The invention relates to a measurement device (10) for measuring light (200) from a light source (2), comprising an optical unit (30) with a delay element (31) for splitting a polarized light beam (210) of the light (200) into a first partial beam (211) and a second partial beam (212), which have a defined phase shift relative to one another. Furthermore, the invention relates to a measurement system (1), as well as a measurement method (100).

The present invention relates to an optical shape sensing system, comprising an optical fiber sensor comprising an optical fiber having embedded therein a number of at least four fiber cores (1 to 6) arranged spaced apart from a longitudinal center axis (0) of the optical fiber, the fiber cores each having a resonance wavelength in response to light introduced into the fiber cores (1 to 6) in an unstrained state thereof. The system further comprises an optical interrogation unit (21) configured to interrogate the fiber cores (1 to 6) with light in a scan wavelength range including the resonance wavelengths of the fiber cores in an unstrained state of the fiber cores (1 to 6). The scan wavelength range is set such that a center wavelength of the scan wavelength range is decentered with respect to the resonance wavelength of at least one of the fiber cores (1 to 6).

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.

An apparatus (1) for determining the aging of a battery cell (2), the battery cell (2) having at least one galvanic element (3) for converting chemical energy into electrical energy and a housing (4) which surrounds the galvanic element (3) and has a wall (8) formed at least on one side of the galvanic element (3), comprising at least one length sensor (5) for sensing a length change of the galvanic element (3), the aging of the battery cell (2) being able to be determined via the length change of the galvanic element (3).

The present invention relates to an optical fiber sensor for shape sensing, comprising an optical fiber having embedded therein a number of at least four fiber cores (1 to 6) arranged at a distance from a longitudinal center axis (0) of the optical fiber, the number of fiber cores (1 to 6) including a first subset of at least two fiber cores (1, 3, 5) and a second subset of at least two fiber cores (2, 4, 6), the fiber cores (2, 4, 6) of the second subset being arranged to provide a redundancy in a shape sensing measurement of the fiber sensor (12′). The fiber cores (1, 3, 5) of the first subset are distributed in azimuthal direction around the center axis (0) with respect to one another, and each fiber core (2) of the second subset is arranged in non-equidistantly fashion in azimuthal direction around the center axis (0) with respect to two neighboring fiber cores (1, 3) of the first subset.

Provided are an apparatus and a method for measuring a nonlinearity parameter using laser, and more particularly, an apparatus and a method for measuring a nonlinearity parameter using laser for computing the nonlinearity parameter by irradiating laser of a toneburst signal on a surface of a sample by non-contact type laser so as to excite the sample, irradiating measurement laser beam on the surface of the sample so as to receive displacement information occurring on the surface of the sample over time, measuring the displacement in an interferometer principle, and performing a bandpass filtering for the measured signal so as to measure amplitude A.sub.1 of a component of a fundamental frequency and amplitude A.sub.2 of a component of a secondary harmonic wave.

Described are methods and systems using optical fiber interferometry to sense interference causing events in a region of interest and differentiate between a strain event and a thermal event. Other methods and systems relate to the use of optical fiber interferometry for determining temperature offset in a region of interest and using the determined temperature offset for determining temperature in the region of interest.

An optical sensor includes an optical fiber inscribed with a repeated refraction pattern such that light scattered from a location on the optical fiber is scattered at multiple frequencies in a range of frequencies. The inscribed patterns overlap at every measurement point along at least a portion of the length of the sensor. An optical sensing system including control circuitry coupled to the optical fiber detects measurement scatter data from the optical fiber over the range of frequencies, determines a change in the detected measurement scatter data over the range of frequencies, and extracts a parameter describing a state of the optical fiber from the determined change in the detected measurement scatter data. The sensor may be made by inscribing a first light refracting pattern on the optical fiber at every measurement point along at least a portion of the length of the sensor and inscribing a second light refracting pattern on the optical fiber that overlaps the first inscribed light refracting pattern at every measurement point along at least that portion of the length of the sensor.

Systems and methods are disclosed for dynamic addressing of optical fiber sensors in fiber optic interferometry systems. Events that occur along the optical fiber span have defining attributes such as location along the optical fiber span, type, magnitude, time of occurrence, and duration. The event attributes may be used to dynamically form a unique address that fully defines and identifies the event. Other information, such as the corresponding identifier for one or more of the optical fiber span and the corresponding fiber optic interrogator may be included as part of the unique address.

A method of monitoring hydraulic fracturing using DAS sensors in a treatment well and/or observation well is described. The raw data is transformed using a low pass filter (≦0.05 Hz) and down-sampled to show the signal as the stimulation progresses. The resulting data can be used to optimize the hydraulic fracturing or improve reservoir models for other reservoirs.