The invention relates to a device and method for detecting an acoustic wave propagating toward a membrane, the membrane carrying a waveguide comprising an optical cavity defining a resonant frequency. Under the effect of a vibration of the membrane, the resonance frequency of the optical cavity varies. The device includes a light source for directing a light wave into the optical cavity, and a servo circuit for servo-controlling the wavelength of the light wave to the resonant wavelength of the optical cavity. Monitoring the variation in the wavelength of the light wave allows an amplitude of the acoustic wave to be estimated.

An advance in the art is made according to aspects of the present disclosure directed to distributed fiber optic sensing systems (DFOS), methods, and structures that advantageously monitor and identify—in real-time—roadway traffic and patterns across a multiple-lane highway by employing a multiple-transverse fiber optic cable arrangement of optical fiber cable positioned under the highway/roadway to detect, monitor, and/or identify traffic.

A position detection device includes a transmitter that transmits an optical pulse into an optical transmission line laid along the movement path of a moving body; a detector that detects back-scattered light in the optical transmission line; a data processor that calculates the intensity of the back-scattered light and the generation position of the back-scattered light; a storage in which the processing results of the data processor are saved; a search range derivation circuit that derives a search range for the position of the moving body; a maximum value extraction circuit that extracts the generation position at which the variation of intensity within the search range is at a maximum, and causes the extracted generation position to be saved in the storage; and an output circuit that outputs the extraction result.

A laser system for acousto-optics imaging is disclosed. The system comprises: a continuous wave laser source; a first beam splitter configured to split a laser emitted by the continuous wave laser source into a lasing beam and a reference beam; a lasing optical fiber diffusing the lasing beam to a subject; a reference optical fiber providing the reference beam; a collecting optical fiber capable of receiving a scattered beam from the subject; a second beam splitter for merging the scattered and reference beams into a merged beam, and at least one photodetector assembly with a bandwidth higher than the ultrasound frequency to detect the merged beam.

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).

The present invention relates to a sensor device comprising an optical fiber to be coupled with a laser beam, a through-fiber fabricated cantilever onto one end of said optical fiber, and a light collector. According to the invention, the through-fiber fabricated cantilever is made of a polymer obtained by photo-structuring at least one photo-sensitive monomer species. The present invention also relates to methods for the measurement of parameters such as temperature, mass, viscosity, analyte concentrations, and the degree of a polymerization process, using the device of the invention.

An aspect of the invention is directed to a system of both atmospheric and underwater sensors for measuring pressure waves from a noise source. A system of pressure sensors can be formed to determine the location of an external noise source, whether in air or underwater. The system includes at least two arrays consisting of pressure sensors, including at least one atmospheric pressure sensor and at least one underwater pressure sensor, such as a hydrophone. Each sensor may be a seven-fiber intensity modulated fiber optic pressure sensor. The system includes an analog to digital converter for digitizing the pressure data received from each sensor and a processor which processes the received signals to calculate an approximate location of the noise source based upon the pressure signals received by the sensors at different times of arrival. The system can provide this capability in remote applications due to its low power requirements.

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).

A sensor includes at least one optical waveguide and an optical reflector optically coupled to the at least one optical waveguide. The optical reflector includes a first substrate portion configured to reflect a first portion of a light beam back to the at least one optical waveguide and a diaphragm configured to reflect a second portion of the light beam back to the at least one optical waveguide. The diaphragm is responsive to a perturbation by moving relative to the first substrate portion. The light beam is centered on a region between the first substrate portion and the diaphragm.

An optical fiber sensing system according to the present disclosure includes: an optical fiber network (10) configured to detect first sensing information related to a first monitoring target and second sensing information related to a second monitoring target; a reception unit (21) configured to receive an optical signal from the optical fiber network (10); a specification unit (22) configured to specify a first monitoring target based on first sensing information superimposed on the optical signal and specify a second monitoring target based on second sensing information superimposed on the optical signal, and a provision unit (23) configured to provide information related to the first monitoring target and information related to the second monitoring target specified by the specification unit (22) for a service providing destination.