially uniform support to the first layer and deflects due to the associated load. The optical sensor is positioned between the first and second layers and senses the strain due to the associated load.

Abstract: The present invention provides a distributed optical fiber sensor capable of measuring the strain and temperature of an object to be measured simultaneously and independently with high spatial resolution. A distributed optical fiber sensor FS is a distributed optical fiber sensor which uses an optical fiber 15 as a sensor, and a strain and temperature detector 14 measures a Brillouin frequency shift amount caused by a strain and a temperature generated in the optical fiber 15 by using a Brillouin scattering phenomenon, measures a Rayleigh frequency shift amount caused by the strain and temperature generated in the optical fiber 15 by using a Rayleigh scattering phenomenon, and calculates the strain and temperature generated in the optical fiber 15 from the measured Brillouin frequency shift amount and Rayleigh frequency shift amount.

Abstract: A system and a method for detecting surface pressure on a surface is provided. A plurality of transponders are located on the surface for transmitting electromagnetic surface waves and for receiving the electromagnetic surface waves upon being reflected, diffracted, refracted, scattered, or otherwise altered by pressure variations on the surface. A controller is coupled to the plurality of transponders. The controller is adapted to coordinate the plurality of transponders for imaging the pressure variations on the surface. The surface includes a surface-wave medium and the surface-wave medium is pressure-sensitive.

Abstract: A cable for distributed fibre optic sensing comprising a flexible tape, an optical fibre suitable for Brillouin scattering measurement forming at least two lengths, and at least one free end of at least one length being connectable to a reading unit, wherein at least a section of the longitudinal length of the flexible tape is situated between at least a section of the two lengths such that the two lengths are in close proximity such that a temperature gradient between the two lengths is minimized, and wherein the section of the tape and the section of lengths can flex together.

Abstract: A system and method for monitoring bending curvature of a flexible pipe structure, including at least one conduit configured to conform to a profile of a bend stiffener of a flexible pipe structure, and the at least one conduit including one or more sensors, wherein each sensor is configured for measuring a bending curvature of the bend stiffener.

Abstract: A fibre optic sensor is embedded in an integral housing block formed by moulding or extrusion. The housing block has a mounting surface for attachment to a wind turbine component by adhesive or mechanical connection. In an arrangement where the sensor is to be isolated from strains on the component, the housing block may be mounted on the component by means of a smaller mounting portion, joining the mounting portion at a neck region.

Abstract: A monitoring device for monitoring a plurality of microactuators includes an optical fibre with a plurality of sensors, each sensor being placed close to a microactuator and having optical properties varying as a function of at least one environmental parameter, the monitoring device also including a polling device with at least one transmitter/receiver for a fibre optic network, and processing means capable of modulating the frequency of the optical signal transmitted by the transmitter to select the sensor close to a given microactuator, and of comparing the received optical signal with a template characteristic of the correct operation of the microactuator, and of generating a resultant signal, representative of the correct operation of the monitored microactuator. The invention has applications in the field of health monitoring of vehicles, notably of aircraft.

Abstract: A method of detecting local mechanical stress in integrated devices is provided, the method comprising: enabling the detection of a photovoltage difference between a scan probe device and a surface portion of an integrated device, the scan probe device being configured to deflect in response to the photovoltage difference; measuring the deflection of the scan probe device in response to the photovoltage difference between the scan probe device and the surface portion of the integrated device; and calculating a local stress level within the integrated device by determining a local work function of the surface portion of the integrated device based upon the deflection of the scan probe device.

Abstract: A fiber-optic based thrust load measurement system is coupled to a bearing housing. The measurement system includes at least one fiber optic sensor configured to detect one or more parameters related to the bearing housing. An optical coupler is configured to regulate light signals emitted from a light source and light signals reflected from the fiber optic sensor. A detector system is configured to receive light signals from the optical coupler. A processor is configured to receive an output from the detector system and to determine a thrust load on a thrust bearing based on the detected one or more parameters related to the bearing housing.

Abstract: A device for detecting lightning currents in a wind turbine comprises an inductive loop (1) for carrying a current representative of a lightning current and a sensitive element, such as a resistance or a piezoelectric element electrically connected to the inductive loop (1). The apparatus further comprises an optical fibre strain sensor mechanically connected to the sensitive element, such that, in use, a lightning current results in expansion of the sensitive element and the optical fibre strain sensor produces an optical signal indicative of the strain on the sensitive element due to the expansion. The device has the advantage that the optical signal from the optical fibre strain sensor can be processed by the same signal processing equipment that processes signals from other strain sensors provided on the wind turbine.

Abstract: In an FBG (Fiber Bragg Grating) sensor, a stress direction converter includes a flat portion to which stresses are applied from the exterior, and stress transmitting sections that are bridged from the flat portion to an optical fiber cable. An inclined portion of the optical fiber cable, through which reflected light reflected by gratings is transmitted, is disposed along an inclined section that makes up one of the stress transmitting sections.

