Abstract: An optical fiber sensor which functions as a tactile sensor includes a plurality of shearing stress sensor sections including respective optical fibers and a plurality of gratings for reflecting light beams having predetermined wavelengths. The gratings are disposed in the optical fibers and arrayed along a plane parallel to the direction in which a shearing stress is applied from an object to the shearing stress sensor sections. The sensor also includes a perpendicular stress sensor section including an optical fiber and a plurality of gratings for reflecting a light beam having a predetermined wavelength. The gratings are disposed in the optical fiber and arrayed along a plane parallel to the direction in which a perpendicular stress is applied from the object to the perpendicular stress sensor section. Preferably, stress direction converting means such as elastic members for converting the direction of an applied stress are mounted on the optical fibers.

Abstract: A grating-based biosensor is disclosed where the biosensor is constructed and arranged such that the grating lines of the sensor align with an optical axis of a birefringent substrate, so as to improve resonance peak uniformity. Methods of manufacturing biosensors to provide alignment of the grating lines with the optical axes of a birefringent substrate are also disclosed. One embodiment uses a grating master wafer to form a grating on a continuous web of substrate material. The grating master wafer is rotated relative to the web until the lines of the grating in the master wafer are in substantial alignment with the optical axis of the web. A UV curable material is applied to the wafer and cured in place to form the grating on the surface of the substrate web. With a web of some preferred materials, such as PET film, one need only determine the optical axis orientation once for a given web since the optical axis orientation is essentially constant along the length of the web.

Abstract: A door handle apparatus for a vehicle, opening and closing a vehicle door, the door handle apparatus includes an informing portion for visually informing a state of the vehicle door, including a locking/unlocking state thereof, to a user by a decorative light, which is a visible light, an operation detecting portion for optically detecting an active-direct operation to the door handle apparatus by the user based on changes in an detection light, and an optical waveguide for transmitting the decorative light and the detection light, which is inputted from a first end portion of the optical waveguide, to a second end portion of the optical waveguide, the optical waveguide functioning as the informing portion by leaking the decorative light on a transmission path so as to be outwardly emitted and as the operation detecting portion by outputting the detection light from the second end portion of the optical waveguide.

Abstract: A method of fabricating a sensor probe comprises: placing the end of an optical fiber 10 in a polymerization space 2; applying a drop of hydrogel pre-gel solution 30 to the end of the fiber; exposing said pre-gel solution to an ultra-violet light source 24 to cause polymerization therein; and monitoring a light signal that has passed down said optical fiber 10 in order to monitor said polymerization.

Abstract: An optical device is presented for use in modulation of light and/or in sensing an external field, by at least partially, directly or indirectly exposing the device to the controllable or unknown external field. The device comprises a waveguide structure configured to define at least a first light channel having a light input and a light output, and having a first deformable resonating structure. The device thereby allows exposure of said at least first channel to the external field of the kind affecting a deformation of the first resonant structure thus causing a change in the first resonant wavelength, resulting in a corresponding change in at least one parameter of light output from said first channel, said change in the output light parameter being indicative of the external field.

Abstract: The invention describes the method and apparatus for enhancement of coupling efficiency in effective-ridge laterally-coupled surface-etched grating waveguide structures, where a slab waveguide has a sequence of the periodic parallel segmented trenches etched from its top surface, such that the segments of intact material having higher refractive index than that in the surrounding segments of periodic trenches form the effective ridges which confine the optical field in and around these ridges, on one hand, and provide bidirectional coupling for the confined modes experiencing Bragg reflection from the segments of the periodic trenches, on the other.

Abstract: The present invention relates to a sensor using a tilted fiber grating to detect physical manifestations occurring in a medium. Such physical manifestations induce measurable changes in the optical property of the tilted fiber grating. The sensor comprises a sensing surface which is to be exposed to the medium, an optical pathway and a tilted grating in the optical pathway. The grating is responsive to electromagnetic radiation propagating in the optical pathway to generate a response conveying information on the physical manifestation.

Abstract: A rod having an embedded optical fibre has a stiff composite outer layer (10) to make the rod self straightening to enable it to be pushed into a pipe or borehole from a spool. This can help enable a reduction of friction between rod and conduit and can enable longer reach. A barrier layer is provided to separate the fibre from the composite layer. The rod can be retrieved after use. The rod can be narrow enough to enable normal flow along the pipe or borehole, and can be injected and retrieved even when the pipe or borehole is pressurised. The fibre can be used for remote sensing of conditions along the conduit. Other tools can be inserted by the rod during the intervention.

