Abstract: A multi-input optical switch can include a base plate that carries at least one photo sensor and multiple LEDs which are arranged at positions separated by approximately the same angular interval. A first mask can be formed in an approximately cylindrical shape and can include multiple through holes. A second mask can be formed as an approximately flat light blocking plate, and can include a translucent area. A translucent light guiding body can include an approximately flat plate portion, a protruded portion which extends downward from a center portion of the plate portion, a rod portion which extends upward from the center portion of the plate portion, a first total reflection surface and a second total reflection surface. A third mask can be provided with a tubular cup shape that diverges downward, and has an opening at a bottom end, a step portion at an intermediate position thereof, and at least one through hole on an upper cylindrical wall above the step portion.

Abstract: The present invention pertains to Lithium-Niobate fiber optical sensors (“LNCF”) and systems for detection of load or pressure and strain or deformation changes that occur in a host material. The host material can be a component of a system, such as a part of a bridge, or a selected material, such as a geofoam, that provides a protective and compliant medium to which the LNCF would be securely attached.

Abstract: 3-Mirror fiber optic sensor for simultaneous measurement of dual parameters such as hydrogen concentration and temperature, is formed from 2 optical leads comprising 3 reflective surfaces, and defining 2 optical cavities. The effect of temperature on each of the cavities and the effect of hydrogen, for example, on the one of the cavities, produces phase shifts in the reflected lights, and interference patterns from which the parameters may be detected.

Abstract: A method of monitoring structural damage in a composite structure manufactured by co-curing, co-bonding or secondary bonding of several sub-components (7, 8), using fibre optic Bragg grating sensors attached or embedded to or between (in the bonding line) said sub-components, comprising a first step of measuring the wavelength spectra (31, 33, 40) of said Bragg grating sensors at the end of the manufacturing of the part, and in a known load condition, considered as reference and a second step of identifying the occurrence of a failure of the structure and the progress of said failure detecting the release of the residual stresses/strains stored during the curing process by measuring changes (31 to 32, 33 to 34, 40 to 41) with respect to said reference wavelength spectra.

Abstract: Interrogation systems for monitoring structural health conditions. An interrogation system includes at least one wave generator for generating a wave signal and optical fiber sensors applied to a structure. The interrogation system also includes at least one electronic module for generating an input sensor signal and sending the input sensor signal to the optical fiber sensors. Each optical fiber sensor impresses the wave signal onto the input sensor signal to generate an output sensor signal that is frequency shifted from the input sensor signal. The electronic module generates an information signal in response to the output sensor signal. The interrogation system also includes a signal processing unit and a relay switch array module that has relay switches. Each relay switch relays the information signal to the signal processing unit and the signal processing unit generates a digital sensor signal that is subsequently sent to a computer.

Abstract: A method is disclosed wherein a portion of a sensor part of an optical fiber sensor is embedded in an adhesive between two joined members, and peeling in an adhesive joint of the two members is detected on the basis of measuring optical characteristics from the optical fiber sensor when the optical fiber sensor is irradiated with light from a light source while one member is vibrated by vibration means. The method comprises the steps of determining the temperature of the two members during measurement on the basis of the optical characteristics from the sensor part exposed outside of the adhesive; determining, on the basis of the temperature determined during the measurement, the measurement range in which the optical characteristics from the optical fiber sensor are measured; and measuring the variation in the optical characteristics from the optical fiber sensor within the determined measurement range while the member is being vibrated by the vibration means.

Abstract: A system for determining at least one condition of a seal including an optical fiber for transmitting light from a light source. The optical fiber is embedded in the seal and operatively coupled to an interferometric system. The interferometric system is operatively coupled to a processor. The interferometric system provides the processor with information relating to wear of the optical fiber, and the processor determines wear of the seal, rate of wear and remaining useful life of the seal based on the information relating to wear of the optical fiber.

Abstract: A substrate incorporates a mechanical cantilever resonator with passive integrated optics for motion detection. The resonator acts as a waveguide, and enables optical detection of deflection/displacement amplitude, including oscillations. In one embodiment, the cantilever comprises a silicon waveguide suspended over a substrate. A reflector structure faces a free end of the suspending cantilever, or a waveguide is supported facing the free end of the suspended cantilever to receive light transmitted through the silicon waveguide cantilever. Deflection/displacement of the cantilever results in modulation of the light received from its free end that is representative of the displacement. Ring resonators may be used to couple different wavelength light to the waveguides, allowing formation of an array of cantilevers.

