Embodiments of the present disclosure include a low crosstalk, optical fiber based disturbance detection system that includes single-mode optical fiber (SMF) arranged into dual ring Sagnac interferometer wherein both rings share a common sensing section of optical fiber path length. Certain embodiments further include fiber Bragg gratings (FBG's), circulators and couplers to be able to separate the optical signals of the two rings of the dual ring Sagnac interferometer and to perform processing of their individual signals. Embodiments are also disclosed that enable the position of a physical disturbance, the magnitude of the physical disturbance and the frequency of the physical disturbance to be known.

An embodiment of a system for measuring a parameter includes at least a first optical fiber and a second optical fiber configured to be disposed in one or more boreholes in an earth formation, the first optical fiber and the second optical fiber including a plurality of sensing locations. The system also includes a first light source configured to launch a first optical signal into at least the first optical fiber, and a second light source configured to launch a second optical signal into at least the second optical fiber, wherein the first optical signal and the second optical signal are launched at least substantially simultaneously. The system further includes a processor configured to receive measurement data generated based on backscattered signals from at least the first optical fiber and the second optical fiber the reflected signals, the processor configured estimate the parameter based on the measurement data.

An optical fiber sensing system according to the present disclosure includes an optical fiber (10) that detects vibration, a detection unit (21) that detects occurrence of a predetermined event, based on an optical signal on which vibration detected by the optical fiber (10) is superimposed, an identification unit (22) that identifies an occurrence location of the predetermined event, based on the optical signal, and identifies a movement destination area serving as a moving destination of an unmanned aerial vehicle that monitors an occurrence location of the predetermined event, based on an occurrence location of the predetermined event, and a control unit (23) that controls the unmanned aerial vehicle to move to the movement destination area.

An optical fiber sensing system according to the present disclosure includes an optical fiber (10) that detects vibration, a detection unit (21) that detects occurrence of a predetermined event, based on an optical signal on which vibration detected by the optical fiber (10) is superimposed, an identification unit (22) that identifies an occurrence location of the predetermined event, based on the optical signal, and identifies a movement destination area serving as a moving destination of an unmanned aerial vehicle that monitors an occurrence location of the predetermined event, based on an occurrence location of the predetermined event, and a control unit (23) that controls the unmanned aerial vehicle to move to the movement destination area.

The present invention is directed to a system for determining the structural characteristics of a machine tool. The system comprises an excitation device configured to induce a dynamic excitation in a tool of the machine tool, a preloading device configured to generate a static force on the tool, and a sensing device for acquiring a set of data based on which the structural characteristics of the tool can be determined.

A sensor is provided. The sensor includes at least one optical waveguide and an optical reflector. The optical reflector is optically coupled to the at least one optical waveguide and includes a first portion and a second portion. The first portion is configured to reflect a first portion of light back to the at least one optical waveguide. The second portion is configured to reflect a second portion of light back to the at least one optical waveguide. The reflected second portion of the light differs in phase from the reflected first portion of the light by a phase difference that is not substantially equal to an integer multiple of when the second portion of the optical reflector is in an equilibrium position in absence of the perturbation.

An electronic module is provided. The electronic module includes a carrier, a movable component and an optical component. The movable component is on the carrier and configured to be movable with respect to the carrier. The optical component is configured to detect a movement of the movable component by an optical coupling between the optical component and the movable component.

A phase sensitive optical time domain reflectometry based distributed acoustic sensing system eliminating a degradation in a sensing performance encountered due to a finite extinction ratio of optical elements used to generate optical pulses is provided. A classical Optical Time Domain Reflectometer (OTDR) concept and a phase-OTDR concept are merged to generate an optic pulse for an interrogation with commercially available optic modulators. Characteristics of a light inside a fiber optic cable carry properties of both classical OTDR and phase-OTDR systems. The proposed solution does not require any modifications in a receiver part of the phase-OTDR systems and the proposed solution is used for any type of phase-OTDR system structure.

The disclosed embodiments include distributed acoustic sensing (DAS) systems, methods to improve DAS properties of optical fibers, and optical fibers having improved DAS properties. In one embodiment, the system includes an optoelectronic device operable to generate optical pulses. The system also includes an optical fiber having a first end and a second end. The optical fiber is formed from a material having a Rayleigh back-scattering coefficient, and is operable to transmit optical pulses from the first end towards the second end and to reflect a first portion of the optical pulses towards the first end. The system further includes perturbations that are selectively imprinted on the optical fiber, where the perturbations are compatible with a range of wavelengths and are operable to reflect a second portion of the optical pulses towards the first end of the optical fiber if a wavelength of the optical pulses is within said range.

A distributed fiber optic acoustic detection device employs a novel distributed acoustic detection method using a phase noise cancelling distributed acoustic sensing (PNC-DAS) technique.