Abstract: A pressure sensor (10) comprising fibre Bragg grating (FBG) strain sensors (12) provided within an optical fibre (14), an optical fibre strain sensor carrier rod 16 and a pressure intensifying sleeve (18). The carrier rod (16) is formed from a first glass fibre reinforced epoxy resin composite material having a first stiffness/elastic modulus the direction of strain sensing. The sleeve (18) is formed from a second composite material, having a lower axial stiffness in the direction of strain sensing than that of the carrier rod (16). Under an applied hydrostatic load, the sleeve (18) exerts an axial compressive load onto the section of rod (16) within the sleeve (18). The axial compressive strain experienced by the rod (16) is thereby increased in the region within the sleeve (18) compared to the axial compressive strain that would be produced in the rod (16) if the sleeve (18) was not present.

Abstract: A sensing method, which comprises subjecting a holographic sensor to an external physical interaction to which the sensor is sensitive, and observing a change in the holographic image.

Abstract: A system and method for monitoring the structural integrity of a structure is provided. An optical fiber is acoustically coupled to one or more of the structural elements. A source of optical energy is configured to inject optical energy into the optical fiber, and an optical detector is configured to detect a first optical return signal having characteristics that are affected by vibrations of the structural elements. An analyzer measures characteristics of the optical return signal to determine information concerning the movement of the structural elements monitored by the fiber optic cable. The results of the analyzer can be stored and so that the analysis of the optical return signal can be compared to previously recorded signals to determine changes in structural integrity over time. Multiple fibers can be acoustically coupled to the monitored structural elements to obtain additional data concerning the structural integrity.

Abstract: An FBG (Fiber Bragg Grating) sensor is equipped with a plurality of stress detection sensors made up from optical fibers in which gratings that reflect light of a specified wavelength are arrayed, and a stress direction converter that converts stresses applied from the exterior into stresses of a direction in which the gratings are arrayed, and which transmits the stresses to each of the gratings. Consequently, the stress direction converter can transmit stresses, which are applied from a body, to a plurality of gratings.

Abstract: The invention relates to a broad band optical strain sensing system for a wind turbine. The strain sensing system includes an optical fibre with an input at one end and an output at the opposite end. The optical fibre is provided with Bragg sensors between the input and the output. By injecting light at the input of the fibre, measuring the spectral intensity distribution of at the output of the fibre and determining spectral locations of intensity notches in the spectral intensity distribution, it is possible to determine strain values at the locations of the Bragg sensors from the transmitted light.

Abstract: The invention relates to a method for sensing strain in a component in a wind turbine comprising an optical sensor system. The method comprises the step of inputting a optical signal into at least one optical fibre of said sensor system comprising one or more fibre Bragg grating sensors. Further, the method comprises the step of measuring the transmitted optical signals of said one or more sensors with at least one light detector connected to the other end of said at least one optical fibre, and processing the measured signals in a control unit in order to establish a value of the strain for the component. The invention also relates to an optical strain sensing system for a component in a wind turbine and uses hereof.

Abstract: A residual stress measuring method capable of measuring residual stress of the surface of an object to be inspected rapidly in a non-destructive non-contact manner, as well as a residual stress measuring system having such characteristics and being high in portability, are provided. The residual stress measuring system comprises a heating laser for heating an inspection area of an object to be inspected, a laser interferometer for irradiating the inspection area interferometric with laser light and measuring a deformation quantity within an elastic deformation range upon stress relief by heating in accordance with a laser interferometric method, and a data processor for measuring residual stress from the deformation quantity within the elastic deformation range upon stress relief of the object to be inspected.

Abstract: The general field of the invention is that of fiber-optic sensors comprising at least one measurement optical fiber having an optically pumped doped amplifying medium, the optical characteristics of which are sensitive to a physical quantity, the fiber having at least one Bragg grating. The fiber is designed so as to generate, in the amplifying medium, two optical waves having different optical frequencies that propagate in the same direction after reflection on the Bragg grating and are emitted by the amplifying medium, the two optical frequencies depending on the physical quantity. The two waves may be generated using either a birefringent polarization-maintaining fiber or a DBR (Distributed Bragg Reflector) laser cavity. Notably, this sensor may be used as a hydrophone.

Abstract: Distributed Strain Sensing (DSS) systems are used to measure strain using optical fibers functioning as linear sensors. Strain is measured along the fiber optic cable over large distances using a BOTDR (Brillouin Optical Time Domain Reflectometer) which is a Fiber Optic Strain Analyzer based on Brillouin technology. This measurement is popular in the Geotechnical field to monitor structural integrity of bridges, tunnels, mines etc. It is also popular in many industries including the Oil and Gas industry. The procedure involves recording strain data traces periodically to compare structural changes that may have developed over time. However, it is difficult to observe small changes from the raw data traces. This is due to the large number of data points and strain irregularities inherited in the fiber cable. This invention provides a simple and economical way to observe clearly very small strain changes acting on a structure. This is done by post processing the data traces with a low pass filter.

Abstract: A fluorescence detecting device irradiates an object to be measured with a laser beam, receives fluorescence generated from the object and processes a fluorescence signal generated when receiving the fluorescence. The device includes a laser light source section outputting the laser beam for irradiating the object, a light receiving section outputting the fluorescence signal of the fluorescence generated by the irradiated object, a light source control section generates a modulation signal having a frequency in order to time-modulate an intensity of the laser beam, and a processing section that calculates a fluorescence relaxation time of the fluorescence of the object based on the fluorescence signal output from the light receiving section. From the detection values acquired by the device including the phase information on the fluorescence, the intensity of the fluorescence is calculated.