Abstract: Ultrasonic measurements of fluid properties are performed with the aid of an optical fiber or a package of optical fibers by exciting ultrasound waves at a first location along the optical fiber in the fluid by means of light from the optical fiber and detecting an effect of the ultrasound waves on light reflection or propagation in the optical fiber and/or a further optical fiber in the package at a second location along the optical fiber or at the end of the optical fiber.

Abstract: A method of monitoring corrosion of an electrical enclosure in a hazardous environment is provided. The method is implemented with at least one computing device in communication with at least one FBG optical sensor reflecting UV light in the electrical enclosure. The method includes measuring wavelength changes of UV light reflected by the at least one sensor, wherein the wavelength changes are a function of corrosion-related strain in the electrical enclosure. The method also includes computing, by the at least one computing device, the corrosion-related strain in the electrical enclosure based on the measured wavelength changes. The method further includes comparing, by the at least one computing device, the computed corrosion-related strain with a predetermined threshold, and recommending preventive corrosion-related maintenance based on the comparison.

Abstract: Provided are robotic systems and methods for navigation of luminal network that can improve strain-based shape sensing. In one aspect, the system can compare strain-based shape data to shape data determined based on robotic data (e.g., kinematic model data, torque measurements, mechanical model data, command data, etc.) and adjust the strain-based shape data as necessary. Any portion of the strain-based shape data can be adjusted, weighted differently, or discarded based on the comparison. For example, data from trustworthy sources may indicate that the shape of an instrument exhibits or should exhibit one or more characteristics. If the system determines that any portion of the strain-based shape data is not in agreement with such characteristics, the system may adjust the portion of the strain-based shape data such that the adjusted strain-based shape data is in agreement with the characteristics of the instrument.

Abstract: An apparatus comprises a first plurality of optical fibers embedded in a first plurality of fabric strands, a second plurality of optical fibers embedded in a second plurality of fabric strands, and a detector. The first plurality of optical fibers are positioned adjacent to each other and oriented along a first direction and the second plurality of optical fibers are positioned adjacent to each other and oriented along a second direction orthogonal to the first direction. The first and second plurality of optical fibers are configured to receive ambient light emitted onto them. The detector detects the light received into at least some of the first and second plurality of optical fibers and creates data configured to be processed to identify an object adjacent to the apparatus. The data is based on the light received into the first plurality of optical fibers and the second plurality of optical fibers.

Abstract: A well system includes a fiber-optic cable that can be positioned downhole along a wellbore. The well system further includes a plurality of opto-electrical interfaces to communicatively couple to the fiber-optic cable to monitor temperature and strain along the fiber-optic cable. Additionally, the well system includes a processing device and a memory device that includes instructions executable by the processing device to cause the processing device to perform operations. The operations include receiving data representing frequency or phase shift measurements from the opto-electrical interfaces using at least two frequency or phase shift measurement techniques. Further, the operations include generating a temperature shift output and a strain change output using an inversion comprising sensitivity ratios and the data representing the frequency or phase shift measurements from the plurality of opto-electrical interfaces.

Abstract: An apparatus has a chassis having a base. A first wall extends substantially perpendicularly from the base at a first edge of the base. The first wall is configured to be a first attachment point for an optical cable comprising one or more optical sensors. An opposing second wall extends substantially perpendicularly from the base at a second edge of the base. A mobile attachment point is configured to be a second attachment point for the optical cable. A spring is coupled to the second wall and the mobile attachment point. The spring is configured to provide a specified force as the mobile attachment point moves.

Abstract: A sensor includes at least one optical waveguide and an optical reflector optically coupled to the at least one optical waveguide. The optical reflector includes a first substrate portion configured to reflect a first portion of a light beam back to the at least one optical waveguide and a diaphragm configured to reflect a second portion of the light beam back to the at least one optical waveguide. The diaphragm is responsive to a perturbation by moving relative to the first substrate portion. The light beam is centered on a region between the first substrate portion and the diaphragm.

Abstract: There is described a method for interrogating optical fiber comprising fiber Bragg gratings (“FBGs”), using an optical fiber interrogator. The method comprises (a) generating an initial light pulse from phase coherent light emitted from a light source, wherein the initial light pulse is generated by modulating the intensity of the light; (b) splitting the initial light pulse into a pair of light pulses; (c) causing one of the light pulses to be delayed relative to the other of the light pulses; (d) transmitting the light pulses along the optical fiber; (e) receiving reflections of the light pulses off the FBGs; and (f) determining whether an optical path length between the FBGs has changed from an interference pattern resulting from the reflections of the light pulses.