Abstract: There is described an optical fiber sensor for sensing one of vibration, temperature, and strain, comprising: a laser source; a first single mode optical fiber having a first end and a second end, the first end connected to the laser source for receiving and propagating light from the laser source; a multimode optical fiber having a first end and a second end, the first end connected to the second end of the first single mode optical fiber for receiving the light and thereby exciting a plurality of modes of the multimode optical fiber, the multimode optical fiber being stretched at an out of band frequency and operated at a point at which an output is a linear function of a displacement of the multimode fiber; and a sampling photo-detector module connected to the second end of the multimode optical fiber for spatially filtering an output of the multimode fiber to obtain a spatially filtered interference pattern, and for detecting a variation of the spatially filtered interference pattern when one of the vibra

Abstract: A method for estimating a shape, the method including: selecting a structure comprising a plurality of strain sensors inoperable communication with the structure, each strain sensor configured to provide a strain measurement; placing the structure in a borehole; receiving the strain measurements from the plurality of strain sensors; creating a mesh grid having nodes, each node related to a location of one strain sensor and assigned a strain value measured by the one strain sensor; creating an additional node for the mesh grid wherein a strain value assigned to the additional node is derived from the strain value corresponding to at least one adjacent node; and performing an inverse finite method using the mesh grid with the assigned strain values to estimate the shape.

Abstract: A strain sensor includes an optical fiber with at least one optical fiber, a reflector body with a reflective surface, a housing affixed to the optical fiber probe and to the reflector body. The reflective surface is spaced apart at a distance d from the ends of the probe's fibers and receives light from the end of the fiber and to reflect at least a portion of the light into the end of the fiber. The housing is attached to the fiber probe at a first end of the housing and attached to the reflector body at a second end of the housing. The housing is affixed to the material to be measured, and in the material causes a change in gap between the fiber end and the reflective surface, modulating the amount of light received in the receiving fiber, detectable by a photodetector connected to the receiving fiber.

Abstract: A method and system for determining the length of collocated waveguides in a high erosion environment, such as a solid rocket motor or a braking system. The system provides for mating optical waveguides having different attenuation coefficients within the combusting, eroding, or otherwise regressing material. Optical energy generated by the environment (e.g., from burning fuel), or which is introduced and scattered into the environment, travels through the waveguides to detector means coupled thereto. The intensities of the arriving optical energy are compared and the length of the collocated waveguides calculated therefrom. By calculating the length of the waveguides over time, a regression rate is determined.

Abstract: A scanning system includes a cable take-up mechanism that uses a series of pulleys that determine the bend diameters of a scanning system. The mechanism is particularly suited for a spectrometric, e.g., infrared, scanning system where moving scanner or sensor head essentially houses only the optical elements while essentially of all the other electronic and optical components associated with the measurement are housed in an easily accessible compartment that is remote from the moving scanner head. Light is transmitted through optical fiber cables. The cable take-up mechanism maintains the fiber optic cable at essentially constant total bend length and bend diameter thereby minimizing any dynamic changes to spectral bend losses as the optical head is scanned. The light weight construction of the sensor head further reduces vibrations associated with the moving scanner head.

Abstract: A system and method for detecting unwanted wrapping of one or more of a plurality of strips of material around a feed roller intended to urge the strips of material forward. During proper operation, the strips of material remain to a first side of the feed roller, but an error may cause the material to pass to a second side of the feed roller. The system for detecting this error may comprise a plurality of send optical fibers configured to send light in a direction toward the second side of the feed roller; a plurality of receive optical fibers configured to receive light reflected off of the feed roller and/or any of the strips of material; and an alarm for notifying a user or an automated system if an amount of light received is not a desired amount of light, indicating reflection off of at least one strip of material.

Abstract: An optical sensor and a method of manufacturing such as sensor are provided. The sensor includes a lead optical fiber with a single piece optical element joined permanently joined to its forward end. The optical element defines a spacer with a cavity therein at one end, and a diaphragm at the opposite end. The diaphragm is flexible in response to a parameter and the sensor defines a sensing Fabry-Perot resonator.

Abstract: A polymer waveguide resonator device for high-frequency ultrasound detection having a optical resonator coupled to a straight optical waveguide which serves as input and output ports. Acoustic waves irradiating the waveguide induce strain modifying the waveguide cross-section or other design property. As a consequence, the effective refractive index of optical waves propagating along the ring is modified. The sharp wavelength dependence of the high Q-factor resonator enhances the optical response to acoustic strain. High sensitivity is demonstrated experimentally in detecting broadband ultrasound pulses from a 10 MHz transducer.

