Abstract: An optical resonator system and method that includes a whispering-gallery mode (WGM) optical resonator that is capable of resonating across a broad, continuous swath of frequencies is provided. The optical resonator of the system is shaped to support at least one whispering gallery mode and includes a top surface, a bottom surface, a side wall, and a first curved transition region extending between the side wall and the top surface. The system further includes a coupler having a coupling surface which is arranged to face the transition region of the optical resonator and in the vicinity thereof such that an evanescent field emitted from the coupler is capable of being coupled into the optical resonator through the first curved transition region.

Abstract: A device operating in an environment includes a fiber optic sensing system having one or more fiber optic sensors disposed in the device and configured to detect one or more parameters related to the device. The parameters may include temperature, strain, pressure, vibration, or combinations thereof.

Abstract: According to embodiments of the present invention, a distributed pressure and shear stress sensor includes a flexible substrate, such as PDMS, with a waveguide formed thereon. Along the waveguide path are several Bragg gratings. Each Bragg grating has a characteristic Bragg wavelength that shifts in response to an applied load due to elongation/compression of the grating. The wavelength shifts are monitored using a single input and a single output for the waveguide to determine the amount of applied pressure on the gratings. To measure shear stress, two flexible substrates with the waveguide and Bragg gratings are placed on top of each other such that the waveguides and gratings are perpendicular to each other. To fabricate the distributive pressure and shear sensor, a unique micro-molding technique is used wherein gratings are stamped into PDMS, for example.

Abstract: The invention discloses multi-channel fiber Bragg grating (FBG) interrogation systems and manufacture thereof. The multi-channel fiber Bragg-grating sensor interrogation unit comprises at least one integrated optic sensor microchip and a signal processing IC-electronics unit in a miniaturized, telecommunications standard, hermetically sealed 2-cm×5-cm SFF single fiber package.

Abstract: The invention relates to an optical strain gage (1) for the multi-axis strain measurement, that includes at least two linear light waveguide sections (2, 3, 4) with Bragg gratings (5). These are arranged next to one another in a prescribed angle (19) of 90° or 45° on a support layer (6) and are supplied with lightwaves by a common infeeding waveguide section (7). This invention is characterized in that all light waveguide sections (2, 3, 4, 7) are provided preferably linearly on the support layer (6), and that a beam dispersion element (8) is arranged between the infeeding waveguide section (7) and the measuring waveguide sections (2, 3, 4) containing the Bragg grating (5).

Abstract: A fiber optic sensor device for detecting the presence of a chromophoric compound in a biological fluid is disclosed.

Abstract: A method for monitoring a workspace comprising deploying a fiber optic distributed temperature sensor cable in the workspace, wherein the sensor is capable of detecting a temperature differential of ±10° F. from baseline. A method for monitoring a workspace comprising deploying a fiber optic distributed temperature sensor cable in the workspace, wherein the sensor is readily accessible for contact by a worker trapped in the workspace to signal a location of the worker. A method for monitoring a workspace comprising deploying a fiber optic distributed temperature sensor cable in the workspace and instructing workers to locate the cable and position themselves in close proximity or direct contact with the cable in order to indicate their position within the workspace.

Abstract: An optical motion sensing device included a sensor frame defining an opening, a sensor pad disposed in the opening, an optical sensing system adapted to detect an amount of movement of the sensor pad in the sensor frame, and an output unit. The optical sensing system includes an optical waveguide, an optical source device, and an optical detector. The optical waveguide is positioned within the sensor frame such that the movement of the sensor pad results in the flexing or compressing of the optical waveguide. The optical source device supplies optical energy to the optical waveguide. The optical detector detects an amount of optical energy exiting the optical waveguide. The output unit is configured to receive a signal indicative of the amount of optical energy exiting the optical waveguide and to generate a measure of the amount of movement of the sensor pad from the received signal.

