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.

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.

A system for interrogating an interferometer. The system comprises an optical signals generation system for concurrently generating a plurality of optical signals that each have a modulation parameter that the other of the plurality of optical signals do not have. The optical signals generation system is for optically coupling each of the plurality of optical signals to a plurality of optical ports of the interferometer for ingress of the plurality of optical signals into the interferometer. The system comprises an interferometer output processing system. Also disclosed herein is an interferometric system and a method for interrogating an interferometer.

The present disclosure relates to an optical fiber detection device for detecting a discharge fault of a high-voltage bushing, which includes an optical fiber sensing unit, an optical fiber delay unit, a photoelectric conversion unit, and a signal collecting and processing unit. The optical fiber sensing unit includes sensing optical fibers; the optical fiber delay unit includes delay optical fibers, a light source, and couplers; the photoelectric conversion unit includes a photodetector; the signal collecting and processing unit includes a high-pass filter. The delay optical fibers are connected to the couplers; an output end of the light source is connected to the light-splitting coupler; an input end of the photodetector is connected to the light-splitting coupler, and an output end of the photodetector is connected to the signal collecting and processing unit; and the light-combining coupler is connected to the sensing optical fibers.

A distributed fiber-optic acoustic sensing system and a signal processing method. The distributed fiber-optic acoustic sensing system is based on a high spatial resolution distributed fiber-optic acoustic sensor. The interval between adjacent sensing units is centimeter or millimeter level. Through specific digital signal processing, signal enhancement can be realized, noise in the system and environment are suppressed, at the same time, problems such as interference fading is solved, and the sensor signal-to-noise ratio of subunits can be increased by two to three orders of magnitude. Each subunit can serve as an independent high-sensitivity sensor for sensing. The multiple subunits can form one or more new sensor arrays. The azimuth estimation and spatial orientation of signal sources can be realized by the array signal processing method.

The present disclosure relates to an optical fiber detection device for detecting a discharge fault of a high-voltage bushing, which includes an optical fiber sensing unit, an optical fiber delay unit, a photoelectric conversion unit, and a signal collecting and processing unit. The optical fiber sensing unit includes sensing optical fibers; the optical fiber delay unit includes delay optical fibers, a light source, and couplers; the photoelectric conversion unit includes a photodetector; the signal collecting and processing unit includes a high-pass filter. The delay optical fibers are connected to the couplers; an output end of the light source is connected to the light-splitting coupler; an input end of the photodetector is connected to the light-splitting coupler, and an output end of the photodetector is connected to the signal collecting and processing unit; and the light-combining coupler is connected to the sensing optical fibers.

A sensor system includes a radiation source, an optical fiber, and a detection device. The radiation source is arranged to emit pulses of radiation. The optical fiber comprises a first end and a core. The first end is arranged to receive pulses of radiation output from the radiation source such that, in use, the pulses of radiation are coupled into the fiber. The core is arranged to support propagation of the pulses of radiation along the fiber. The core includes a plurality of reflectors each comprising a portion of the core having a refractive index which is different to the refractive index of adjacent regions of the core. Reflections of a pulse of radiation from adjacent reflectors output at the first end of the fiber are resolvable from each other in the time domain. The detection device is arranged to measure radiation output from the first end of the fiber and resolve radiation reflected at different locations in the core of the fiber.

A fiber optic sensor and a related method of manufacture are provided. The fiber optic sensor includes an embedded optical fiber contained within a metal diaphragm assembly, where the terminal end of the optical fiber is positioned opposite a diaphragm. The method includes forming a metal-embedded optical fiber by ultrasonic additive manufacturing and securing the metal-embedded optical fiber to a housing having a diaphragm that is opposite of the terminal end of the optical fiber. The sensor can provide extremely accurate pressure measurement at high temperatures and in highly corrosive media. An optical fiber-based pressure sensing system is also provided.

A high-performance distributed fiber sensing system based on EHz ultrafast pulse scanning. During testing of a disturbance signal, an internally frequency converted pulse light emitted by an EHz ultrafast pulse scanning laser enters a sensing fiber after passing through a circulator, and a backward Rayleigh scattering signal transmitted by the sensing fiber enters an unbalanced Michelson interferometer after passing through a coupler. By designing an arm length difference between two interference arms, interferences sequentially occur for the backward Rayleigh scattering light at a position where lengths of two adjacent arms differ. A signal received after passing through the unbalanced Michelson interferometer includes a phase difference signal caused by an external disturbance signal in the sensing fiber. Finally, variations of the phase difference signal over time are demodulated by using a phase demodulation unit, so that a dynamic measurement of the disturbance signal in the sensing fiber may be performed.

A system for interrogating an interferometer. The system comprises an optical signals generation system for concurrently generating a plurality of optical signals that each have a modulation parameter that the other of the plurality of optical signals do not have. The optical signals generation system is for optically coupling each of the plurality of optical signals to a plurality of optical ports of the interferometer for ingress of the plurality of optical signals into the interferometer. The system comprises an interferometer output processing system. Also disclosed herein is an interferometric system and a method for interrogating an interferometer.