Abstract: An emissions control system for a gas turbine system includes a reducing agent supply, at least one sensor, at least one valve, and a controller. The reducing agent supply has one or more conduits configured to couple to one or more fluid pathways of the gas turbine system, which are fluidly coupled to a flow path of an exhaust gas from a combustor through a turbine of the gas turbine system. The at least one sensor is configured to obtain a feedback of one or more parameters of the gas turbine system, which are indicative of a visibility of emissions of the exhaust gas. The at least one valve is coupled to the reducing agent supply. The controller is communicatively coupled to the at least one sensor and the at least one valve, such that, in response to the feedback, the controller adjusts the at least one valve to adjust a flow of the reducing agent to reduce the visibility of the emissions of the exhaust gas.

Abstract: A method for testing physical properties of a material includes inserting coherent light into a waveguide such that the coherent light exits the waveguide at an end of the waveguide that is embedded within the material, thereby causing the coherent light to interact with the material. The method also includes detecting a reaction of the material to the coherent light.

Abstract: A surgical visualization system is disclosed. The surgical visualization system includes a control circuit communicatively coupled to a straight line laser source, a structured light emitter, and an image sensor; and a memory communicatively coupled to the control circuit. The memory stores instructions which, when executed, cause the control circuit to control the straight line laser source to project a straight laser line reference; control the structured light source to emit a structured light pattern onto a surface of an element of a surgical device; control the image sensor to detect the projected straight laser line and structured light reflected from the surface of the element of the surgical device; and determine a position of the element of the surgical device relative to the projected straight laser line reference.

Abstract: A fracturing treatment optimization system using multi-point pressure sensitive fiber optic cables to measure interwell fluid interaction data, microdeformation strain data, microseismic data, distributed temperature data, distributed acoustic data, and distributed strain data from multiple locations along a wellbore. The fracturing treatment optimization system may analyze the interwell fluid interaction data, microdeformation strain data, microseismic data, distributed temperature data, distributed acoustic data, and distributed strain data, modify a subsurface fracture network model, and calculate interwell fluid interaction effects. The fracturing treatment optimization system may use the fracture network model to measure current and predict future fracture growth, hydraulic pressure, poroelastic pressure, strain, stress, and related completion effects. The fracturing treatment optimization system may enable real-time monitoring and analysis of treatment and monitoring wells.

Abstract: A two-dimensional waveguide light multiplexer is described herein that can efficiently multiplex and distribute a light signal in two dimensions. An example of a two-dimensional waveguide light multiplexer can include a waveguide, a first diffraction grating, and a second diffraction grating disposed above the first diffraction grating and arranged such that the grating direction of the first diffraction grating is perpendicular to the grating direction of the second diffraction grating. Methods of fabricating a two-dimensional waveguide light multiplexer are also disclosed.

Abstract: A microwave oscillator ultrasound receiver which includes one or more pressure sensitive microwave resonators having a perturbable resonant frequency; one or more signal generators operable to generate one or more microwave carrier signals; one or more detectors configured to detect at one or more of: an amplitude and phase modulation of the one or more carrier microwave signals corresponding to resonance perturbations; and a computer processing device arranged to analyze any of the following: amplitude and phase modulation, and measure, based on the amplitude and phase modulation, an ultrasound signal, so that the resonance perturbations arise in response to the ultrasound signal being received by the pressure sensitive microwave resonator, the ultrasound signal effecting pressure changes on the pressure sensitive microwave resonator and thereby perturbing the perturbable resonant frequency.

Abstract: Aspects of the present disclosure describe systems, methods and structures for determining any location on a deployed fiber cable from an optical time domain reflectometry (OTDR) curve using a movable mechanical vibration source to stimulate tiny vibration of fiber in deployed fiber cable along the cable route and a fiber sensing system at a central office to detect the vibration(s). Latitude and longitude of the location(s) of the vibration source is measured with a GPS device and a dynamic-OTDR distance is measured at central office (CO) simultaneously. The collected GPS location data and corresponding dynamic-OTDR distance data are paired and saved into a database. This saved data may be processed to graphically overlie a map thereby providing exact cable location on the map thereby providing carriers/service providers the ability to improve fiber fault location on a deployed fiber cable much faster and more accurately than presently possible using methods available in the art.