Abstract: A fiber optics differential pressure transducer (100, 200, 300, 400) containing Bragg networks (118), said transducer being used to measure the differential pressure in a Venturi installed inside a pipe (1), through which a fluid like oil is displaced. The transducer comprises a body (110, 230, 360, 410) of different geometries and a diaphragm (2), at least one Bragg network (118) being attached on each of the surfaces of the same. The diaphragm (2) is placed parallel or transversal to the transducer's body (100, 200, 300, 400). The transducer (200) is isolated from the process fluid by flexible mechanical seals (201) which transmit the pressure up to surfaces of the diaphragm (2). The transducer (300, 400) is provided with two relief microvalves for the purpose of protecting the sensor [diaphragms (2)] in overpressure events.

Abstract: A method for controlling one or more temperature dependent optical properties of a structure in accordance with embodiments of the present invention includes heating at least a portion of a photonic band-gap structure and oxidizing the portion of the photonic band-gap structure during the heating to alter at least one temperature dependent optical property of the stack.

Abstract: An optical transducer for determining the presence or absence of liquid or the like in a reservoir includes a housing with a hollow interior and an optical probe that extends through the housing. The optical probe has a central axis, a proximal end positioned in the hollow interior and a distal end positioned outside of the housing. The distal end has first and second measurement surfaces that intersect at a transverse edge. The transverse edge extends at an acute angle with respect to the central axis. A light source is arranged for projecting radiant energy into the optical probe toward the distal end. A photosensor is arranged for detecting radiant energy reflected from the distal end to thereby detect the presence and absence of liquid on the optical probe.

Abstract: The present invention comprises the use of a fiber in a sensing optical fiber system operated in a region of negative chromatic dispersion to minimize modulation instability thereby enabling the identification and measurement of the information-carrying signals. The present invention may be used in a variety of sensing environments.

Abstract: An optical fiber pH sensor 100, 200, 300 is described, where a transducer mechanically couples a Bragg grating to a pH-sensitive hydrogel, said sensor comprising a central part 110, 210, 301 where are placed the optical fiber 121 containing a Bragg grating 122, the pH-sensitive hydrogel set of discs 130, and the mechanical transducer which is a spring 123 a beam 215 or still the optical fiber itself 121, the mechanical transducer assuring the strain on the Bragg grating 122. The change in hydrogel hydrodynamic volume resulting from a change of the pH of the medium introduces a force that is sufficient to cause a strain in the Bragg grating. The measure of the pH change is retrieved using the usual techniques for wavelength measurement. The pH sensor 100, 200, 300 of the invention is useful for the indirect evaluation and control of corrosion in petroleum wells and is suitable for multiplexing with other optical fiber sensors measuring the same or different parameters.

Abstract: A sensing apparatus consisting of more than one diode laser having select lasing frequencies, a multiplexer optically coupled to the outputs of the diode lasers with the multiplexer being further optically coupled to a pitch side optical fiber. Multiplexed laser light is transmitted through the pitch side optical fiber to a pitch optic operatively associated with a process chamber which may be a combustion chamber or the boiler of a coal or gas fired power plant. The pitch optic is oriented to project multiplexed laser output through the process chamber. Also operatively oriented with the process chamber is a catch optic in optical communication with the pitch optic to receive the multiplexed laser output projected through the process chamber. The catch optic is optically coupled to an optical fiber which transmits the multiplexed laser output to a demultiplexer.

Abstract: Methods for determining a preferred application of a plurality of transducers or sensors to a structure are disclosed for monitoring and imaging deformation of the structure as it is subjected to various forces.

Abstract: A novel fiber ringdown (FRP) pressure sensor is provided for measuring extremely high pressures under extreme environmental conditions of cold and heat. Pressure measurements are achieved in a time domain by measuring ringdown times of emitted light through the fiber optic loop of the device. The novel FRP sensor can include a light source, such as a diode laser light source, two 2×1 fiber couplers, a section of fused silica single mode fiber, a photodetector, and an electronic control. The novel FRP sensor's performance in the areas of stability, reproducibility, dynamic range, and temperature tolerance are far above those of conventional sensors.

Abstract: A method and system producing and transmitting pulsed or continuous wave signals through one or more optical fibers to a plurality of remote sensors provided in a hostile environment. The produced signals transmitted along one of the optical fibers would be demultiplexed and transmitted to separate sensors. The sensors would then modulate these signals which would then be combined onto a single output optical fiber which is to be analyzed. A spectrometer or other signal processing device, generally included in a shielded environment, would be utilized to process the modulated signals.

