The present invention relates to an FBG sensor for measuring a maximum strain of an object being measured, a method for manufacturing the sensor, and a method of using the sensor. To this end, provided is the FBG sensor for measuring a maximum strain, comprising: an optical fiber (130) having an FBG sensor (150) therein; a first metallic foil (120) contacting the optical fiber (130) on one surface thereof; a second metallic foil (120) which comes into surface-contact with the one surface; an adhesive layer (140) provided between the first and second metallic foils (100, 120); a means for measuring a residual strain of the first and second metallic foils (100, 120) through the FBG sensor (150); and a means for calculating a maximum strain on the basis of the measured residual strain and a sensitivity coefficient (Csen) obtained through experimentation.

There are described methods, systems, and computer-readable media for detecting events in a conduit. Multiple lengths of optical fiber positioned alongside a conduit are used to detect a signal. For each length of optical fiber, interferometric data is obtained from the detected signal. The interferometric data obtained for one length of optical fiber is compared to the interferometric data obtained for one or more other lengths of optical fiber. Based on the comparison, it is determined whether the signal originated from the conduit.

Methods and apparatus for fast sweeping a spectral bandwidth in order to distinguish among signals received from effectively wavelength division multiplexed (WDMed) and time division multiplexed (TDMed) optical components on a single fiber. For some embodiments, a method for interrogating optical elements having characteristic wavelengths spanning a sweep range is provided. The method generally includes introducing a pulse of light, by an optical source, into an optical waveguide to interrogate at least a first set of optical elements having different characteristic wavelengths by performing a sweep of wavelengths over a period of the pulse, wherein the period is less than a round-trip time for light reflected from an optical element closest to the optical source to reach a receiver and processing the reflected light to determine a parameter based on the times at which signals are received.

A level sensor assembly includes a fiber that is configured to be at least partially disposed in a tank and to be coupled to a light source and to a light detector. The fiber includes a plurality of sensing regions spaced apart along a length of the fiber. Each sensing region of the plurality of sensing regions includes a Bragg grating configured to generate a reflection spectrum responsive to incident light and a strain layer around the Bragg grating. Each strain layer is configured to induce a strain on the fiber at a respective Bragg grating based on a temperature of the strain layer such that shifts in the reflection spectra of the Bragg gratings indicate which of the sensing regions are submerged in a liquid.

A multilayer polymer film comprising an outer skin layer, an inner seal layer and at least one core layer disposed between the inner and outer skin layer, wherein the outer skin layers comprises a metallocene-catalyzed ethylene polymer having a density of equal to or greater than about 0.945 g/cc and a melt index equal to or greater than 0.5 g/10 min. A multilayer polymer film comprising a metallocene-catalyzed high-density polyethylene homopolymer skin layer and at least one core layer comprising a high-density polyethylene having a melt index of less than or equal to 2.0 g/10 min. A multilayer polymer film comprising at least a skin layer and a core layer wherein the skin layer comprises a metallocene-catalyzed ethylene polymer provided from a catalyst composition comprising a single metallocene and an activator support.

A vibration detection apparatus includes a ring laser resonator, a fiber Bragg grating and a detection system. The ring laser resonator generates a laser beam propagating a ring shaped optical path. The fiber Bragg grating is disposed in the ring laser resonator such that the laser beam enters the grating, and has a transmittance distribution characteristic of transmitted light in a wavelength direction, which changes in accordance with vibration of an object. The detection system detects the vibration based on the transmitted light through the fiber Bragg grating.

It is made possible to amplify signal light of an optical fiber sensor and to perform measurement in a long distance. At least one of a plurality of core wires in a multicore optical fiber is used as a signal-light propagating core wire 133 and the other is used as a reference-light propagating core wire 134. Also, homodyne detection of signal light and reference light reflected by an FBG sensor unit 132 arranged in each measurement point is performed. Thus, signal light is amplified. In order to make a difference between optical path lengths of the signal light and the reference light equal to or smaller than a coherence length, an optical path-length adjustment unit including a piezoelectric element or the like is arranged in an optical path of the reference light.

A method including transmitting, by a mobile device, a first encrypted gadget token over a wireless link to an Information Handling System (IHS). The method further including transmitting, by the IHS, an encrypted system token based on the first decrypted gadget token over the wireless link to the mobile device, transmitting, by the mobile device, a second encrypted gadget token based on the decrypted system token over the wireless link to the IHS, authenticating, by the IHS, the second decrypted gadget token, and unlocking the IHS based on the second authenticated gadget token.

An optical shape sensing method is provided. The method comprises: providing first and second optical fibre portions arranged to receive light from at least one common lasers such that a path length of the light from the laser to the first optical fibre portion differs from a path length of the light from the lasers to the second optical fibre portion by a first distance; wherein the first and second optical fibre portions are spaced apart from each other in a first direction; and wherein the first and second optical fibre portions comprise a plurality of reflectors spaced along the length of the optical fibre portions, wherein the reflectors are arranged in sets of reflectors, each set including one reflector from each of the optical fibre portions, wherein the reflectors in each set are aligned with one another in a second direction that is perpendicular to the first direction when the optical fibre portions are in neutral positions; supplying light from the laser to the optical fibre portions; detecting an interferometric signal from the optical fibre portions at a common detector; determining, for each set of reflectors, optical path length differences between the reflectors in the set of reflectors based on the detected interferometric signal; determining a curvature of the optical fibre portions in the first direction based on the optical path length differences, between the reflectors in the first and second optical fibre portions, for the sets of reflectors. An optical shape sensor and optical shape sensing system are also provided.

An advanced monitoring device and an implementation method for a whole-process deformation curve of a surrounding rock during tunnel excavation is disclosed, comprising a steel pipe elastic body, a cathetometer structure and an embedded optical fiber, and an implementation step; the cathetometer is an equidistant series structure, and fixed in the steel pipe; the embedded optical fiber is encapsulated in the surface slot of the steel pipe; the cathetometer and the embedded optical fiber and the steel pipe form a deformation coordination structure, and the deformation of the surrounding rock can be deduced by calculating the variation of the cathetometer and the deformation of the optical fiber. The invention can test and calculate the deformation curve of the surrounding rock in front of the excavation face during tunnel excavation, and provide support for engineering dynamic design, construction and safety.