An optical fiber sensing system is acquired by adding an optical fiber sensing function to an optical communication cable system, and the optical fiber sensing is performed by an interrogator by sending probe light to an optical fiber, detecting backscattered light of the probe light, and performing sensing on environmental information around the optical fiber. A first sensing device installed at a remote place different from a terminal station of the optical communication cable system includes the interrogator, a power source unit configured to receive power via the optical communication cable system and supply power into the device, and a communication unit configured to communicate with a second sensing device. The interrogator generates sensing data at each point on the optical fiber by performing sensing on environmental information around the optical fiber being connected to the first sensing device.

The invention relates to a method (1) for reconstructing an electromagnetic vector wave backscattered in all or part of an optical fiber (106), comprising: A step (200) of injecting into the optical fiber (106) a light signal of a frequency v.sub.0 or v.sub.0+v.sub.A, A step (300) of polarization-resolved heterodyne optical detection including the generation of at least two orthogonally polarized backscattered light signals, producing a beat preferably of a frequency v.sub.A, A step (400) of converting, by at least one photodetector (203), the orthogonally polarized backscattered light signals into initial analog signals, A step (500) of electrical homodyne detection, by an IQ demodulator (211, 302), so as to generate I (I.sub.1, I.sub.2) and Q (Q.sub.1, Q.sub.2) demodulated analog signals, and A step (600) of reconstructing, by a processing module (209), the electromagnetic vector wave backscattered in all or part of the optical fiber (106).

It is intended to provide a phase measurement method and a signal processing device that are capable of reducing influence of noise of a measuring device without increasing the peak intensity of an incident light pulse when measuring the phase of scattered light in DAS-P.

A phase measurement method according to the present invention causes wavelength-multiplexed pulse light to be incident on a measurement target optical fiber, produces a scattered light vector obtained by plotting scattered light from the measurement target optical fiber for each wavelength onto a two-dimensional plane having the in-phase component thereof on the horizontal axis and the orthogonal component thereof on the vertical axis, rotates the produced scattered light vector for each wavelength at each place in the measurement target optical fiber to align the directions of the vectors, generates a new vector by calculating the arithmetic average of the vectors having the aligned directions, and calculates the phase by using the values of the in-phase and orthogonal components of the generated new vector.

An optical fiber sensing system according to the present disclosure comprises: an optical fiber (10) that is laid in a pipe (30); a reception unit (21) configured to receive, from the optical fiber (10), an optical signal superimposed with vibration detected by the optical fiber (10); and an assessment unit (22) configured to extract a vibration pattern of the vibration detected by the optical fiber (10) from the optical signal and determine the degradation state of the pipe (30) based on the extracted vibration pattern.

There is provided an OTDR receive device and an OTDR system comprising an OTDR receive device wherein the OTDR unit and the OTDR receive device are to be connected at opposite ends of an optical fiber link under test. The OTDR receive device comprises means for the OTDR system to detect an established connectivity between the OTDR unit and the OTDR receive device via the optical fiber link under test and a status indicator to notify a user of the receive device of the connectivity status and optionally an OTDR measurement status. Connectivity detection allows to check for continuity between the OTDR unit and the OTDR receive device before launching an OTDR measurement. A user of the OTDR unit does not need to communicate with the user of the OTDR receive device to know when to start the acquisition.

Aspects of the present disclosure describe optical fiber sensing systems, methods and structures disclosing a distributed optical fiber sensor network constructed on a switched optical fiber telecommunications infrastructure to detect temperatures, acoustic effects, and vehicle traffic—among others—demonstrated with a number of different network topologies.

A multilinear domain-specific domain generalization (MDSDG) approach that utilizes information stored in multilinear indices of data domains to improve machine learning. In particular—based on limited sample size(s) in observed scenarios—an array of models is jointly trained, which advantageously are generalized to a new, unseen scenario, where only domain descriptions in the form of multilinear indices are available.

Distributed fiber optic sensing (DFOS)/distributed acoustic sensing (DAS) techniques coupled with frequency domain decomposition (FDD) are employed to determine the presence of 120 HZ operating power frequency to determine when street lights are energized and on thereby providing continuous status monitoring of the operational status of street lights and locating affected street lights at a particular utility pole location.

Materials, methods of making, and methods of sensing liquid droplets with high spatial resolution as a signature of the on-set of corrosion using a hierarchical sensor network A hierarchical sensor network for sensing liquid droplets with high spatial resolution as a signature of the on-set of corrosion, including an interrogation system; and an intermediate sensor array layer in communication with the interrogation system. The network includes an interrogation system and an intermediate sensor array layer in communication with the interrogation system.

A distributed optical detection system comprising: a broadband optical source; and a phase and amplitude receiver for measuring phases and amplitudes of distributed backscattered signals from a sensing medium. Methods of quantitatively sensing optical path length changes along a sensing medium in a distributed manner are also disclosed.