An object detection device includes: an optical fiber at least partially including a sensor optical fiber configured to transmit light with a loss of 0.3 dB/m or more; and a light receiving unit configured to receive, from the optical fiber, the light received by the sensor optical fiber, wherein the object detection device is configured to detect an object based on an intensity of the light received by the light receiving unit.

An optical fiber sensor system includes a light source, a modulation unit, an optical coupler, a polarization separator, a first polarization controller optically coupled to the polarization separator, and a first detection unit that includes a first optical detector that receives the first component, converts the first component into a first electrical signal, and detects stress. The first polarization controller controls a polarization state of light input to the polarization separator so that the first electrical signal exhibits a first-order response to the stress.

A direct light bend sensor is disclosed. A system that includes direct light bend sensor and method for measuring the force using a direct light bend sensor are also disclosed. In some embodiments, the direct light and sensor includes a tube that is elastically flexible, made of a darkening material, and has a light absorbing inner surface. In the embodiment, a light source is disposed in a first end portion of the tube and a photodetector is disposed in a second end portion of the tube. In the embodiment, an inner surface of the tube defines a bend-dependent direct light path from the light source to the photodetector through the tube.

This application relates to a fibre optic cable structure suitable for use as a sensing fibre optic for distributed acoustic sensing and having an improved sensitivity to transverse pressure waves. The application describes a fibre optic cable (300) having a longitudinal cable axis and comprising at least one optical fibre (301). The cable also comprises a compliant core material (303) mechanically coupled to the optical fibre(s), possible via a buffer (302) such that a longitudinal force acting on the compliant core material induces a longitudinal strain in the optical fibre(s). At least one deformable strain transformer (304) is coupled to the compliant core material and configured such that a force acting on the strain transformer in a direction transverse to the cable axis results in a deformation of the strain transformer thereby applying a longitudinal force to the compliant core material.

A fibre optic cable structure (300) suitable for fibre optic sensing with an improved sensitivity to an environmental parameter is described. The structure (300) includes an optical fibre (301) and a bend inducer (304) responsive to the environmental parameter to control bending of the optical fibre. The bend inducer (304) is configured to adopt a first configuration, that induces a first curvature of the optical fibre, at a first value of the environmental parameter and to adopt a second configuration at a second, different, value of the environmental parameter that induces a second, different, curvature of the optical fibre. By action of the bend inducer (304) a change in value of the environmental parameter imparts a bending force on the optical fibre.

A thrust bearing for a vehicle includes an upper case that abuts against a vehicle body-side attaching portion and a lower case on which the upper case is provided so that the lower case is rotatable with respect to the upper case about an axial center AX of a piston rod used in a shock absorber of a suspension of the vehicle, characterized in that the thrust bearing further includes a load sensor for measuring a load vertically acting on the suspension.

Disclosed herein is a system, apparatus and method directed to detecting damage to an optical fiber of a medical device. The optical fiber includes core fibers including a plurality of sensors configured to (i) reflect a light signal based on received incident light, and (ii) change a characteristic of the reflected light signal based on experienced strain. The system also includes a console having memory storing logic that, when executed, causes operations of providing receiving reflected light signals of different spectral widths of the broadband incident light by one or more of the plurality of sensors, processing the reflected light signals to detect fluctuations of a portion of the optical fiber, and determining a location of the portion of the optical fiber or a defect affecting a vessel in which the portion is disposed based on the detected fluctuations. The portion may be a distal tip of the optical fiber.

A drilling optimization collar for use proximate a drilling tool within a wellbore includes a fiber optic sensor filament that is sized and configured to fit within a groove formed within the drilling optimization collar. The drilling optimization collar may be a pipe segment that is sized and configured to be installed in a drill string proximate the drilling tool, and may have a plurality of sensor elements. All or a portion of the sensor elements may be formed by discrete segments of the sensor filament, and as such, the sensor filament includes sensor elements that are configured to sense a condition of the wellbore and a load on the drilling optimization collar.

A pressure sensor includes: a light source that outputs signal light; a sensor optical fiber where the signal light is input and the signal light is propagated with a loss of 0.3 dB/m or more; and an optical receiver that receives the signal light propagated through the sensor optical fiber. Further, pressure applied to the sensor optical fiber is detected on a basis of intensity of the signal light received by the optical receiver.

An extended length of optical fiber having an offset core with an inscribed Bragg grating is used a distributed sensor in combination with an optical frequency domain reflectometer (OFDR) to enable measurement small-scale (e.g., sub-millimeter) contortions and forces as applied to the fiber. The offset core may be disposed in a spiral configuration around the central axis of the optical fiber to improve the spatial resolution of the measurement. A reference surface exhibit a predetermined texture (in the form of a series of corrugations, for example, that may be periodic or aperiodic, as long as known a priori) is disposed adjacent to a longitudinal portion of the sensor fiber. The application of a force to the combination of the plate and the fiber creates a local strain in the grating formed along the offset core of the fiber that results in a shift in the Bragg wavelength of the grating. Using ODFR measurement techniques, an analysis of the Bragg wavelength shift allows for a high resolution force measurement to be obtained.