Abstract: A photonic chip including a trench at the periphery of the photonic chip forming a recessed rim, wherein the recessed rim includes at least one geometric feature separating a plurality of waveguide locations, the at least one geometric feature suitable to prevent adhesive flow between the plurality of waveguide locations and method for preventing adhesive flow from interfering with bonding of optical fibers to the photonic chip is disclosed. A photonic chip including at least one optical fiber groove which includes an entrance portion and a non-entrance portion, wherein the entrance portion includes a flared opening having a greater clearance than the non-entrance portion and method for attaching an optical fiber to the photonic chip minimizing damage to at least one of the optical fiber and the photonic chip is disclosed.

Abstract: A pressure sensor having unevenness and a manufacturing method therefor are disclosed. The disclosed pressure sensor senses pressure in a vertical direction and includes a first pressure sensor unit and a second pressure sensor unit, wherein the first pressure sensor unit and the second pressure sensor unit are stacked, and unevenness is formed on the upper surface of the first pressure sensor unit and on the lower surface of the second pressure sensor unit.

Abstract: A monitoring humidity measurement system includes: a humidity measurement optical fiber including a first optical fiber and a humidity detection layer provided so as to annularly cover the first optical fiber; a reference optical fiber including a second optical fiber; a plurality of optical communication cables; and a signal processing device configured to, with a laser beam entering into the first and second optical fibers, calculate and obtain Brillouin frequency shift and Rayleigh frequency shift of backscatter light from the first and second optical fibers based on the entering laser beam, and store predetermined constants, wherein reference data and target data are measured from the Rayleigh frequency shift and an initial humidity value calculated from the Brillouin frequency shift, and the value of humidity at the present time is calculated on the basis of Rayleigh frequency shift per unit humidity calculated from a difference between the above two data.

Abstract: In-well steam monitoring for SAGD operations using permanent fiber optic sensors installed behind the casing of an injector or producer well provides continuous monitoring of downhole steam injection. Using in-well sensor measurements, the system may also adjust or otherwise manipulate the volume of injected steam over time.

Abstract: The following relates generally to ensuring patient safety while operating a Magnetic Resonance Imaging (MRI) machine. Many MRI systems operate using: fiber optic cables to carry signals, electrically conductive cables to carry other signals, and radio frequency (RF) coils to create an electromagnetic field. Typically, the electrically conductive cables and RF coils do not interact in a way that causes harm to a patient. However, certain shapes and/or lengths of cables exhibit the phenomenon of “resonance” that increases their propensity to concentrate RF currents induced by the RF coils. This may increase the temperature of the cable or other component in the MRI system leading to patient harm. The methods disclosed herein provide a solution to this by sensing a shape of the fiber optic cable and determining if the fiber optic cable will exhibit resonance. If it is determined that resonance may potentially occur, an alarm may be generated or a radio frequency amplifier may be interlocked.

Abstract: Disclosed are embodiments of an on-chip polarizer and of methods of forming the polarizer. The polarizer includes first and second waveguides with different shapes at different design levels above a substrate. The first waveguide has a main body between an input end and an output end. The second waveguide is spiral in shape with an inner end and with an outer end that is evanescently coupled to the main body of the first waveguide. Light signals, including first light signals with a first type polarization and second light signals with a second type polarity, are received at the input end of the first waveguide. The first waveguide passes the first light signals to the output end and passes at least some second light signals out the main body and into the outer end of the second waveguide. The second waveguide attenuates the received second light signals.

Abstract: An instrument system that includes an elongate instrument body and an optical fiber sensor is provided. The optical fiber sensor includes an elongate optical fiber that is coupled to the elongate instrument body, wherein a portion of the optical fiber is coupled to the elongate instrument body in a manner to provide slack in the fiber to allow for axial extension of the elongate instrument body relative to the optical fiber.

Abstract: Systems and associated methods for utilizing an artificial hair sensor to gather fluid flow data sensed on a surface. The artificial hair sensors are disposed on a surface to acquire flow sensory data in approximately real-time and for a plurality of dynamic flow parameters on the surface. The sensory data is based on a quantity of the artificial hair sensors that can be configured in an array of sensors. A mapping module, such as a neural network, is operatively coupled to the artificial hair sensor array and receives the sensory data acquired by the artificial hair sensors and generates a time-varying signal, which is based on the quantity of dynamic parameters. A real-time representation of the time-varying signal is generated.