Abstract: Surface profiling apparatus (10) according to one embodiment comprises three long period gratings (LPGs) (12, 14, 16) fabricated in progressive three layered (PTL) fibre (18) and embedded within a deformable carrier member (40) comprising a skeleton (42) provided between two sheets of flexible rubber skin (44, 46). The LPGs (12, 14, 16) are illuminated by three wavelength modulated, narrow bandwidth optical signals, each having a different wavelength and modulation frequency. A photodetector (26) connected to three lock-in amplifiers (28, 30, 32) measures the amplitudes of the first and second harmonic frequency components of the photodetector output signal corresponding to each LPG (12, 14, 16). Similar surface profiling apparatus (10) forms the basis for respiratory function monitoring apparatus (100) in which five LPGs are provided within each of four PTL fibres (104, 106, 108, 110) and embedded in four carrier members (40a–d) attached to a garment (114) to be worn by a subject.

Abstract: An optical fiber grating part including an elongated pedestal, and a base plate installed on said pedestal, and having a different coefficient of linear thermal expansion from said pedestal, and an optical fiber passing through said pedestal, and connected to connection points installed on said pedestal or said base plate located apart from each other in the longitudinal direction of said pedestal, and having an optical fiber grating located between said connection points, wherein a predetermined tensile force is added to said optical fiber grating, and said pedestal and said base plates thermally expand or thermally shrink independently in the longitudinal direction of said pedestal, and an extension line of an axis of said optical fiber joining said connection points passes through a contact surface between said pedestal and said base plate.

Abstract: A tunable fiber optic component providing environmental isolation, thermal tuning, and mechanical tuning and a method of tuning a fiber optic component using application of substantially simultaneous varying of temperature and mechanical strain is disclosed. A method of using a tunable fiber optic component, for example, a distributed feedback fiber laser, to compensate variations in an optical system, and a method of making a tunable fiber optic component are also disclosed.

Abstract: The invention provides a fiber-optic sensing system for measuring a curvature in a small and elongated cavity of an object. The system includes a light source, an optical fiber and a light signal reflecting device disposed at a distal end of the optical fiber. The optical source emits a light signal into the optical fiber. The distal section of the optical fiber is inserted into the cavity of the object which curvature is to be measured. The curvature of the cavity bends the distal section of the optical fiber so that attenuation of light signal transmitting through the distal section occurs. This attenuated signal is reflected by a reflecting device and coupled into a measuring device. Thereby the curvature is deduced in accordance with the amount of energy attenuation in the reflected light signal.

Abstract: An optical fiber wound onto an exterior surface of a composite structure in a two-dimensional pattern and adhered thereto to detect damage to the structure caused by impacts to or handling of the composite structure.

Abstract: In accordance with the invention, a variable optical delay line with a large continuous tuning range comprises an incremental variable delay line to provide delay selected from a sequence of incrementally differing delays and a continuous variable delay line to provide a continuously variable delay over a range encompassing a delay increment in the first variable delay line. In a preferred embodiment, the first variable delay line comprises an array of delay paths where each path is curved differently from the others to provide an incrementally different delay. The second variable delay line is a tunable delay path continuously tunable over the delay increment of the first.

Abstract: The present invention concerns an optical sensor located on a preferred azimuthal portion of the side of an optical fiber. An optical fiber having two opposite ends, a core and a cladding and at least one sensing area is disclosed. Each of the sensing areas is located between the two opposite ends and each has a longitudinal, a radial and an azimuthal portion of the fiber that has been removed and replaced by a sensing material. The sensing collected light is thus representative of a parameter to be measured, such as temperature. Placing the sensing material in a lateral side portion of the fiber increases the sensitivity of the sensor, particularly when it comes to contact temperature measurement in vivo.

Abstract: An optical sensing device including a force-applying assembly for providing a force and a Fabry-Perot (FP) element including a large-diameter waveguide having a core and having a cavity in line with the core, the cavity having reflective surfaces and having an optical path length related to the distance between the reflective surfaces, the FP element being coupled to the force so that the optical path length changes according to the force, the FP element for providing an output optical signal containing information about a parameter that relates to the force. Sometimes the large-diameter waveguide is formed by collapsing a glass tube, having a bore and having an outer diameter of about one millimeter, onto a pair of optical fibers arranged in tandem in the bore and separated by a predetermined distance, and respective end faces of the optical fibers form the cavity and are coated with a wholly or partially reflective material.

