Abstract The detection of trace biomarkers is an important supplementary approach for early screening and diagnoses tumors. An optical fiber near‐field enhanced plasmonic resonance immunoprobe developed the hepatocellular carcinoma biomarker, i.e., alpha‐fetoprotein. Generic principles based on dispersion models finite element analysis (FEA) are to realize optimized configuration spectral characteristics immunoprobe. Dispersion provide theoretical guidance design multilayer sensing structure...

Optical fiber surface plasmon resonance (SPR) sensors point toward promising application potential in the fields of biomarker detection, food allergen screening, and environmental monitoring due to their unique advantages. This review outlines approaches improving SPR sensing performance, e.g., sensitivity, detection accuracy, reliability, cross-sensitivity, selectivity, convenience efficiency, corresponding applications. The principles sensors, especially performance indicators influencing...

A dispersion model is developed to provide a generic tool for configuring plasmonic resonance spectral characteristics. The customized design of the curve aiming at specific detection requirements can be achieved. According model, probe-type nano-modified fiber optic configurable (NMF-CPR) sensor with tip hot spot enhancement demonstrated measurement refractive index in range 1.3332–1.3432 corresponding low-concentration biomarker solution. new-type sensing structure avoids excessive...

Surface Plasmon resonance (SPR) provides an efficacious and label-free detection method for optical fiber bio-sensing. MoSe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is one of the transition metal dichalcogenides (TMDCs) which has broad applications in detecting specific reactions. Cysteamine hydrochloride with enriched groups can generate self-assemble films tight attachment. In this study we aimed to combine rapid response SPR...

Multi-class sensing recognition is important in optical fiber distributed vibration systems, since accurate detections on the vibrations can significantly improve performance of systems engineering applications. In this work, we have developed an ameliorated deep learning (DL) approach based serial fusion feature extraction model for multi-category systems. Thus, effective features be extracted automatically and recognized accurately with proposed approach. Firstly, use a conversion...

A phase demodulation method for quasi-distributed acoustic sensing (DAS) systems based on a dual-identical-chirped-pulse and weak fiber Bragg gratings (WFBGs) is proposed. Compared to the use of Rayleigh backscattering light in optical fibers, implementation WFBGs can contribute obtaining an signal with higher signal-to-noise ratio (SNR). The generated by time-delay fiber, sinusoidal carrier interference between two chirped pulses reflected adjacent WFBGs. represents dynamic strain change...

Abstract The accurate measurement of mass flux is identified as being essential for the successful use phase‐Doppler anemometry (PDA) in many applications, particular with sprays. Thus measured sizes individual droplets and cross‐sectional area to which referenced must be reliable. This paper investigates sources error each these quantities provides means eliminates or minimize errors. A new PDA configuration, termed dual–mode PDA, introduced an implementation suggestions. Example...

In recent years, traditional perimeter security system is gradually replaced by optical fiber distributed vibration sensing system, as it has superior advantages such high sensitivity, fast response, and simple structure. However, still challenging to accurately realize multievent pattern recognition in practical applications. Accurate can reduce the false alarm rate significantly increase stability of system. this article, we proposed a approach based on short-time Fourier transform (STFT)...

Abstract The principle of the dual burst technique (DBT) based on phase‐Doppler anemometry (PDA) is proposed for simultaneous particle refractive index, size and velocity measurements. This used trajectory effects in PDA systems to separate two contributions different scattering processes. In case forward refracting particles, it shown that from phase reflected contribution, diameter can be deduced, whereas refracted contribution index obtained. Furthermore, intensity ratio these processes...

Optical fiber sensor networks (OFSNs) are facing the problem of a lack systematic evaluation criteria to assess network performance. In this paper, universal quantitative robustness model for OFSNs is proposed. The defines as mathematical expectation monitoring coverage ratio, which has taken into account performance under all possible states and probability each state. This applied four basic topologies including line, ring, star bus topologies, their expressions derived by analyzing in...

An all-optical fiber multi-layer surface plasmon resonance (SPR) biosensor based on a sandwich structure of polydopamine-MoSe 2 @Au nanoparticles-polydopamine (PDA-MoSe @AuNPs-PDA) was designed for the detection specific immunoreactions. By optimizing and ratio MoSe : AuNPs, sensitivity 5117.59 nm/RIU has been obtained, which is more than double that only Au-filmed optical SPR sensor. A large area produced by integrating primitive unit cell AuNPs into hybrid plasmonic nanostructure @AuNPs,...

The key technology to demodulate the vibration position along sensing fiber link in asymmetric interferometer based sensors is extract similar variation features with high efficiency, so that asymmetry of can be effectively eliminated. wavelet-based approaches have been developed and demonstrated as effective methods for time-frequency feature analysis non-stable signals. In this article, an ameliorated real-time positioning algorithm using maximal overlap discrete wavelet transformation...

In this article, we theoretically and experimentally report a newly-designed biosensor, which consists of particular graphene-oxide (GO)-coated-U-bent long-period fiber grating inscribed in two-mode (LPFG-TMF). Due to the enhancement evanescent field, bent LPFG-TMF is more sensitive surrounding refractive index it allows an extremely high sensitivity. The impact radius on sensing performance discussed. experimental result demonstrates, sensitivity increases nonlinearly with highest reaches...

In recent years, denoising methods for improving the performance of phase-sensitive optical time-domain reflectometry ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Phi $ </tex-math></inline-formula> -OTDR) system have been restricted by deficiencies time-consuming and limited effect. this work, a trained convolutional neural network (CNN)-based image model is proposed to greatly eliminate unwanted...

In this paper, an improved positioning algorithm is proposed for a long-range asymmetric perimeter security system. This employs zero-crossing rate to detect the disturbance starting point, and then utilizes empirical mode decomposition obtain effective time-frequency distribution of extracted signal. end, cross-correlation used estimate time delay The scheme also verified analyzed experimentally. field test results demonstrate that can achieve detection 96.60% errors distributed within...

Refractive index (RI) sensing is a promising technique in variety of different scientific and industrial applications. In this paper, we theoretically experimentally propose newly-designed RI sensor. The proposed sensor consists particular long-period fiber grating inscribed two-mode (LPFG-TMF) coated with tunable graphene oxide (GO), the special structure allows an extremely high sensitivity transition region. mode coupling between LP11 core sixth-order cladding LPFG-TMF offers apparently...

The Gaussian beam defect is now a well documented deficiency of conventional phase Doppler anemometers and leads to significant errors in particle size estimation when the takes on dimensions same order as measurement volume. In present paper, an alternative operation mode conventional, two-component anemometry systems proposed, which removes these for many applications. new approach analysed theoretically its improved performance verified experimentally. Furthermore, effect slit aperture...

In fiber-optic vibration-sensing applications, intelligent sensing analysis is an important task for reducing costs and improving the overall quality of monitoring. Most existing methods show a low accuracy because their feature extractions significantly relied on prior knowledge ability classifier designer. To deal with challenges, effective scalable engineering method that uses vibration time-frequency imaging deep learning has been proposed in this study. order to improve effectiveness...