Abstract: A distributed sensing apparatus based on Optical Time Domain Reflectometry, OTDR, including an optical source; an optical splitter in optical communication with the optical source, the optical splitter having first and second outputs; a sensing fibre in optical communication with the first output of the optical splitter; a combining unit arranged to combine a reference signal derived from the second output of the optical splitter with a backscattered signal derived from the sensing fibre, wherein the combining unit comprises one or more 3×3 fused fibre couplers; and a signal processing unit configured for processing information derived from the combining unit so as to provide distributed sensing data. The combining unit includes a polarization diversity arrangement including one or more polarization sensitive elements.

Abstract: A sensor system for detection and localisation of changes in or values for at least one environmental condition includes a source of pulses of electromagnetic radiation, wherein the source is configured to emit electromagnetic radiation at a plurality of different wavelengths, an optical fibre in optical communication with the source of pulses, wherein the optical fibre includes a fibre Bragg grating having a reflectance and/or transmittance which varies in dependence on the at least one environmental condition, and a detection unit for detecting electromagnetic radiation which has been reflected or transmitted by the fibre Bragg gratings, wherein the detection unit is configured for detecting electromagnetic radiation at the plurality of wavelengths, such that a spectral response can be determined for different spatial regions along the optical fibre, wherein a change in or value for the environmental condition at a spatial region may be determined by monitoring the respective spectral response.

Abstract: An apparatus for digitizing an optical signal comprises: an optical detector to detect an optical signal and to generate an electric signal corresponding to the optical signal; an envelope curve detector to determine the amplitude of the electric signal or a modified electric signal resulting from the electric signal, and to supply an amplitude signal corresponding to the amplitude; an analog to digital converter to digitize the amplitude signal and to supply a corresponding digitized amplitude signal; and a variable voltage source to calibrate the envelope curve detector.

Abstract: A distributed sensing apparatus based on Optical Time Domain Reflectometry, OTDR, including an optical source; an optical splitter in optical communication with the optical source, the optical splitter having first and second outputs; a sensing fibre in optical communication with the first output of the optical splitter; a combining unit arranged to combine a reference signal derived from the second output of the optical splitter with a backscattered signal derived from the sensing fibre, wherein the combining unit comprises one or more 3×3 fused fibre couplers; and a signal processing unit configured for processing information derived from the combining unit so as to provide distributed sensing data. The combining unit includes a polarization diversity arrangement including one or more polarization sensitive elements.

Abstract: A sensor system for detection and localisation of changes in or values for at least one environmental condition comprises a source of pulses of electromagnetic radiation, wherein the source is configured to emit electromagnetic radiation at a plurality of different wavelengths, an optical fibre in optical communication with the source of pulses, wherein said optical fibre includes one or more fibre Bragg gratings having a reflectance and/or transmittance which varies in dependence on the at least one environmental condition, and a detection unit for detecting, at a plurality of different times, electromagnetic radiation which has been reflected or transmitted by at least one of the fibre Bragg gratings, wherein the detection unit is configured for detecting electromagnetic radiation at the plurality of different wavelengths, such that a spectral response can be determined for different spatial regions along the optical fibre, wherein a change in or value for the environmental condition at a spatial region may

Abstract: Device for monitoring a submarine cable (1) comprising at least one optical fiber (2) which is arranged in or on the submarine cable (1), at least one laser light source (3), the light of which can be coupled into the optical fiber (2), wherein portions of the light back-scattered in the optical fiber (2) can be coupled out from the optical fiber (2), detection and evaluation means (5) capable of detecting the back-scattered light and determining from the detected light spatially resolved the temperature of the optical fiber (2), detection means (6) for the electric current flowing in the submarine cable (1), evaluation means (7) capable of storing the time profile of the detected temperature and the time profile of the detected electric, wherein the evaluation means (7) are capable of calculating from the time profiles of the temperature and the electric current spatially resolved the thermal resistance of the soil surrounding the submarine cable (1) and inferring from the spatially resolved determined therm

Abstract: Device for spatially resolved measurement of temperature, strain, or both by Brillouin scattering, with a laser light source (1) for generating a laser radiation, an optical fiber (5) used for the measurement, into which the laser radiation can be coupled in and from which Brillouin signals generated by Brillouin scattering can be coupled out, sensors for detecting the coupled-out Brillouin signals, evaluators for determining spatially resolved from the detected Brillouin signals the temperature, strain, or both of sections of the optical fiber (5), a polarization beam splitter (10, 11) capable of splitting the coupled-out Brillouin—signals into two components (12, 13) having mutually different polarizations, and an optical coupler (16, 17) for admixing a laser radiation to the Brillouin signal.