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: A distributed acoustic sensing (DAS) system based on space-division multiplexing with multi-core fiber (MCF) is proposed. It relates to a technical field of distributed optical fiber sensing. The present invention maintains the advantage of single-ended measurement in the standard DAS system, and realizes the intensity accumulation of the Rayleigh backscattering light within each core of the MCF, which can greatly improve the strain resolution of DAS systems. Moreover, the introduction of optical switch can make different code sequences transmit in the different core of the MCF simultaneously, which can make the single-pulse response with coding gain demodulated without sacrificing the frequency responding bandwidth. Furthermore, the utilization of space-division multiplexing can make multiple pulses with precious time delay transmit in the MCF simultaneously, which can greatly improve the frequency responding bandwidth of DAS system.

Abstract: A smart part comprising: a body, manufactured by a three-dimensional (3D) additive manufacturing (AM) process, having high-stress and low-stress sections, wherein when the smart part is in operational use the high-stress section is subjected to higher stress than the low-stress section; and wherein the body comprises a void having a predefined geometry intentionally created within the high-stress section of the body during the AM process, such that the void is completely embedded within the body and is configured to provide quality assurance information.

Abstract: Techniques to determine wellbore leak crossflow rate between formations in an injection well are described. The techniques repurpose well performance principles to achieve the objective of cross flow rate quantification without the need to run a flowmeter.

Abstract: An opening and closing detection sensor of the present invention includes a fixed base, a moving base, an optical fiber, and a moving member. The moving base is disposed so as to be movable relative to the fixed base. The optical fiber includes an FBG part where a Bragg wavelength varies responding to an interval between the fixed base and the moving base. The moving member moves between a first position corresponding to either one of an opened state or a closed state of an object and a second position corresponding to the other state. The moving member includes a locking part. The locking part abuts on the moving base between a third position located between the first position and the second position, and the second position, thereby moving the moving base together with the moving member, and moving the moving base in a direction separated from the fixed base.

Abstract: A method for measuring a concentration of at least one target species includes generating first and second laser beams having respective first and second wavelengths each corresponding to respective absorption lines of the at least one target species. The method includes coupling the first and second laser beams to proximal ends of first and second fundamental modes of first and second optical waveguides, respectively. The method includes transmitting through a measurement zone, for a distal end of the first and second optical waveguides, a probe signal including the first and second laser beam. The method includes determining a first signal strength of the probe signal at the first wavelength and a second signal strength of the probe signal at the second wavelength, and determining, from the first signal strength and the second signal strength, a concentration of the at least one target species.

Abstract: A conveyor employs electrostatic force to selectively adhere packages to an inclined conveying surface and selectively release packages from the inclined conveying surface to separate the packages from each other. A pair of electrodes embedded in the body of a conveyor belt module are selectively energized via electrically conductive hinge rods used to connect conveyor belt modules together to generate the electrostatic force.

Abstract: A method of monitoring variation in the thrust exerted by at least one buoy exerting traction on an undersea pipe, wherein: 1) the deformation of at least one optical fiber is measured by measuring variation of an optical signal in said fiber extending on the surface or embedded securely in the bulk of at least one of the following support elements: a) the buoy; b) at least a portion of: b1) the length of the tubular wall of the pipe or b2) an anticorrosion coating or a thermally insulating material fastened on the surface of said pipe, on which said buoy exerts traction, and c) an abutment part secured to said pipe or buoy, and on which said buoy exerts said thrust; 2) a variation of said thrust exerted by said buoy is determined as a function of said variation of the optical signal.

Abstract: A core-stiffed composite structure includes a plurality of bonded layers forming the core-stiffened composite structure, a fiber optic conductor embedded between two of the plurality of bonded layers, the fiber optic conductor including a terminal end, and a protective box embedded in the core-stiffened composite structure and bonded to one or more of the plurality of bonded layers, wherein the terminal end of the fiber optic conductor projects into the protective box.

Abstract: This patent document discloses fiber sensing techniques and devices for shape monitoring by using single- and multi-core optical fiber implementations and optical interferometry. Implementations can be made based on coherent optical time domain reflectometry (OTDR) or optical frequency domain reflectometry (OFDR).

Abstract: Disclosed herein are various implementations of a fiber optic shape-sensing system comprising a plurality of optical fibers helically twisted and rigidly bonded to form a linearly-running shape-sensing bundle for measuring position, bend, and twist of the shape-sensing bundle, wherein each optical fiber from among the plurality of optical fibers comprises a single core. Several such implementations of the systems further comprise an array of Fiber Bragg Gratings (FBGs) disposed within the core of each single-core optical fiber from among the plurality of single-core optical fibers.