Abstract: An embodiment of a sensor fiber includes: at least two fiber sections with a plurality of holes; and at least one other fiber section situated between said at least two fiber sections, wherein the at least one other fiber sections being without the plurality of holes.

Abstract: A leak detection apparatus comprising an optical fibre sensor (2) arranged to detect leakage of fluid through a hose carcass (6, 8), wherein the sensor is arranged to detect the location of the leak along a section (4) of the hose.

Abstract: A torsion sensor using an optical waveguide in optical communication with a diffraction grating, preferably a tilted grating, and most preferably a tilted Bragg grating, which provides the optical waveguide and grating with a torsion-dependent collective optical transmission spectrum. Changes in the collective optical transmission spectrum of the waveguide and grating, induced by changes in the amount of torsion applied to the waveguide, may be detected by detecting a corresponding change in the intensity of optical radiation transmitted through the grating from a controlled optical source. The degree of change in the collective optical transmission spectrum is dependent upon the degree of torsion (twist) applied to the optical waveguide. Measuring the magnitude and/or sense (i.e. increase/decrease) in the intensity of optical radiation transmitted through the grating from an optical source enables torsion to be sensed.

Abstract: A catheter with many fiber optic pressure sensors. The sensor diaphragm is formed from a wafer with a thin silicon layer and a silicon substrate layer separated by a silicon dioxide layer. A method includes masking and etching channels through the silicon substrate layer in a pattern of concentric circles to form a concentric circular etched channels and cylindrical unetched portions of the silicon substrate layer between the channels, exposing the silicon dioxide in the etched regions, and dissolving the exposed silicon dioxide to expose the crystalline silicon layer in the etched regions. The unetched cylindrical portion of the silicon substrate forms the diaphragm support element and the thin silicon layer forms the diaphragm. After applying a reflective coating to the exposed thin silicon layer, the support element face is adhered to the end face of a tubular housing, and a fiber optic probe is inserted in the tubular housing.

Abstract: A method for detecting cracks in a carbon fiber bicycle frame using an embedded optical fiber is provided. Optical time-domain reflectometry is employed to detect cracks in a bicycle frame made of carbon fibers intertwining with a single-mode optical fiber. The single-mode optical fiber is thus embedded into the bicycle frame and consolidated with the carbon fibers during a manufacturing process of the bicycle frame. Integration of the single-mode optical fiber, which has a small diameter, low cost and lightweight, into the bicycle frame adds little to a production cost and weight of the bicycle frame. The optical fiber consolidated within the bicycle frame can be connected with an optical time-domain reflectometer for efficiently detecting twists or cracks of the carbon fibers in the bicycle frame, both as a quality check in the manufacturing process and as a safety check after the bicycle frame has been used for some time.

Abstract: A random array of holes is created in an optical fiber by gas generated during fiber drawing. The gas forms bubbles which are drawn into long, microscopic holes. The gas is created by a gas generating material such as silicon nitride. Silicon nitride oxidizes to produce nitrogen oxides when heated. The gas generating material can alternatively be silicon carbide or other nitrides or carbides. The random holes can provide cladding for optical confinement when located around a fiber core. The random holes can also be present in the fiber core. The fibers can be made of silica. The present random hole fibers are particularly useful as pressure sensors since they experience a large wavelength dependant increase in optical loss when pressure or force is applied.

Abstract: Disclosed is an apparatus for measuring convergence using a fiber Bragg grating sensor measuring slight deformation, capable of measuring the convergence such as the inclination or the gravitational acceleration of a measurement target including a bridge or a tunnel by measuring the deformation of the fiber Bragg grating sensor when the measurement target is inclined or vibrated, as well as a measurement method using the apparatus.

Abstract: A patient monitoring system includes a plurality of diffraction gratings integrated along the length of an optical fiber, wherein the optical fiber and each grating are together configured to alter either the effective refractive index or grating periodicity of the respective grating at its corresponding location along the fiber in response to at least one desired external stimulus.

Abstract: Apparatus and method for estimating the 3D orientation angles for remotely deployed devices with flexible arms such as dipole antennas of receivers used in marine controlled-source electromagnetic surveys to explore for hydrocarbons. Acoustic transponders or transducers, or other positioning sensors such as attitude sensors or strain-sensitive fiber optic cables are placed on each electrode arm of the receiver. Acoustic sensors (101) on the receiver frame (94) work in conjunction with the positioning sensor(s) (101) on the electrode arms (92) to provide accurate 3D spatial position of the receiver electrodes (93) relative to the receiver frame. Alternatively, sonar transducers mounted on the frame are used to image the electrode arms, which image can be enhanced by fixing reflectors to the arms. An attitude sensor is mounted on the receiver frame, enabling conversion of the relative electrode positions to an earth reference frame.