Abstract: Device for spatially resolved measurement of temperature and/or strain by Brillouin scattering, with a laser light source (1) for generating a laser radiation, an optical fiber (5) used for the measurement, into which the laser radiation can be coupled in and from which Brillouin signals generated by Brillouin scattering can be coupled out, sensors for detecting the coupled-out Brillouin signals, evaluators for determining spatially resolved from the detected Brillouin signals the temperature and/or strain of sections of the optical fiber (5), a polarization beam splitter (10, 11) capable of splitting the coupled-out Brillouin-signals into two components (12, 13) having mutually different polarizations, and an optical coupler (16, 17) for admixing a laser radiation to the Brillouin signal.

Abstract: Device for monitoring a submarine cable (1) comprising at least one optical fiber (2) which is arranged in or on the submarine cable (1), at least one laser light source (3), the light of which can be coupled into the optical fiber (2), wherein portions of the light back-scattered in the optical fiber (2) can be coupled out from the optical fiber (2), detection and evaluation means (5) capable of detecting the back-scattered light and determining from the detected light spatially resolved the temperature of the optical fiber (2), detection means (6) for the electric current flowing in the submarine cable (1), evaluation means (7) capable of storing the time profile of the detected temperature and the time profile of the detected electric, wherein the evaluation means (7) are capable of calculating from the time profiles of the temperature and the electric current spatially resolved the thermal resistance of the soil surrounding the submarine cable (1) and inferring from the spatially resolved determined therm

Abstract: Apparatus for spatially resolved temperature measurement, comprising at least one optical fiber (4) for spatially resolved temperature measurement, at least one laser light source (1), the light (11) from which can be coupled into the optical fiber (4), wherein those components (12, 12a, 12b) of the light (11) produced by the laser light source (1) which are scattered back in the optical fiber (4) can be coupled out of the optical fiber (4) and detected, modulator means (2) permitting the modulation of the light (11) that is to be coupled into the optical fiber (4), and also demodulator means (5, 6) which permit a demodulation of those components (12, 12a, 12b) of the light (11) which are coupled out of the optical fiber (4), wherein the demodulator means (5, 6) are designed as optical demodulator means (5, 6) and/or wherein the modulator means (2) are designed as optical modulator means (2).

Abstract: Apparatus for monitoring a reactor surface with a sensor cable, which is during operation at least partially arranged in the region of the reactor surface, has at least two optical fibers (1, 2) arranged in the sensor cable, has at least one laser light source whose light is coupled at least partially into the optical fibers (1, 2) during the operation of the apparatus, and evaluation means, in which portions of the light coupled out of the optical fibers (1, 2) are evaluated during the operation of the apparatus, for monitoring at least partially the reactor surface with respect to at least one physical size in a spatially resolved manner. The apparatus includes magnetic retaining means (8) for attaching the sensor cable (10) on the reactor surface.

Abstract: Fiber-optic cable useful in a borehole is provided, with at least one optical waveguide (2), at least one metallic tube (1) which at least partially surrounds the at least one optical waveguide (2), and at least one additional layer, which at least partially surrounds the at least one metallic tube (1). The fiber-optic cable includes a separator which contributes to or cause mechanical decoupling of individual components of the fiber-optic cable.

Abstract: A device for spatially resolved measuring of a physical variable has a device for generating a first electrical signal with a first frequency and a device for generating a second electrical signal with a second frequency. The second frequency differs from the first frequency by a difference frequency. An optical radiation source generates an optical signal modulated by the first frequency. The optical signal can interact with a test object and be modified in the process. A mixer can mix an electrical signal emerging from the optical signal with the second signal. A device, particularly embodied as a DDS system, generates a third electrical signal with a third frequency that corresponds to the difference frequency or a multiple of the difference frequency. A digital/analog converter digitizes the at least one mixed signal by sampling the mixed signal at the third frequency in order to digitize it.

