An advanced monitoring device and an implementation method for a whole-process deformation curve of a surrounding rock during tunnel excavation is disclosed, comprising a steel pipe elastic body, a cathetometer structure and an embedded optical fiber, and an implementation step; the cathetometer is an equidistant series structure, and fixed in the steel pipe; the embedded optical fiber is encapsulated in the surface slot of the steel pipe; the cathetometer and the embedded optical fiber and the steel pipe form a deformation coordination structure, and the deformation of the surrounding rock can be deduced by calculating the variation of the cathetometer and the deformation of the optical fiber. The invention can test and calculate the deformation curve of the surrounding rock in front of the excavation face during tunnel excavation, and provide support for engineering dynamic design, construction and safety.

A distributed optical detection system comprising: a broadband optical source; and a phase and amplitude receiver for measuring phases and amplitudes of distributed backscattered signals from a sensing medium. Methods of quantitatively sensing optical path length changes along a sensing medium in a distributed manner are also disclosed.

An optical sensor includes an optical fiber inscribed with a repeated refraction pattern such that light scattered from a location on the optical fiber is scattered at multiple frequencies in a range of frequencies. The inscribed patterns overlap at every measurement point along at least a portion of the length of the sensor. An optical sensing system including control circuitry coupled to the optical fiber detects measurement scatter data from the optical fiber over the range of frequencies, determines a change in the detected measurement scatter data over the range of frequencies, and extracts a parameter describing a state of the optical fiber from the determined change in the detected measurement scatter data. The sensor may be made by inscribing a first light refracting pattern on the optical fiber at every measurement point along at least a portion of the length of the sensor and inscribing a second light refracting pattern on the optical fiber that overlaps the first inscribed light refracting pattern at every measurement point along at least that portion of the length of the sensor.

An optical shape sensing system and method with at least two optical fibers (OSF1, OSF2) both comprising optical shape sensing elements. A processor (P) is arranged to register a coordinate system indicative of a position of one of the optical fibers (OSF1) in space, and to register a position (R2) of the other optical fiber (OSF2) in relation to this coordinate system. An optical console system (C, C1, C2) serves to interrogate the optical shape sensing elements in both optical fibers (OSF1, OSF2), and to accordingly determine a measure of a three-dimensional shape (I) of both optical fibers (OSF1, OSF2), based on the registered position (R2) of the second optical fiber (OSF2) in relation to the coordinate system. This provide the possibility of providing 3D optical shape sensing of the length of both optical fibers (OSF1, OSF2), thus allowing 3D shape reconstruction of e.g. long medical devices with lengths of several meters. More than two shape sensing optical fibers, e.g. incorporated in separate devices, can be registered in this manner in a hierarchical data structure, thus allowing shape sensing of very long instruments.

A curve sensor universally applicable to even a curving measurement target having a relatively small diameter is provided. A curve sensor to measure the curving of a curving measurement target includes a light supply unit which guides light, a curve measurement unit which includes a curved state detection unit and which measures the curved state of the measurement target by the change in the amount of light output through the curved state detection unit, a light transmission unit which transmits the light from the light supply unit to the curve measurement unit and a holding portion which holds the light supply unit and the curve measurement unit at predetermined positions on the measurement target.

A LiDAR sensor unit is configured to detect information of an outside area of a vehicle with sensing light. A cover covers the LiDAR sensor unit so as to allow passage of the sensing light while forming a part of an outer surface of the vehicle. A strain gage is disposed on the cover and configured to output a strain signal corresponding to strain generated in the cover. A processor is configured to detect a foreign substance adhered to the cover based on the strain signal.

Disclosed is detection apparatus for flow deformation of foundation layer in horizontal direction including: housing, rotation assembly rotatably disposed within accommodation cavity of the housing, and measurement assembly including first optical fiber lead wire, first optical fiber sensor disposed on first optical fiber lead wire, second optical fiber lead wire, and second optical fiber sensor disposed on second optical fiber lead wire, and disposed within the accommodation cavity. First optical fiber sensor is configured to measure tensile strain of first optical fiber lead wire and first optical fiber sensor before and after the rotation assembly rotates; second optical fiber sensor is configured to measure tensile strain of second optical fiber lead wire and second optical fiber sensor before and after the rotation assembly rotates, to obtain strain amount and displacement change amount, and further to obtain flow deformation degree and flow deformation direction of soil mass of the foundation layer.

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.

There is described a method for interrogating optical fiber comprising fiber Bragg gratings (“FBGs”), using an optical fiber interrogator. The method comprises (a) generating an initial light pulse from phase coherent light emitted from a light source, wherein the initial light pulse is generated by modulating the intensity of the light; (b) splitting the initial light pulse into a pair of light pulses; (c) causing one of the light pulses to be delayed relative to the other of the light pulses; (d) transmitting the light pulses along the optical fiber; (e) receiving reflections of the light pulses off the FBGs; and (f) determining whether an optical path length between the FBGs has changed from an interference pattern resulting from the reflections of the light pulses.

Interferometric measurement signals are detected by a single optical interferometric interrogator for a length of a sensing light guide and an interferometric measurement data set corresponding to the interferometric measurement signals is generated. The interferometric measurement data set is transformed into a spectral domain to produce a transformed interferometric measurement data set. The transformed interferometric measurement data set is compared to a baseline interferometric data set to identify a time-varying signal corresponding to a time-varying disturbance. The baseline interferometric data set is representative of the sensing light guide not being subjected to the time-varying disturbance. A compensating signal is determined from the time-varying signal and used to compensate at least a portion of the interferometric measurement data set for the time-varying disturbance as part of producing a measurement of the parameter.