A detection system for measuring one or more conditions within a predetermined area includes a fiber harness having at least one fiber optic cable for transmitting light, the at least one fiber optic cable defining a node arranged to measure one or more conditions within the predetermined area. A control system is operably coupled to the fiber harness such that scattered light associated with the node is transmitted to the control system, wherein the control system analyzes the light transmitted from the node by comparing multiple wavelengths of scattered light to determine at least one of a presence and magnitude of the one or more conditions at the node.

In an embodiment an optoelectronic sensor arrangement includes a carrier substrate, an illuminating device, a frequency-selective optical element and a photodetector, wherein the illuminating device and the photodetector form a stacked arrangement on or with the carrier substrate, wherein the frequency-selective optical element is arranged between the illuminating device and the photodetector, wherein the photodetector is arranged in a cavity of the carrier substrate which is covered by the illuminating device and/or the frequency-selective optical element, and wherein the frequency-selective optical element includes a divider mirror and an optical filter.

It is an object of the present invention to provide an aerial optical fiber cable inspection method, an aerial optical fiber cable inspection device, and a program which can identify a cable sagging section from vibration sensing results. In the aerial optical fiber cable inspection method according to the present invention, a vibration distribution waveform along the longitudinal direction of an aerial optical fiber cable measured using an optical fiber vibration sensing device is received as an input, a standard deviation of the amplitude of vibration at each position in the vibration distribution waveform is calculated, and a section with a standard deviation larger than that of other sections is identified as a cable sagging section.

A monitoring humidity measurement system includes: a humidity measurement optical fiber including a first optical fiber and a humidity detection layer provided so as to annularly cover the first optical fiber; a reference optical fiber including a second optical fiber; a plurality of optical communication cables; and a signal processing device configured to, with a laser beam entering into the first and second optical fibers, calculate and obtain Brillouin frequency shift and Rayleigh frequency shift of backscatter light from the first and second optical fibers based on the entering laser beam, and store predetermined constants, wherein reference data and target data are measured from the Rayleigh frequency shift and an initial humidity value calculated from the Brillouin frequency shift, and the value of humidity at the present time is calculated on the basis of Rayleigh frequency shift per unit humidity calculated from a difference between the above two data.

Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously enable anomaly detection resulting from construction—or other activity based on image processing that may advantageously detect/notify/prevent damage to a fiber optic network infrastructure before such damage occurs.

A distributed fiber sensing system may use an integrated coherent receiver. The integrated coherent receiver may include a planar lightwave circuit including various optical components.

The present invention provides novel apparatus and methods for fast quantitative measurement of perturbation of optical fields transmitted, reflected and/or scattered along a length of an optical fibre. The present invention can be used for point sensors as well as distributed sensors or the combination of both. In particular this technique can be applied to distributed sensors while extending dramatically the speed and sensitivity to allow the detection of acoustic perturbations anywhere along a length of an optical fibre while achieving fine spatial resolution. The present invention offers unique advantages in a broad range of acoustic sensing and imaging applications. Typical uses are for monitoring oil and gas wells such as for distributed flow metering and/or imaging, seismic imaging, monitoring long cables and pipelines, imaging within large vessel as well as for security applications.

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 provide the continuous monitoring of aerial cables using distributed acoustic sensing (DAS) and operational modal analysis (OMA).

An optical fiber sensor irradiates light pulses into an optical fiber cable and analyses backscattered light thereof. The optical fiber sensor comprises: a determination part that determines a timing at which measurement of an environmental change starts and a timing at which measurement of the environmental change ends, based on the backscattered light; and an occurrence region estimation part that estimates an occurrence region of the environmental change in a longitudinal direction of the optical fiber cable, based on the timing at which measurement of the environmental change starts; the timing at which measurement of the environmental change ends; and a pulse width of the light pulses.

Aspects of the present disclosure describe distributed fiber optic sensing systems, methods, and structures that advantageously are employed to determine the location and depth of underground fiber-optic facilities that may be carrying telecommunications traffic.