A traffic monitoring apparatus includes a distributed acoustic sensor (DAS) for acquiring waterfall data, wherein the waterfall data includes a generation position of a vibration on a roadway adjacent to the DAS, a generation time of the vibration and an amplitude of the vibration. The traffic monitoring apparatus further includes a processor connected to the DAS. The processor is configured to receive the waterfall data from the DAS. The processor is further configured to preprocess the waterfall data. The processor is further configured to separate the preprocessed waterfall data into a plurality of patches, wherein a size of each patch of the plurality of patches is determined based on a parameter of the roadway. The processor is further configured to process each of the plurality of patches to estimate at least one traffic flow property of the roadway.

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.

Methods, systems, and techniques for determining whether an event has occurred from dynamic strain measurements involve determining, using a processor, at least one event parameter from a signal representing the dynamic strain measurements, and then having the processor use the at least one event parameter to determine whether the event has occurred. The at least one event parameter is any one or more of a measure of magnitude of the signal, frequency centroid of the signal, filtered baseline of the signal, harmonic power of the signal, and time-integrated spectrum flux of the signal.

A traffic monitoring apparatus includes a distributed acoustic sensor (DAS) for acquiring waterfall data, wherein the waterfall data includes a generation position of a vibration on a roadway adjacent to the DAS, a generation time of the vibration and an amplitude of the vibration. The traffic monitoring apparatus further includes a processor connected to the DAS. The processor is configured to receive the waterfall data from the DAS. The processor is further configured to preprocess the waterfall data. The processor is further configured to separate the preprocessed waterfall data into a plurality of patches, wherein a size of each patch of the plurality of patches is determined based on a parameter of the roadway. The processor is further configured to process each of the plurality of patches to estimate at least one traffic flow property of the roadway.

A warning device for preventing underground cables against accidental excavation comprises an optical fiber vibration sensor having a mode recognition function, a signal processing unit, a wireless communication unit and a power supply unit, wherein the signal processing unit is connected to the optical fiber vibration sensor, the wireless communication unit and the power supply unit, and the optical fiber vibration sensor is installed within a set range of a cable and is used to monitor vibration signals around the cable, so that once a behavior possibly endangering the cable occurs, an alarm is given out in time to reduce power transmission and transformation accidents. Compared with the prior art, the warning device has the advantages of low false alarm rate, rapid response and accurate localization region.

An embodiment of a system includes a light source, an optical assembly, and an electronic circuit. The light source (e.g., a laser) is configured to generate a source optical signal. The optical assembly is configured to direct the source optical signal into an end of an optical-fiber assembly that includes an optical fiber having a section wrapped multiple turns around a mandrel and including mandrel zones, and to receive, from the end of the optical-fiber assembly, a return optical signal. The electronic circuit is configured to select at least one mandrel zone in response to a component of the return optical signal from the at least one mandrel zone, and to detect an acoustic signal incident on the mandrel in response to the component of the return optical signal.

The present invention is directed to a system for determining the structural characteristics of a machine tool. The system comprises an excitation device configured to induce a dynamic excitation in a tool of the machine tool, a preloading device configured to generate a static force on the tool, and a sensing device for acquiring a set of data based on which the structural characteristics of the tool can be determined.

The present invention relates to a micro-optomechanical system (500) and to a method for the production thereof. The micro-optomechanical system (500) comprises at least one optical subsystem (100) configured for emitting at least one optical actuator signal (212) and for receiving at least one optical sensor signal (211); and at least one optomechanical structure (150) which is producible in direct contact with the optical subsystem (100) by means of a direct writing microstructuring method, wherein the optical subsystem (100) comprises at least one optical actuation element (219) and at least one optical sensor element (140), wherein the optical actuator signal (212) in interaction with the optical actuation element (219) is configured for changing a mechanical state of the optomechanical structure (150), and wherein the optical sensor signal (211) in interaction with the optical sensor element (140) is configured for detecting the change in the mechanical state of the optomechanical structure (150) or a variable related thereto.

The micro-optomechanical systems (500) provided have virtually any desired shaping in conjunction with very high resolution and are therefore suitable for a wide range of applications.

A phase sensitive optical time domain reflectometry based distributed acoustic sensing system eliminating a degradation in a sensing performance encountered due to a finite extinction ratio of optical elements used to generate optical pulses is provided. A classical Optical Time Domain Reflectometer (OTDR) concept and a phase-OTDR concept are merged to generate an optic pulse for an interrogation with commercially available optic modulators. Characteristics of a light inside a fiber optic cable carry properties of both classical OTDR and phase-OTDR systems. The proposed solution does not require any modifications in a receiver part of the phase-OTDR systems and the proposed solution is used for any type of phase-OTDR system structure.

Distributed The disclosed embodiments include distributed acoustic sensing (DAS) systems, methods to improve DAS properties of optical fibers, and optical fibers having improved DAS properties. In one embodiment, the system includes an optoelectronic device operable to generate optical pulses. The system also includes an optical fiber having a first end and a second end. The optical fiber is formed from a material having a Rayleigh back-scattering coefficient, and is operable to transmit optical pulses from the first end towards the second end and to reflect a first portion of the optical pulses towards the first end. The system further includes perturbations that are selectively imprinted on the optical fiber, where the perturbations are compatible with a range of wavelengths and are operable to reflect a second portion of the optical pulses towards the first end of the optical fiber if a wavelength of the optical pulses is within the range.