Abstract: An arrangement for high rate fiber optical distributed acoustic sensing includes an optical fiber, a light launch module adapted to inject a first coherent light pattern into the optical fiber and to inject a second coherent light pattern into the optical fiber while first Rayleigh backscatter light of the first light pattern is propagating in the optical fiber, wherein the first coherent light pattern and the second coherent light pattern have a light pattern power above a nonlinear effect related power limit; and a detector adapted to detect the first Rayleigh backscatter light and to detect second Rayleigh backscatter light of the second light pattern.

Abstract: An arrangement for distributed acoustic sensing and sensor integrity monitoring is adapted to operate in a first operation mode and in a second operation mode. In the first operation mode, the arrangement injects a first light pattern (and successively injects a second light pattern having substantially the same wavelength, both light patterns generated using a light launching module, into the fiber; determines a backscatter change between first backscatter dependent light and second backscatter dependent light detected by the detector, to determine a time change of a characteristic of the fiber. In the second operation mode, the arrangement injects another first light pattern and successively another second light pattern; to determine a backscatter average of other first backscatter dependent light and other second backscatter dependent light detected by the detector, to determine a static characteristic of the fiber.

Abstract: A method of high rate fiber optical distributed acoustic sensing includes injecting a first coherent light pattern comprising first light into an optical cable, the optical cable having at least a first reflector pair and a second reflector pair arranged at different positions along the optical cable; injecting a second coherent light pattern comprising second light into the optical cable while first backscatter light of the first light pattern is propagating in the optical cable; detecting first reflected light originating from reflection of the first light pattern from the first reflector pair and/or the second reflector pair; and, at a different interval in time: detecting second reflected light originating from reflection of the second light pattern from the first reflector pair and/or the second reflector pair.

Abstract: A distributed acoustic sensing (DAS) system has a coherent light source device that repeatedly sends a coherent interrogating light pattern (CILP) into an optical sensing fiber during a measurement duration that is equal to or greater than a down-up travel time of the optical sensing fiber. The CILP is one of a plurality of patterns composed of coherent carrier light. A detection device detects backscattered light in the optical sensing fiber in response to the CILP and generates a signal indicative of the detected backscattered light. An evaluation device analyses the signal. Each CILP has similar physical properties that render the light patterns indistinguishable by comparing physical properties of the backscattered light responsive to at least two successive interrogating light patterns as detected. The coherent light source device can change the time between successively sent interrogating light patterns after the passing of at least one measurement time duration.

Abstract: An arrangement for distributed acoustic sensing and sensor integrity monitoring is adapted to operate in a first operation mode and in a second operation mode. In the first operation mode, the arrangement injects a first light pattern (and successively injects a second light pattern having substantially the same wavelength, both light patterns generated using a light launching module, into the fiber; determines a backscatter change between first backscatter dependent light and second backscatter dependent light detected by the detector, to determine a time change of a characteristic of the fiber. In the second operation mode, the arrangement injects another first light pattern and successively another second light pattern; to determine a backscatter average of other first backscatter dependent light and other second backscatter dependent light detected by the detector, to determine a static characteristic of the fiber.

Abstract: Provided is a method for determining strain change in an optical fiber.

Abstract: An arrangement for high rate fiber optical distributed acoustic sensing includes an optical fiber, a light launch module adapted to inject a first coherent light pattern into the optical fiber and to inject a second coherent light pattern into the optical fiber while first Rayleigh backscatter light of the first light pattern is propagating in the optical fiber, wherein the first coherent light pattern and the second coherent light pattern have a light pattern power above a nonlinear effect related power limit; and a detector adapted to detect the first Rayleigh backscatter light and to detect second Rayleigh backscatter light of the second light pattern.

Abstract: A distributed sensing device for determining a physical quantity, the device comprising a measuring unit configured for measuring at least two signals correlated to the physical quantity by distributed sensing, and a determining unit configured for bringing the at least two signals into a first relation used to determine the physical quantity, performing a correction based on a second relation between the at least two signals, and determining the physical quantity based on the first relation under consideration of the correction.

Abstract: A method of high rate fiber optical distributed acoustic sensing includes injecting a first coherent light pattern comprising first light into an optical cable, the optical cable having at least a first reflector pair and a second reflector pair arranged at different positions along the optical cable; injecting a second coherent light pattern comprising second light into the optical cable while first backscatter light of the first light pattern is propagating in the optical cable; detecting first reflected light originating from reflection of the first light pattern from the first reflector pair and/or the second reflector pair; and, at a different interval in time: detecting second reflected light originating from reflection of the second light pattern from the first reflector pair and/or the second reflector pair.

Abstract: A distributed acoustic sensing (DAS) system has a coherent light source device that repeatedly sends a coherent interrogating light pattern (CILP) into an optical sensing fiber during a measurement duration that is equal to or greater than a down-up travel time of the optical sensing fiber. The CILP is one of a plurality of patterns composed of coherent carrier light. A detection device detects backscattered light in the optical sensing fiber in response to the CILP and generates a signal indicative of the detected backscattered light. An evaluation device analyses the signal. Each CILP has similar physical properties that render the light patterns indistinguishable by comparing physical properties of the backscattered light responsive to at least two successive interrogating light patterns as detected. The coherent light source device can change the time between successively sent interrogating light patterns after the passing of at least one measurement time duration.

