A system can calculate estimated strain data for a fracture in a geological formation at each of a plurality of selected locations detectable by a strain measurement device. The system can receive real strain data from the strain measurement device for the geological formation. The system can perform an inversion to determine a probable distribution of fluid volume and hydraulic fracture orientation in the geological formation based on the estimated strain data and real strain data. The system can determine adjustments for a fracturing operation based on the inversion.

The present disclosure relates to a sensor module for measuring a displacement occurring in a sensor by a confocal principle, a strain sensor device comprising the same, and a method for measuring a strain in a target using the same. Specifically, the sensor module according to an embodiment of the present disclosure includes a first single-mode optical fiber, a first GRIN optical fiber, a multi-mode optical fiber, a second GRIN optical fiber and a second single-mode optical fiber connected in an axial direction, wherein light inputted through the first single-mode optical fiber is transmitted to the second single-mode optical fiber through the series of optical fibers, and light forming a focal point in the core of the second single-mode optical fiber is detected using a confocal principle.

A semi-translucent photovoltaic device is described having a translucent substrate with a photovoltaic stack interrupted in spatially distributed openings filled with a translucent polymer. Also disclosed is a method of manufacturing the device. The method comprises providing the substrate at a first side with the photovoltaic stack; removing material from the stack in spatially distributed regions, therewith forming openings within these regions; blanket-wise depositing a protective layer over the substrate with the photovoltaic stack; blanket-wise depositing a layer of a radiation-curable precursor for the translucent polymer over the protective layer; irradiating the substrate from a second side opposite its first side to therewith selectively cure the radiation-curable precursor within and in front of the spatially distributed openings, the radiation-curable precursor being converted therewith into said translucent polymer; removing an uncured remainder of the layer of the radiation-curable precursor.

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.

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.

Embodiments of the present invention include a system and method for detecting or sensing damage within a target material, as well as related devices. In some embodiments, a damage sensing system including a target material, an optical fiber embedded into the target material, where the optical fiber has an outer surface running the length of the optical fiber, a photosensitive receiver, and a triboluminescent coating coated on the optical fiber.

An optical cable (31) includes: a stress wave detection optical cable (30) having an optical fiber (7) and a plurality of first steel wires (8) which are helically wound so as to surround the optical fiber (7) and which are surrounded by a flexible material (9); and second steel wires (32) different from the first steel wires (8). The stress wave detection optical cable (30) and the plurality of second steel wires (32) are helically wound to form one annular body as a whole, and a winding angle (α) of the stress wave detection optical cable (30) with respect to the axis is determined by a property value prescribed by Lamé constants of the flexible material (9).

An identification system (1) includes a transmitter (131) for transmitting pulsed light via an optical fiber (10); a receiver (132) for receiving backscattering light of the pulsed light from the optical fiber (10); a detector (133) for detecting, from the backscattering light, the condition of environment surrounding the optical fiber (10); and an identifier (320) for identifying sagging of the optical fiber (10) from a detection result by the detector (133).

An adhesive strain sensing pod includes at least one strain sensor, electronics for electrically sensing at least one strain signal from the at least one strain sensor, and a sensor adhesive for adhering the strain sensor to a surface of a structural element. The pod may have a protective case for protecting the strain sensor and the electronics and for transferring at least part of a force, pressing the pod against the surface, to press the strain sensor against the surface. The sensor adhesive may be a liquid adhesive contained in a fragile pouch that ruptures when the pod is forced against the surface, or may be a thermally activated adhesive film that is activated to bond the strain sensor to the surface. A protective film may protect the sensor adhesive prior to installation of the pod and is removed prior to installation of the pod on the surface.

A multi-core fiber includes multiple optical cores, and for each different core of a set of different cores of the multiple optical cores, a total change in optical length is detected. The total change in optical length represents an accumulation of all changes in optical length for multiple segments of that different core up to a point on the multi-core fiber. A difference is determined between the total changes in optical length for cores of the set of different cores. A twist parameter and/or a bend angle associated with the multi-core fiber at the point on the multi-core fiber is/are determined based on the difference.