A system for an aircraft that includes a plurality of zones including: a first fiber optic cable routed through a zone of the plurality of zones. The first fiber optic cable is attached to a landing gear of the aircraft in the zone of the plurality of zones; and a first controller configured to provide a first optical signal to the first fiber optic cable and obtain a first optical response signal from the first fiber optic cable. The first controller is further configured to determine at least one temperature within the zone of the plurality of zones based on the first optical response signal, the first optical signal, and coherent optical frequency domain reflectometry (COFDR).

In an optical fiber monitoring system which detects physical disturbance or other parameters such as temperature or strain of a fiber where a monitor signal is transmitted along the optical fiber and analyzed to detect changes which are indicative of an event, a method is provided for periodically checking proper operation of the optical fiber monitoring system. A fiber disturbance actuator periodically causes a pattern of disturbances of a portion of the fiber at a predetermined location thereon where the disturbance is characteristic of the event to be monitored. The monitor signal is analyzed to detect the pattern of changes and in the event that expected changes are not detected, a warning is issued that the intrusion detection system is not properly operating.

An optical fiber characteristics measuring apparatus includes: a light source that outputs frequency-modulated continuous wave of light; a first optical branching unit that branches the continuous light into pump light and reference light; a second optical branching unit that outputs backscattered light generated by making the pump light incident from one end of an optical fiber to be measured, wherein the backscattered light is Brillouin scattering in the optical fiber; a detector that detects interference light of the backscattered light and the reference light; a measuring unit that measures characteristics of the optical fiber by using a detection signal output from the detector; and a controller that controls the light source to change modulation frequency of the continuous light in units of one period or half a period of a modulation period corresponding to the modulation frequency.

A sensor system includes a sensor network comprising at least one optical fiber having one or more optical sensors. At least one of the optical sensors is arranged to sense vibration of an electrical device and to produce a time variation in light output in response to the vibration. A detector generates an electrical time domain signal in response to the time variation in light output. An analyzer acquires a snapshot frequency component signal which comprises one or more time varying signals of frequency components of the time domain signal over a data acquisition time period. The analyzer detects a condition of the electrical device based on the snapshot frequency component signal.

A fibre-optic measurement system equipped with a controlled light generation system (1) and a receiving system (2) connected via an optical path which comprises a directional device (4) and which, in addition, has a processing unit (9) for controlling the light generation system (1) and for receiving and processing the signal from the receiving system (2), according to the invention, it is characterized by the fact that it has a selective mode device (5) and is adapted to be connected to a fibre-optic telecommunications network by a selective mode device (5) and the processing unit (9) is adapted to implement the OFDR and/or COTDR measurement technique for measuring changes in the optical distance and processing them into one or more parameters. Moreover, the object of the invention is also the method of adaptation of a telecommunications network into a sensor network and a fibre-optic measurement and communication system.

A system for monitoring of the resin front during resin infusion into a fiber preform for the manufacturing of composites. Such monitoring is based on Optical Frequency Domain Reflectometry by emitting light pulses through optic fibers which forms a resin infusion mesh in a fiber preform.

The present disclosure provides a secondary battery module capable of optically transmitting measurement data on characteristics of cells forming a battery pack and further reducing a complicated procedure of wiring. The secondary battery module of the present disclosure includes: a battery pack in which a plurality of cell units are connected, each of the cell units including a cell and a light-emitting unit, the cell including a stacked unit and an electrolyte, the light-emitting unit being configured to measure characteristics of the cell and generate an optical signal according to the characteristics; and an optical waveguide into which an optical signal is introduced from the light-emitting unit of each of the cell units, wherein the number of optical waveguides is less than the number of optical signals, and the optical waveguide provides a common optical path through which optical signals are propagated from the light-emitting units provided in the battery pack.

Aspects of the present disclosure describe distributed fiber optic sensing (DFOS)/distributed acoustic sensing (DAS) systems, methods, and structures that advantageously employ chirped interrogation pulses (sensing signals) that exhibit a smooth amplitude profile produced by appending leading and trailing edges of the sensing signals with out-of-band chirps. By appending leading and trailing out-of-band signals to a chirped pulse sensing signal to produce a “smooth” amplitude profile a coexistence of sensing and telecommunications signals on a same optical fiber is facilitated.

To suppress expansion of damage to a working-state cable due to work being continued without detecting breakage of the working-state cable when the breakage occurs, the working-state cable protection monitoring system is provided with: a working means that moves or installs a wire cable-shaped construction material including an optical fiber having at least one core; an interrogator that acquires environment information about each position of the construction material, sensed by the optical fiber; and an abnormal event detection means that, when the environment information acquired at each position of the construction material satisfies an abnormal pattern, detects an abnormal event at the position, where in the working means stops movement and installment of the wire cable-shaped construction material when the abnormal event has been detected.

A method for monitoring the structural health of a structure that supports guided propagation modes of elastic waves, includes the following steps: a) acquiring an ambient noise propagating through the structure by means of at least one pair of non-collocated elastic-wave sensors; b) estimating a function representative of an impulse response of the structure for elastic propagation between the constituent sensors of said pair; c) extracting at least one dispersion curve of the elastic propagation through the structure by time-frequency analysis of this function representative of an impulse response; and d) estimating at least one parameter indicative of a mechanical property of a constituent material of the structure from the dispersion curve obtained in step c). A system for implementing such a method is also provided.