A well system includes a fiber-optic cable that can be positioned downhole along a wellbore. The well system further includes a plurality of opto-electrical interfaces to communicatively couple to the fiber-optic cable to monitor temperature and strain along the fiber-optic cable. Additionally, the well system includes a processing device and a memory device that includes instructions executable by the processing device to cause the processing device to perform operations. The operations include receiving data representing frequency or phase shift measurements from the opto-electrical interfaces using at least two frequency or phase shift measurement techniques. Further, the operations include generating a temperature shift output and a strain change output using an inversion comprising sensitivity ratios and the data representing the frequency or phase shift measurements from the plurality of opto-electrical interfaces.

The present invention is to provide a backscattered light amplification device, an optical pulse test apparatus, a backscattered light amplification method, and an optical pulse test method for amplifying a desired propagation mode of Rayleigh backscattered light with a desired gain by stimulated Raman scattering in a fiber under test having the plurality of propagation modes. The backscattered light amplification device according to the present invention is configured to control individually power, incident timing, and pulse width of a pump pulse for each propagation mode when the pump pulse is incident in a plurality of propagation modes after the probe pulse is input to the fiber under test in any propagation mode.

An object of the present disclosure is to detect a microbend in an optical fiber before the light-receiving intensity of a transmission device decreases. The present disclosure relates to a device configured to measure guided acoustic wave Brillouin scattering in a measurement target optical fiber, and detect a microbend in the measurement target optical fiber based on a characteristic around a peak of the guided acoustic wave Brillouin scattering.

Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously sense/monitor outdoor facilities and structures including outdoor cabinets containing fiber optic facilities in which the cabinet/fiber optic cable contained therein are configured to provide superior acoustic sensing. Further outdoor facilities and structures that are monitored include manhole structures. Superior DFOS/DAS monitoring results are obtained by employing a machine learning-based analysis method that employs a temporal relation network (TRN).

The present invention relates to an optical fiber BOCDA sensor. A purpose of the present invention is to provide an optical fiber BOCDA sensor which uses two phase codes to control a correlation peak position, thereby further simplifying control design and device configuration and improving spatial resolution to enhance a sensing performance and detection accuracy in comparison with the prior art.

This application describes a fibre optic cable structure which is advantageous for distributed fibre optic sensing, for example distributed acoustic sensing (DAS). The fibre optic cable structure includes an optical fibre for distributed fibre optic sensing and is configured to comprise at least one longitudinal section of a first type, which exhibits a change in effective optical path length of the optical fibre of one polarity in response to a given applied force, and which is adjacent to at least one longitudinal section of a second type, which exhibits a change in effective optical path length of the optical fibre of the opposite polarity in response to an equivalent applied force. When used for DAS, the response of a sensing portion that includes sections of both the first and second types, will include or exclude certain wavenumber by summation, which provides a directional sensitivity to incident waves.

According to examples, an optical fiber-based sensing membrane may include at least one optical fiber, and a substrate. The at least one optical fiber may be integrated in the substrate. The optical fiber-based sensing membrane may include, based on a specified geometric pattern of the at least one optical fiber, an optical fiber-based sensing membrane layout. The substrate may include a thickness and a material property that are specified to ascertain, via the at least one optical fiber and based on the optical fiber-based sensing membrane layout, a thermal and/or a mechanical property associated with a device, or a radiation level associated with a device environment.

The present disclosure provides a Brillouin optical time domain reflectometer with an ultra-high spatial resolution based on bipolar differential phase encoding, including a narrow-linewidth laser, a polarization maintaining coupler, a differential encoder, a Mach-Zehnder modulator, an optical pulse amplifier, an optical circulator and a sensing fiber, an optical amplifier, a coherent optoelectronic receiver, a sideband demultiplexer, and a result measurement module. By implementing the present disclosure, a spatial resolution for measuring a Brillouin scattering spectrum can be effectively improved, and measurement precision can be effectively improved by increasing a quantity of times of superposition and averaging. In addition, measurement performance can be effectively improved by directly using a bipolar encoding sequence.

Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously identify location(s) of construction—or other activities—taking place along fiber optic cable routes that can damage the fiber optic cables.

Methods of measuring an anomaly, any induced change in physical parameters such as strain, temperature, and so forth, in an optical fiber. One method may include launching a plurality of probe pulses from a probe source; recording a Brillouin scattering spectrum from a plurality of reflection signals generated in the optical fiber, responsive to the plurality of probe pulses; determining a relative motion between the optical fiber and the anomaly during the recording the Brillouin back-scattering spectrum; and dynamically adjusting the Brillouin back-scattering spectrum according to the relative motion, or performing an adjustment of the Brillouin back-scattering spectrum after acquisition of the Brillouin back-scattering spectrum.