Abstract: A fiber measurement device for measuring a physical quantity by a fiber and a method for shaping a pulse of electromagnetic radiation are disclosed. The fiber measurement device comprises an electromagnetic radiation source and an adjustment unit. The electromagnetic radiation source generates at least one pulse of electromagnetic radiation as primary electromagnetic radiation to be coupled into the fiber, and an adjustment unit. The adjustment unit, prior to, during or after application of the primary electromagnetic radiation to the fiber, adjusts a shape of the at least one pulse for at least partially compensating a deviation between a target shape and an actual shape of the at least one pulse.

Abstract: A distributed sensing device for determining a physical quantity which includes a measuring unit configured for measuring signals over time and space by distributed sensing, a determining unit configured for determining, based on the measured signals, data being correlated to the physical quantity, and a filtering unit configured for filtering the data to reduce noise and substantially preserve real features based on at least one filter parameter which is determined depending on the data which relate to the physical quantity at a plurality of different times.

Abstract: Provided is a method for determining strain change in an optical fiber.

Abstract: According to an embodiment there is provided a distributed optical sensing apparatus for determining of a primary quantity along a waveguide, the distributed optical sensing apparatus comprising: an electromagnetic radiation source adapted for coupling electromagnetic radiation into the waveguide to thereby generate in the waveguide (e.g. by interaction with the waveguide) a first response radiation and a different second response radiation; a detector device adapted for providing a first measurement signal indicative of the first response radiation and a second measurement signal indicative of the second response radiation; an evaluation unit adapted for deriving a secondary quantity (e.g. a loss) based on the first measurement signal and the second measurement signal; the evaluation unit being further adapted for deriving the primary quantity based on the secondary quantity and at least one of the first measurement signal and the second measurement signal.

Abstract: A fiber measurement device for measuring a physical quantity by a fiber and a method for shaping a pulse of electromagnetic radiation are disclosed. The fiber measurement device comprises an electromagnetic radiation source and an adjustment unit. The electromagnetic radiation source generates at least one pulse of electromagnetic radiation as primary electromagnetic radiation to be coupled into the fiber, and an adjustment unit. The adjustment unit, prior to, during or after application of the primary electromagnetic radiation to the fiber, adjusts a shape of the at least one pulse for at least partially compensating a deviation between a target shape and an actual shape of the at least one pulse.

Abstract: A distributed sensing device for determining a physical quantity which comprises a measuring unit configured for measuring signals over time and space by distributed sensing, a determining unit configured for determining, based on the measured signals, data being correlated to the physical quantity, and a filtering unit configured for filtering the data to reduce noise and substantially preserve real features based on at least one filter parameter which is determined depending on the data which relate to the physical quantity at a plurality of different times.

Abstract: A distributed sensing device for determining a physical quantity, the device comprising a measuring unit configured for measuring at least two signals correlated to the physical quantity by distributed sensing, and a determining unit configured for bringing the at least two signals into a first relation used to determine the physical quantity, performing a correction based on a second relation between the at least two signals, and determining the physical quantity based on the first relation under consideration of the correction.

Abstract: Distributed optical sensing devices are provided. The device may comprise a computing unit configured to receive signals indicative of an amount of light backscattered in an optical fiber and detected by a light detector; wherein the computing unit is further configured to correct the received signal for an amount of backscattered light undetected by the light detector due to dead time of the light detector. Or, the device may comprise a first light detector having a first light sensitivity and configured to detect light backscattered in a first distance range of an optical fiber; and a second light detector different to the first light detector and having a second light sensitivity being higher than the first light sensitivity, wherein the second light detector is configured to detect light backscattered in a second distance range of an optical fiber being farther away from the second light detector than the first distance range is away from the first light detector.

Abstract: According to an embodiment there is provided a distributed optical sensing apparatus for determining of a primary quantity along a waveguide, the distributed optical sensing apparatus comprising: an electromagnetic radiation source adapted for coupling electromagnetic radiation into the waveguide to thereby generate in the waveguide (e.g. by interaction with the waveguide) a first response radiation and a different second response radiation; a detector device adapted for providing a first measurement signal indicative of the first response radiation and a second measurement signal indicative of the second response radiation; an evaluation unit adapted for deriving a secondary quantity (e.g. a loss) based on the first measurement signal and the second measurement signal; the evaluation unit being further adapted for deriving the primary quantity based on the secondary quantity and at least one of the first measurement signal and the second measurement signal.

Abstract: Determining a measuring uncertainty and/or maximum measuring error of a polarization dependent loss—PDL—tester for determining a PDL value of a device under test—DUT—is provided by using the PDL tester for determining a value of PDL of a verification element having an actual value of PDL greater than a maximum value of a specified measuring range, wherein the PDL tester has an expected measuring uncertainty and/or expected maximum measuring error. The measuring uncertainty and/or maximum measuring error or the tester is then derived from the determined value of PDL of the verification element in conjunction with the actual value of PDL of the verification element.