Abstract: A photonic coupler including a substrate, first and second waveguides disposed along a longitudinal direction of the substrate for propagation of respective first and second optical signals along the longitudinal direction, and a coupling region between the first and second waveguides and including a medium of a refractive index different from the first and second waveguides. The coupling region has a width extending from the first waveguide to the second waveguide and a breadth extending laterally to form an angle to the longitudinal direction for frustrated total internal reflection of the first optical signal at an interface between the coupling region and the first waveguide.

Abstract: A device (10) for sensing an acoustic signal is described. The device includes a flexible portion (14) including a laser active region (13) whose emitted wavelength varies according to a mechanical force acting on the flexible portion (14) and a flexible support member (24) operable to flex or bend according to the acoustic signal. The flexible portion (14) is coupled with the support member (24) so as to cause the flexible portion to flex or bend in accordance with the support member (24) thereby changing the emitted wavelength of the laser active region (13) of the flexible portion (14).

Abstract: A device to measure a fluid pressure comprises a pressure sensing element 10 and a pressure readout element 20. The pressure sensing element 10 comprises a cavity 11 capped by a flexible membrane 13, the cavity having a length d that varies with the fluid pressure P1 applied on the flexible membrane 13. The pressure readout element 20 comprises a light source 24 for providing an incident beam of a determined wavelength range directed towards the cavity and an optical spectral analyzer 25 for measuring a power spectrum of a return beam reflected by the cavity, and processing means 27 for determining the cavity length d and the fluid pressure P1 based on the power spectrum.

Abstract: A variable optical attenuator for adjusting a power of light which is output from an output end of a first optical fiber and is to be led to an input end of a second optical fiber, includes a reflection member which reflects the light output from the output end of the first optical fiber, a density filter which transmits the light reflected from the reflection member and controls the power of the light which is transmitted by the density filter depending on a light-transmitting position on the density filter, and an optical member which reflects the light transmitted by the density filter to lead the light to the reflection member. The reflection member is disposed tiltably, the power of the light transmitted by the density filter attenuates along a direction in which the light-transmitting position is changed, and the light-transmitting position of the light is changed by tilting the reflection member.

Abstract: A touch panel optical waveguide which obviates the need for positioning light receiving cores of the optical waveguide with respect to light emitting cores of the optical waveguide, and to provide a touch panel employing the optical waveguide. A projection (5) is provided in one of longitudinally opposite end portions of an elongated optical waveguide (A), and a recess (6) to be engaged with the projection (5) is provided in the other end portion of the elongated optical waveguide (A). By engaging the projection (5) with the recess (6), distal ends of light emitting cores (3) are automatically and accurately opposed to distal ends of light receiving cores (3) with the intervention of a display screen of a touch panel.

Abstract: The invention relates to a composite structure (11) formed by a plurality of layers (13, 15, 15, 19, 21, 23) including an optical fiber (25) for structural monitoring purposes which is at least partly embedded in a surface layer (13) of said structure (11), and insulation means of the optical fiber (25) areas susceptible to repair with respect to the surface layer (13) in which they are integrated, particularly a protective cover (27) and top and bottom separating films (31, 33), and a process of repairing said areas comprising the following steps: removing the protective cover (27) and the top separating film (31), extracting the area, repairing the optical fiber, relocating the area and providing a new protective cover (27).

Abstract: An optical fiber (100) utilized as a sensor for measuring a parameter of interest 122 such as temperature, strain, photonic energy intensity, electric field intensity and magnetic field intensity is provided. A first optical cladding layer (104) is disposed on an optically transmissive core (102) that includes one or more optical gratings (114-1). The optical grating(s) (114-1) modifies a propagation path of selected wavelengths of light propagating through the core (102). The optical grating(s) (114-1) also varies the index of refraction of the first optical cladding layer (104). The selected wavelengths of light are determined in part by the index of refraction of the core material 105 as dependent upon a parameter of interest 122 applied to the core material 105 and as varied by the optical grating(s) (114-1). One or more detectors (410, 430, 450, 455) are used for determining the properties of the reflected and/or transmitted light.

