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

Abstract: A system and method for dynamically calibrating a distributed fiber optic sensing system is disclosed. The calibration system includes a light source for generating pulses of coherent light, an optical fiber arranged at least partly in a ground soil region to guide the light and a photo detector for detecting scattered light returning from the optical fiber in dependence of time. The method includes obtaining information from which a temporal change of an acoustic transfer characteristic of the ground soil region is derivable and calibrating a distributed acoustic sensing system based on the changed acoustic transfer characteristic.

Abstract: An arrangement having an electric cable, at least one fiber at least a part of which being aligned along and motionally coupled with the electric cable, and a device for detecting effects in the electric cable via said at least one fiber.

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.