Abstract: An assembly assembled by a plurality of sections put together, wherein the section includes an elongated structure having a left end and a right end, an optical fiber having a left end and a right end and extending from its left end to its right end so that: the left ends of the elongated structure and of the optical fiber are located on the same left side of the section, and the right ends of the elongated structure and of the optical fiber are located on the same right side of the section, each end of the optical fiber is enclosed in a junction box, the box of the right or left end of the optical fiber of the section being assembled with the junction box of the left end or right end of the optical fiber of another similar section to optically connect the optical fibers of two sections.

Abstract: A process including the following steps: injecting in an optical fiber a first optical pump at a first optical frequency that evolves in time or not, and a second optical pump at a second optical frequency that evolves in time or not, the first optical frequency and the second optical frequency being different at each given time; a first detection of a first Rayleigh backscattered signal at the first optical frequency from the optical fiber; a second detection, separated from the first detection, of a second Rayleigh backscattered signal at the second optical frequency from the optical fiber; and analyzing the detected first Rayleigh backscattered signal and the detected second Rayleigh backscattered signal.

Abstract: A device for calibrating distributing sensing technologies is presented. The device includes an optical fiber, a first input arranged for receiving at least one optical pulse and injecting this at least one optical pulse towards the optical fiber, an output arranged for receiving a backscattered signal generated in the optical fiber. The optical fiber includes at least one event, each event being a part of the optical fiber and having at least one modified physical state or property that is different from the physical state or property of the rest of the optical fiber. The device includes structure creating different optical paths for the at least one optical pulse, the different optical paths having different lengths, each optical path passing through the at least one event. The invention also relates to a process implemented in the device.

Abstract: A method of determining deformation in a structure around which a sensing optical fiber is helically wound, includes performing a distributed measurement at a point along the fiber, to obtain a frequency gain spectrum at that point. Performing a distributed measurement includes, adjusting a pulse width of a pulse pump signal to achieve a predefined spatial resolution and providing the pulse pump signal with adjusted pulse width in the fiber to generate scattering, which is used to obtain the frequency gain spectrum. Identifying at least two curves which, when added together, best fit the frequency gain spectrum. Identifying the frequency at which peaks of the curves occur. Determining deformation in the structure by determining deformation in the fiber at the point using a frequency at which a peak of an identified curve occurs. The amount of deformation in the fiber corresponds to the amount of deformation in the structure.

Abstract: A method for detecting a structural fault in a structure includes the steps of, (a) performing a Brillouin measurement at a point along a sensing optical fiber which operably cooperates with the structure, to obtain a Brillouin gain spectrum at that point; (b) identifying at least two curves which, when added together, best fit the Brillouin gain spectrum; (c) identifying if peaks of the least two curves occur at different frequencies so as to determine if the structure has a structural fault. There is further provided a corresponding apparatus for detecting a structural fault in a structure.

Abstract: A method for performing distributed pressure sensing including the steps of, forming a grating in a birefringent fiber, measuring the birefringence distribution along the length of the birefringent fiber, and determining pressure present along the length of the fiber using the measured the birefringence distribution. The invention also relates to a corresponding sensing device.

Abstract: According to the invention, these aims are achieved by means of a sensor, suitable for sensing one or more properties of one or more structures, the sensor comprising, a first optical propagation path which is configurable to cooperate with a structure whose properties are to be sensed; a second optical propagation path which is configurable to cooperate with a structure whose properties are to be sensed; a third optical propagation path; a means for amplifying a signal which propagates in the third optical propagation path, so that the signal is amplified before it begins propagation along the second optical propagation path, and a means to prevent the propagation of signals from the second optical propagation path to the third optical propagation path. There is further provided a corresponding method of sensing.

Abstract: A Brillouin optoelectronic measurement method includes the steps of, providing a pump signal in a first end of an optical fiber to generate Brillouin backscattering, using the generated Brillouin backscattering to perform a measurement, wherein the pump signal includes a front pulse and a rear pulse, wherein the front pulse is modulated.

Abstract: According to the present invention there is provided a method for installing a sensing cable along a pipeline, comprising the steps of, attaching one or more conduits to an outer-surface of a pipe which is to be installed in a bore hole to form a pipeline assembly; moving the pipeline assembly into the bore hole; moving an fiber optic sensing cable into one or more of the conduit after the pipeline assembly has been moved into the bore hole or before the pipeline assembly has been moved into the bore hole. There is further provided a corresponding pipeline assembly, and a attachment head which can facilitate attachment of a pulling line to a pipeline assembly.