Abstract: In order to identify an optical cable for optical communication from a remote place, a Sagnac interferometer including two strands of an optical fiber is formed in the optical cable, and a worker in the remote place applies a disturbance of a popping sound to an optical cable to be identified. The disturbance applied by the worker is detected and regenerated in the form of a sound. The optical cable can be easily identified by comparing the regenerated signal and the disturbed signal in the remote place to thereby prevent an incorrect optical cable from being cut. In addition, the optical cable can be more precisely identified by selecting a different light detecting frequency component in accordance with environment conditions.

Abstract: An anti-intrusion device for fences or the like, comprising at least one, preferably two or more cables (3), each one composed of at least one or a bundle of optical fibres (103) and of an outer protection sheath (203), which optical fibre cables (3) are subtended in a substantially longitudinal direction of a section or a perimeter to be protected and are supported or holded each one at a different height at a plurality of supporting points spaced apart arranged and wherein, at least at some of said supporting points, first means (8, 9) deforming and/or blocking each optical fibre cable (3) are provided, which first deforming and/or blocking means (8, 9) may be moved from a rest position in which they do not interfere with the optical fibre cable (3) to an active position deforming and/or blocking the optical fibre cable (3) in which an optical signal transmitted through the optical fibre cable (3) is attenuated under a predetermined threshold value or it is anyway modified, and which first deforming and/or

Abstract: A method for measuring micro displacements generally includes the steps of: (a) providing a micro displacement sensor with a first photonic crystal module with a number of first crystals, a second photonic crystal module with a number of second crystals, a laser, and a detector; the first crystal module and the second crystal module having a first light guide channel and a second light guide channel therein, respectively; (b) securing the second crystal module onto a sample, the first channel and the second channel being optically coupled together; and (c) during operation, emitting light from the laser, directing such light into the first channel, a first portion of the light exiting from the first channel and a second portion of the light entering the second channel, and analyzing a “light intensity vs. displacement” sine curve to obtain a horizontal micro displacement of the sample.

Abstract: Structural joint strain monitoring apparatus 92 comprises jacket means 52 in the form of first and second jacket elements 62, each having a primary jacket part 62a and substantially perpendicular secondary jacket part 62b which together define a compartment for receiving a joint, between two pipes 54, 56, to be monitored. The jacket means 52 additionally comprises two primary web elements 76, 78 provided between the primary and secondary jacket parts 62a, 62b. Three fibre Bragg grating (FBG) strain sensors 96, 98, 100 and an FBG temperature sensor 102 are provided within an optical fibre 104, bonded to the primary web elements 76, 78 and each end of the second jacket element 62 respectively, for measuring strain or temperature at their respective locations. The FBG sensors 96, 98, 100, 102 are optically coupled, via optical fibre 104, to optical fibre sensor interrogation apparatus 94, operable to interrogate each FBG sensor.

Abstract: An optical sensor has: a sensing portion having an optical fiber to be disposed at a measurement point of temperature, distortion, pressure etc.; a light source to output a light to the sensing portion; and a photodetector to detect a backscattered light from the sensing portion. The sensing portion has a tape sheet and the optical fiber shaped into a corrugated form with a predetermined curvature. Alternatively, the sensing portion has a polymer optical waveguide with a core shaped into a corrugated form with a predetermined curvature.

Abstract: A technique is provided for utilizing an optical fiber in a variety of sensing applications and environments by beneficially routing the optical fiber. A continuous optical fiber is created to provide optical continuity between two ends of the optical fiber. The optical continuity is created with the assistance of an optical turnaround constructed in a simple, dependable form able to control the bend of the optical fiber as it extends through the optical turnaround.

Abstract: The present invention relates to an optical fiber cable for use with a system for determining a velocity profile of sound in a medium. The optical fiber cable comprises an inner layer of strength members, an outer layer of strength members, and at least one tube containing at least one optical fiber incorporated into the outer layer. The at least one optical fiber has a plurality of Bragg grating sensors spaced along its length.

Abstract: An optical fiber sensor comprising a housing having a cavity defined therein; at least two plastic optical fibers disposed such that cleaved ends of the respective fibers are located opposite each other within the cavity; a light source coupled to one of the fibers; and a detector coupled to the other fiber.