Abstract: The present application achieves luminance uniformity of a light-emitting region substantially circular in shape, desired high contrast, and low power consumption. A lighting device (1) is configured such that assuming that L is an external diameter of a light-emitting region (E), Xmax is the number of divisions for concentrically dividing the light-emitting region (E), and d is a radial pitch between LEDs (11) which include a centered LED (11) and LEDs (11) arranged substantially concentrically around the centered LED, d=L/(2Xmax+1), and that, in each of the n-th ring regions (Xn), an 8n number of LEDs (11) are arranged at equal pitches in a circumferential direction and are positioned at a distance equivalent to a radius nd from the centered LED (11).

Abstract: Autonomous closed loop control of a flexible tendon-driven continuum manipulator having a sensor at a distal tip is performed by measuring spatial attributes of a sensor at the distal tip and estimating an orientation of a base of an articulating region of the flexible tendon-driven continuum manipulator from a kinematic model and the spatial attributes of the sensor. The manipulator control in a task space uses the estimated orientation, a desired trajectory in the task space, and the position of the sensor at the distal tip. The sensor at the distal tip may be a magnetic sensor, impedance sensor, or optical sensor.

Abstract: A fiber optic force sensing assembly for detecting forces imparted at a distal end of a catheter assembly. The structural member may include segments adjacent each other in a serial arrangement, with gaps located between adjacent segments that are bridged by flexures. Fiber optics are coupled to the structural member. In one embodiment, each fiber optic has a distal end disposed adjacent one of the gaps and oriented for emission of light onto and for collection of light reflected from a segment adjacent the gap. The optical fibers cooperate with the deformable structure to provide a change in the intensity of the reflected light, or alternatively to provide a variable gap interferometer for sensing deformation of the structural member. In another embodiment, the gaps are bridged by fiber Bragg gratings that reflect light back through the fiber optic at central wavelengths that vary with the strain imposed on the grating.

Abstract: A shape estimation device includes an input circuit, a storage circuit and an arithmetic circuit. The input circuit receives light amount information being a relationship between a wavelength and a light amount. The light amount information is acquired by using a sensor configured such that the light amount to be detected with respect to the wavelength corresponding to each of sensing parts varies in accordance with a shape of each of the sensing parts. The storage circuit stores a relationship among the shape, the wavelength and the light amount with respect to each sensing part. The arithmetic circuit calculates the shape of each sensing part, based on the light amount information, and a light amount estimation value being a relationship between the wavelength and the light amount.

Abstract: The present disclosure relates to a terahertz imaging system for imaging a lumen of a human, such as an intravascular space. A system may include a catheter and a terahertz transceiver device coupled to the catheter. The terahertz transceiver device may be operative to output terahertz radiation through a lumen of a human and to receive reflection signals based on the terahertz radiation. A power source may be coupled to the terahertz transceiver device. The system may further include a controller in communication with the terahertz transceiver device. The controller is operative to obtain an image of the lumen based on the reflection signals.

Abstract: An ablation catheter system configured with a compact force sensor at a distal end for detection of contact forces exerted on an end effector. The force sensor includes fiber optics operatively coupled with reflecting members on a structural member. In one embodiment, the optical fibers and reflecting members cooperate with the deformable structure to provide a variable gap interferometer for sensing deformation of the structural member due to contact force. In another embodiment, a change in the intensity of the reflected light is detected to measure the deformation. The measured deformations are then used to compute a contact force vector. In some embodiments, the force sensor is configured to passively compensate for temperature changes that otherwise lead to erroneous force indications. In other embodiments, the system actively compensates for errant force indications caused by temperature changes by measuring certain local temperatures of the structural member.

Abstract: Methods of manufacturing a flexible force sensor include forming a first sensor part providing a plurality of spaced first electrode plates in an electrically non-conductive material. A second sensor part is also formed and includes a plurality of second electrode plates in an electrically non-conductive material. The second electrode plates are identical to the first electrode plates at least in terms of spacing. The first part is assembled to the second part such that each of the first electrode plates are aligned with and parallel to, yet spaced from, respective ones of the second electrode plates, establishing a plurality of capacitive sensing components. The first electrode plates are movable relative to the corresponding second electrode plates, establishing a variable gap therebetween. The sensor parts can be ring-shaped. The sensor parts can be formed via MEMS techniques, with the non-conductive material being a polymer.

