An optical fiber distributed acoustic sensor system makes use of a specially designed optical fiber to improve overall sensitivity of the system by a factor in excess of 10. This is achieved by inserting into the fiber weak broadband reflectors periodically along the fiber. The reflectors reflect a small proportion of the light from the DAS incident thereon back along the fiber, typically in the region of 0.001% to 0.1%. To allow for temperate compensation to ensure that the same reflectivity is obtained if the temperature changes, the reflection bandwidth is relatively broadband. The reflectors are formed from a series of fiber Bragg gratings, each with a different center reflecting frequency, the reflecting frequencies and bandwidths of the gratings being selected to provide the broadband reflection. The reflectors are spaced at the desired spatial resolution of the optical fiber DAS.

The present disclosure provides an optical fiber. The optical fiber includes a core. The core has high compressive stress. The compressive stress of the core is in a range of about 20 to 60 MPa. The optical fiber includes a cladding. The cladding is divided into a first cladding layer and a second cladding layer. The second cladding layer has a high residual stress. The high residual stress of the second cladding layer is in a range of about 20 to 60 MPa. The optical fiber enables reduction of particle related breaks. Further, the optical fiber has elevated LLT strength. The LLT strength is about 6 Kg. The optical fiber has high proof test yield. Furthermore, the optical fiber is highly sensitive to micro-bending of the optical fiber.

A waveguide for guiding an electro-magnetic wave comprises: a first waveguide part; and a second waveguide part; wherein the first waveguide part has a first width in a first direction (Y) perpendicular to the direction of propagation of the electro-magnetic wave and the second waveguide part has a second width in the first direction (Y), wherein the second width is larger than the first width; and wherein the first and the second waveguide parts are spaced apart by a gap in a second direction (Z) perpendicular to the first and second planes in which the waveguide parts are formed, wherein the gap has a size which is sufficiently small such that the first and second waveguide parts unitely form a single waveguide for guiding the electro-magnetic wave.

A photonic integrated circuit component, a sensor and an actuator comprising the waveguide are disclosed.

In a sensor device, a plurality of light guides having a respective first end and a respective second end are arranged on a common carrier, with the first end of each light guide of the plurality of light guides at a respective defined position on the carrier. At each of the second ends of the light guides there is provided at least one sensor element which exhibits an optical behavior dependent on an analyte. The second ends are at defined perpendicular distances to the carrier. At least two of the second ends differ with respect to the defined perpendicular distances.

A steel cable includes steel wires and at least one light wave guide which is surrounded by the steel wires and provided for detecting load-dependent cable strains, and has a glass fiber surrounded by a plastic casing. At least the steel wires closest to the light wave guide are crimped with the light wave guide and permanently pressed against the casing surface thereof, whereby the cross-sectional shape of the casing surface of the light wave guide deviates from an unloaded shape, in particular a circular shape, and the light wave guide is clamped continuously along at least one part of the longitudinal extension thereof, in a slip-free manner between the steel wires closest to same. A method produces a steel cable of this type.

This application relates to methods and apparatus for distributed fibre optic sensing that can provide an indication of the absolute value of pressure acting on a sensing portion of a fibre optic cable. A sensor apparatus (600) has a first fibre optic cable structure (102) comprising a first optical fibre (101) and an interrogator (103) configured to perform distributed acoustic sensing on the first optical fibre (101) to provide a measurement signal from at least one sensing portion of the first optical fibre. The first fibre optic cable structure (102) is configured such that a sensitivity of a sensing portion (603, 604) to an incident pressure stimulus (P1, P2) depends on the ambient pressure (AP1, AP2) at the location of the respective sensing portion. A processor (104) is configured to process the measurement signal in response to an incident pressure stimulus (P1, P2) based on a predetermined sensitivity profile (504, 701) to determine an indication of the ambient pressure at the respective sensing portion.

An optical fiber sensor device includes a control section configured to compute a physical quantity in an optical fiber installed at plural measurement locations based on intensity of scattered light received, and to compute an average of the computed physical quantity for the optical fiber. The control section is configured to compute the average of the physical quantity based on the computed physical quantity and on a length of the optical fiber. A length of the optical fiber installed at the measurement location is increased as a distance between a light source and the respective measurement location increases.

A device for measuring force and for monitoring wear on overhead lines includes a force-measuring system which includes two contact bars which, in an operating state, are oriented at a right angle to an overhead line to be monitored, and two connection bars, which, in the operating state, are oriented parallel to the overhead line. A bar-shaped force transducer is fastened to each end portion of the two connection bars and each of the bar-shaped force transducers extends in an axial direction of the respective connection bar.

An optical component may be provided having a substrate with a first refractive index, in which space regions with a second refractive index are arranged, wherein the optical component contains at least one optical metamaterial, which contains a plurality of individual pixels each comprising a space region which has the first or the second refractive index, wherein the substrate contains at least one polymer. Further, a sensor may be provided with such an optical component and a process for measuring any of an expansion or a temperature.

An impact-detection device includes at least one waveguide provided at each of the two ends thereof with a connector. The device further includes a ring with a curved outer contour. The ring forms a separate part with planar radial surfaces. The waveguide is built into the body of the ring about the ring, and the two ends of the waveguide are arranged on the outside of the ring.