Abstract: In accordance with one exemplary embodiment the invention provides a multi-parameter fiber optic sensing system with an aperiodic sapphire fiber grating as sensing element for simultaneous temperature, strain, NOx, CO, O2 and H2 gas detection. The exemplary sensing system includes an aperiodic fiber grating with an alternative refractive index modulation for such multi-function sensing and determination. Fabrication of such quasiperiodic grating structures can be made with point-by-point UV laser inscribing, diamond saw micromachining, and phase mask-based coating and chemical etching methods. In the exemplary embodiment, simultaneous detections on multi-parameter can be distributed, but not limited, in gas/steam turbine exhaust, in combustion and compressor, and in coal fired boilers etc.

Abstract: A strain sensing device has a sub-assembly with at least one optical fiber therein, and a metallic coating encasing the sub-assembly. The metallic coating is strain coupled to the sub-assembly. A strain sensing system and a method of anticipating failure in a structure are provided. The strain sensing system and method of anticipating failure in a structure use the strain on the strain sensing device to calculate the strain on a structure of interest.

Abstract: Disclosed herein is a carrier for an optical fiber having a plurality of optical sensors located thereon. The carrier has a test section comprising a cavity and at least one geometric discontinuity, wherein in response to a pressure applied to the test section, a stress concentration is formed proximate to the geometric discontinuity, and wherein the optical sensor is adhered to at least a part of the geometric discontinuity. The cavity may be filled with a liquid or a gel. A temperature optical sensor may also be provided adjacent to the pressure optical sensor.

Abstract: Disclosed herein is a carrier for an optical fiber having a plurality of optical sensors located thereon. Such carrier can be a thick-walled capillary tube or other shapes. The carrier has a sealed hollow body with a side wall. The side wall is profiled at least one predetermined location to form a thin-walled section and at least one optical sensor is attached to said thin-walled section. As the thin-walled section flexes in response to a pressure difference across it, the pressure difference is sensed by the optical sensor. The carrier may also have a slot defined on its side wall to receive the optical fiber. A temperature optical sensor may also be provided adjacent to the pressure optical sensor.

Abstract: The optic fiber Bragg grating (FBG) sensor comprises of an elastic circular diaphragm and one or two FBG attached to the bottom surface of the elastic circular diaphragm. Two ends of the FBG are connected to an optic fiber for signal transmission. The FBG sensor readouts are independent of temperature fluctuation. The FBG sensor mechanism according to the present invention may be applied for various purposes such as a gauge pressure transducer, differential pressure transducer, load cell and displacement transducer with distributive capabilities.

Abstract: A system for measuring simultaneously both temperature and ac voltage and/or ac current, the system comprising: a piezo-electric sensor; and optical fiber that includes an optical strain sensor being in contact with the piezo-electric sensor and able to expand or contract therewith and an analyzer for analyzing an optical output of the fiber and strain sensor in response to an optical input, the analyzer being operable to use the optical output to determine the temperature and the ac voltage and/or ac current.

Abstract: A sensing module positioned about an optical fiber cable having a long axis. The optical fiber includes a core that transmits light through the optical fiber cable. The sensing module includes a first short-period fiber grating positioned about the core. A second short-period fiber grating is positioned about the core and at a distance along the long axis with respect to the first short-period fiber grating. At least one of a long-aperiod fiber grating and a long-period fiber grating is positioned between the first short-period fiber grating and the second short-period fiber grating. A fiber cladding is positioned around the long-period grating and/or the long-aperiod grating of the sensing module. A sensing skin is positioned about the fiber cladding and includes a chemical gas active material.

Abstract: An optical fiber sensor (8) has an optical fiber (2) and, a light emitting member (3) connected to a first end (20) of the optical fiber (2), a light receiving member (4) connected to a second end (21) of the optical fiber (2). The light emitting member (3) has a light emitting portion (300) through which light is radiated to the first end (20) of the optical fiber (2). The light receiving member (4) has a light receiving portion (400) for receiving light radiated from the second end (21) of the optical fiber (2). The light emitting portion (300) is smaller than a sectional area of a core portion (25) of the optical fiber (2).