Abstract: Devices for monitoring structural health conditions of host structures. A device includes at least one optical fiber sensor and an electronic module. The optical fiber sensor includes a rolled optical fiber cable operative to generate a frequency shift of a light signal passing therethrough and a coating layer applied to the rolled optical cable. The frequency shift is commensurate with vibration of the host structure. The electronic module sends an input light signal to the optical fiber sensor, receives a sensor signal from the optical fiber sensor, and processes the sensor signal.

Abstract: An optical fiber strain sensor, a method of fabricating the same, and a method of sensing strain (1200). The method of strain sensing comprises providing an optical fiber having at least a first fiber Bragg grating (FBG) and a second FBG formed therein (1202); subjecting the optical fiber to a strain inducing force such that a grating period in the first FBG compresses and a grating period in the second FBG extends (1204); and optically interrogating the first and second FBG to determine peak reflection wavelengths of the first and second FBGs respectively (1206), whereby a separation between the peak reflection wavelengths of the first and second FBGs is representative of the strain induced.

Abstract: An arrangement for a fiber optic microphone having at least one pair of optical fibers, each having an input end portion and an output end portion made of a material having a critical refractive angle ?crit and having a numerical aperture NA. The input end portion of a first fiber is connectable to a source of light and the output end portion of a second fiber is connectable to a photoelectrical transducer. Both end portions have an inner diameter, an axis and a rim. The input and output end portions are mutually affixed along a single plane with their rims touching each other at a point, the axes forming an angle ? therebetween. The rims are cut with respect to the axis, at an angle in a plane perpendicular to the single plane and to a bisector of angle ? at the point, where ?=2×?crit?NA.

Abstract: A sensor apparatus for sensing parameters of an object may include at least one optical fiber, one or more attaching members and a tensioner. The one or more attaching members may be coupled to the optical fiber and may attach the one optical fiber to an object. The tensioner may be coupled to the optical fiber and may secure the one or more optical fiber against a surface of an object.

Abstract: Systems and methods comprise or involve optical fibers having Bragg gratings. The optical fibers can be assembled in a parallel manner into a fiber sensor configuration. Bragg gratings can be written onto different cores of optical fibers. Bragg gratings may be written at a same or nearly same axial position for all optical fibers in the configuration and may be written at the same time and may have a substantially equal index of refraction variation and unequal lengths. Spaced Bragg gratings may also have characteristic sidelobe spectrums for tagging the respective gratings. Gratings can also be written at different wavelengths and over another grating at the same location.

Abstract: A process for locating and measuring deformation in a civil engineering structure wherein at least one geosynthetic fabric (1) containing a plurality of optical fibers (2a to 2e) in parallel and capable of transmitting signals is applied in the structure or under the structure. The optical fibers contain Bragg gratings (3), evenly spaced in series (4) of N1 consecutive gratings that correspond to the same wavelength. The series is distributed in identical sets, each of which contains N2 consecutive series that correspond to the different wavelengths, and, in at least two optical fibers, the numbers N1 of gratings of a series and the numbers N2 of series (4) of a set (5) are determined to locate the deformations to which the structure is subjected on the one hand and, on the other, to measure the elongation of the said optical fibers where the deformation occurs.

Abstract: A light activated optical switch has a piezoelectric element that has at least two layers of piezoelectric material with each layer having different piezoelectric characteristics. The piezoelectric characteristics of the layers are selected to enhance the performance of the piezoelectric element and ultimately to enhance the performance of the optical switch.

Abstract: An optical sensor includes a support structure. An optical fiber has a plurality of bends arranged proximate the support structure. The optical fiber follows a circuitous path and is adapted to establish a detection zone.

Abstract: A sensor for measuring at least one of temperature and pressure in a borehole, the sensor including a mixing medium disposed in a housing adapted for insertion into the borehole, the mixing medium exposed to at least one of the temperature and the pressure; wherein the mixing medium is used for four wave mixing of light to provide a signal that indicates at least one of the temperature and the pressure.

Abstract: An optical fiber strain-temperature sensing system includes first and second optical sources respectively generating first and second light signals having different wavelengths. Optical circulators direct the light signals to an external sensing cable for the respective generation of first and second Brillouin scattered light signals. First and second frequency mixers have a first input respectively coupled to the first and second optical light sources. The optical circulators direct the first and second Brillouin scattered light signals respectively to second inputs of the first and second frequency mixers. First and second transducers are respectively coupled to an output of the first and second frequency mixers and are respectively configured for generating first and second electrical signals indicative of a Brillouin frequency shift of the first and second light signals.