Abstract: A telecommunications optical fiber is secured against intrusion by detecting manipulation of the optical fiber prior to an intrusion event. This can be used in a non-locating system where the detection end is opposite the transmit end or in a locating system which uses Fresnel reflections and Rayleigh backscattering to the transmit end to detect and then locate the motion. The Rayleigh backscattering time sliced data can be stored in a register until an intrusion event is detected. The detection is carried out by a polarization detection system which includes an optical splitter which is manufactured in simplified form for economic construction. This uses a non-calibrated splitter and less than all four of the Stokes parameters. It can use a polarimeter type function limited to linear and circular polarization or two linear polarizers at 90 degrees.

Abstract: Sensors and systems for monitoring structural health conditions. The present invention provides a device for monitoring structural health conditions including a dielectric substrate, a piezoelectric device for actuating and/or sensing Lamb waves, a molding layer deposited over the piezoelectric device, a cover layer deposited over the molding layer and a hoop layer surrounding the piezoelectric device and being attached to the substrate. The device further includes an optical fiber coil sensor attached to the dielectric substrate, where the coil sensor has a rolled optical fiber cable and a coating layer applied to the rolled optical fiber cable. The present invention also provides a diagnostic patch network that includes a plurality of patch sensors attached to a host structure and a bridge box connected to the patch sensors. The bridge box sends information of structural health conditions to and receive power from a ground control system using a wireless communication technique.

Abstract: An optical fiber inclinometer comprises a pair of fiber Bragg grating devices, a fixed base, a connection plate, and a rotatable base. One end of the connection plate is fixed to the fixed base, whereas the other end of the connection plate is connected to the rotatable base through the joint of a turning pair mechanism between them. The two ends of each fiber Bragg grating device are installed onto the fixed base and the rotatable base respectively, and the two devices are mounted on the opposite side of the connection plate. Once the rotatable base rotates around the joint of the connection plate, axial tensile elongation occurs in one of the fiber Bragg grating devices, whereas axial compressive deformation occurs in the other device. The rotation angle of the rotatable base relative to the connection plate can be obtained by measuring and calculating the Bragg wavelength drifts of the pair of fiber Bragg grating devices respectively.

Abstract: The present invention relates to a temperature-compensated optical fiber pressure detector for detecting pressure variations in at least one medium in relation to a reference medium such as the atmosphere or a medium where a back pressure prevails. The detector essentially comprises a deformable element (2) such as a bellows (5) exposed on one side to the reference medium and on the opposite side to the pressure to be measured, an optical fiber portion (F1) including at least one optical grating such as a Bragg grating (B1), which is connected on one side to deformable element (2) and on the opposite side to a fixed point. The optical fiber portion is subjected to a prestress by a device (6, 15, 20, 21) and its elongation varies with the displacements of the deformable element. The device applies the prestress to optical fiber portion (F1) between deformable element (2) and another fixed element (15) isolated from the medium by a rigid housing (1).

Abstract: A biosensor substrate structure is provided that eliminates the effects of optical interference of light reflected from a substrate/air interface with light reflected by the biosensor's active surface by incorporating a roughened or “non-specular” surface on the lower surface of the substrate opposite the grating. One can generate a useful non-specular or “anti-interference” surface in a number of ways in accordance with this disclosure, including (1) by adding a coating of optically diffuse material, such as UV cured acrylate, to the sensor substrate, (2) etching or otherwise roughening the surface of the sensor substrate, or (3) applying a grating structure to the surface.

Abstract: A method of determining the path of a projectile comprises detecting multiple time of arrivals of the projectile in multiple intersecting planes and determining the path and speed of the projectile based on the multiple times of arrivals.

Abstract: The invention provides a fiber-optic sensing system, utilizing a fiber-grating-based sensor, for a physical parameter, e.g., a pressure or a temperature. Different kinds of fiber-grating-based sensors may be used for this purpose but in-fiber gratings such as Fiber Bragg Grating, Long Period Grating and Surface Corrugated Long Period Fiber Grating are particularly suitable. Due to the small size of the optical fiber and the fact that same fiber acts as the sensing element as well as the signal conducting medium, it is possible to install the sensor in a small diameter needle which is commonly used for medical diagnosis and treatment. As a result, when the fiber-optic sensing system of the invention is used for in-vivo measurement of a biological parameter, such a sensing needle can be used for different in-vivo pressure or temperature sensing applications without causing too much harm and discomfort to the subject tested.