Abstract: Provided herein are fiber optic force sensors for measuring shear force which include an optical fiber with at least one optical core and a Bragg grating. Also provided arc fiber optic force sensor arrays for measuring a plurality of shear forces which include an optical fiber with at least one optical fiber core and a plurality of Bragg gratings.

Abstract: An optical motion sensing device included a sensor frame defining an opening, a sensor pad disposed in the opening, an optical sensing system adapted to detect an amount of movement of the sensor pad in the sensor frame, and an output unit. The optical sensing system includes an optical waveguide, an optical source device, and an optical detector. The optical waveguide is positioned within the sensor frame such that the movement of the sensor pad results in the flexing or compressing of the optical waveguide. The optical source device supplies optical energy to the optical waveguide. The optical detector detects an amount of optical energy exiting the optical waveguide. The output unit is configured to receive a signal indicative of the amount of optical energy exiting the optical waveguide and to generate a measure of the amount of movement of the sensor pad from the received signal.

Abstract: A fiber optic sensor for measuring static pressure includes a cartridge housing having an end that is exposed to the atmosphere, a thin flexible membrane covering the exposed end of the cartridge housing such that the flexible membrane has an exposed side and a protected side, and a fiber bundle disposed within the cartridge housing, the fiber bundle comprising at least one fiber having a first polished end for transmitting light toward the membrane and a second end for being coupled to a light source or a receiver, the housing arranged to maintain the membrane at a distance from the first end of the fiber in a direction along a fiber axis, with free space between the first fiber end and the protected side of the flexible membrane.

Abstract: High-resolution, scalable multi-touch sensing display systems and processes based on frustrated total internal reflection employ an optical waveguide that receives light, such as infrared light, that undergoes total internal reflection and an imaging sensor that detects light that escapes the optical waveguide caused by frustration of the total internal reflection due to contact by a user. The optical waveguide when fitted with a compliant surface overlay provides superior sensing performance, as well as other benefits and features. The systems and processes described provide true multi-touch (multi-input) and high-spatial and temporal resolution capability due to the continuous imaging of the frustrated total internal reflection that escapes the entire optical waveguide. Among other features and benefits, the systems and processes are scalable to large installations.

Abstract: A medical instrument system includes an elongate flexible instrument body with an optical fiber substantially encapsulated in a wall of the instrument body, the optical fiber including one or more fiber gratings. A detector is operatively coupled to the optical fiber and configured to detect respective light signals reflected by the one or more fiber gratings. A controller is operatively coupled to the detector, and configured to determine a twist of at least a portion of the instrument body based on detected reflected light signals. The instrument may be a guide catheter and may be robotically or manually controlled.

Abstract: The present invention relates a fiber optic transducer (FOT) and methods for measuring the pressure and temperature of a flowing fluid using such FOT, wherein such FOT contains a fiber optic having fiber Bragg gratings. The fiber Bragg gratings are measured during a flowing fluid to determine the difference in the change in wavelength exhibited by a reflected optical signal from the gratings.

Abstract: The present invention provides an optical device which comprises a light guide incorporating a Bragg grating. The apparatus also comprises a moveable wall portion which is coupled to the Bragg grating so that a movement of the wall portion causes a force that effects a change in strain of the Bragg grating and thereby effects a change in an optical period of the Bragg grating. A temperature related change in the optical period of the Bragg grating is reduced by a temperature related change in the force on the Bragg grating by the moveable wall portion.

Abstract: The present invention relates to a device comprising a fibre-reinforced part and including at least one system comprising at least one optical fibre as well as connecting means adapted for connection of light emitting means and light receiving means to the optical fibre, said optical fibre comprising a number of reflecting structures. One object of the invention is to provide means suitable for use in providing compensation for temperature change in strain measurement, which may be built into fibre-reinforced parts of a device. This is obtained by having holding means adapted to hold one or more loops formed on the optical fibre, in a way where at least one loop may substantially freely change length when subject to a change in temperature.