Abstract: An exemplary method of controlling an artificial lift system may include monitoring, via a downhole phase change sensor, for an indication of steam breakthrough, determining the occurrence of a steam breakthrough event based on the indication of steam breakthrough, and adjusting one or more parameters of the artificial lift system based on the determination. One example system for controlling an artificial lift system may include a downhole phase change sensor configured to monitor for an indication of steam breakthrough and a processing system configured to determine the occurrence of a steam breakthrough event based on the indication of steam breakthrough and adjust one or more parameters of the artificial lift system based on the determination.

Abstract: This disclosure describes circuit boards configured for optical data transmission using fibers of the reinforcing material of the circuit board substrate as optical fibers. The disclosure is directed to circuit boards that include a plurality of fibers and a dielectric matrix material. Each fiber of the plurality of fibers includes a core material substantially transparent to a wavelength range of interest and a cladding material. The refractive index of the cladding material is less than a refractive index of the core material. The plurality of fibers are interwoven in a weave. The weave is at least partially encapsulated by the dielectric matrix material. The weave provides structural support for the circuit board and a plurality of optical paths for optical signals.

Abstract: A method of determining stress variations over time in an undersea pipe for transporting fluids, the method comprising: installing along the entire length of the pipe (1) at least one distributed optical fiber sensor (2-1 to 2-4) using Rayleigh backscattering, the sensor being dedicated to measuring at least one degree of freedom of movement variation over time in the pipe at each cross section of the pipe; continuously measuring movement variation of the optical fiber sensor over time; and determining stress variations over time at each point in the pipe by time integration of the measured movement variation of the optical fiber sensor.

Abstract: A force sensor for measuring force and/or pressures disclosed. In some embodiments, the sensor includes first and second layers, each layer having one or more electrodes arranged in a repeating, undulating pattern. Such an undulating pattern may include a serpentine pattern or a repeating v-shaped pattern. When arranged, the one or more electrodes on the first layer are placed in facing relationship and cross the one or more electrodes on the second layer to form a plurality of electrode intersections. When stretched, the one or more electrodes on the first layer move relative to the one or more electrodes on the second layer while creating new electrode intersections.

Abstract: A multi-mode optical fiber includes a glass center for conducting fundamental and high order modes of light waves, the high order modes including a first desired group of high order modes and a second undesired group of high order modes. A cladding surrounds the glass center, the glass center and cladding forming a core. A trench within the cladding surrounds the glass center reflecting the first and second groups of high order modes into the core. An acrylic layer surrounds the core. A buffer coating of polymer surrounds the acrylic layer and the core. The buffer coating is a pressure extruded polymer, where the buffer coating retains at least some of the pressure from the pressure extrusion and applies continuous pressure to the acrylic layer and the core therein, along the length of the fiber, such that the at least the first group of desired high order modes are permitted to be transmitted through the core and where the second group of undesired high order modes are suppressed.

Abstract: An impact sensor for a vehicle. The impact sensor includes at least one strain-sensitive sensor element which comprises a sensor material, and at least two terminals, between which the sensor material is electrically connected. The sensor material is a metal-containing carbon material.

Abstract: Method for creating an optical sensing fiber having a reflective structure integrally disposed therein, comprising: providing an optical fiber having a core and a cladding layer disposed in optical contact with the core, and having a polymer coating layer disposed in contact with and surrounding the cladding layer, the coating layer at least partially transparent in the wavelengths of 390-600 nm; providing a source of electromagnetic radiation having a wavelength in the range of 390-600 nm; and delivering a selected wavelength of the electromagnetic radiation through the coating layer to a selected location within the fiber core or cladding such that the delivered electromagnetic radiation alters the core or cladding to create at least one reflective structure in the core or cladding at the selected location.

Abstract: A fiber optic sensor for measuring voltage in direct current and alternating current systems is disclosed. The sensor may include an optical fiber probe containing transmitting and receiving fibers, fixed conductor elements, and a dynamic conductor element with a reflective surface or material. The reflector may be attached to a dynamic conductor. The two fixed conductors may be placed parallel to one another and coupled to a static voltage source. The dynamic conductor may bisect the fixed conductors and be coupled to a voltage source. The dynamic conductor may be spaced apart from the ends of the fibers in the fiber probe, and positioned so that light transmitted through the transmitting fiber is reflected by that surface into a receiving fiber. A light sensing means may be coupled to the receiving fiber, so light from a light reflected by the reflector body back into the receiving fibers is detected.

Abstract: An apparatus for determining the position of an object having one or more magnetic elements. The apparatus includes magnetostrictive optical sensors, each arranged to produce a signal which is indicative of a proximity of the sensor to the one or more magnetic elements. The apparatus is arranged to determine the position of the object based on a plurality of such proximity signals.