A shape-sensing system can include an optical-fiber probe and a vibration-assisted torsion-management means for managing torsion in the optical-fiber probe. The optical-fiber probe can be configured to be removably disposed in an elongate medical device. The optical-fiber probe can include an inner construction and an outer construction over the inner construction but detached therefrom over a majority of the optical-fiber probe. The inner construction can include one or more optical-fiber cores disposed in a cladding. The outer construction can include a mechanical layer. The vibration-assisted torsion-management means can be operably coupled to the optical-fiber probe for vibrating either the inner construction or the outer construction of the optical-fiber probe relative to the other, which mitigates or eliminates any optical signal-distorting torsion in the inner construction of the optical-fiber probe. A method of the shape-sensing system can include managing torsion of the optical-fiber probe with the vibration-assisted torsion-management means.

An electric monitoring optical fiber package for an electrical monitoring sensing system is described, the system is used for monitoring and adjusting the electric or magnetic properties of an electric system or cable. The optical fiber package comprises at least one optical fiber, a portion of the optical fiber being coated with a coating material selected from the range of; electrostrictive material, magnetostrictive material, polarisation sensitive material, piezo-electric material; wherein the coating material is a polymeric material. The coated portion of the optical fiber is arranged to provide at least one sensing portion; the sensing portion comprising a sensing portion diameter. The invention aims to provide a low-cost, simpler electrical monitoring sensing system capable of sensing disturbances and anomalies in an adjacent electric system or cable.

A method of manufacturing a transducer includes forming a support structure from a transparent material, the support structure configured to support a sensing element and deform in response to an environmental parameter. Forming the support structure includes modifying a first portion of the transparent material by exposing the first portion to laser radiation, and removing the first portion by an etching process. The method also includes disposing the sensing element at a fixed position relative to the support structure, the sensing element configured to generate a signal indicative of deformation of the support structure.

An optical fiber transducer usable in environments of extreme operating temperature features a stationary support, a movable body displaceable back and forth relative thereto, and an optical fiber connected between the support and the movable body. The fiber has a Fiber Bragg Grating in an intermediate region thereof between the support and movable body. To accommodate varying coefficients of thermal expansion (CTEs) among these components, one or more tubes close circumferentially around the fiber. Each tube has a CTE that is greater than that of the fiber, and less than that of the constituent material of the support and movable body. The fiber is bonded to an interior of the tube(s), while an exterior of the tube(s) is bonded to the support and movable body.

The present invention provides novel apparatus and methods for fast quantitative measurement of perturbation of optical fields transmitted, reflected and/or scattered along a length of an optical fibre. The present invention can be used for point sensors as well as distributed sensors or the combination of both. In particular this technique can be applied to distributed sensors while extending dramatically the speed and sensitivity to allow the detection of acoustic perturbations anywhere along a length of an optical fibre while achieving fine spatial resolution. The present invention offers unique advantages in a broad range of acoustic sensing and imaging applications. Typical uses are for monitoring oil and gas wells such as for distributed flow metering and/or imaging, seismic imaging, monitoring long cables and pipelines, imaging within large vessel as well as for security applications.

An apparatus (32) includes an electronic circuit (76, 80, 84), an electro-acoustic transducer (60) and a coupler (64). The electronic circuit is configured to receive data to be transmitted over an optical cable (24), and to convert the data into a modulating signal. The electro-acoustic transducer is configured to convert the modulating signal into an acoustic wave. The coupler is mechanically coupled to a section of the optical cable, and is configured to apply to the section a longitudinal strain that varies responsively to the acoustic wave, so as to modulate the data onto an optical carrier traversing the optical cable.

The invention is directed at an optical sensor device, comprising a sensing element for receiving an input action, an optical fiber comprising an intrinsic fiber optic sensor, and a transmission structure arranged for exerting a sensing action on the optical fiber in response to the input action received by the sensing element, wherein the optical fiber in a first connecting part thereof is connected to a reference body and wherein the optical fiber in a second connecting part thereof is to the transmission structure for receiving the sensing action, the first connecting part and the second connecting part of the optical fiber being located on either side of the intrinsic fiber optic sensor, wherein the transmission structure comprises a bi-stable spring having a first and a second stable deflection position and a negative stiffness range around an unstable equilibrium position between the first and second stable deflection position, and wherein the optical fiber between the transmission structure and the reference body is pre-stressed such as to be tensed, said optical fiber thereby acting as a spring having a first spring constant of positive value, wherein the optical fiber thereby counteracts a spring action of the bi-stable spring such as to operate the bi-stable spring in a deflection position range within the negative stiffness range, the deflection position range not including the unstable equilibrium position of the bi-stable spring.

A fiber optic cable assembly includes an elongate housing, a signal fiber placed inside the housing and extending longitudinally, and a plurality of sensing fibers placed inside the housing and extending longitudinally. The plurality of sensing fibers is placed around the signal fiber. Each of the plurality of sensing fibers carries a respective laser signal of a distinct frequency. The signal fiber carries one or more evanescent coupling signals responsive to the laser signals in the plurality of sensing fibers.

A fiber optic cable assembly includes an elongate housing, a signal fiber placed inside the housing and extending longitudinally, and a plurality of sensing fibers placed inside the housing and extending longitudinally. The plurality of sensing fibers is placed around the signal fiber. Each of the plurality of sensing fibers carries a respective laser signal of a distinct frequency. The signal fiber carries one or more evanescent coupling signals responsive to the laser signals in the plurality of sensing fibers.

A resin impregnation detection device configured to detect resin impregnation in a resin impregnation process for a coil insulation layer. The resin impregnation detection device can be inserted in a narrow portion, is capable of detecting impregnation with a liquid resin, and does not leave metal foreign materials other than an optical fiber in a product even after the resin impregnation. The resin impregnation detection device includes an optical fiber including an FBG sensor, and a coating resin, which coats the FBG sensor. The coating resin includes a resin to be softened by contact with a detection target resin. The FBG sensor is applied with a compressive strain caused by cure shrinkage of the coating resin or heat shrinkage thereof from a curing temperature to a normal temperature.