Abstract: A fiber-optic sensor head is disclosed for an optical current or magnetic-field sensor which can have an optical fiber which includes a magnetooptically active sensor fiber which is optically connected to at least one polarization-defining element. The sensor fiber can be arranged in a magnetic field to be measured or around a conductor carrying current to be measured and can be in the form of a coil, with the coil defining a coil plane (A) with a surface normal (Ns), and with the at least one polarization-defining element having a marked axis (f). The sensor head can be flexible in the area of the sensor fiber, and an adjustment means can be provided for adjustment of a predeterminable angle ? between the marked axis,(f) and the surface normal (Ns) or for adjustment of predeterminable angles ?, ?? between the marked axes (f) and the surface normal (Ns).

Abstract: A method of detecting collisions between elements in a medical procedure such as between a magnet and another element in the procedure mounting on the medical device a flexible body within which is mounted one or more parallel side by side optical fibers arranged such that the impact causes bending of one or more of the optical fibers and detecting changes in light transmission through the optical fiber to detect the bending and thus the collision. The single fiber or fibers are located in a junction between a lower body of resilient foam and a surface layer of a stiffer flexible material.

Abstract: An apparatus for measuring an internal dimension of a well-bore comprising a tool (1) adapted to be positioned inside the well bore. The tool comprises an optical caliper (312) comprising an optical sensor providing a response correlated to the internal dimension of the well bore, the optical sensor being coupled to an optical fiber (311A).

Abstract: An optical sensor assembly comprising a plurality of optical fibre sensor coils optically coupled by optical fibre; and an elongate support element, on which said plurality of optical fibre sensor coils and optically coupling optical fibre are mounted is disclosed. The support element has an elastic limit such that when said support element is bent from the elongate axis, the optical fibre fracture limit is reached before the elastic limit is reached. An array of these optical sensor assemblies, the mandrel on which the sensing coils are mounted and their method of manufacture are also disclosed.

Abstract: An integrated fiber optic assembly includes some of the active components that are otherwise found in a typical transceiver. For example, a transmitter optical assembly includes a laser source, a laser driver, and a component for administering diagnostic data. A receiver optical assembly includes a photo-diode an optical converter, such as a transimpedance amplifier, and a processing control that can administer, for example diagnostic data associated with the receiver optical assembly. A combination optical assembly includes a photo-diode and a laser source, as well as many of the active components for driving, operating, or administering the laser source. In part since the active components can be placed in close proximity to each other, electrical impedance is reduced that would otherwise be present in a typical transceiver and optical subassembly.

Abstract: Complex data is obtained from OFDR backscatter measurements for an optical device under test (DUT). That complex scatter pattern data may be used along with a previously-determined fiber segment pattern to identify the fiber segment within the DUT, even when the DUT is an optical network DUT that includes multiple fibers coupled to perform one or more functions. In other non-limiting example applications, the OFDR scatter pattern data can be used to identify where in the DUT a loss occurred and where in the DUT a temperature change occurred.

Abstract: A configuration detection device includes a light-providing optical fiber, a light reflector a curvature-detecting optical fiber, and a light modulator. The light-providing optical fiber transmits detection light in a plurality of wavelength ranges that have different wavelengths from one another, The light reflector reflects the detection light as reflected light. The curvature-detecting optical fiber transmits the reflected light, and is bent together with an endoscope. The light modulator modulates at least one of the strength or the wavelength of the reflected light for each of the wavelength ranges. Based on at least one of the strength or the wavelength of the reflected light that is pre-modulated and post-modulated, and based on the distance between the light modulator and the output end of the curvature-detecting optical fiber, the configuration of the endoscope is detectable.

Abstract: A pressure sensor including: a deflectable diaphragm including a substantially central boss and channel; and, an optical waveguide having first and second arms, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel.

Abstract: A distributed temperature sensing system and method includes an optical sensing waveguide. The optical sensing waveguide is a single mode waveguide having a substantially pure silica core and a large outer diameter. The system further includes an optical instrument optically connected to the optical sensing waveguide. The optical instrument is configured for generating an optical excitation signal along the optical sensing waveguide, and is also configured for receiving a return optical signal indicative of the temperature at one or more locations along the optical sensing waveguide.