Abstract: An intensity modulated broadband optical signal source is arranged to produce optical signals in a plurality of wavelength bands. A demultiplexer/multiplexer pair receives optical signals from the optical signal source and produces a separate optical signal for each wavelength band. An optical coupler is arranged to receive the separate optical signals. Optical fiber loops connected to the optical coupler guides both clockwise and counter clockwise waves for each of the separate optical signals. The optical signals propagate through a sensor in each loop and then combine in the optical coupler to form a plurality of interference signals in each wavelength band. A multiplexer is optically coupled to the optical coupler to receive the interference signals therefrom, and a detector array having a selected detector corresponding to the each of the plurality of wavelength bands is arranged to provide an electrical signal that indicates the interference signals for each wavelength band.

Abstract: An acoustic sensor includes at least one photonic crystal structure having at least one optical resonance with a resonance frequency and a resonance lineshape. The acoustic sensor further includes a housing substantially surrounding the at least one photonic crystal structure and mechanically coupled to the at least one photonic crystal structure. At least one of the resonance frequency and the resonance lineshape is responsive to acoustic waves incident upon the housing.

Abstract: A device capable of obtaining information about objects both in contact with a surface and near to, but not in contact with, a surface of the device. The information may include position relative to the surface, pressure when in contact with the surface, shape of the object or objects, and many other properties. Certain embodiments make use of optical waveguides comprising a photoluminescent material which responds to first electromagnetic radiation of a first spectrum propagated through the system by emitting second electromagnetic radiation of a second spectrum. The distribution of the first electromagnetic radiation is altered by pressure on the surface or by the presence of objects near the surface of the device. The distribution of the second electromagnetic radiation is measured using photosensors and processed to determine desired information.

Abstract: A perimeter security system is disclosed which includes a first cable (40) and a second cable (60) buried beneath the ground in a zig-zag pattern. The first cable (40) has a first fibre (44) and a further fibre (42). Second cable (60) has a second fibre (62). The first and second fibres (44) and (62) are connected by a coupler (52) at one end so that light can be launched into the first and second fibres (44) and (62) to propagate in one direction. The further fibre (42) is connected to a coupler (70) which also connects to the other end of the first and second fibres (44) and (62) so light can be launched into the fibres from the other end and travel in the opposite direction.

Abstract: An optical fiber strain sensor, a method of fabricating the same, and a method of sensing strain. The method of strain sensing comprises providing an optical fiber having a fiber Bragg grating (FBG) formed therein; subjecting the optical fiber to a strain inducing force such that a grating period in a first portion of the FBG compresses and a grating period in a second portion of the FBG extends; and optically interrogating the FBG to determine a measure of a change in bandwidth of the FBG as a result of the compression and extension of the grating periods in the first and second portion respectively; whereby the measure of the change in the bandwidth is representative of the strain induced.

Abstract: A fiber optic sensor includes a housing having first and second end plates with a sidewall extending therebetween with the sidewall having an inwardly facing groove. A flexural disk having a central passage therethrough has an outer edge portion mounted in the inwardly facing groove in the housing. The flexural disk has a stepped thickness that is thinner at the outer edge portion than at a region spaced apart from the housing. A first fiber optic coil is mounted on a first side of the flexural disk in the thicker region of the flexural disk, and a second optical fiber is mounted on a second side of the flexural disk opposite the first fiber optic coil. The first and second fiber optic coils are optically coupled together by a fiber optic coupler to form an interferometer that produces an output signal in response to axial acceleration of the flexural disk.

Abstract: The present invention includes a method and system of measuring alteration, alteration type, and alteration-causing species in process fluids and equipment and for controlling the process feeds and conditions to maximize the yields and equipment lifetime by minimizing the alteration. The invention includes an optical sensor comprising an optical fiber, a fiber grating written within the optical fiber, strain-tuned elements fixed to the optical fiber and an unaltered element, and an altered element fixed to the unaltered element.

Abstract: A spatially distributed sensor system has an optical transmitter, an optical conduit optically coupled to the optical transmitter at an input position, and a sensing element optically coupled to the optical conduit at a position along the optical conduit spatially separated from the input position. The sensing element is structured to split off a fraction of light from the optical transmitter upon being coupled into the optical conduit and to return light to the optical conduit. The spatially distributed sensor system also has an optical receiver coupled to the optical conduit to receive at least a portion of light from the optical conduit that includes light returned to the optical conduit from the sensing element. An analysis of light received by the optical receiver provides information to determine a position of the sensing element.