Abstract: A sensing cable including one or more optical fibers and a coating which is provided on the one or more optical fibers. The coating is configured so that pressure applied to the sensing cable, along one or more axes, induces less lateral compression on the one or more optical fibers than pressure applied to the sensing cable along one or more other axes so as to change birefringence in the one or more optical fibers.

Abstract: A Brillouin optoelectronic measurement method includes the steps of, providing a pump signal in a first end of an optical fiber to generate Brillouin backscattering, using the generated Brillouin backscattering to perform a measurement, wherein the pump signal includes a front pulse and a rear pulse, wherein the front pulse is modulated.

Abstract: The present invention relates to a Brillouin optoelectronic measurement method comprising the step of, providing a signal (s1) in an optical fiber (100), wherein said signal (s1) is time-frequency coded. The present invention further relates to a corresponding device for use in such a method.

Abstract: A method for performing distributed pressure sensing including the steps of, forming a grating in a birefringent fiber, measuring the birefringence distribution along the length of the birefringent fiber, and determining pressure present along the length of the fiber using the measured the birefringence distribution. The invention also relates to a corresponding sensing device.

Abstract: The present invention relates to a method of sensing permanent deformation of a structure, the method comprising the steps of; determining the strain required to permanently deform a structure; securing to the structure one or more strain sensors so that a strain sensor will deform when the structure is deformed, wherein the or each strain sensor comprises one or more optical fibers and wherein the or each strain sensor is configured such that it will permanently deform only when the structure permanently deforms; carrying out distributed fiber optic analysis to sense if a strain sensor has been permanently deformed, wherein a permanent deformation of a strain sensor indicates permanent deformation of the structure. The present invention also relates to a corresponding assembly.

Abstract: According to the present invention there is provided a method for installing a sensing cable along a pipeline, comprising the steps of, attaching one or more conduits to an outer-surface of a pipe which is to be installed in a bore hole to form a pipeline assembly; moving the pipeline assembly into the bore hole; moving an fiber optic sensing cable into one or more of the conduit after the pipeline assembly has been moved into the bore hole or before the pipeline assembly has been moved into the bore hole. There is further provided a corresponding pipeline assembly, and a attachment head which can facilitate attachment of a pulling line to a pipeline assembly.

Abstract: According to the invention, these aims are achieved by means of a sensor, suitable for sensing one or more properties of one or more structures, the sensor comprising, a first optical propagation path which is configurable to cooperate with a structure whose properties are to be sensed; a second optical propagation path which is configurable to cooperate with a structure whose properties are to be sensed; a third optical propagation path; a means for amplifying a signal which propagates in the third optical propagation path, so that the signal is amplified before it begins propagation along the second optical propagation path, and a means to prevent the propagation of signals from the second optical propagation path to the third optical propagation path. There is further provided a corresponding method of sensing.

Abstract: The present invention relates to a method of sensing permanent deformation of a structure, the method comprising the steps of; determining the strain required to permanently deform a structure; securing to the structure one or more strain sensors so that a strain sensor will deform when the structure is deformed, wherein the or each strain sensor comprises one or more optical fibers and wherein the or each strain sensor is configured such that it will permanently deform only when the structure permanently deforms; carrying out distributed fiber optic analysis to sense if a strain sensor has been permanently deformed, wherein a permanent deformation of a strain sensor indicates permanent deformation of the structure. The present invention also relates to a corresponding assembly.

Abstract: According to the present invention there is provided a strain sensor apparatus comprising, two or more strain sensors each of which is capable of measuring strain and each of which is configured such that it can be arranged to cooperate with a structure to be monitored so that strain in the structure can be detected by a strain sensor, and one or more position references which is/are arranged in a predetermined position relative to the two or more strain sensors and wherein the one or more position references are each configured such that they are suitable for cooperating with a measuring means; one or more measuring means which is configured to cooperate with the one or more position references so that the angular orientation of the one or more position references can be determined. There is further provided a corresponding method for sensing strain in a structure.

Abstract: The present invention relates to a Brillouin optoelectronic measurement method comprising the step of, providing a signal (s1) in an optical fibre (100), wherein said signal (s1) is time-frequency coded. The present invention further relates to a corresponding device for use in such a method.