To achieve data-driven intelligence in engineering applications, the key requirements for distributed optical fiber sensor networks are large capacity, long distance, dense distribution, fast response, and high signal-to-noise ratio (SNR). Combining traditional reflectometry techniques with large-scale Bragg grating (FBG) array fabricated on-line by a drawing tower, multiplexing demodulation of thousands FBG sensors is successfully demonstrated, which greatly expands application to field...

Distributed static and dynamic sensing is demonstrated with an ultra-short fiber Bragg grating (USFBG) array. The USFBGs serve as the sensors reflection mirrors at same time. performed by demodulating strain-induced or temperature-induced wavelength shift of each USFBG. Dynamic vibration realized based on phase variation between two adjacent USFBG reflected pulses. Static temperature are applied to FBG array simultaneously. experiments show that measurement from 30 °C 80 achieved...

A scheme is proposed for the identification of surface intrusion events, from signals detected by an ultra-weak fiber Bragg grating array in a subway tunnel. The spectral subtraction and root mean square power density are combined to extract event signals. local characteristics-scale decomposition multi-scale permutation entropy employed subsequently feature extraction, which can improve recognition rate perspective analysis. Experimental demonstration verifies that identify four common...

China's new poverty alleviation strategy has been focusing on the 14 undeveloped poverty-stricken areas including Qinba, which faces frequent natural disasters, fragile ecological environment, and high incidence of poverty. With government initiation, farmers in Qinba have participated inclusive financial services. Based 587 rural household field survey data area, this article examines farmers' participation level finance. It uses VEP model to measure vulnerability Then it empirically...

This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR (optical time-domain reflectometry). Ultra-weak fiber Bragg gratings (UWFBG), whose backward light intensity is 2-4 orders of magnitude higher than that Rayleigh scattering, are used as the reflection markers. A medium-coherence laser can substitute conventional narrow bandwidth source to achieve an excellent performance since our unbalanced interferometer matches interval UWFBGs. The 3 m spatial...

Reliable sensing and accurate location of a weak small hot spot are critical for applications in industrial infrastructure monitoring. We propose experimentally demonstrate practical reliable distributed detection method using ultra-weak fiber Bragg gratings (UWFBGs) array optical time-domain reflectometry (OTDR) based interrogator. To reliably detect the spots, grating spacing sensor is decreased to similar size spot. All UWFBGs within section (FS) considered as one element,...

A micro-cavity array (MCA) fiber based on a dense ultra-short Bragg grating (FBG) is proposed for high-accuracy fully distributed sensing. In the MCA fiber, each pair of adjacent FBGs forms micro-cavity, which acts as sensing element. The high finesse interference spectra micro-cavities facilitate demodulation accuracy. Large-scale multiplexing 8557 results in 8556 7.18-m fiber. Combined with optical frequency-domain reflectometry, temperature spatial resolution less than 1 mm and...

Virtual power plant (VPP) is a carrier that organically combines distributed generation, dispatchable load, and energy storage, then realizes the integrated regulation of various storage (DER) through matched methods communication technology. Combined with construction an emerging system, this paper expounds in detail on operation characteristics functional virtual as well its participation market auxiliary service market. Finally, according to requirements plant, management platform studied...

An interrogation technique for large-capacity densely spaced fiber Bragg grating (FBG) arrays is demonstrated using incoherent optical frequency domain reflectometry (I-OFDR). A distributed-feedback laser diode under chaotic oscillation, modulated by a frequency-swept microwave, adopted as the source. The reflected sensing signals are converted into electrical and subsequently mixed with original microwave. Fast Fourier transform applied to generated beat signal obtain position of individual...

Under realistic scenarios, more fiber Bragg gratings (FBGs) are always expected to be multiplexed in one sensor array share the expensive optical components and electrical devices. However, either sensing number or interrogation frequency is limited previous works due huge amount of data generated from large-scale arrays. This paper presents a field-programmable gate (FPGA)-based dynamic wavelength system for thousands identical FBGs. With advantages parallel controlling pipeline processing,...

A noise-resilient demodulation technique is proposed and demonstrated with an interferometric-noise-suppressing (INS-) Golay coded optical pulse source for a quasi-distributed sensor array constructed by identical ultra-weak fiber Bragg gratings (UWFBGs).In combination medium coherence light source, coding-based time-efficient noise reduction facilitated closely-multiplexed UWFBG arrays, which conventional coding inapplicable. With 32-bit INS-Golay trains, 5.6-dB signal-to-noise ratio...

An optical time-domain reflectometry (OTDR) based fiber Bragg grating (FBG) interrogation technique using wide pulse signals for the large-capacity cascaded FBGs with narrow spacing is proposed and demonstrated in this letter. The waveform subtraction at each scanned lasing wavelength obtained by injecting two separated different pulse-width to FBG array used distinguish FBG. spatial resolution determined effective of differential signal rather than either signal. experimental results show...

A directional curvature sensor using excentric heterogeneous fiber (EHF) filled polydimethylsiloxane (PDMS) with spherical structure is proposed and prepared. The main of the an EHF cascaded two structures made single-mode fibers (SMFs), cladding eccentric core are corroded PDMS. asymmetry causes it to transmit asymmetric modes. It produces different spectral shift effects for bending in directions, so can be used detection multiple directions. Experimental results show that range 0–0.73...

A high-speed distributed vibration sensor based on balanced Mach-Zehnder interference and optical time-domain reflectometer is introduced to distinguish multiple simultaneously. The experimental results show a high spatial resolution fast frequency response.

A noise-resilient demodulation technique is proposed and demonstrated with a Golay coded optical pulse source, for quasi-distributed sensor array constructed by identical ultra-weak fiber Bragg gratings (UWFBGs). We set up light which line width over 20GHz, to avoid the interference between adjacent as result of wide pulses in train. Attributed special autocorrelation property code, wavelength UWFBGs achieved improved noise resistance. With 32-bit train, temperature sensing 3-m spatial...

This paper selects panel data of 29 provinces in mainland China from 2010-2017 and combines a DEA-SBM model that takes into account non-desired outputs the Malmquis index method to study static dynamic changes regional green innovation efficiency. It is found overall level efficiency low, but trend on rise there more room for improvement. The differences values among three regions East, West Central Asia are obvious, with eastern region developing at higher than central western regions, gap...

We developed a large multiplexing capacity randomly distributed characteristic parameters (RDCP)-FBG array for sensing applications. Large-scale of 10000 FBGs along 10m-long fiber is achieved, equivalent to 1mm spatial resolution.

The transient surface current density reflects the external coupling of electromagnetic pulse (EMP) to tested device. In this paper, generation mechanism and measurement principle conductor are introduced, distribution irradiated by EMP on a typical aircraft structure is simulated analyzed. traditional usually measured B-dot antenna, but its output signal differential signal, so additional integrators or numerical integration data required. self-integrating sensor based optical fiber...

In non-cooperative scenarios, wideband frequency hopping (FH) communication reconnaissance including FH signal detection, parameter estimation, and network sorting under single-channel reception is challenging. The pattern contains the most information about signals. So it core of estimation. Based on task analysis, this paper proposes a blind prediction framework combining deep learning (DL) clustering methods to improve accuracy efficiency estimation for mixed signals in spectrum. unique...