Abstract: Certain exemplary embodiments comprise a system comprising a spatially distributed multimode optical fiber; a pixelated photodetector configured to detect a plurality of optical signals provided from said fiber, a first portion of the optical signals indicative of modal conversion and a second portion of the optical signals indicative of modal interference, a predetermined area of said pixelated photodetector adapted to be illuminated by the first portion of the optical signals; and a signal processing module adapted to decode and interpret a plurality of detected variables related to the optical signals.

Abstract: A tunable fiber optic component providing environmental isolation, thermal tuning, and mechanical tuning and a method of tuning a fiber optic component using application of substantially simultaneous varying of temperature and mechanical strain is disclosed. A method of using a tunable fiber optic component, for example, a distributed feedback fiber laser, to compensate variations in an optical system, and a method of making a tunable fiber optic component are also disclosed.

Abstract: Certain exemplary embodiments comprise a spatially distributed multimode optical fiber; a photodetector configured to detect optical signals provided from said fiber; a wireless digital module coupled to said photodetector and adapted to wirelessly transmit a wireless signal encoding a plurality of detected variables of the optical signals; a wireless receiver adapted to receive the wireless signal; and a signal processing module coupled to said wireless receiver and adapted to decode and interpret the plurality of detected variables of the optical signals.

Abstract: Extensometer with flexible test specimen and Bragg gratings applied in particular to the monitoring of concrete structures, is configured to measure deformations of a host material and comprises at least one test specimen which undergoes linear bending stresses, and at least one Bragg grating formed in an optic fibre and fixed to the test specimen. The extensometer configured such that any deformation of the host material is transmitted to the grating via the test specimen. The extensometer also comprises mechanical means which transform deformation of the material into bending of the test specimen, which deforms the grating.

Abstract: A pressure sensor with a Bragg grating that may be particularly applicable to the chemical industry and for example includes an optical fiber and a Bragg grating formed in a portion of the fiber, submitted to pressure, and a lateral support of the portion. The portion is submitted to a compression prestress with a small value compared with a measurement range of the sensor.

Abstract: The invention relates to a sensor arrangement for seat occupation detection, comprising a fiber-optic sensor network consisting of at least two sensors. The sensor network detest for example local damping modifications in a fiber network that are caused by microbends or modifications of the Bragg wavelength of fiber-optic Bragg grating sensors (FBGS) distributed in the fiber network that are ceased by loads. The optical sensor network is resistant to electromagnetic parasitic inductions. Due to the nature of the optical lass or polymer optical fibers it is for example possible to integrate the network into the textile cover of the seat or into a cushion.

Abstract: The invention relates to devices and methods for detecting a ligand in a liquid, based on deflection of one or more microscopic cantilevers. Each cantilever has an optical waveguide fixed thereto or integral therewith. Deflection of the cantilever is detected by assessing coupling of light between the optical waveguide on the cantilever and an optical waveguide fixed distally thereto.

Abstract: A pressure transducer has a cane waveguide geometry with “side-holes” in the cane waveguide cross-section that reduce the force required to compress the waveguide. The cane waveguide is a large diameter optical waveguide with a cross-section of at least about 0.3 millimeters, at least one inner core, a Bragg grating arranged therein, a cladding surrounding the inner core, and a structural configuration for providing a reduced bulk modulus of compressibility and maintaining the anti-buckling strength of the waveguide. The structural configuration reduces the cross-sectional area of the waveguide. These side holes reduce the amount of glass that needs to be compressed, but retains the large diameter. The waveguide responds to an optical signal, further responds to an external pressure that causes a differential strain across the inner core, for providing a Bragg grating optical-signal containing information about a birefringence of the Bragg grating that is proportional to the external pressure.

Abstract: Integral fiber optic-based condition sensors detect conditions of a composite structure, e.g., a coated wire assembly so as to detect damage or conditions that may damage the same. Preferably, at least one optical fiber sensor having a plurality of Bragg gratings written into the fiber at spaced-apart locations along its axial length is integrated into the electrical insulator coating of a wire, wire bundle or wiring harness. The fiber optic sensor may thus be employed to measure the environmental loads on the electrical wiring including stresses from bending, axial loading, pinch points, high temperature excursions and chemical damage. The system is capable of detecting and locating transient conditions that might cause damage to a wiring system or permanent changes in state associated with damage events. The residual stress in the electrical insulator coating of a wire, wire bundle, or wiring harness are used to monitor the evolution of damage by wear or chaffing processes.