Abstract: Apparatus for a spatially resolved temperature measurement, with at least one optical fiber (6) for the spatially resolved temperature measurement, and at least one laser light source (2) producing light (3, 23) which can be coupled into the optical fiber (6), wherein the portions of the light (3, 23) backscattered in the optical fiber (6) can be coupled out of the optical fiber (6) and evaluated. The apparatus further includes means for reducing polarization-induced effects, wherein the means may be, for example, a polarization modifier (4) capable of at least partially depolarizing the light (3).

Abstract: A device for calibrating a fiber-optic temperature measuring system has a broadband light source, a coupling-in device, which can couple light generated by the light source for calibration into an optical fiber of the temperature measuring system, a coupling-out device, which can couple components of the light source-generated light that are backscattered in the optical fiber out of the optical fiber. An evaluation device performs a calibration of the temperature measuring system on the basis of the backscattered components of the light.

Abstract: Apparatus for spatially resolved temperature measurement, comprising at least one optical fibre (4) for spatially resolved temperature measurement, at least one laser light source (1), the light (11) from which can be coupled into the optical fibre (4), wherein those components (12, 12a, 12b) of the light (11) produced by the laser light source (1) which are scattered back in the optical fibre (4) can be coupled out of the optical fibre (4) and detected, modulator means (2) permitting the modulation of the light (11) that is to be coupled into the optical fibre (4), and also demodulator means (5, 6) which permit a demodulation of those components (12, 12a, 12b) of the light (11) which are coupled out of the optical fibre (4), wherein the demodulator means (5, 6) are designed as optical demodulator means (5, 6) and/or wherein the modulator means (2) are designed as optical modulator means (2).

Abstract: The invention relates to a device for a spatially-resolved measurement of mechanical parameters, in particular mechanical vibrations, comprising at least one optical fiber (3) for measuring at least one mechanical parameter with spatial resolution, at least one laser light source (1), the light from which can be coupled into the optical fiber (3), wherein in the optical fiber (3), backscattered portions of the light generated by the laser light source (1) can be coupled out of the optical fiber (3), tuning means (2) that can tune the laser light source (1) within a time period of less than 50 ms, detection means that can detect the portions of the backscattered light that are coupled out of the optical fiber (3), and analysis means that can determine at least one mechanical parameter of the optical fiber (3) in a spatially-resolved manner from the captured portions of the backscattered light.

Abstract: A device for spatially resolved measuring of a physical variable has a device for generating a first electrical signal with a first frequency and a device for generating a second electrical signal with a second frequency. The second frequency differs from the first frequency by a difference frequency. An optical radiation source generates an optical signal modulated by the first frequency. The optical signal can interact with a test object and be modified in the process. A mixer can mix an electrical signal emerging from the optical signal with the second signal. A device, particularly embodied as a DDS system, generates a third electrical signal with a third frequency that corresponds to the difference frequency or a multiple of the difference frequency. A digital/analog converter digitizes the at least one mixed signal by sampling the mixed signal at the third frequency in order to digitize it.

Abstract: Apparatus for a spatially resolved temperature measurement, with at least one optical fiber (6) for the spatially resolved temperature measurement, and at least one laser light source (2) producing light (3, 23) which can be coupled into the optical fiber (6), wherein the portions of the light (3, 23) backscattered in the optical fiber (6) can be coupled out of the optical fiber (6) and evaluated. The apparatus further includes means for reducing polarization-induced effects, wherein the means may be, for example, a polarization modifier (4) capable of at least partially depolarizing the light (3).

Abstract: A device for calibrating a fiber-optic temperature measuring system has a broadband light source, a coupling-in device, which can couple light generated by the light source for calibration into an optical fiber of the temperature measuring system, a coupling-out device, which can couple components of the light source-generated light that are backscattered in the optical fiber out of the optical fiber. An evaluation device performs a calibration of the temperature measuring system on the basis of the backscattered components of the light.