Abstract: A method for manufacturing an optical device is provided. The device includes an optical waveguide path having a Bragg grating and a movable portion disposed near the Bragg grating. A displacement of the movable portion provides a change of spacing of the Bragg grating so that a light passing through the optical waveguide path is changed. The optical device detects the physical quantity based on a change of the light. The method includes steps of: forming the optical waveguide path with the Bragg grating on a first part of a silicon substrate; and forming the movable portion on a second part of the silicon substrate.

Abstract: A multi-layer sensor (10) and a use for the sensor (10) are described. This sensor is multi-layered in construction. 5 An optical wave guide (18) is passed through the sensor (10) such that in the event of an external application of force the force acts on the optical wave guide.

Abstract: An optical sensing system detects pressure through attenuation of light in an optical fiber. This is particularly useful for measuring the weight and position of a load on a mat including multiple such optical fibers, which may be positioned in an automobile seat to determine theses parameters for a passenger in that seat. This information can be presented to an airbag deployment system in a form that will easily enable the airbag to be deployed (when needed) in a manner sensitive to the weight and position of the occupant. It provides based on this detection system a technique to suppress airbag deployment based on passenger profile. Further, the system and method use an optical fabric methodology such that loads, load movement, load position can be detected in vehicles.

Abstract: A technique is provided for utilizing an optical fiber in a variety of sensing applications and environments by beneficially routing the optical fiber. A continuous optical fiber is created to provide optical continuity between two ends of the optical fiber. The optical continuity is created with the assistance of an optical turnaround constructed in a simple, dependable form able to control the bend of the optical fiber as it extends through the optical turnaround.

Abstract: An optical fiber 1 includes a core 11 and a cladding material 12. In a collision detection optical fiber sensor 100, a plurality of linear members 2 and 3 are twisted around an outer periphery of the cladding material 12 of the optical fiber 1. An elastic member 6 of the liner member 2 has an elasticity different from that of an elastic member 7 of the first linear member 3. The hardness of the elastic member 6 is lower than that of the elastic member 7. A rubber hardness difference measured by a durometer type A according to a JIS K6253 between the elastic member 6 and the elastic member 7 is not less than 10.

Abstract: In accordance with one exemplary embodiment the invention provides a multi-parameter fiber optic sensing system with an aperiodic sapphire fiber grating as sensing element for simultaneous temperature, strain, NOx, CO, O2 and H2 gas detection. The exemplary sensing system includes an aperiodic fiber grating with an alternative refractive index modulation for such multi-function sensing and determination. Fabrication of such quasiperiodic grating structures can be made with point-by-point UV laser inscribing, diamond saw micromachining, and phase mask-based coating and chemical etching methods. In the exemplary embodiment, simultaneous detections on multi-parameter can be distributed, but not limited, in gas/steam turbine exhaust, in combustion and compressor, and in coal fired boilers etc.

Abstract: An optical fiber sensor comprising a housing having a cavity defined therein; at least two plastic optical fibers disposed such that cleaved ends of the respective fibers are located opposite each other within the cavity; a light source coupled to one of the fibers; and a detector coupled to the other fiber.

Abstract: An optical fiber sensor can be interposed between a bumper reinforcement and a load transmitting plate to extend in the direction of width of a vehicle along with the bumper reinforcement. In this case, when a change does not occur substantially in an immediately previous predetermined period in an output voltage of a light emission amount of the optical fiber sensor, a feedback control is performed in such a way that the change becomes a level of zero of the output voltage of the optical fiber sensor. In contrast, when a change in the output voltage is not substantially zero, the immediately previous state of emission of light is maintained. Accordingly, it is possible to effectively compensate a zero point shift caused by a temperature change or/and an aging degradation of the optical fiber sensor.

Abstract: A fiber optic acoustic transducer includes a mandrel having a first portion that preferably formed generally as a cylinder having a projection extending from one end. A grating collar also preferably formed in a generally cylindrical configuration. The grating collar has a passage extending therethrough so that it may mounted on the projection. An optical fiber has a sensor portion wound around the first portion of the mandrel and a second portion wound around the grating collar with a fiber Bragg grating being formed in the second portion of the optical fiber.