Abstract: An optical fiber sensor array is disclosed which includes a first sensor fiber and a first reference fiber coupled at one end thereof to one side of a first optical coupling. A first wavelength selective reflector is coupled to the other end of each of the first sensor fiber and the first reference fiber. A second sensor fiber is coupled at one end to one side of a second optical coupling. The other side of the second optical coupling is coupled to an opposite side of one of the first wavelength selective reflectors coupled on one side to the first sensor fiber and the first reference fiber. The array also includes a second wavelength selective reflector coupled to the other end of each of the second sensor fiber and the second reference fiber. The second wavelength selective reflectors are operative at a wavelength different from an operative wavelength of the first wavelength selective reflectors.

Abstract: A fiber optic pressure sensor includes an optical fiber for transmitting light. The optical fiber has an axis. The fiber optic pressure sensor also includes an etched diaphragm perpendicular to the axis. The diaphragm includes an operative side located at a distance from the optical fiber sufficient to reflect a portion of the transmitted light into the optical fiber. The etched diaphragm includes a semiconductor, a dielectric, and/or a metal.

Abstract: The invention relates to a method and an apparatus for manufacturing an optical coupling arrangement, and a specific coupling arrangement. A substrate waveguide (306) and at least one coupling element (304, 306) in the coupling arrangement are made of polymer material in the same replication process at the same time. At least one diffractive coupling element (304, 306) is then formed in the polymer material by placing the polymer material against a replication mould, which comprises a surface profile model of at least one diffractive coupling element (304, 306) that is patterned into the replication mould by means of micro lithography.

Abstract: A telecommunications optical fiber is secured against intrusion by detecting manipulation of the optical fiber prior to an intrusion event. This can be used in a non-locating system where the detection end is opposite the transmit end or in a locating system which uses Fresnel reflections and Rayleigh backscattering to the transmit end to detect and then locate the motion. The Rayleigh backscattering time sliced data can be stored in a register until an intrusion event is detected. The detection is carried out by a polarization detection system which includes an optical splitter which is manufactured in simplified form for economic construction. This uses a non-calibrated splitter and less than all four of the Stokes parameters. It can use a polarimeter type function limited to linear and circular polarization or two linear polarizers at 90 degrees.

Abstract: A proof mass is suspended in a cavity in a housing. The proof mass moves along a sensing axis in response to linear acceleration. Elastic support members are connected between the proof mass and the housing and are arranged to exert a reaction force on the proof mass in response to displacement of the proof mass along the sensing axis. An optical fiber is connected between the proof mass and opposite sidewall portions of the housing such that displacement of the proof mass along the sensing axis elongates a first portion of the optical fiber and shortens another portion. An optical signal source provides a broadband optical signal input to the optical fiber. A fiber optic Bragg grating is formed in the optical fiber and arranged to reflect a portion of the optical signal. Acceleration of the proof mass modulates the wavelength of the reflected optical signal.

Abstract: A differential pressure transducer which incorporates a Fabry-Perot sensor for direct quantitative measurements of the distance displaced by a piston abutting two pressure boundaries is described. The apparatus includes a piston with an annular protrusion which is fitted into a transducer housing having a peripheral groove that serves as a stop to prevent damage to the in overpressure situations. A method of measuring differential pressure using a Fabry-Perot sensor is also contemplated.

Abstract: A tunable fiber optic component providing environmental isolation, thermal tuning, and mechanical tuning and a method of tuning a fiber optic component using application of substantially simultaneous varying of temperature and mechanical strain is disclosed. A method of using a tunable fiber optic component, for example, a distributed feedback fiber laser, to compensate variations in an optical system, and a method of making a tunable fiber optic component are also disclosed.

Abstract: A tunable optical fiber has a grating which is attached to an expander responsive to an external control including a temperature or a magnetic field. The expander changes length, and this is coupled to the optical fiber, which changes pitch, thereby accomplishing a tuning change. The expander may be coupled to the grating directly, or through an expansion reducer, which produces a greater range of tuning. Terfenol-D™ may be used for the expander material, and tubes which include a bonding point adjacent to the extents of the grating may form the extent reducers.

Abstract: An optical position detection device is formed by an optical sending and receiving unit, which has a sender with associated transmission optics and a receiver arranged at a given distance or position from the sender with associated reception optics, and an optical lightguide unit. The two units can move relative to each other and are configured so that, when they are at the given distance or position relative to each other, a light beam emitted from the sender of the transmission optics is directed to the reception optics.