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 fiber. 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 fiber 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 fiber. 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 fiber 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.

Apparatus and methods for fast quantitative measurement of perturbation of optical fields transmitted, reflected and/or scattered along a length of an optical fiber 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 fiber while achieving fine spatial resolution. Advantages of this technique include 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 sensing system including: a sensor located in an external environment, including: an electrically powered sensor element sensing an environment variable and converting the sensing to a corresponding analog electrical value measure; an electrically powered sensor value conversion system connected to the electrically powered sensor and converting the analog electrical value measure to a digital measure, in addition to encoding the digital measure with sensor identification information; a transducer element for sending the sensed data information over an optical conduit for inputting an optical power signal and outputting optical sensed data information; a coupler splitting a first portion of the optical power signal to an energy storage system; and an energy storage system converting the first portion of the optical power signal into corresponding electrical energy and storing it for on demand usage; said electrically powered sensor value conversion system being supplied with electrical power from said energy storage system.

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.

A system may include a first sensor of a first type and a second sensor of a second different type and having a detector. A field of view of the second sensor may be formed by a plurality of regions of interest (ROIs) defined by the detector. Control circuitry of the system may be configured to perform operations including obtaining, from the first sensor, first sensor data representing an environment, and determining, based on the first sensor data, information associated with a feature of interest within the environment. The operations may also include determining, based on the information, a particular ROI that corresponds to an expected position of the feature at a later time, obtaining a plurality of ROI sensor data from the particular ROI instead of obtaining full-resolution sensor data, and analyzing the plurality of ROI sensor data to determine one or more attributes of the feature.

An optical fiber changes a polarization state of a propagating light when at least one of a vibration and a displacement occurs. An optical transmitter inputs a first wavelength light to the optical fiber via a separator, and an optical transmitter inputs a second wavelength light to the optical fiber via a separator. The first and second wavelength lights propagated through the optical fiber in mutually opposite directions are respectively received by optical receivers (13 and 12) via the separators (18 and 17), and a fluctuation of a polarization is detected in polarization fluctuation detectors (16 and 15). A data processing device collects data indicating the fluctuation of the polarization detected by the polarization fluctuation detector and data indicating the fluctuation of the polarization detected by the polarization fluctuation detector.

A four-dimensional multiplexing method and four-dimensional multiplexing system are provided for optical networks. The method includes receiving sensor data to be transmitted on an optical network. The method also includes encoding the sensor data into an optical signal employing one or more multiplexing systems. The method additionally includes transmitting the optical signal over the optical network. The method further includes decoding the optical signal into the sensor data employing the one or more multiplexing systems. The method also includes controlling an operation of a processor-based machine responsive to the sensor data.

A system, apparatus and method directed to detecting damage to an optical fiber. 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 can include 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 measurement system for performing measurement by Brillouin scattering analysis, the system comprising a laser emitter device (10) configured to emit an incident wave (0) and a reference wave (0B), the incident wave presenting an incident frequency (0) and the reference wave presenting a reference frequency (0B), the reference frequency (0B) being shifted from the incident frequency (0) by a predetermined value (B). The system is configured to: project the incident wave (0) into the optical fiber (25); receive in return a backscattered wave (0S); generate a composite wave (0-S, 0-B) combining the backscattered wave (0S) and the reference wave (S0B); and determine at least one property relating to the fiber by analyzing a Brillouin spectrum of the composite wave (0-S, 0-B).

Advantageously, the incident wave and the reference wave come from a dual-frequency vertical-cavity surface-emitting laser source (12) forming part of the laser emitter device.